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Sample records for composition-dependent spectroscopic properties

  1. Composition dependent spectroscopic properties of Er{sup 3+}-doped boro-tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Selvaraju, K.; Marimuthu, K. [Department of Physics, Gandhigram Rural University, Gandhigram-624 302 (India); Vijaya, N. [Department of Physics, Sri Venkateswara University, Tirupati-517502 (India); Lavin, V. [Department de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, 38200 San Cristobal de La Laguna, Santa Cruz de Tenerife (Spain)

    2013-03-15

    A new series of Er{sup 3+}-doped boro-tellurite glasses have been prepared and their spectroscopic behavior were explored through absorption and luminescence measurements. The nature of the Er{sup 3+}-ligand bond in the host matrix were studied through bonding parameter studies using absorption spectra. Davis and Mott theory is used to determine the optical band gap energy for the direct and indirect allowed transitions of the title glasses. Optical band gap energy for the indirect allowed transitions are found to be in the range of 3.03-2.36 eV. The Judd-Ofelt intensity parameters {Omega}{sub {lambda}} ({lambda} = 2, 4, and 6) were determined from the absorption spectra and used to derive the radiative properties like stimulated emission cross-section and gain bandwidth for the emission transition {sup 4}I{sub 13/2} {yields} {sup 4}I{sub 15/2} of the Er{sup 3+} ions. The spectroscopic properties of the prepared glasses were studied as a function of TeO{sub 2} in the host matrix and discussed with reported literature. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Composition dependent spectroscopic properties of Nd3+ doped sodium lead borate glasses

    Science.gov (United States)

    Mohan, Shaweta; Thind, Kulwant Singh

    2016-05-01

    Nd3+ doped oxide glasses of the type xNa2O-30 PbO-(69.5-x) B2O3-0.5Nd2O3 were prepared and investigated for physical and spectroscopic properties. Optical absorption spectra and Judd-Ofelt theory has been used to determine the oscillator strengths and the intensity parameters Ωλ (λ=2, 4, 6). The radiative transition probability (A), radiative lifetime (τR) and branching ratio (βR) for the fluorescent levels of Nd3+ in the prepared glasses have been determined. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Ω4 / Ω6), the value of which is in the range 0.2-1.5, typical for Nd3+ in different laser hosts. The radiative transition probability of the potential lasing transition 4F3/2 → 4I11/2 of Nd3+ ions is found to increase with increase in content of Na2O.

  3. Compositional-dependent lead borate based glasses doped with Eu3+ ions: Synthesis and spectroscopic properties

    Science.gov (United States)

    Pisarski, W. A.; Pisarska, J.; Dominiak-Dzik, G.; Mączka, M.; Ryba-Romanowski, W.

    2006-12-01

    New multicomponent lead borate based glasses with various PbO/B2O3 weight ratio were prepared. The glass samples were analyzed in detail by using Raman and IR absorption spectroscopy. Optical properties of Eu3+ ions have been investigated in lead borate based systems, in which PbO/B2O3 weight ratios were changed from 1:2 to 8:1 in glass composition. The values of the phonon energy of the host and 5D0 lifetime of Eu3+ decrease, whereas absorption and emission intensities, as well as bonding parameter increase with increasing PbO concentration. Additionally, spectral lines are shifted in direction to the lower frequency region. Non-monotonic dependence of the fluorescence intensity ratio R (5D0 7F2/5D0 7F1) upon PbO/B2O3 content has been observed in contrast to bonding parameter that is also non-linear but monotonic. Some structural and spectroscopic aspects for Eu-doped lead borate based glasses are presented.

  4. Composition Dependence of Spectroscopic Properties of Er3+ Doped TeO2-WO3-ZnO Glasses

    Institute of Scientific and Technical Information of China (English)

    李家成; 李顺光; 胡和方; 干福熹

    2004-01-01

    Er3+-doped TeO2-WO3-ZnO glasses were prepared and the absorption spectra, emission spectra and fluorescence lifetimes were measured. With more TeO2 content in the glasses, the emission full width at half maximum (FWHM) increaseswhile the lifetime of the 4 I13/2 level of Er3+ decreases. The stimulated emission cross-section of Er3+ calculated by the McCumber theory is as large as 0.86pm2. The product of the FWHM and the emission cross-section σe of Er3+ in TeO2-WO3-ZnO glass is larger than those in other glasses, which indicates that the glasses are promising candidates for Er3+-doped broadband amplifiers. The Judd-Offelt parameter Ω6 shows close composition dependence of the 1.5 μm emission bandwidth. The more the TeO2 content is, the larger the values of Ω6 and FWHM.

  5. Composition dependence of magnetic and magnetotransport properties in C60-Co granular thin films

    Science.gov (United States)

    Sugai, Isamu; Sakai, Seiji; Matsumoto, Yoshihiro; Naramoto, Hiroshi; Mitani, Seiji; Takanashi, Koki; Maeda, Yoshihito

    2010-09-01

    Composition dependence of magnetic and magnetotransport properties in C60Cox thin films exhibiting large magnetoresistance (MR) effect was investigated in the Co composition range of x =8-20, where x denotes the number of Co atoms per C60 molecule. From the superparamagnetic magnetization curves observed, the average diameter (dave) of Co nanoparticles dispersed in the matrix phase was evaluated to be approximately 1 nm for the sample of x =8, and increased with the Co composition, x. By analyzing the temperature (T) dependence of resistivity based on the model by Abeles et al. [Adv. Phys. 24, 407 (1975)], the average charging energies (⟨ÊC⟩) of Co nanoparticles were evaluated to be 2-9 meV for the samples of x =8-17 while the considerably weak temperature dependence suggested much smaller values of ⟨ÊC⟩ for the samples of x >17. The composition dependence of dave and ⟨ÊC⟩ revealed a structural transition from well-defined granular structures in the range of x =8-17 to magnetically and electronically coupled states of Co nanoparticles over x ˜17. As a result of the structural change, the MR behavior became different between the two composition regions separated at x ˜17. In particular, for the samples of x =8-17, the bias-voltage (V) dependence of the MR ratio in the low-V region fits well with an unusual exponential form of MR=MR0 exp(-V/Vc) at T proportion to ⟨ÊC⟩ and also that the fitting parameter Vc is closely correlated with ⟨ÊC⟩. These results indicate that the charging effect of Co nanoparticles plays an important role in the anomalously large MR effect of C60-Co granular films. In addition, the power-law dependence of MR on T (MR∝T-α,α˜2) was also observed at relatively high temperature range T ≥10 K in the wide range of the composition.

  6. Spectroscopic properties of chlorophyll f.

    Science.gov (United States)

    Li, Yaqiong; Cai, Zheng-Li; Chen, Min

    2013-09-26

    The absorption and fluorescence spectra of chlorophyll f (newly discovered in 2010) have been measured in acetone and methanol at different temperatures. The spectral analysis and assignment are compared with the spectra of chlorophyll a and d under the same experimental conditions. The spectroscopic properties of these chlorophylls have further been studied by the aid of density functional CAM-B3LYP and high-level symmetric adapted coupled-cluster configuration interaction calculations. The main Q and Soret bands and possible sidebands of chlorophylls have been determined. The photophysical properties of chlorophyll f are discussed.

  7. Composition-dependent variation of magnetic properties and interstitial ordering in homogeneous expanded austenite

    DEFF Research Database (Denmark)

    Brink, Bastian K.; Ståhl, Kenny; Christiansen, Thomas Lundin;

    2016-01-01

    The crystal structure and magnetic properties of austenitic stainless steel with a colossal interstitial content, so-called expanded austenite, are currently not completely understood. In the present work, the magnetic properties of homogeneous samples of expanded austenite, as prepared by lowera......The crystal structure and magnetic properties of austenitic stainless steel with a colossal interstitial content, so-called expanded austenite, are currently not completely understood. In the present work, the magnetic properties of homogeneous samples of expanded austenite, as prepared...... by lowerature nitriding of thin foils, were investigated with magnetometry and Mössbauer spectroscopy. At room temperature, expanded austenite is paramagnetic for relatively low and for relatively high nitrogen contents (yN = 0.13 and 0.55, respectively, where yN is the interstitial nitrogen occupancy), while...... ferromagnetism is observed for intermediate nitrogen loads. Spontaneous volume magnetostriction was observed in the ferromagnetic state and the Curie temperature was found to depend strongly on the nitrogen content. For the first time, X-ray diffraction evidence for the occurrence of long-range interstitial...

  8. Composition dependence of the magnetic properties of strontium hexaferrite doped with rare earth ions

    Science.gov (United States)

    Singh, Taminder; Batra, M. S.; Singh, Iqbal; Katoch, Arun

    2014-09-01

    Rare earth substituted ferrite Sr1-xRExFe12O19 (where RE = La, Gd and Dy, x = 0.0, 0.10, 0.20 and 0.30), have been prepared by employing the ceramic technique and subsequent heat treatment. The magnetic properties of the calcined samples were characterized with a Vibrating Sample Magnetometer (VSM). The samples were sintered at 1150°C for 8 hours. The samples were characterized for magnetic properties such as specific saturation magnetization MS, specific remanence magnetization Mr, and coercivity Hc as well as microstructure. It has been observed that all these parameters depend on the composition and heat treatment of the prepared samples. The coercively Hc exhibits an increase as the RE content increases in Sr1-xRExFe12O19 ferrite. With increasing RE content the MS and Mr decrease due to dissolution of RE ion into hexaferrite lattice.

  9. Composition dependence of the optical and structural properties of Eu-doped oxyfluoride glasses

    DEFF Research Database (Denmark)

    Zhu, C.F.; Wu, D.Q.; Zhang, Y.F.

    2015-01-01

    on the base glass compositions. For certain base glass compositions, CaF2 crystals can form during the melt cooling process, and thereby enhance the conversion from Eu3+ to Eu2+. The formation of CaF2 crystals can be suppressed by adding CaO, Al2O3 and B2O3, but enhanced by adding Na2O and K2O in glass...... compositions. Finally, we propose a mechanism to explain how the glass structure affects the reduction of Eu ions as well as optical properties of the glasses.......Europium doped oxyfluoride glasses were prepared by the melt quenching method for the light emitting diodes applications. The optical and structural properties of these glasses were studied by means of photoluminescence spectra, Commission Internationale de L'Eclairage chromaticity coordinates, X...

  10. Compositional dependence of microstructure and tribological properties of plasma sprayed Fe-based metallic glass coatings

    Institute of Scientific and Technical Information of China (English)

    YANG Qin; LI Ran; LIU ZengQian; SHI MinJie; LUO XueKun; ZHANG Tao

    2012-01-01

    Gas-atomized powders of three Fe-based glass-forming alloys were sprayed on mild steel substrates by atmospheric plasma spaying using the same spaying parameters.Microstructures,thermal stabilities and tribological properties of the sprayed coatings were analyzed.The coating performances showed a strong dependence on the intrinsic characters of the compositions,i,e.,glass-forming ability (GFA) and supercooled liquid region (ΔTx).The coatings tended to exhibit higher amorphous phase fraction for the composition with higher GFA and lower porosity for that with larger ΔTx.All the coatings exhibited superior wear resistance compared with the substrate.Higher wear resistance could be obtained in coatings with higher amorphous phase fraction,i.e.higher GFA of the composition.This study has important implications for composition selecting and optimizing in the fabrication of metallic glass coatings.

  11. Composition dependences of thermodynamical properties associated with Pb-free ternary, quaternary, and quinary solder systems

    Science.gov (United States)

    Dogan, A.; Arslan, H.

    2016-05-01

    In the present study, Chou's General Solution Model (GSM) has been used to predict the enthalpy and partial enthalpies of mixing of the liquid Ag-In-Sn ternary, Ag-In-Sn-Zn quaternary, and Ag-Au-In-Sn-Zn quinary systems. These are of technical importance to optimize lead-free solder alloys, in selected cross-sections: x In/ x Sn = 0.5/0.5 (ternary), Au-In0.1-Sn0.8-Zn0.1, Ag-In0.1-Sn0.8-Zn0.1 (quaternary), and t = x Au/ x In = 1, x In = x Sn = x Zn (quinary) at 1173, 773, and 773 K, respectively. Moreover, the activity of In content in the ternary alloy system Ag-In-Sn has been calculated and its result is compared with that determined from the experiment, while the activities of Ag contents associated with the alloys mentioned above have been calculated. The other traditional models such as of Colinet, Kohler, Muggianu, Toop, and Hillert are also included in calculations. Comparing those calculated from the proposed GSM with those determined from experimental measurements, it is seen that this model becomes considerably realistic in computerization for estimating thermodynamic properties in multicomponent systems.

  12. Metal oxide/polyaniline nanocomposites: Cluster size and composition dependent structural and magnetic properties

    Indian Academy of Sciences (India)

    Raksha Sharma; Rakesh Malik; Subhalakshmi Lamba; S Annapoorni

    2008-06-01

    Nanocomposites of iron oxide with conducting polymer in the form of powders of varying compositions have been studied to understand the effects of particle size, cluster size and magnetic inter-particle interactions. The sizes of the nanoparticles were estimated to be ∼ 10–20 nm from the X-ray diffraction (XRD) and the transmission electron micrographs (TEM). XRD shows a single crystalline phase for the -Fe2O3. The presence of conducting polymer was confirmed through Fourier transform infrared (FTIR) spectroscopy. The amount of polymer present in the composite, the transition temperature of iron oxide and the thermal stability of polymer was determined through thermogravimetric and differential thermal analysis (TGA–DTA). The room temperature magnetic hysteresis measurements show reduction in saturation magnetization with increasing polymer concentrations. A low value of coercivity was observed for low polymer composites. On increasing the polymer concentration, the coercivity and remanence become negligible indicating a superparamagnetic phase at room temperature. Beyond a certain composition, the system shows paramagnetic behaviour which is also confirmed through zero field cooled–field cooled (ZFC–FC) measurements. We also report preliminary results on the magnetic properties of self standing sheets prepared using -Fe2O3 and NiFe2O4 nanoparticles and conducting polymers.

  13. Composition-dependent photoluminescence properties of CuInS{sub 2}/ZnS core/shell quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Hua, Jie [Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping 136000, Jilin (China); College of Information Technology, Jilin Normal University, Siping 136000, Jilin (China); Du, Yuwei; Wei, Qi [College of Information Technology, Jilin Normal University, Siping 136000, Jilin (China); Yuan, Xi; Wang, Jin [Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping 136000, Jilin (China); College of Information Technology, Jilin Normal University, Siping 136000, Jilin (China); Zhao, Jialong [Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping 136000, Jilin (China); Li, Haibo, E-mail: lihaibo@jlnu.edu.cn [Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping 136000, Jilin (China)

    2016-06-15

    CuInS{sub 2}/ZnS (CIS/ZnS) core/shell quantum dots (QDs) with various Cu/In ratios were synthesized using the hot-injection method, and their photoluminescence (PL) properties were investigated by measuring steady-state and time-resolved PL spectroscopy. The emission peak of the CIS/ZnS QDs were tuned from 680 to 580 nm by decreasing the Cu/In precursor ratio from 1/1 to 1/9. As the Cu/In ratio decreases, the PL lifetimes and PL quantum yields (QYs) of CIS/ZnS core/shell QDs increased firstly and then decreased. Two dominant radiative recombination processes were postulated to analyze composition-dependent PL properties, including the recombination from a quantized conduction band to deep defects state and donor-acceptor pair (DAP) recombination. The decrease of PL efficiency resulted from high density defects and traps, which formed at the interface between CIS core and ZnS shell due to the large off-stoichiometry composition. The PL intensity and peak energy for CIS/ZnS core/shell QDs as a function of temperature were also provided. The thermal quenching further confirmed that the PL emission of CIS/ZnS QDs did not come from the recombination of excitons but from the recombination of many kinds of intrinsic defects inside the QDs as emission centers.

  14. Composition dependence of dielectric properties in Se{sub 100-x}Cu{sub x} glassy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, J.; Shrotriya, D.; Kumar, S., E-mail: dr-santosh-kr@yahoo.com [Department of Physics, Christ Church College, Kanpur-208001 (India)

    2015-06-24

    In this paper we report the composition dependent of dielectric properties in Se{sub 100-x}Cu{sub x} (x = 0, 2, 4 and 6) glassy alloys. The temperature and frequency dependence of the dielectric constants and the dielectric losses in the above glassy systems in the frequency range (1k Hz-5 M Hz) and temperature range (300 K–350 K) have been measured. It has been found that dielectric constant and the dielectric loss both are highly dependent on frequency and temperature and also found to increase with increasing concentration of Cu in pure amorphous Se. The role of Cu, as an impurity in the pure a-Se glassy alloy, is also discussed in terms of electronegativity difference between the elements used in making the aforesaid glassy system. Apart from this, the results have been also correlated in terms of a dipolar model which considers the hopping of charge carriers over a potential barrier between charged defect states.

  15. Optical properties of Ge-rich G e1 -xS ix alloys: Compositional dependence of the lowest direct and indirect gaps

    Science.gov (United States)

    Xu, Chi; Gallagher, J. D.; Senaratne, C. L.; Menéndez, J.; Kouvetakis, J.

    2016-03-01

    Ge-rich G e1 -xS ix alloys have been investigated using spectroscopic ellipsometry and photoluminescence at room temperature. Special emphasis was placed on the compositional dependence of the lowest-energy interband transitions. For x ≤0.05 , a compositional range of particular interest for modern applications, we find E0=0.799 (1 ) +3.214 (45 ) x +0.080 (44 ) x2 (in eV) for the lowest direct gap. The compositional dependence of the indirect gap is obtained from photoluminescence as Eind=0.659 (4 ) +1.18 (17 ) x (in eV). We find no significant discrepancies between these results and the extrapolations from measurements at higher Si concentrations. Such discrepancies had been suggested by recent work on G e1 -xS ix films on Si. Accurate knowledge of the interband transition energies is an important requirement for the design of devices incorporating Ge-rich G e1 -xS ix alloys and for the understanding of more complex systems, such as ternary G e1 -x -yS ixS ny alloys, in terms of its binary constituents.

  16. Composition dependent structural, Raman and nonlinear optical properties of PVA capped Zn1-x-yCdxCuyS quantum dots

    Science.gov (United States)

    Vineeshkumar, T. V.; Rithesh Raj, D.; Prasanth, S.; Sankar, Pranitha; Unnikrishnan, N. V.; Mahadevan Pillai, V. P.; Sudarsanakumar, C.

    2016-08-01

    Composition dependent structural, optical nonlinear and limiting properties of PVA capped Zn1-x-yCdxCuyS quantum dots at different Cu:Zn ratio synthesized by insitu technique is subjected to detailed investigation. Cubic phase of the quantum dots were identified from XRD with particle size in the range 2.5 nm-3.5 nm find excellent correlation with the particle size measured from TEM. With increase in Cu concentration: systematic increment in lattice parameter, red shift in absorption edges and luminescence quenching is observed. Raman scattering reveals good photoactivity evidenced by intensity variation and shifting of LO and TO phonon modes. The intensity dependent third order nonlinearity is studied using Q switched Nd: YAG laser with 532 nm irradiation. Progressive increase in 3 PA coefficient indicated that prepared samples exhibit good nonlinear and optical limiting properties.

  17. Transition metal (Cr{sup 3+}) and rare earth (Eu{sup 3+}, Dy{sup 3+}) ions used as a spectroscopic probe in compositional-dependent lead borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Pisarski, W.A., E-mail: Wojciech.Pisarski@us.edu.p [University of Silesia, Institute of Chemistry, Szkolna 9, 40-007 Katowice (Poland); Pisarska, J. [Silesian University of Technology, Department of Materials Science, Krasinskiego 8, 40-019 Katowice (Poland); Dominiak-Dzik, G.; Ryba-Romanowski, W. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw (Poland)

    2009-09-18

    Compositional-dependent lead borate glasses doped with transition metal and rare earth ions were studied using absorption and luminescence spectroscopy. The trivalent Cr{sup 3+}, Eu{sup 3+} and Dy{sup 3+} ions were used as a spectroscopic probe in glass samples with various PbO/B{sub 2}O{sub 3} ratios. Spectral analysis indicates that Cr{sup 3+} ions occupy intermediate field sites; the both sites coexist and emit from the {sup 4}T{sub 2} (low-field) and the {sup 2}E (high-field) states, respectively. The R and Y/B values due to {sup 5}D{sub 0}-{sup 7}F{sub 2}/{sup 5}D{sub 0}-{sup 7}F{sub 1} and {sup 4}F{sub 9/2}-{sup 6}H{sub 15/2}/{sup 4}F{sub 9/2}-{sup 6}H{sub 13/2} luminescence intensity ratios of Eu{sup 3+} and Dy{sup 3+} ions, respectively, increase with increasing heavy metal (PbO) content, suggesting higher asymmetry and more covalent bonding character between rare earth and oxygen ions.

  18. Properties of sintered Al2O3-Cr composites depending on the method of preparation of the powder mixture

    Directory of Open Access Journals (Sweden)

    Chmielewski M.

    2006-01-01

    Full Text Available Continuous progress in modern science and industry depends on the availability of new effective devices and materials. New generation materials should be characterized by a specified combination of properties which sometimes exclude one another. Al2O3-Cr composites belong to this group of materials. This study is concerned with the effect of the method of preparation of the starting powders upon the properties of sintered Al2O3-Cr composites. The composites were produced using powder mixtures with various volumetric shares of the starting powders (from 25 to 75vol.%. The mixtures were prepared by conventional mechanical mixing in a ball-mill or by mechanical alloying in a high-energy mill of the attritor type. It has been found that with mechanically alloyed powders the Al2O3-Cr composites have better bending strength, hardness and frictional wear resistance.

  19. Surface modification of bacterial cellulose nanofibers for property enhancement of optically transparent composites: dependence on acetyl-group DS.

    Science.gov (United States)

    Ifuku, Shinsuke; Nogi, Masaya; Abe, Kentaro; Handa, Keishin; Nakatsubo, Fumiaki; Yano, Hiroyuki

    2007-06-01

    Bacterial cellulose (BC) nanofibers were acetylated to enhance the properties of optically transparent composites of acrylic resin reinforced with the nanofibers. A series of BC nanofibers acetylated from degree-of-substitution (DS) 0 to 1.76 were obtained. X-ray diffraction profiles indicated that acetylation proceeded from the surface to the core of BC nanofibers, and scanning electron microscopy images showed that the volume of nanofibers increases by the bulky acetyl group. Since acetylation decreased the refractive index of cellulose, regular transmittance of composites comprised of 63% BC nanofiber was improved, and deterioration at 580 nm because of fiber reinforcement was suppressed to only 3.4%. Acetylation of nanofibers changed their surface properties and reduced the moisture content of the composite to about one-third that of untreated composite, although excessive acetylation increased hygroscopicity. Furthermore, acetylation was found to reduce the coefficient of thermal expansion of a BC sheet from 3 x 10(-6) to below 1 x 10(-6) 1/K.

  20. Compositional dependence of the optical properties of amorphous semiconducting glass Ge10AsxSe(90-x) thin films

    Science.gov (United States)

    Shaaban, E. R.

    2007-03-01

    Optical properties of ternary chalcognide amorphous Ge10AsxSe(90-x) (with 10⩽x⩽25 at%) thin films prepared by thermal evaporation have been measured in visible and near-infrared spectral region. The straightforward analysis proposed by Swanepoel has been successfully employed, and it has allowed us to determine the average thickness d¯, and the refractive index, n, of the films, with high accuracy. The refractive index, n and the average thickness d¯ has been determined from the upper and lower envelopes of the transmission spectra measured at normal incidence, in the spectral range 400 2500 nm. The absorption coefficient α, and therefore extinction coefficient k, have been determined from the transmission spectra in the strong-absorption region. The dispersion of the refractive index is discussed in terms of the single oscillator Wemple DiDomenico model, and the optical absorption edge is described using the ‘nondirect transition’ model proposed by Tauc. Likewise, the optical energy gap is derived from Tauc's extrapolation. The relationship between the optical gap and chemical composition in Ge10AsxSe(90-x) amorphous system is discussed in terms of the average heat of atomization Hs and average coordination number Nc. Finally, the chemical bond approach has been also applied successfully to interpret the decrease of the glass optical gap with increasing As content.

  1. Molten-salt synthesis and composition-dependent luminescent properties of barium tungsto-molybdate-based solid solution phosphors

    Science.gov (United States)

    Xiang-Hong, He; Zhao-Lian, Ye; Ming-Yun, Guan; Ning, Lian; Jian-Hua, Sun

    2016-02-01

    Pr3+-activated barium tungsto-molybdate solid solution phosphor Ba(Mo1-zWz)O4:Pr3+ is successfully fabricated via a facile molten-salt approach. The as-synthesized microcrystal is of truncated octahedron and exhibits deep-red-emitting upon blue light excitation. Powder x-ray diffraction and Raman spectroscopy techniques are utilized to investigate the formation of solid solution phosphor. The luminescence behaviors depend on the resulting composition of the microcrystals with fixed Pr3+-doping concentration, while the host lattices remain in a scheelite structure. The forming solid solution via the substitution of [WO4] for [MoO4] can significantly enhance its luminescence, which may be due to the fact that Ba(Mo1-zWz)O4:Pr3+ owns well-defined facets and uniform morphologies. Owing to its properties of high phase purity, well-defined facets, highly uniform morphologies, exceptional chemical and thermal stabilities, and stronger emission intensity, the resulting solid solution phosphor is expected to find potential applications in phosphor-converted white light-emitting diodes (LEDs). Project supported by the Construction Fund for Science and Technology Innovation Group from Jiangsu University of Technology, China, the Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, China (Grant No. KHK1409), the Priority Academic Program Development of Jiangsu Higher Education Institutions, China, and the National Natural Science Foundation of China (Grant No. 21373103).

  2. Composition dependent structural and optical properties of PbF₂-TeO₂-B₂O₃-Eu₂O₃ glasses.

    Science.gov (United States)

    Wagh, Akshatha; Raviprakash, Y; Upadhyaya, Vyasa; Kamath, Sudha D

    2015-12-01

    Boric oxide based quaternary glasses in the system PbF2-TeO2-B2O3-Eu2O3 have been prepared by melt quenching technique. Density, molar volume, FTIR, UV-Vis techniques were used to probe the structural modifications with incorporation of europium ions in the glass network. An increase in glass density & decrease in molar volume (Vm) values proved the structural changes occurring in coordination of boron atom [conversion of BO3 units to BO4]. This resulted in the increase of the compaction of the prepared glasses with increase in Eu2O3 contents. The amorphous natures of the samples were ascertained by XRD and metallization criterion (M) studies. XPS study showed the values of core-level binding energy [O1s, Eu3d, Eu4d, Te3d, Te4d, Pd4f, Pb5d, O1s, and F1s] of (PbF2-TeO2-B2O3-Eu2O3) the glass matrix. The frequency and temperature dependence of dielectric properties of present glasses were investigated in the frequency range of 1 Hz-10 MHz and temperature range of 313-773K. The study of dielectric measurements proved good insulating and thermal stability of the prepared glasses. At room temperature, dielectric loss [tanδ] values were negligibly small for prepared glasses and increased with increase in temperature. FTIR spectroscopy results were in good agreement with optical band energy gap, density, molar volume and hardness values revealing network modifications caused by europium ions in the glass structure.

  3. Exploring the spectroscopic properties of relic radiogalaxies

    CERN Document Server

    Capetti, Alessandro; Baldi, Ranieri D; Buttiglione, Sara; Axon, David J; Celotti, Annalisa; Chiaberge, Marco

    2013-01-01

    From an optical spectroscopic survey of 3CR radiogalaxies (RGs) with z<0.3, we discovered three objects characterized by an extremely low level of gas excitation and a large deficit of line emission with respect to RGs of similar radio luminosity. We interpreted these objects as relic active galactic nuclei (AGN), i.e., sources observed after a large drop in their nuclear activity. We here present new spectroscopic observations for these three galaxies and for a group of "candidate" relics. None of the candidates can be convincingly confirmed. From the new data for the three relics, we estimate the density of the line-emitting gas. This enables us to explore the temporal evolution of the line ratios after the AGN "death". The characteristic timescale is the light-crossing time of the emission line region, a few thousand years, too short to correspond to a substantial population of relic RGs. Additional mechanisms of gas ionization, such as "relic shocks" from their past high power phase or stellar sources,...

  4. Spectroscopic properties of Callinectes sapidus hemocyanin subunits

    Science.gov (United States)

    Stoeva, Stanka; Dolashka, Pavlina; Bankov, Banko; Voelter, Wolfgang; Salvato, Benedeto; Genov, Nicolay

    1995-10-01

    The two major subunits of the Callinectes sapidus hemocyanin were isolated and characterized by spectroscopic techniques. They consist of 641 and 652 residues, respectively. Circular dichroism spectra showed that the structural integrity of the isolated polypeptide chains is preserved. Tryptophan fluorescence parameters were determined for the hemocyanin aggregates and for the subunits Cs1 and Cs2. The emitting tryptophyl fluorophores in the native hemocyanin are deeply buried in hydrophobic regions and are shielded from the solvent by the quaternary structure of the protein aggregates. In two subunits, obtained after dissociation of the aggregates, these residues become "exposed". It is concluded that the tryptophyl side chains in Cs1 and Cs2 are located in subunit interfaces (contact regions) in a negatively charged environment when the polypeptide chains are aggregated. Most probably they participate in hydrophobic protein-protein interactions. The environment of these fluorophores is more negatively charged after the dissociation of the aggregates to subunits.

  5. Optimization of spectroscopic properties of ytterbium-doped laser glasses

    Institute of Scientific and Technical Information of China (English)

    姜淳[1; 张俊洲[2; 邓佩珍[3; 黄国松[4; 毛涵芬[5; 干福熹[6

    1999-01-01

    Four laser glasses with high emission cross sections are experimentally obtained. The laser performance parameters are determined from the spectroscopic parameters of these glasses and compared with those of developing laser glasses abroad. It is shown that Yb3--doped telluorogermanate, Yb3+-doped niobosilicate glasses have the highest emission cross section and gain coefficient, the smallest minimum pumping intensity and saturation pumping intensity, and the lowest minimum fraction of excited ions. Yb3+-doped borate glass follows just behind them. These glasses have some spectroscopic advantages over laser glasses developed recently elsewhere. Yb3+-doped phosphate glass is comparable to phosphate laser glass which had high emission cross section and was developed recently by HOYA Corporation in Japan.The domestic glasses with optimum spectroscopic properties may be promising candidates for applications in high-average power and high-peak power solid state lasers, especially laser for the ne

  6. Spectroscopic properties of the B meson

    Directory of Open Access Journals (Sweden)

    Devlani Nayneshkumar

    2015-01-01

    Full Text Available Investigation of the B(bq̄; q = u, d meson properties is carried out using variational method within phenomenological quark antiquark potential(coulomb plus power model using the Gaussian wave function. O(1/m correction to the potential energy term and relativistic corrections to the kinetic energy term of the hamiltonian are incorporated. Spin-orbit, spin-spin and tensor interactions are employed to obtain the mass spectra. Various other properties such as the decay constants, e1 and m1 transitions are also obtained

  7. Spectroscopical properties of organic/metal nanohybrids.

    Science.gov (United States)

    Dellepiane, Giovanna; Cuniberti, Carla; Alloisio, Marina; Demartini, Anna

    2010-03-28

    The aim of our work was to prepare stable nanohybrids of controlled size and shape consisting of a noble metal core decorated with polydiacetylenes (PDAs). Due to the combination of the outstanding linear and nonlinear optical properties of the polydiacetylenic chains with the electromagnetic field-enhancing capability of metal nanostructures, these novel composites can find potential application in different fields. In particular, the different colours exhibited by PDAs in relation to the chemical nature of the monomer and the polymerization procedure, as well as in response to environmental perturbations, make them excellent materials for the fabrication of sensing devices. On the basis of our previous work on PDA self-assembled monolayers on flat metal surfaces, the results of which are briefly reported, we prepared differently-shaped gold and silver nanocores (spheres, cages) coated with various diacetylenic monomers having end-groups able to firmly anchor to the metal surface. These nanohybrids exhibit in aqueous colloidal solution an enhanced photochemical polymerization monitored step by step with UV-Vis and SERS techniques. It is shown that in these stable assemblies an intra-particle polymerization takes place and that the dominant PDA form is conditioned by the core size and geometry. While the nanoparticles are SERS active in the visible, the nanocages should be excellent SERS substrates from the visible to the near infrared regions.

  8. Elastic properties and spectroscopic studies of Na2O–ZnO–B2O3 glass system

    Indian Academy of Sciences (India)

    V C Veeranna Gowda; R V Anavekar

    2004-04-01

    Elastic properties, 11B MAS–NMR and IR spectroscopic studies have been employed to study the structure of Na2O–ZnO–B2O3 glasses. Sound velocities and elastic moduli such as longitudinal, Young’s, bulk and shear modulus have been measured at a frequency of 10 MHz as a function of ZnO concentration. Both sound velocities and elastic moduli increase with increasing ZnO concentration. Poisson’s ratio and Debye temperature were also found to increase with ZnO concentration. 11B MAS–NMR and IR spectra show characteristic features of borate network and compositional dependence trends as a function of Na2O/ZnO concentration. The results are discussed in view of borate network and dual structural role of Zn2+ ion into the network. The results indicate that the Zn2+ ions are likely to occupy network forming positions in this glass system.

  9. Spectroscopic properties of rare earths in optical materials

    CERN Document Server

    Parisi, Jürgen; Osgood, R; Warlimont, Hans; Liu, Guokui; Jacquier, Bernard

    2005-01-01

    Aimed at researchers and graduate students, this book provides up-to-date information for understanding electronic interactions that impact the optical properties of rare earth ions in solids. Its goal is to establish a connection between fundamental principles and the materials properties of rare-earth activated luminescent and laser optical materials. The theoretical survey and introduction to spectroscopic properties include electronic energy level structure, intensities of optical transitions, ion-phonon interactions, line broadening, and energy transfer and up-conversion. An important aspect of the book lies in its deep and detailed discussions on materials properties and the potential of new applications such as optical storage, information processing, nanophotonics, and molecular probes that have been identified in recent experimental studies. This volume will be a valuable reference book on advanced topics of rare earth spectroscopy and materials science.

  10. [Preparation and spectroscopic properties of terbium polypropenic acid film].

    Science.gov (United States)

    Wang, Xi-gui; Wu, Hong-ying; Weng, Shi-fu; Wu, Jin-guang

    2002-12-01

    The bonding-type rare earth polymers-polypropenic-acid terbium film was prepared through the bonding way. Three-dimension fluorescence spectra showed that the optimum excitation wavelength was 306 nm, the strongest emission wavelength was 544 nm. The terbium polypropenic-acid film showed the characteristic Tb3+ emission when excited at 306 nm due to 5D4-7FJ transition (J = 6, 5, 4 and 3). The emission maximum at 544 nm was ascribed to 5D4-7F5 transition of Tb3+ and presented strong green emission. The luminescent properties of Tb3+ were not affected by polymerism of propenic-acid and the transparency of polypropenic-acid in visible light region was not affected by the dopping Tb3+. The fluorescence properties and spectroscopic properties of the terbium polypropenic-acid were investigated by excitation spectrum, emission spectrum, IR, far-IR, and Raman spectrum.

  11. Composition dependent interfacial thermal stability, band alignment and electrical properties of Hf{sub 1−x}Ti{sub x}O{sub 2}/Si gate stacks

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J.W. [School of Physics and Materials Science, Radiation Detection Materials & Devices Lab, Anhui University, Hefei 230039 (China); He, G., E-mail: hegang@ahu.edu.cn [School of Physics and Materials Science, Radiation Detection Materials & Devices Lab, Anhui University, Hefei 230039 (China); National Laboratory for Infrared Physics, Chinese Academy of Sciences, Shanghai Institute of Technical Physics, 500 Yutian Road, Shanghai 200083 (China); Liu, M., E-mail: mliu@issp.ac.cn [Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanostructure, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Chen, H.S.; Liu, Y.M.; Sun, Z.Q. [School of Physics and Materials Science, Radiation Detection Materials & Devices Lab, Anhui University, Hefei 230039 (China); Chen, X.S. [National Laboratory for Infrared Physics, Chinese Academy of Sciences, Shanghai Institute of Technical Physics, 500 Yutian Road, Shanghai 200083 (China)

    2015-08-15

    Highlights: • Sputtered Hf{sub 1−x}Ti{sub x}O{sub 2} gate dielectrics with different TiO{sub 2} concentration have been deposited on Si substrates. • Decrease in interfacial layer thickness reduction in band gap with increasing the TiO{sub 2} component has been determined. • Hf{sub 1−x}Ti{sub x}O{sub 2} with incorporating TiO{sub 2} of 9% shows to be a promising candidate for high-k gate dielectrics. - Abstract: The optical properties, interface chemistry and band alignment of Hf{sub 1−x}Ti{sub x}O{sub 2} (x = 0.03, 0.08, 0.12 and 0.20) high-k gate dielectric thin films, deposited by RF sputtering on Si substrate, have been systematically investigated. The effect of TiO{sub 2} incorporation on the interfacial chemical structure and energy-band discontinuities has been investigated by using X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectroscopy (UV–vis). It has been found that the band gap and band offsets of the Hf{sub 1−x}Ti{sub x}O{sub 2} thin film decrease with the increase of TiO{sub 2} concentration. Meanwhile, the obtained band offsets are all over 1 eV. Thin film capacitors fabricated with the MOS configuration of Al/Hf{sub 1−x}Ti{sub x}O{sub 2}/n-Si/Al exhibits excellent electrical properties with low interface state density, hysteresis voltage and low leakage current density. The suitable band gap, symmetrical band offsets relative to Si and prominent electrical properties render sputtering-derived Hf{sub 1−x}Ti{sub x}O{sub 2} with 9% TiO{sub 2} films as promising candidates for high-k gate dielectrics.

  12. Hydrothermal synthesis, characterization and composition-dependent magnetic properties of LaFe 1- xCr xO 3 system (0≤ x≤1)

    Science.gov (United States)

    Hu, Weiwei; Chen, Yan; Yuan, Hongming; Zhang, Ganghua; Li, Guanghua; Pang, Guangsheng; Feng, Shouhua

    2010-07-01

    Hydrothermal synthesis, characterization and magnetic properties of a series of ABO 3-perovskites LaFe 1- xCr xO 3 (0≤ x≤1) are reported. The alkalinity in initial reaction mixtures plays a critical role in controlling the designed stoichiometry of the final compositions. Their magnetic properties are strongly dependent on the compositions and a maximum magnetic moment is found for the sample at x=0.5. Weak ferromagnetic interaction observed for the samples from x=0 to 0.9 arises from the presence of Fe-O-Fe antisymmetric exchange and Fe-O-Cr superexchange interaction. The weak ferromagnetism as well as the linear variation of the lattice parameters implies the possible random distribution of Fe and Cr ions in B sites of the perovskites. The evolution of magnetic ordering transition temperatures has a close relationship with substituent ratios, for the competition of antiferromagnetism and ferromagnetism. The saturated magnetic moment shows a great improvement compared with that for the samples synthesized by solid state method.

  13. Composition-dependent magnetic properties of melt-spun La or/and Ce substituted nanocomposite NdFeB alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, M.; Zhao, L.Z.; Zhang, C.; Jiao, D.L.; Zhong, X.C.; Liu, Z.W.

    2016-02-15

    Aiming at high-performance low-cost NdFeB magnets, the magnetic properties and microstructure for melt spun nanocrystalline (Nd{sub 1−x}M{sub x}){sub 10}Fe{sub 84}B{sub 6} (M=La, Ce, or La{sub 0.5}Ce{sub 0.5}; x=0–0.7) alloys were investigated. Relatively, LaCe-substituted alloys show high values of the remanent magnetization M{sub r}, the maximum energy product (BH){sub max} and the coercivity H{sub c}, up to 114 emu/g (1.07 T), 147 kJ/m{sup 3} and 471 kA/m, respectively, at x=0.1. The unusual increase in coercivity for the alloys with 10% La or 10% La{sub 0.5}Ce{sub 0.5} substitution is possibly attributed to the phase segregation in alloys with certain La or LaCe contents. The reduced Curie temperature and spin-reorientation temperature were obtained for La, Ce or LaCe substituted alloys. Transmission electron microscope analysis has revealed that a fine and uniform distributed grain structure leads to remanence enhancement for La{sub 0.5}Ce{sub 0.5} substituted alloys. The present results indicate that partially substituting Nd by La or/and Ce cannot only effectively reduce the cost of nanocrystalline NdFeB based magnetic powders but also can maintain a relatively good combination of magnetic properties.

  14. Spectroscopic properties of nuclear skyrme energy density functionals.

    Science.gov (United States)

    Tarpanov, D; Dobaczewski, J; Toivanen, J; Carlsson, B G

    2014-12-19

    We address the question of how to improve the agreement between theoretical nuclear single-particle energies (SPEs) and observations. Empirically, in doubly magic nuclei, the SPEs can be deduced from spectroscopic properties of odd nuclei that have one more or one less neutron or proton. Theoretically, bare SPEs, before being confronted with observations, must be corrected for the effects of the particle vibration coupling (PVC). In the present work, we determine the PVC corrections in a fully self-consistent way. Then, we adjust the SPEs, with PVC corrections included, to empirical data. In this way, the agreement with observations, on average, improves; nevertheless, large discrepancies still remain. We conclude that the main source of disagreement is still in the underlying mean fields, and not in including or neglecting the PVC corrections.

  15. Using spectroscopic data to disentangle stellar population properties

    CERN Document Server

    Cardiel, N; Sánchez-Blazquez, P; Cenarro, A J; Pedraz, S; Bruzual, G; Klement, J

    2003-01-01

    It is well known that, when analyzed at the light of current synthesis model predictions, variations in the physical properties of single stellar populations (e.g. age, metallicity, initial mass function, element abundance ratios) may have a similar effect in their integrated spectral energy distributions. The confusion is even worsened when more realistic scenarios, i.e. composite star formation histories, are considered. This is, in fact, one of the major problems when facing the study of stellar populations in star clusters and galaxies. Typically, the observational efforts have been aimed to find the most appropriate spectroscopic indicators in order to avoid, as far as possible, degeneracies in the parameter space. However, from a practical point of view, the most suited observables are not, necessarily, those that provide more orthogonality in that parameter space, but those that give the best balance between parameter degeneracy and sensitivity to signal-to-noise ratio per Angstrom, SN_A. In order to a...

  16. Spectroscopic properties of $Pr^{3+}$-doped erbiumoxalate crystals

    Indian Academy of Sciences (India)

    R Pragash; N V Unnikrishnan; C Sudarsanakumar

    2011-12-01

    Spectroscopic properties of praseodymium ions-doped erbium oxalate ($Er_2(C_2O_4)_3 \\cdot nH_2O$) crystals have been investigated. The crystals were grown by hydro silica gel method under suitable pH conditions and by single diffusion method. The well-grown crystals are bright and transparent. The dark green colour of these crystals changes with the variation of the concentrations of the dopant ions. The absorption spectra have been measured in the region 200–800 nm at room temperature. Judd–Ofelt intensity parameters for f–f transitions of the $Pr^{3+}$ ions have been determined as 2 = 166.7, 4 = 1.103 and 6 = 2.898. Analyses of the absorption spectra also show a possible energy transfer from the host material to the dopant.

  17. Compositional dependence of the thermoelectric properties of (Sr(x)Ba(x)Yb₁₋₂x)(y)Co₄Sb₁₂ skutterudites.

    Science.gov (United States)

    Rogl, G; Grytsiv, A; Melnychenko-Koblyuk, N; Bauer, E; Laumann, S; Rogl, P

    2011-07-13

    High temperature thermoelectric (TE) properties for triple-filled skutterudites (Sr(x)Ba(x)Yb₁₋₂x)(y)Co₄Sb₁₂ were investigated for alloy compositions in two sections of the system: (a) for x = 0.25 with a filling fraction y ranging from 0.1 to 0.25 and (b) for 0 < x < 0.5 and y = 0.11 + 0.259x. The representation of the figure of merit, ZT, as a function of skutterudite composition, defined the compositional range (0.25 < x < 0.4; 0.18 < y < 0.24) with ZT over 1.4 at 800 K. It was shown that an enhanced TE performance for these triple-filled skutterudites is caused by low electrical resistivities and low lattice thermal conductivities, as well as by a fine tuning of the chemical composition. Low temperature measurements for the samples with the highest ZT values showed that even a small change of the filler ratios changes the contribution of scattering effects, the carrier concentration and the mobility.

  18. Composition dependences of crystal structure and electrical properties of epitaxial Pb(Zr,Ti)O3 films grown on Si and SrTiO3 substrates

    Science.gov (United States)

    Okamoto, Shoji; Okamoto, Satoshi; Yokoyama, Shintaro; Akiyama, Kensuke; Funakubo, Hiroshi

    2016-10-01

    {100}-oriented Pb(Zr x ,Ti1- x )O3 (PZT) thin films of approximately 2 µm thickness and Zr/(Zr + Ti) ratios of 0.39-0.65 were epitaxially grown on (100)cSrRuO3//(100)SrTiO3 (STO) and (100)cSrRuO3//(100)cLaNiO3//(100)CeO2//(100)YSZ//(100)Si (Si) substrates having different thermal expansion coefficients by pulsed metal-organic chemical vapor deposition (MOCVD). The effects of Zr/(Zr + Ti) ratio and type of substrate on the crystal structure and dielectric, ferroelectric and piezoelectric properties of the films were systematically investigated. The X-ray diffraction measurement showed that both films changed from having a tetragonal symmetry to rhombohedral symmetry through the coexisting region with increasing Zr/(Zr + Ti) ratio. This region showed the Zr/(Zr + Ti) ratios of 0.45-0.59 for the films on the STO substrates that were wider than the films on the Si substrates. Saturation polarization values were minimum at approximately Zr/(Zr + Ti) = 0.50 for the films on the STO substrates, and no obvious Zr/(Zr + Ti) ratio dependence was detected in the films on the Si substrates. On the other hand, the maximum field-induced strain values measured by scanning force microscopy at approximately Zr/(Zr + Ti) = 0.50 at 100 kV/cm were about 0.5 and 0.1% in the films on the Si and STO, respectively.

  19. Spatially Offset Active Galactic Nuclei. I. Selection and Spectroscopic Properties

    Science.gov (United States)

    Barrows, R. Scott; Comerford, Julia M.; Greene, Jenny E.; Pooley, David

    2016-09-01

    We present a sample of 18 optically selected and X-ray-detected spatially offset active galactic nuclei (AGNs) from the Sloan Digital Sky Survey (SDSS). In nine systems, the X-ray active galactic nucleus (AGN) is spatially offset from the galactic stellar core that is located within the 3″ diameter SDSS spectroscopic fiber. In 11 systems, the X-ray AGN is spatially offset from a stellar core that is located outside the fiber, with an overlap of two. To build the sample, we cross-matched Type II AGNs selected from the SDSS galaxy catalog with archival Chandra imaging and employed our custom astrometric and registration procedure. The projected angular (physical) offsets span a range of 0.″6 (0.8 kpc) to 17.″4 (19.4 kpc), with a median value of 2.″7 (4.6 kpc). The offset nature of an AGN is an unambiguous signature of a galaxy merger, and these systems can be used to study the properties of AGNs in galaxy mergers without the biases introduced by morphological merger selection techniques. In this paper (Paper I), we use our sample to assess the kinematics of AGN photoionized gas in galaxy mergers. We find that spectroscopic offset AGN selection may be up to {89}-16+7% incomplete due to small projected velocity offsets. We also find that the magnitude of the velocity offsets are generally larger than expected if our spatial selection introduces a bias toward face-on orbits, suggesting the presence of complex kinematics in the emission line gas of AGNs in galaxy mergers.

  20. Spectroscopic properties of multilayered gold nanoparticle 2D sheets.

    Science.gov (United States)

    Yoshida, Akihito; Imazu, Keisuke; Li, Xinheng; Okamoto, Koichi; Tamada, Kaoru

    2012-12-11

    We report the fabrication technique and optical properties of multilayered two-dimensional (2D) gold nanoparticle sheets ("Au nanosheet"). The 2D crystalline monolayer sheet composed of Au nanoparticles shows an absorption peak originating from a localized surface plasmon resonance (LSPR). It was found that the absorption spectra dramatically change when the monolayers are assembled into the multilayers on different substrates (quartz or Au). In the case of the multilayers on Au thin film (d = 200 nm), the LSPR peak is shifted to longer wavelength at the near-IR region by increasing the number of layers. The absorbance also depends on the layer number and shows the nonlinear behavior. On the other hand, the multilayers on quartz substrate show neither such LSPR peak shift nor nonlinear response of absorbance. The layer number dependence on metal surfaces can be interpreted as the combined effects between the near-field coupling of the LSPR and the far-field optics of the stratified metamaterial films, as proposed in our previous study. We also report the spectroscopic properties of hybrid multilayers composed of two kinds of monolayers, i.e., Au nanosheet and Ag nanosheet. The combination of the different metal nanoparticle sheets realizes more flexible plasmonic color tuning.

  1. Spatially Offset Active Galactic Nuclei I: Selection and Spectroscopic Properties

    CERN Document Server

    Barrows, R Scott; Greene, Jenny E; Pooley, David

    2016-01-01

    We present a sample of 18 optically-selected and X-ray detected spatially offset active galactic nuclei (AGN) from the Sloan Digital Sky Survey (SDSS). In 9 systems, the X-ray AGN is spatially offset from the galactic stellar core that is located within the 3'' diameter SDSS spectroscopic fiber. In 11 systems, the X-ray AGN is spatially offset from a stellar core that is located outside the fiber, with an overlap of 2. To build the sample, we cross-matched Type II AGN selected from the SDSS galaxy catalogue with archival Chandra imaging and employed our custom astrometric and registration procedure. The projected angular (physical) offsets span a range of 0."6 (0.8 kpc) to 17."4 (19.4 kpc), with a median value of 2."7 (4.6 kpc). The offset nature of an AGN is an unambiguous signature of a galaxy merger, and these systems can be used to study the properties of AGN in galaxy mergers without the biases introduced by morphological merger selection techniques. In this paper (Paper I), we use our sample to assess t...

  2. The structural and spectroscopic properties for uranium oxides

    Institute of Scientific and Technical Information of China (English)

    Li Peng; Jia Ting-Ting; Gao Tao; Li Gan

    2012-01-01

    The equilibrium structures,the charge population,and the spectroscopic properties of UO,UO2,UO3,and U2O3 molecules are systematically investigated using the density functional theory (DFT) with the method of generalized gradient approximation (GGA).The bond lengths and the vibrational frequencies of the ground states of UO,UO2,and UO3 molecules are all in agreement with available experimental data.For U2O3 molecules,our calculations indicate that the ground state of the U2O3 molecule is an X7A'1 state with D3h (trigonal bipyramid) symmetry (R1 (U-O)=0.2113 nm,R2(U1-U2)=0.2921 nm,∠U1OU2 =87.5°,dihedral angle θ(U,O1,O2,O3)=62.40°).The harmonic frequency,the IR intensity and the spin density of the U2O3 molecule are all obtained for the first time in theory.For the ground state of U2O3 molecules,the vibrational frequencies are 178.46 (A′1),276.79 (E″1),310.77 (E′1),396.63 (A″2),579.15 (E′1),and 614.98 (A′1) cm-1.The vibrational modes corresponding to the IR maximum peaks are worked out for UO3 and U2O3 molecules.Besides,the results of Gophinatan-Jug bond order indicate that UO,UO2,and UO3 molecules possess U=O double bonds and that the U2O3 molecule possesses U-O single bonds and a U-U single bond.

  3. The Spectroscopic and Conductive Properties of Ru(II Complexes with Potential Anticancer Properties

    Directory of Open Access Journals (Sweden)

    Adebayo A. Adeniyi

    2014-01-01

    Full Text Available Different density functional methods (DFT have been used to optimize and study the chemistry of five potential anticancer complexes in terms of their electronic, conductive, and spectroscopic properties. Many of the computed properties in addition to the IR and QTAIM analysis of the NMR are dipole moment vector (μi, linear polarizability tensor (αij, first hyperpolarizability tensors (βijk, polarizability exaltation index (Γ, and chemical hardness (η of the complexes. Stable low energy geometries are obtained using basis set with effective core potential (ECP approximation but, in the computation of atomic or molecular properties, the metal Ru atom is better treated with higher all electron basis set like DGDZVP. The spectroscopic features like the IR of the metal-ligand bonds and the isotropic NMR shielding tensor of the coordinated atoms are significantly influenced by the chemical environment of the participating atoms. The carboxylic and pyrazole units are found to significantly enhance the polarizabilities and hyperpolarizabilities of the complexes while the chloride only improves the polarity of the complexes. Fermi contacts (FC have the highest effect followed by the PSO among all the four Ramsey terms which defined the total spin-spin coupling constant J (HZ of these complexes.

  4. Transition moment directions and selected spectroscopic properties of Ivabradine

    Science.gov (United States)

    Synak, A.; Pikul, P.; Bojarski, P.; Nowakowska, J.; Wiczk, W.; Łukaszewicz, A.; Kubicki, A. A.

    2013-01-01

    Based on the Kawski-Gryczynski method the value of angle β = 38° between absorption and fluorescence transition moments of Ivabradine was determined. Such a high value of β is responsible for low emission anisotropy of Ivabradine in a rigid polyvinyl alcohol matrix and in anhydrous glycerol despite the elongated shape of the fluorophore. Selected steady-state and time-resolved spectroscopic results support the analysis.

  5. Spectroscopic properties of trivalent praseodymium in barium yttrium fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Di Bartolo, B. E-mail: dibartob@bc.edurinodiba@attbi.com; Bowlby, B.E

    2003-05-01

    We have conducted a spectroscopic investigation of Pr{sup 3+} in barium yttrium fluoride (BaY{sub 2}O{sub 8}). Two doping concentrations were used: BaY{sub 2}F{sub 8}:Pr{sup 3+} (0.3%) and BaY{sub 2}F{sub 8}:Pr{sup 3+} (1%). The measurements included absorption, luminescence under continuous and pulsed excitations, and thermal effects on some sharp lines. The experimental results were used to characterize this system.

  6. Characterization by spectroscopic Ellipsometry, the physical properties of silver nanoparticles.

    Science.gov (United States)

    Coanga, Jean-Maurice

    2013-04-01

    Physicists are able to change their minds through their experiments. I think it is time to go kick the curse and go further in research if we want a human future. I work in the Nano-Optics and Plasmonics research. I defined with ellipsomètrie the structure of new type of Nano particles of silver. It's same be act quickly to replace the old dirty leaded electronic-connexion chip and by the other hand to find a new way for the heath care of cancer disease by nanoparticles the next killers of bad cells. Silver nanoparticle layers are obtained by Spark Plasma Sintering are investigated as an alternative to lead alloy based material for solder joint in power mechatronics modules. These layers are characterized by mean of conventional techniques that is the dilatometry technique, the resistivity measurement through the van der Pauw method, and the flash laser technique. Furthermore, the nanoparticles of silver layer are deeply studied by UV-Visible spectroscopic ellipsometry. Spectroscopic angles parameters are determined in function of temperature and dielectric constants are deduced and analyzed through an optical model which takes into account a Drude and a Lorentz component within the Bruggeman effective medium approximation (EMA). The relaxation times and the electrical conductivity are plot in function of temperature. The obtained electrical conductivity give significant result in good agreement to those reported by four points electrical measurement method.

  7. Study on Thermal Stability and Spectroscopic Properties of Nd3+ -Doped Phosphate Laser Glasses

    Institute of Scientific and Technical Information of China (English)

    Shi Qi; Lv Jingwen; Cheng Hong; Fu Xingguo; Sun Yu

    2004-01-01

    Fluorescence spectra, absorption spectra and thermal stability properties of Nd3 + -doped phosphate laser glasses were tested in this work. We calculated spectroscopic parameters of Nd3 + -doped phosphate laser glasses according to their absorption spectrum. Measuring and calculating linear thermal expansion coefficient, and analysising thermal stability of glasses show that this kind of Nd3 + -doped phosphate laser glasses has thermal expansion coefficient α = 38.75× 10 -7/℃ and optimal spectroscopic properties which extend application range of Nd +3-doped phosphate laser glasses.

  8. Study of physical properties of spectroscopic binary stars

    Science.gov (United States)

    Popova, E. I.; Tutukov, A. V.; Yungelson, L. R.

    1982-11-01

    The main results of a study of a catalogue of physical parameters of 1041 spectroscopic binaries are presented. The results of the analysis of the observed distributions of SB's over the main, genetically and evolutionary stipulated parameters, such as apparent brightness and orbital periods, are given. The main effects of observational selection that prevent the direct analysis of innate distributions of SB's over masses, mass ratios of components, and the large semiaxes of their orbits are briefly discussed. Models of observed distributions of bright SB's over M(1), M(2)/M(1) and the large semiaxes are computed by a program which, starting with arbitrary distributions, generates models of observed distributions, taking into account the important effects of observational selection and stellar evolution.

  9. Conformational, IR spectroscopic and electronic properties of conium alkaloids and their adducts with C60 fullerene

    Science.gov (United States)

    Zabolotnyi, M. A.; Prylutskyy, Yu I.; Poluyan, N. A.; Evstigneev, M. P.; Dovbeshko, G. I.

    2016-08-01

    Conformational, IR spectroscopic and electronic properties of the components of Conium alkaloids (Conium maculatum) in aqueous environment were determined by model calculations and experiment. With the help of FT-IR spectroscopy the possibility of formation of an adduct between γ-coniceine alkaloid and C60 fullerene was demonstrated, which is important for further application of conium analogues in biomedical purposes.

  10. Transient Spectroscopic Properties of [60]Fullerene-Containing Cyclic Sulphoxide

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The properties of the triplet excited state of [60]fullerene-containing cyclic sulphoxide have been investigated by time-resolved absorption spectroscopy. Transient absorption bands of [60]fullerene-containing cyclic sulphoxide showed two decay-components, which were attributed to triplet excited states of different spin multiplicity. The properties of photoexcited states of [60]fullerene-containing cyclic sulphoxide are also reported.

  11. Optical properties of InN studied by spectroscopic ellipsometry

    Science.gov (United States)

    Chunya, Ye; Wei, Lin; Jin, Zhou; Shuping, Li; Li, Chen; Heng, Li; Xiaoxuan, Wu; Songqing, Liu; Junyong, Kang

    2016-10-01

    With recently developed InN epitaxy via a controlling In bilayer, spectroscopic ellipsometry (SE) measurements had been carried out on the grown InN and the measured ellipsometric spectra were fitted with the Delta Psi2 software by using a suitable model and the dispersion rule. The thickness was measured by a scanning electron microscope (SEM). Insight into the film quality of InN and the lattice constant were gained by X-ray diffraction (XRD). By fitting the SE, the thickness of the InN film is consistent with that obtained by SEM cross-sectional thickness measurement. The optical bandgap of InN was put forward to be 1.05 eV, which conforms to the experimental results measured by the absorption spectrum and cathodoluminescence (CL). The refractive index and the extinction coefficient of interest were represented for InN, which is useful to design optoelectronic devices. Project supported by the State Key Development Program for Basic Research of China (No. 2012CB619301), the National High Technology Research and Development Program of China (No. 2014AA032608), the National Natural Science Foundation of China (Nos. 11204254, 11404271), and the Fundamental Research Funds for the Central Universities (Nos. 2012121014, 20720150027).

  12. Spectroscopic properties of five-coordinated Co2+ in phosphates.

    Science.gov (United States)

    Hunault, M; Robert, J-L; Newville, M; Galoisy, L; Calas, G

    2014-01-03

    Co3(PO4)2, SrCo2(PO4)2, Co2P2O7, BaCoP2O7 and SrCoP2O7 present different geometries of five-coordinated Co(2+) (([5])Co(2+)) sites, coexisting with ([6])Co(2+) in Co3(PO4)2 and Co2P2O7, and ([4])Co(2+) in SrCo2(PO4)2. ([5])Co K-edge XANES spectra show that the intensity of the pre-edge and main-edge is intermediate between those of ([6])- and ([4])Co. Diffuse reflectance spectra show the contributions of Co(2+) in (D3h) symmetry for SrCo2(PO4)2, and (C4v) symmetry for BaCoP2O7 and SrCoP2O7. In Co3(PO4)2 and Co2P2O7 the multiple transitions observed arise from energy level splitting and may be labeled in (C2v) symmetry. Spectroscopic data confirm that (D3h) and (C4v) symmetries may be distinguished upon the intensity of the optical absorption bands and crystal field splitting values. We discuss the influence of the geometrical distortion and of the nature of the next nearest neighbors.

  13. Structure, reactivity and spectroscopic properties of minerals from lateritic soils : insights from ab initio calculations

    OpenAIRE

    Balan, Etienne; Lazzeri, M.; Mauri, F.; Calas, G.

    2007-01-01

    We review here some recent applications of ab initio calculations to the modelling of spectroscopic and energetic properties of minerals, which are key components of lateritic soils or govern their geochemical properties. Quantum mechanical ab initio calculations are based on density functional theory and density functional perturbation theory. Among the minerals investigated, zircon is a typical resistant primary mineral. Its resistance to weathering is at the origin of the peculiar geochemi...

  14. Structure-spectroscopic property relationships in a series of platinum acetylides

    Science.gov (United States)

    Cooper, Thomas M.; Haley, Joy E.; Krein, Douglas M.; Burke, Aaron R.; Slagle, Jonathan E.

    2016-09-01

    In order to understand electronic and conformational effects on structure-spectroscopic property relationships in platinum acetylides, we synthesized a model series of chromophores trans-Pt(PBu3)2(C-CPhenyl-X)2, where X = NH2, OCH3, diphenylamino, t-Bu, methyl, H, F, benzothiazole, trifluoromethyl, CN and nitro. We collected linear spectra, including ground state absorption, phosphorescence and phosphorescence excitation spectra. We also performed DFT and TDDFT calculations on the ground and excited state properties of these compounds. The calculations and experimental data show the excited state properties are a function of the electronic properties of the substituents and the molecular conformation.

  15. Synthesis, Mesogenic and Spectroscopic Properties of 2,5-Disubstituted Thiophene Derivatives

    Institute of Scientific and Technical Information of China (English)

    HAN Jie; WANG Yan-Mei; WANG Xiao-Guang

    2006-01-01

    Two series of 2,5-disubstituted thiophene derivatives (series 1: 2,5-bis(p-alkoxyphenylethynyl)thiophene and series 2: 2,5-bis[p-(p-alkoxyphenylethynyl)(phenylethynyl)]thiophene) were synthesized and characterized by 1H NMR, 13C NMR, HRMS and elemental analysis. The relationship between the structure and the mesogenic and spectroscopic properties has been discussed. The results show thatcompounds 1a-1f all exhibited an enantiotropic nematic mesophase, which was confirmed by the polarized optical microscopy (POM), differential scanning calorimeter (DSC) and variable temperature powder X-ray diffraction (PXRD). In contrast, the extended onjugatedanalogues 2a-2b had no liquid crystal properties. As for the spectroscopic properties, ncorporating more phenylethynyl units results in red-shifted absorption and emission spectra, greatly enhanced quantum efficiency.

  16. Substituent Effects on Cytotoxic Activity, Spectroscopic Property, and DNA Binding Property of Naphthalimide Derivatives.

    Science.gov (United States)

    Wang, Ke-Rang; Qian, Feng; Sun, Qian; Ma, Cui-Lan; Rong, Rui-Xue; Cao, Zhi-Ran; Wang, Xiao-Man; Li, Xiao-Liu

    2016-05-01

    A series of novel naphthalimide derivatives NI1-5 containing piperazine moieties (N-(2-hydroxyethyl)piperazine and 1-piperazinepropanol) and piperidine moieties (4-piperidinemethanol, 4-hydroxypiperidine and 4-piperidineethanol) have been synthesized and evaluated for their cytotoxic activity, spectroscopic property, and DNA binding behaviors. It was found that substituents at the 4-position remarkably influence the various activities of this series of compound. Compounds NI3-5 modified with piperidines exhibited potent cytotoxic activities against Hela, SGC-7901, and A549 cells with the IC50 values from 0.73 μm to 6.80 μm, which are better than NI1-2 functionalized with piperazines. Compounds NI1-2 showed higher binding capacity with Ct-DNA than compounds NI3-5 based on studies of UV-vis, fluorescence and CD spectra. Furthermore, compounds NI3-5, as DNA intercalators, showed fluorescence enhancement upon binding with Ct-DNA. More interestingly, fluorescence imaging studies of compound NI4 with A549 cells showed that the fluorescence predominantly appeared in the cytoplasm. These results provided a potential application of NI3-5 as anticancer therapeutic and cancer cell imaging agents.

  17. Spectroscopic properties, NLO, HOMO-LUMO and NBO of maltol

    Science.gov (United States)

    KrishnaKumar, V.; Barathi, D.; Mathammal, R.; Balamani, J.; Jayamani, N.

    2014-03-01

    Maltol (3-hydroxy-2-methyl-4pyrone) is widely known as metal ions chelator with many practical applications in catalysis, medicine and food chemistry. The FTIR and FT-Raman spectra of maltol have been recorded in the region 4000-400 and 4000-50 cm-1, respectively. The conformational analysis, optimized geometry, frequency and intensity of the vibrational bands of maltol were obtained by the density functional theory (DFT) with complete relaxation in the potential energy surface using 6-31G* basis set. The observed and the calculated frequencies are found to be in good agreement. The 1H and 13C NMR spectra have been recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method and their respective linear correlations were obtained. The electronic properties HOMO and LUMO energies were measured. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound were calculated. The Mulliken charges, the values of electric dipole moment (μ) of the molecule were computed using DFT calculations. The first order hyperpolarizability (βo) and related properties (β, αo and Δα) of both are calculated using B3LYP/6-31G* method on the finite-field approach. The calculated first hyperpolarizability shows that the molecules are an attractive molecule for future applications in non-linear optics. The intramolecular contacts have been interpreted using Natural Bond Orbital (NBO).

  18. The Spectroscopic Properties of Bright Extragalactic Planetary Nebulae

    CERN Document Server

    Richer, M G

    2006-01-01

    The properties of bright extragalactic planetary nebulae are reviewed based upon the results of low and high resolution spectroscopy. It is argued that bright extragalactic planetary nebulae from galaxies (or subsystems) with and without star formation have different distributions of central star temperature and ionization structure. As regards the chemical compositions, oxygen and neon are generally found to be unchanged as a result of the evolution of the stellar progenitors. Nitrogen enrichment may occur as a result of the evolution of the progenitors of bright planetary nebulae in all stellar populations, though this enrichment may be (more) random in old stellar populations. Helium abundances appear to be influenced by the chemical evolution of the host galaxy, with planetary nebulae in dwarf spheroidals having systematically elevated abundances. Neither the age nor the metallicity of the progenitor stellar population has a strong effect upon the kinematics observed for nebular shells. Both the range of ...

  19. Spectroscopic comparison of effects of electron radiation on mechanical properties of two polyimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.

    1987-01-01

    The differences in the radiation durabilities of two polyimide materials, Du Pont Kapton and General Electric Ultem, are compared. An explanation of the basic mechanisms which occur during exposure to electron radiation from analyses of infrared (IR) and electron paramagnetic resonance (EPR) spectroscopic data for each material is provided. The molecular model for Kapton was, in part, established from earlier modeling for Ultem (pp. 1293-1298 of IEEE Transactions on Nuclear Science, December 1984). Techniques for understanding the durability of one complex polymer based on the understanding of a different and equally complex polymer are demonstrated. The spectroscopic data showed that the primary radiation-generated change in the tensile properties of Ultem (a large reduction in tensile elongation) was due to crosslinking, which followed the capture by phenyl radicals of hydrogen atoms removed from gem-dimethyl groups. In contrast, the tensile properties of Kapton remained unchanged because radical-radical recombination, a self-mending process, took place.

  20. Reconstruction of explicit structural properties at the nanoscale via spectroscopic microscopy

    OpenAIRE

    Cherkezyan, Lusik; Zhang, Di; Subramanian, Hariharan; Taflove, Allen; Backman, Vadim

    2016-01-01

    The spectrum registered by a reflected-light bright-field spectroscopic microscope (SM) can quantify the microscopically indiscernible, deeply subdiffractional length scales within samples such as biological cells and tissues. Nevertheless, quantification of biological specimens via any optical measures most often reveals ambiguous information about the specific structural properties within the studied samples. Thus, optical quantification remains nonintuitive to users from the diverse fields...

  1. The K20 survey. III. Photometric and spectroscopic properties of the sample

    CERN Document Server

    Cimatti, A; Daddi, E; Pozzetti, L; Fontana, A; Saracco, P; Poli, F; Renzini, A; Zamorani, G; Broadhurst, T J; Cristiani, S; D'Odorico, S; Giallongo, E; Gilmozzi, R; Menci, N

    2002-01-01

    The K20 survey is an ESO VLT optical and near-infrared spectroscopic survey aimed at obtaining spectral information and redshifts of a complete sample of about 550 objects to K_s\\leq20.0 over two independent fields with a total area of 52 arcmin^2. In this paper we discuss the scientific motivation of such a survey, we describe the photometric and spectroscopic properties of the sample, and we release the $K_s$-band photometric catalog. Extensive simulations showed that the sample is photometrically highly complete to K_s=20. The observed galaxy counts and the R-K_s color distribution are consistent with literature results. We observed spectroscopically 94% of the sample, reaching a spectroscopic redshift identification completeness of 92% to K_s\\leq20.0 for the observed targets, and of 87% for the whole sample (i.e. counting also the unobserved targets). Deep spectroscopy was complemented with multi-band deep imaging in order to derive tested and reliable photometric redshifts for the galaxies lacking spectr...

  2. Dielectric properties of WS2-coated multiwalled carbon nanotubes studied by energy-loss spectroscopic profiling

    Science.gov (United States)

    Stolojan, Vlad; Silva, S. R. P.; Goringe, Michael J.; Whitby, R. L. D.; Hsu, Wang K.; Walton, D. R. M.; Kroto, Harold W.

    2005-02-01

    We investigate experimentally the electronic properties of the coating for multiwalled carbon nanotubes covered in tungsten disulfide (WS2) of various thicknesses. Coatings of thicknesses between 2 and 8 monolayers (ML) are analyzed using energy-loss spectroscopic profiling (ELSP), by studying the variations in the plasmon excitations across the coated nanotube, as a function of the coating thickness. We find a change in the ELSP for coatings above 5 ML thickness, which we interpret in terms of a change in its dielectric properties.

  3. Perturbed Angular Correlation (PAC)/NMR spectroscopic properties and dynamics of compounds containing metal ions

    DEFF Research Database (Denmark)

    Arcisauskaité, Vaida

    steps towards understanding how Zn(II) reaches its target position in biological systems in vivo and in vitro experiments in aqueous solution, is the detailed investigation of water exchange reactions for Zn(II)(aq). A very advanced (albeit not complete) picture of structure and dynamics of solvated Zn......199mHg PAC and 199Hg NMR spectroscopic properties, nuclear quadrupole coupling constants, Q, asymmetry parameters, , and chemical shifts, , respectively, are the fingerprint of the local molecular and electronic structure, at the probed Hg nuclei. For this reason, these spectroscopic techniques...... compounds in terms of the atomic constituents. The analysis provided a chemophysical interpretation of changes in Vzz upon structural distortions and ligand exchange. The gained insights can be useful when predicting and understanding changes in Q values for Hg binding sites in proteins. One of the first...

  4. Spectroscopic properties of Nd3+ in orthorhombic δ-BiB3O6 crystal

    Science.gov (United States)

    Ikonnikov, D. A.; Malakhovskii, A. V.; Sukhachev, A. L.; Zaitsev, A. I.; Aleksandrovsky, A. S.; Jubera, V.

    2012-09-01

    Absorption spectra of the Nd3+ ions in an orthorhombic δ-BiB3O6 single crystal were measured in the spectral range 11,000-20,500 cm-1. The f-f transition intensities were analyzed in terms of the Judd-Ofelt theory, and the following parameters of the theory were obtained: Ω2 = 6.35 × 10-20 cm2, Ω4 = 4.86 × 10-20 cm2, and Ω6 = 11.233 × 10-20 cm2. The strengths, spontaneous emission probabilities, branching ratios, spectroscopic quality factor and excited state radiative lifetime were calculated for laser transitions from the 4F3/2 state to 4IJ manifold. Spectroscopic properties of Nd3+:δ-BiB3O6 crystal favor lasing at 1.3 μm, where this crystal possesses near non-critical phase matching for second harmonic generation.

  5. Fiber optic spectroscopic digital imaging sensor and method for flame properties monitoring

    Science.gov (United States)

    Zelepouga, Serguei A.; Rue, David M.; Saveliev, Alexei V.

    2011-03-15

    A system for real-time monitoring of flame properties in combustors and gasifiers which includes an imaging fiber optic bundle having a light receiving end and a light output end and a spectroscopic imaging system operably connected with the light output end of the imaging fiber optic bundle. Focusing of the light received by the light receiving end of the imaging fiber optic bundle by a wall disposed between the light receiving end of the fiber optic bundle and a light source, which wall forms a pinhole opening aligned with the light receiving end.

  6. Spectroscopic properties of Eu3+ doped YBO3 nanophosphors synthesized by modified co-precipitation method

    Institute of Scientific and Technical Information of China (English)

    A. Szczeszak; S. Lis; V. Nagirnyi

    2011-01-01

    Y1-xEuxBO3 nanophosphors were synthesized by a modified co-precipitation method.The structure of the obtained nanocrystals was determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM).The average crystallite size was calculated from the full-width at half-maximum (FWHM) of the diffraction peaks by the Scherrer equation.The average particles size was 25±10 nm.The spectroscopic properties of the Y1-xEuxBO3 nanoborates were characterized by excitation and emission spectra under UV and VUV excitation.In order to improve colour purity,the chromaticity coordinates were also calculated.

  7. Spectroscopic, luminescent and laser properties of nanostructured CaF2:Tm materials

    Science.gov (United States)

    Lyapin, A. A.; Fedorov, P. P.; Garibin, E. A.; Malov, A. V.; Osiko, V. V.; Ryabochkina, P. A.; Ushakov, S. N.

    2013-08-01

    The laser quality transparent СаF2:Tm fluoride ceramics has been prepared by hot forming. Comparative study of absorption and emission spectra of СаF2:Tm (4 mol.% TmF3) ceramic and single crystal samples demonstrated that these materials possess almost identical spectroscopic properties. Laser oscillations of СаF2:Tm ceramics were obtained at 1898 nm under diode pumping, with the slope efficiency of 5.5%. Also, the continuous-wave (CW) laser have been obtained for СаF2:Tm single crystal at 1890 nm pumped by a diode laser was demonstrated.

  8. Optical properties of nitrogen-doped graphene thin films probed by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Shen, C.C. [Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan (China); Tseng, C.C.; Lin, C.T.; Li, L.J. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Liu, H.L., E-mail: hliu@ntnu.edu.tw [Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan (China)

    2014-11-28

    Nitrogen-doped graphene thin films were prepared by either chemical vapor deposition (CVD) or electrochemical exfoliation (ECE). Their optical properties were determined in the spectral region of 0.73–6.42 eV and at temperatures between 200 and 350 K by spectroscopic ellipsometry. The parameters of the dispersive structures were derived by numerical fitting of the experimental data to the stacked layer model. The optical absorption spectrum of the CVD-grown thin films is characterized by an asymmetric Fano resonance in the ultraviolet frequency region. In contrast, the line shape of the ECE-grown thin films displays less asymmetric. The excitonic resonance of the nitrogen-doped thin films is overall blue shifted by ∼ 0.2–0.3 eV compared with that of undoped analog. We interpret these results in terms of the exothermic nature of triazine molecule adsorption due to binding to graphene's surface via electron rich nitrogen. - Highlights: • Optical properties of N-doped graphene films determined by spectroscopic ellipsometry • Fano resonance in the ultraviolet frequency region of all graphene film absorption spectra • Blueshift in the excitonic resonance of N-doped graphene thin films is observed.

  9. Effects of 5f-elements on electronic structures and spectroscopic properties of gold superatom model

    Science.gov (United States)

    Gao, Yang; Wang, Zhigang

    2016-08-01

    5f-elements encaged in a gold superatomic cluster are capable of giving rise to unique optical properties due to their hyperactive valence electrons and great radial components of 5f/6d orbitals. Herein, we review our first-principles studies on electronic structures and spectroscopic properties of a series of actinide-embedded gold superatomic clusters with different dimensions. The three-dimensional (3D) and two-dimensional (2D) superatom clusters possess the 18-electron configuration of 1S21P61D10 and 10-electron configuration of 1S21P41D4, respectively. Importantly, their electronic absorption spectra can also be effectively explained by the superatom orbitals. Specifically, the charge transfer (CT) transitions involved in surface-enhance Raman spectroscopy (SERS) spectra for 3D and 2D structures are both from the filled 1D orbitals, providing the enhancement factors of the order of ˜ 104 at 488 nm and ˜ 105 at 456 nm, respectively. This work implies that the superatomic orbital transitions involved in 5f-elements can not only lead to a remarkable spectroscopic performance, but also a new direction for optical design in the future. Project supported by the National Natural Science Foundation of China (Grant No. 11374004), the Science and Technology Development Program of Jilin Province, China (Grant No. 20150519021JH), the Fok Ying Tung Education Foundation, China (Grant No. 142001), and the Support from the High Performance Computing Center (HPCC) of Jilin University, China.

  10. Natural organic UV-absorbent coatings based on cellulose and lignin: designed effects on spectroscopic properties.

    Science.gov (United States)

    Hambardzumyan, Arayik; Foulon, Laurence; Chabbert, Brigitte; Aguié-Béghin, Véronique

    2012-12-10

    Novel nanocomposite coatings composed of cellulose nanocrystals (CNCs) and lignin (either synthetic or fractionated from spruce and corn stalks) were prepared without chemical modification or functionalization (via covalent attachment) of one of the two biopolymers. The spectroscopic properties of these coatings were investigated by UV-visible spectrophotometry and spectroscopic ellipsometry. When using the appropriate weight ratio of CNC/lignin (R), these nanocomposite systems exhibited high-performance optical properties, high transmittance in the visible spectrum, and high blocking in the UV spectrum. Atomic force microscopy analysis demonstrated that these coatings were smooth and homogeneous, with visible dispersed lignin nodules in a cellulosic matrix. It was also demonstrated that the introduction of nanoparticles into the medium increases the weight ratio and the CNC-specific surface area, which allows better dispersion of the lignin molecules throughout the solid film. Consequently, the larger molecular expansion of these aromatic polymers on the surface of the cellulosic nanoparticles dislocates the π-π aromatic aggregates, which increases the extinction coefficient and decreases the transmittance in the UV region. These nanocomposite coatings were optically transparent at visible wavelengths.

  11. Effect of lithium-potassium mixed alkali on spectroscopic properties of Er3+-doped aluminophosphate glasses

    Institute of Scientific and Technical Information of China (English)

    Fang Yong-Zheng; Liao Mei-Song; Hu Li-Li

    2007-01-01

    Er3+-doped lithium-potassium mixed alkali aluminophosphate glasses belonging to the oxide system xK2O-(15-x)Li2O-4B2O3-11Al2O3-5BaO-65P2O5 are obtained in a semi-continuous melting quenching process. Spectroscopic properties of Er3+-doped glass matrix have been analysed by fitting the experimental data with the standard Judd- Ofelt theory. It is observed that Judd- Ofelt intensity parameters Ωt(t = 2, 4 and 6) of Er3+ change when the second alkali is introduced into glass matrix. The variation of line strength Sed[4I13/2,4I15/2] follows the same trend as that of the Ω6 parameter. The effect of mixed alkali on the spectroscopic properties of the aluminophosphate glasses, such as absorption cross-section, stimulated emission cross-section, spontaneous emission probability, branching ratio and the radiative lifetime, has also been investigated in this paper.

  12. Quantum chemical calculations and spectroscopic measurements of spectroscopic and thermodynamic properties of given uranyl complexes in aqueous solutions with possible environmental and industrial applications

    Directory of Open Access Journals (Sweden)

    Višňak Jakub

    2016-01-01

    Full Text Available A brief introduction into computational methodology and preliminary results for spectroscopic (excitation energies, vibrational frequencies in ground and excited electronic states and thermodynamic (stability constants, standard enthalpies and entropies of complexation reactions properties of some 1:1, 1:2 and 1:3 uranyl sulphato- and selenato- complexes in aqueos solutions will be given. The relativistic effects are included via Effective Core Potential (ECP, electron correlation via (TDDFT/B3LYP (dispersion interaction corrected and solvation is described via explicit inclusion of one hydration sphere beyond the coordinated water molecules. We acknowledge limits of this approximate description – more accurate calculations (ranging from semi-phenomenological two-component spin-orbit coupling up to four-component Dirac-Coulomb-Breit hamiltonian and Molecular Dynamics simulations are in preparation. The computational results are compared with the experimental results from Time-resolved Laser-induced Fluorescence Spectroscopy (TRLFS and UV-VIS spectroscopic studies (including our original experimental research on this topic. In case of the TRLFS and UV-VIS speciation studies, the problem of complex solution spectra decomposition into individual components is ill-conditioned and hints from theoretical chemistry could be very important. Qualitative agreement between our quantum chemical calculations of the spectroscopic properties and experimental data was achieved. Possible applications for geochemical modelling (e.g. safety studies of nuclear waste repositories, modelling of a future mining site and analytical chemical studies (including natural samples are discussed.

  13. Quantum chemical calculations and spectroscopic measurements of spectroscopic and thermodynamic properties of given uranyl complexes in aqueous solutions with possible environmental and industrial applications

    Science.gov (United States)

    Višňak, Jakub; Sobek, Lukáš

    2016-11-01

    A brief introduction into computational methodology and preliminary results for spectroscopic (excitation energies, vibrational frequencies in ground and excited electronic states) and thermodynamic (stability constants, standard enthalpies and entropies of complexation reactions) properties of some 1:1, 1:2 and 1:3 uranyl sulphato- and selenato- complexes in aqueos solutions will be given. The relativistic effects are included via Effective Core Potential (ECP), electron correlation via (TD)DFT/B3LYP (dispersion interaction corrected) and solvation is described via explicit inclusion of one hydration sphere beyond the coordinated water molecules. We acknowledge limits of this approximate description - more accurate calculations (ranging from semi-phenomenological two-component spin-orbit coupling up to four-component Dirac-Coulomb-Breit hamiltonian) and Molecular Dynamics simulations are in preparation. The computational results are compared with the experimental results from Time-resolved Laser-induced Fluorescence Spectroscopy (TRLFS) and UV-VIS spectroscopic studies (including our original experimental research on this topic). In case of the TRLFS and UV-VIS speciation studies, the problem of complex solution spectra decomposition into individual components is ill-conditioned and hints from theoretical chemistry could be very important. Qualitative agreement between our quantum chemical calculations of the spectroscopic properties and experimental data was achieved. Possible applications for geochemical modelling (e.g. safety studies of nuclear waste repositories, modelling of a future mining site) and analytical chemical studies (including natural samples) are discussed.

  14. Modeling the transport properties of epitaxially grown thermoelectric oxide thin films using spectroscopic ellipsometry

    KAUST Repository

    Sarath Kumar, S. R.

    2012-02-01

    The influence of oxygen vacancies on the transport properties of epitaxial thermoelectric (Sr,La)TiO3 thin films is determined using electrical and spectroscopic ellipsometry (SE) measurements. Oxygen vacancy concentration was varied by ex-situ annealing in Ar and Ar/H2. All films exhibited degenerate semiconducting behavior, and electrical conductivity decreased (258–133 S cm−1) with increasing oxygen content. Similar decrease in the Seebeck coefficient is observed and attributed to a decrease in effective mass (7.8–3.2 me ), as determined by SE. Excellent agreement between transport properties deduced from SE and direct electrical measurements suggests that SE is an effective tool for studying oxide thin film thermoelectrics.

  15. Spectroscopic properties and thermal stability of Er3+/Yb3+-codoped fluorophosphate glasses

    Institute of Scientific and Technical Information of China (English)

    Li Tao; Zhang Qin-Yuan; Zhao Chun; Feng Zhou-Ming; Shi Dong-Mei; Deng Zai-De; Jiang Zhong-Hong

    2005-01-01

    A comprehensive study on the thermal stability and spectroscopic properties of Er3+/Yb3+-codoped Al(PO3)3-based fluorophosphate glasses is reported of the 1.5μm fibre amplifiers in this paper. From optical absorption spectra, the Judd-Ofelt parameters of Er3+ in the glasses and several important optical properties, such as the radiative transition probability, the branching ratio and the spontaneous emission probability, have been calculated by using Judd-Ofelt theory. The fluorophosphate glass exhibits broadband near-infrared emission at 1.53 μm with a full width at halfmaximum over 63nm, and a large calculated stimulated-emission cross-section of 6.85 × 10-21cm2.

  16. Spectroscopic study on variations in illite surface properties after acid-base titration

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    FT-IR, Raman microscopy, XRD, 29 Si and 27 Al MAS NMR, were used to investigate changes in surface properties of a natural illitesample after acid-base potentiometric titration. The characteristic XRD lines indicated the presence of surface Al-Si complexes, preferable to Al(OH)3 precipitates. In the microscopic Raman spectra, the vibration peaks of Si-O and Al-O bonds diminished as a result of treatment withacid, then increased after hydroxide back titration. The varied ratio of signal intensity between Ⅳ Al and Ⅵ At species in 27 Al MAS NMRspectra, together with the stable BET surface area after acidimetric titration, suggested that edge faces and basal planes in the layer structure ofillite participated in dissolution of structural components. The combined spectroscopic evidence demonstrated that the reactions between illitesurfaces and acid-leaching silicic acid and aluminum ions should be considered in the model description of surface acid-base properties of theaqueous illite.

  17. Accurate molecular structure and spectroscopic properties for nucleobases: A combined computational - microwave investigation of 2-thiouracil as a case study

    Science.gov (United States)

    Puzzarini, Cristina; Biczysko, Malgorzata; Barone, Vincenzo; Peña, Isabel; Cabezas, Carlos; Alonso, José L.

    2015-01-01

    The computational composite scheme purposely set up for accurately describing the electronic structure and spectroscopic properties of small biomolecules has been applied to the first study of the rotational spectrum of 2-thiouracil. The experimental investigation was made possible thanks to the combination of the laser ablation technique with Fourier Transform Microwave spectrometers. The joint experimental – computational study allowed us to determine accurate molecular structure and spectroscopic properties for the title molecule, but more important, it demonstrates a reliable approach for the accurate investigation of isolated small biomolecules. PMID:24002739

  18. Temperature and composition dependence of crystal structures and magnetic and electronic properties of the double perovskites La2-xSrxCoIrO6 (0≤x≤2)

    Science.gov (United States)

    Narayanan, N.; Mikhailova, D.; Senyshyn, A.; Trots, D. M.; Laskowski, R.; Blaha, P.; Schwarz, K.; Fuess, H.; Ehrenberg, H.

    2010-07-01

    X-ray, synchrotron, and neutron powder diffraction techniques were combined to investigate the evolution of crystal structure and physical properties of La2-xSrxCoIrO6 with temperature and composition x . The following sequence of first- and second-order phase transitions is observed in this system, induced by increasing Sr content and temperature: P21/n↔P21/n+I2/m↔I2/m↔I4/m↔Fm3¯m . The low-temperature magnetic structures are characterized by the propagation vector k=(0,0,0) for x=0 , k=(1/2,0,1/2) for x=1 , and k=(0,1/2,1/2) or k=(1/2,0,1/2) for 1.5 and 2. Different noncollinear magnetic structures are concluded from the combination of magnetization measurements and neutron powder diffraction. Resistivity measurements reveal that the whole series behaves like nonmetals with electronic transport described by a combination of thermal activation and variable range hopping. Band gaps determined by electronic structure calculations agree very well with the experimental data for x=0 and 1, and the calculated occupation of the d bands of Co and Ir are in good agreement with a transition IS/HS-Co2+/LS-Ir4+→HS-Co3+/LS-Ir5+ with increasing Sr content.

  19. Spectroscopic properties of LaZnPO polycrystals doped with Nd{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Lemański, K. [Institute of Low Temperature and Structure Research Polish Academy of Sciences, Department of Spectroscopy of Excited States, ul. Okólna 2, 50-422 Wrocław (Poland); Babij, M. [Institute of Low Temperature and Structure Research Polish Academy of Sciences, Department of Spectroscopy of Excited States, ul. Okólna 2, 50-422 Wrocław (Poland); University of Wrocław, Faculty of Chemistry, ul. F. Joliot-Curie 14, 50-383 Wrocław (Poland); Ptak, M.; Bukowski, Z. [Institute of Low Temperature and Structure Research Polish Academy of Sciences, Department of Spectroscopy of Excited States, ul. Okólna 2, 50-422 Wrocław (Poland); Dereń, P.J., E-mail: P.Deren@int.pan.wroc.pl [Institute of Low Temperature and Structure Research Polish Academy of Sciences, Department of Spectroscopy of Excited States, ul. Okólna 2, 50-422 Wrocław (Poland)

    2015-09-15

    LaZnPO phosphide oxide was synthesized by a solid state reaction. The crystal structure has been confirmed using the X-Ray Powder Diffraction. LaZnPO possesses a tetragonal crystal structure with a space group P4/nmm. The absorption, FTIR, Raman and luminescence spectra have been measured and analyzed. For the neodymium(III) ions the spectroscopic quality parameter and the luminescence branching ratio were estimated from the emission spectra. The investigated crystals may find applications as a down-shifting material, to enhance the yield of solar cells. - Highlights: • Spectroscopic properties of LaZnPO:Nd{sup 3+} were investigated for the first time. • Broad absorption band occurs in the visible range. • The energy transfer from the host to the doped Nd{sup 3+} ions occurs. • The Stark energy levels of Nd{sup 3+} ions in LaZnPO were obtained. • LaZnPO:Nd{sup 3+} may find applications as a down-shifting material.

  20. Spectroscopic analysis of radiation-generated changes in tensile properties of a polyetherimide film

    Science.gov (United States)

    Long, E. R., Jr.; Long, S. A. T.

    1985-01-01

    The effects of electron radiation on Ultem, a polyetherimide were studied for doses from 2 x 10 to the 9th power to 6 x 10 to the 9th power rad. Specimens were studied for tensile property testing and for electron paramagnetic resonance and infrared spectroscopic measurements of molecular structure. A Faraday cup design and a method for remote temperature measurement were developed. The spectroscopic data show that radiation caused dehydrogenation of methyl groups, rupture of main-chain ether linkage, and opening of imide rings, all to form radicals and indicate that the so-formed atomic hydrogen attached to phenyl radicals, but not to phenoxyl radicals, which would have formed hydroxyls. The observed decays of the radiation-generated phenoxyl, gem-dimethyl, and carbonyl radicals were interpreted as a combining of the radicals to form crosslinking. This crosslinking is the probable cause of the major reduction in the elongation of the tensile specimens after irradiation. Subsequent classical solubility tests indicate that the irradiation caused massive crosslinking.

  1. Spectroscopic ellipsometry investigations of the optical properties of manganese doped bismuth vanadate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Neelam; Krupanidhi, S.B. [Materials Research Center, Indian Institute of Science, Bangalore 560012 (India); Varma, K.B.R., E-mail: kbrvarma@mrc.iisc.ernet.in [Materials Research Center, Indian Institute of Science, Bangalore 560012 (India)

    2010-04-15

    The optical properties of Bi{sub 2}V{sub 1-x}Mn{sub x}O{sub 5.5-x} {l_brace}x = 0.05, 0.1, 0.15 and 0.2 at.%{r_brace} thin films fabricated by pulsed laser deposition on platinized silicon substrates were studied in UV-visible spectral region (1.51-4.17 eV) using spectroscopic ellipsometry. The optical constants and thicknesses of these films have been obtained by fitting the ellipsometric data ({Psi} and {Delta}) using a multilayer four-phase model system and a relaxed Lorentz oscillator dispersion relation. The surface roughness and film thickness obtained by spectroscopic ellipsometry were found to be consistent with the results obtained by atomic force and scanning electron microscopy. The refractive index measured at 650 nm does not show any marginal increase with Mn content. Further, the extinction coefficient does not show much decrease with increasing Mn content. An increase in optical band gap energy from 2.52 to 2.77 eV with increasing Mn content from x = 0.05 to 0.15 was attributed to the increase in oxygen ion vacancy disorder.

  2. Synthesis and spectroscopic properties of some new difluoroboron bis-β-diketonate derivatives.

    Science.gov (United States)

    Pi, Yan; Wang, Dun-Jia; Liu, Hua; Hu, Yan-Jun; Wei, Xian-Hong; Zheng, Jing

    2014-10-15

    Six new bis-β-diketones (RCOCH2CO-C7H7N-COCH2COR) were synthesized from 3,5-diacetyl-2,6-dimethylpyridine via Claisen condensation with the corresponding esters, and then reacted with boron trifluoride etherate to afford difluoroboron bis-β-diketonate derivatives. Their spectroscopic properties were investigated by UV-vis, FTIR, (1)H NMR and fluorescence spectroscopic techniques. It was found that these boron complexes exhibited violet or blue fluorescence emission at 422-445nm and possessed high extinction coefficients. The results indicate that the extending π-conjugation can increase the fluorescence intensity and quantum yield for these boron complexes. Especially, the compound 2b displayed the stronger fluorescence intensity and the highest fluorescence quantum yield (Φu=0.94) in these boron compounds. However, compounds 2c and 2d had the lower fluorescence intensity and quantum yield as a result of the heavy atom effect of the chlorine atom in the molecules.

  3. In-plane orientation and composition dependences of crystal structure and electrical properties of {100}-oriented Pb(Zr,Ti)O3 films grown on (100) Si substrates by metal organic chemical vapor deposition

    Science.gov (United States)

    Okamoto, Shoji; Sankara Rama Krishnan, P. S.; Okamoto, Satoshi; Yokoyama, Shintaro; Akiyama, Kensuke; Funakubo, Hiroshi

    2017-10-01

    In-plane orientation-controlled Pb(Zr x ,Ti1‑ x )O3 (PZT) films with a thickness of approximately 2 µm and a Zr/(Zr + Ti) ratio of 0.39–0.65 were grown on (100) Si substrates by pulsed metal–organic chemical vapor deposition (MOCVD). In-plane-oriented epitaxial PZT films and in-plane random fiber-textured PZT films with {100} out-of-plane orientation were grown on (100)c SrRuO3//(100)c LaNiO3//(100) CeO2//(100) YSZ//(100) Si and (100)c SrRuO3/(100)c LaNiO3/(111) Pt/TiO2/SiO2/(100) Si substrates, respectively. The effects of Zr/(Zr + Ti) ratio and in-plane orientation on the crystal structure, dielectric, ferroelectric, and piezoelectric properties of the films were systematically investigated. The X-ray diffraction measurement showed that the epitaxial PZT films had a higher volume fraction of (100) orientation than the fiber-textured PZT films in the tetragonal Zr/(Zr + Ti) ratio region. A large difference was not detected between the epitaxial films and the fiber-textured films for Zr/(Zr + Ti) ratio dependence of the dielectric constant, and remanent polarization. However, in the rhombohedral phase region [Zr/(Zr + Ti) = 0.65], coercive field was found to be 1.5-fold different between the epitaxial and fiber-textured PZT films. The maximum field-induced strains measured at 0–100 kV/cm by scanning atomic force microscopy were obtained at approximately Zr/(Zr + Ti) = 0.50 and were about 0.5 and 0.3% for the epitaxial and fiber-textured PZT films, respectively.

  4. In vivo endoscopic tissue diagnostics based on spectroscopic absorption, scattering, and phase function properties.

    Science.gov (United States)

    Thueler, Philippe; Charvet, Igor; Bevilacqua, Frederic; St Ghislain, M; Ory, G; Marquet, Pierre; Meda, Paolo; Vermeulen, Ben; Depeursinge, Christian

    2003-07-01

    A fast spectroscopic system for superficial and local determination of the absorption and scattering properties of tissue (480 to 950 nm) is described. The probe can be used in the working channel of an endoscope. The scattering properties include the reduced scattering coefficient and a parameter of the phase function called gamma, which depends on its first two moments. The inverse problem algorithm is based on the fit of absolute reflectance measurements to cubic B-spline functions derived from the interpolation of a set of Monte Carlo simulations. The algorithm's robustness was tested with simulations altered with various amounts of noise. The method was also assessed on tissue phantoms of known optical properties. Finally, clinical measurements performed endoscopically in vivo in the stomach of human subjects are presented. The absorption and scattering properties were found to be significantly different in the antrum and in the fundus and are correlated with histopathologic observations. The method and the instrument show promise for noninvasive tissue diagnostics of various epithelia.

  5. Electronic properties of diphenyl-s-tetrazine and some related oligomers. An spectroscopic and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Moral, Monica; Garcia, Gregorio [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Penas, Antonio [Departamento de Quimica Inorganica y Organica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Garzon, Andres; Granadino-Roldan, Jose M. [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Melguizo, Manuel [Departamento de Quimica Inorganica y Organica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain); Fernandez-Gomez, Manuel, E-mail: mfg@ujaen.es [Departamento de Quimica Fisica y Analitica, Facultad de Ciencias Experimentales, Universidad de Jaen, Campus las Lagunillas, E23071 Jaen (Spain)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer We study properties of Ph{sub 2}Tz and (PhTz){sub n}Ph as candidates for organic electronics. Black-Right-Pointing-Pointer The synthesis of Ph{sub 2}Tz was performed through a modified Pinner-type reaction. Black-Right-Pointing-Pointer IR/Raman spectra allowed to conclude that Ph{sub 2}Tz is nearly planar in liquid phase. Black-Right-Pointing-Pointer Electronic structure was studied by UV-Vis/TD-DFT methods in different solvents. Black-Right-Pointing-Pointer Bandgap, E{sub LUMO}, electron mobility predict some n-type character for limit polymer. -- Abstract: This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph{sub 2}Tz) and some oligomeric derivatives. Ph{sub 2}Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV-Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.

  6. Structural and mechanical properties of cellulose acetate/graphene hybrid nanofibers: Spectroscopic investigations

    Directory of Open Access Journals (Sweden)

    B. S. Kim

    2013-06-01

    Full Text Available Cellulose acetate/graphene (CA/graphene and cellulose acetate/graphene-COOH (CA/graphene-COOH hybrid nanofibers were fabricated via electrospinning technique, and their morphologies, crystallinity and mechanical properties were investigated. The added amounts of graphene and graphene-COOH were varied from 0.5 to 5.0 wt%. The crystal structures and morphologies of the resultant hybrid nanofibers were investigated by wide angle X-ray diffraction (WAXD, scanning electron microscopy (SEM and transmission electron microscopy (TEM, respectively. Graphene-COOH incorporated CA nanofiber mats showed higher Young’s modulus of about 910 MPa among than those of CA/graphene nanofibers, which is due to molecular interactions between –COOH groups in acid-treated graphene and C=O groups in CA via hydrogen bonding. This specific interaction was demonstrated by spectroscopic studies (Raman and Fourier transform infrared (FT-IR spectroscopies.

  7. Spectroscopic properties of a two-level atom interacting with a complex spherical nanoshell

    CERN Document Server

    Moroz, A

    2004-01-01

    Frequency shifts, radiative decay rates, the Ohmic loss contribution to the nonradiative decay rates, fluorescence yields, and photobleaching of a two-level atom radiating anywhere inside or outside a complex spherical nanoshell, i.e. a stratified sphere consisting of alternating silica and gold concentric spherical shells, are studied. The changes in the spectroscopic properties of an atom interacting with complex nanoshells are significantly enhanced, often more than two orders of magnitude, compared to the same atom interacting with a homogeneous dielectric sphere. The changes strongly depend on the nanoshell parameters and the atom position. When an atom approaches a metal shell,the radiative decay rates are strongly enhanced and they increase faster than the Ohmic loss contribution to the nonradiative decay rates. However, the majority of the emitted radiation does not escape to spatial infinity but instead is absorbed. The enhancement of the radiative decay rates in a close proximity of metal boundaries...

  8. Spectroscopic properties of Eu-doped antimony-germanate glass and glass-ceramics

    Science.gov (United States)

    Zmojda, J.; Kochanowicz, M.; Miluski, P.; Ragin, T.; Dorosz, D.; ZajÄ c, A.

    2016-09-01

    In our work we focused on possibility of obtaining phosphate nano-phase structures in antimony-germanate glasses doped with europium ions. The glasses with molar composition of 50(Sb2O3 - GeO2) - 50(SiO2 - Al2O3 - Na2O) doped with 0.5mol% Eu2O3 were prepared by standard melt-quenching method. In order to optimize glass-ceramic system the influence of phosphate concentration (up to 10mol%) on spectroscopic properties have been investigated. The symmetry nature of molecular structure around europium ions have been determined from the intensity ratio between (5D0 →7F2)/(5D0 →7F1) transitions. The effect of prominent Stark splitting of luminescence band at 612 nm characterised as "hypersensitive transition" into 3 sub-wavelength was observed in glasses with 1mol% and 3mol% of P2O5.

  9. RETRACTED: Effect of F- ions on spectroscopic properties of Yb3+-doped zinc tellurite glasses

    Science.gov (United States)

    Wang, Guonian; Zhang, Junjie; Dai, Shixun; Yang, Jianhu; Jiang, Zhonghong

    2005-06-01

    This article has been retracted at the request of the Editors, after a reader brought the following to their attention. Reason: The article substantially reproduces parts of articles published by the same authors in the Journal of Luminescence (“Effect of F- ions on physical and spectroscopic properties of Yb3+-doped TeO2 glasses”, Volume 113, Issues 1-2, Pages 27-32) and the Journal of Alloys and Compounds (“Fluorescence lifetime increase by introduction of F- ions in ytterbium-doped TeO2-based glasses”, Volume 393, Issues 1-2, Pages 279-282). There was also a failure to cite either of these articles. These other articles have also been retracted. This action has been agreed by the Editors of the three journals.

  10. Synthesis, spectroscopic properties and theoretical studies of bis-Schiff bases derived from polyamine and pyrazolones.

    Science.gov (United States)

    Ren, Tiegang; Liu, Shuyun; Li, Guihui; Zhang, Jinglai; Guo, Jia; Li, Weijie; Yang, Lirong

    2012-11-01

    A series of novel bis-Schiff base were synthesized from 1-aryl-3-methyl-4-benzoyl-5-pyrazolones and diethylenetriamine (or triethylenetetramine) as the starting materials. All of these bis-Schiff bases were characterized by means of NMR, IR, and MS. The UV-vis absorption spectra and fluorescent spectra of these bis-Schiff bases were also measured. Moreover, the B3LYP/6-31G(d) method was used to optimize the ground state geometry of the bis-Schiff bases; and the UV-vis spectroscopic properties of the products were computed and compared with corresponding experimental data based on cc-pVDZ basis set of TD-B3LYP method. It has been found that all of these bis-Schiff bases show a remarkable absorption peak in a wavelength range of 270-340 nm; and their maximum emission peaks are around 348 nm.

  11. Spectroscopic Properties of Nd3+-Doped High Silica Glass Prepared by Sintering Porous Glass

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new kind of Nd3+-doped high silica glass (SiO2>96% (mass fraction)) was obtained by sintering porous glass impregnated with Nd3+ ions. The absorption and luminescence properties of high silica glass doped with different Nd3+ concentrations were studied. The intensity parameters Ωt (t=2, 4, 6), spontaneous emission probability, fluorescence lifetime, radiative quantum efficiency, fluorescence branching ratio, and stimulated emission cross section were calculated using the Judd-Ofelt theory. The optimal Nd3+ concentration in high silica glass was 0.27% (mole fraction) because of its high quantum efficiency and emission intensity. By comparing the spectroscopic parameters with other Nd3+-doped oxide glasses and commercial silicate glasses, the Nd3+-doped high silica glasses are likely to be a promising material used for high power and high repetition rate lasers.

  12. Thermal Stability and Spectroscopic Properties of Yb3+-Doped New Gallium-Lead-Germanate Glass

    Institute of Scientific and Technical Information of China (English)

    XU Shi-Qing; FENG Ai-Ming; ZHANG Li-Yan; ZHAO Shi-Long; WANG Bao-Ling; ZHANG Jue; WANG Wei; BAO Ren-Qiang

    2006-01-01

    @@ Yb3+-doped new gallium-lead-germanate glass is presented. Thermal stability, spectroscopic and laser performance parameters of the Yb3+-doped new gallium-lead-germanate glass are calculated. The results show that the Yb3+-doped new gallium-lead-germanate glass has good thermal stability (△T = 198 ℃), high stimulated emission cross section (0.79pm2), and long fluorescence lifetime (1.46ms). Compared with other Yb3+-doped glass hosts, the Yb3+-doped new gallium-lead-germanate glass has better laser performance parameters and laser properties, indicating that Yb3+-doped new gallium-lead-germanate glass is a promising laser material for short pulse generation in diode pumped lasers, short pulse generation tunable laser, high-peak power and high-average power lasers.

  13. Spectroscopic properties of oxygen vacancies in LaAlO3

    Energy Technology Data Exchange (ETDEWEB)

    Dicks, Oliver A.; Shluger, Alexander L.; Sushko, Peter V.; Littlewood, Peter B.; Clegg, Richard Donald

    2016-04-25

    Oxygen vacancies in LaAlO3 (LAO) play an important role in the formation of the two-dimensional electron gas observed at the LaAlO3/SrTiO3 interface and affect the performance of MOSFETs using LAO as a gate dielectric. However, their spectroscopic properties are still poorly understood, which hampers their experimental identification. Here we predict the absorption spectra and ESR parameters of oxygen vacancies in LAO using periodic and embedded cluster methods and density functional theory (DFT). The structure, charge distribution, and spectroscopic properties of the neutral (V 0 O) and charged (V + O and V 2+ O ) oxygen vacancies in cubic and rhombohedral LaAlO3 are investigated. The highest intensity optical transitions [calculated using time-dependent DFT (TDDFT)], from the oxygen vacancy states to the conduction-band states have onsets at 3.5 and 4.2 eV for V 0 O and 3.6 eV for V + O in rhombohedral LAO and 3.3 and 4.0 eV for V 0 O and 3.4 eV for V + O in cubic LAO, respectively. Also reported are the isotropic g value (2.004026) and hyperfine coupling constants of V + O , which are compared to the experimental data obtained using electron spin resonance (ESR) spectroscopy, and accurately predict both the position and the width (3 mT) of its ESR signature. These results may further facilitate the experimental identification of oxygen vacancies in LAO and help to establish their role at the LAO/STO interfaces and in nanodevices using LAO.

  14. The effect of OH- groups on the spectroscopic properties of erbium-doped tellurite glasses

    Institute of Scientific and Technical Information of China (English)

    YU; Chunlei; DAI; Shixun; ZHOU; Gang; ZHANG; Junjie; HU; Li

    2005-01-01

    A series of five different concentration erbium-doped tellurite glasses with various hydroxl groups were prepared. Infrared spectra of glasses were measured. In order to estimate the exact content of OH- groups in samples, various absorption coefficients of the OH- vibration band were analyzed under the different oxygen bubbling times. The absorption spectra of the glasses were measured, and the Judd-Ofelt intensity parameters Ωi of samples with the different erbium ions concentration and OH- Contents were calculated on the basis of the Judd-Ofelt theory. The peak stimulated emission cross-section of 4I13/2→4I15/2 transition of the samples was finally calculated by using the McCumber theory. The fluorescence spectra of Er3+:4I13/2→4I15/2 transition and the lifetime of Er3+:4I13/2 level of the samples were measured. The effects of OH- groups on the spectroscopic properties of Er3+ doped samples with the different concentrations were discussed. The results showed that the OH- groups had great influences on the Er3+ lifetime and the fluorescence peak intensity. The OH- Group is a main influence factor of fluorescence quenching when the doping concentration of Er2O3 is smaller than 1.0 mol%, but higher after this concentration, the energy transfer of Er3+ ions turns into the main function of the fluorescence quenching. And basically, there is no influence on the other spectroscopic properties (FWHM, absorption spectra, peak stimulated emission cross section, etc.).

  15. Reconstruction of explicit structural properties at the nanoscale via spectroscopic microscopy

    Science.gov (United States)

    Cherkezyan, Lusik; Zhang, Di; Subramanian, Hariharan; Taflove, Allen; Backman, Vadim

    2016-02-01

    The spectrum registered by a reflected-light bright-field spectroscopic microscope (SM) can quantify the microscopically indiscernible, deeply subdiffractional length scales within samples such as biological cells and tissues. Nevertheless, quantification of biological specimens via any optical measures most often reveals ambiguous information about the specific structural properties within the studied samples. Thus, optical quantification remains nonintuitive to users from the diverse fields of technique application. In this work, we demonstrate that the SM signal can be analyzed to reconstruct explicit physical measures of internal structure within label-free, weakly scattering samples: characteristic length scale and the amplitude of spatial refractive-index (RI) fluctuations. We present and validate the reconstruction algorithm via finite-difference time-domain solutions of Maxwell's equations on an example of exponential spatial correlation of RI. We apply the validated algorithm to experimentally measure structural properties within isolated cells from two genetic variants of HT29 colon cancer cell line as well as within a prostate tissue biopsy section. The presented methodology can lead to the development of novel biophotonics techniques that create two-dimensional maps of explicit structural properties within biomaterials: the characteristic size of macromolecular complexes and the variance of local mass density.

  16. Spectroscopic properties of Sm3+ doped lead bismosilicate glasses using Judd-Ofelt theory

    Science.gov (United States)

    Bhardwaj, Sunil; Shukla, Rajni; Sanghi, Sujata; Agarwal, Ashish; Pal, Inder

    2014-01-01

    The spectroscopic properties of Sm3+ ions in lead bismosilicate glasses (PBSS) as a function of bismuth oxide were investigated using optical absorption and fluorescence spectra. These glasses have shown strong absorption and emission bands in the near infrared and visible region respectively. From the measured absorption spectra, Judd-Ofelt intensity parameters Ω2, Ω4 and Ω6 were determined by applying least square analysis method. The variation of Ω2 and Ω6 with Bi2O3 content has been attributed to changes in the asymmetry of the ligand field at the rare earth ion site and to the changes in the rare earth oxygen (RE-O) covalency. The variation of Ω4 with Bi2O3 content has been attributed to rigidity of the samples. Using the Judd Ofelt intensity parameters the other radiative properties like radiative transition probability, radiative life time, branching ratio and the stimulated emission cross-sections of prepared PBSS glasses have been calculated. The values of radiative properties indicate that Sm3+ ions emit intense reddish-orange emission (4G5/2 → 6H7/2) under excitation at 450 nm wavelength.

  17. Accurate spectroscopic calculations of 21 electronic states of ClO radical including transition properties

    Science.gov (United States)

    Wang, Xinxin; Shi, Deheng; Sun, Jinfeng; Zhu, Zunlue

    2016-08-01

    The potential energy curves were calculated for the 21 states (X2Π, A2Π, 32Π, 42Π, 52Π, 12Σ+, 22Σ+, 32Σ+, 12Σ-, 22Σ-, 32Σ-, 12Δ, 22Δ, 32Δ, 12Φ, 14Σ+, a4Σ-, 24Σ-, 14Π, 24Π and 14Δ), which originated from the two lowest dissociation channels of ClO radical. The calculations were done for internuclear separations approximately from 0.08 to 1.10 nm using the CASSCF method, which was followed by the icMRCI approach with the aug-cc-pV5Z basis set. Of these 21 states, the 14Π, 24Π, 32Δ, 42Π, 52Π, 12Φ, 32Σ+, 14Δ and 24Σ- states are repulsive. The 12Δ, 12Σ-, 14Σ+, 22Σ-, 12Σ+, 22Σ+, 22Δ and 32Σ- states are very weakly bound. Only the A2Π state has one barrier. The avoided crossing exists between the A2Π and the 32Π state. However, the avoided crossing does not generate any double wells. Core- valence correlation correction was accounted for at the level of an aug-cc-pCVQZ basis set. Scalar relativistic correction was included by the third-order Douglas-Kroll Hamiltonian approximation at the level of an aug-cc-pVQZ basis set. All the potential energy curves were extrapolated to the complete basis set limit. The spectroscopic parameters were determined. The 12Σ-, 22Σ-, 32Σ- and 14Σ+ states may be very difficult to be detected in an experiment, since each of these Λ-S states has only one or two vibrational states. The Franck-Condon factors and radiative lifetimes were calculated for several low vibrational levels of the A2Π - X2Π, 32Π - a4Σ-, 22Δ - a4Σ- and 32Σ- - 12Σ- transitions. The spin-orbit coupling effect on the spectroscopic parameters of the X2Π, A2Π, 32Π, a4Σ- and 22Σ+ states were discussed. The spectroscopic properties reported here can be expected to be reliably predicted ones.

  18. Spectroscopic properties of Sm3+ doped sodium-tellurite glasses: Judd-Ofelt analysis

    Science.gov (United States)

    Mawlud, Saman Q.; Ameen, Mudhafar M.; Sahar, Md. Rahim; Mahraz, Zahra Ashur Said; Ahmed, Kasim F.

    2017-07-01

    Modifying the optical response of rare earth doped inorganic glasses for diverse optical applications is the current challenge in materials science and technology. We report the enhancement of the visible emissions of the Sm3+ ions doped sodium-tellurite (TNS) glasses. The impacts of varying Sm3+ ions concentration on the spectroscopic properties of such glass samples are evaluated. Synthesized glass samples are characterized via emission and absorption measurements. The UV-Vis-NIR absorption spectra revealed nine absorption peaks which are assigned to the transitions from the ground level (6H5/2) to 6P3/2, 4I11/2, 6F11/2, 6F9/2, 6F7/2, 6F5/2, 6F3/2, 6H15/2 and 6F1/2 excited energy levels of Sm3+ ions. Emission spectra of the prepared glass under 404 nm excitation wavelength consisted of four bands centered at 561 nm, 598 nm, 643 nm and 704 nm which are originated from 4G5/2→6HJ (J = 5/2, 7/2, 9/2 and 11/2) transitions. The experimental oscillator strengths, fexp are calculated from the area under absorption bands. Using Judd-Ofelt theory and fit process of least square, the phenomenological intensity parameters Ωλ (λ = 2, 4, 6) are obtained. In order to evaluate potential applications of Sm3+ ions in telluride glasses, the spectroscopic parameters: radiative transition probability AR, branching ratio BR, radiative life time τr and stimulated emission cross section σλ for each band are calculated. These glass compositions could be a potential candidate for lasers.

  19. Effect of Network Modifiers on Spectroscopic Properties of Erbium-doped Phosphate Glasses

    Institute of Scientific and Technical Information of China (English)

    YANG Gangfeng; JIANG Zhonghong; DENG Zaide; YIN Bing; YING Tingzhao; FENG Zhouming

    2005-01-01

    The integrated absorption cross section Σabs, peak emission cross section σemi, Judd-Ofeld intensity parameters Ωt(t=2,4,6), and spontaneous emission probability AR of Er3+ ions were determined for Erbium doped alkali and alkaline earth phosphate glasses. It is found the compositional dependence of σemi is almost similar to that of Σabs, which is determined by the sum of Ωt (3Ω2+10Ω4+21Ω6). In addition, the compositional dependence of Ωt was studied in these glass systems. As a result, compared with Ω4 and Ω6, the Ω2 has a stronger compositional dependence on the ionic radius and content of modifiers. The covalency of Er-O bonds in phosphate glass is weaker than that in silicate glass, germanate glass, aluminate glass, and tellurate glass, since Ω6 of phosphate glass is relatively large. AR is affected by the covalency of the Er3+ ion sites and corresponds to the Ω6 value.

  20. Spectroscopic properties of transparent Er-doped oxyfluoride glass-ceramics with GdF₃.

    Science.gov (United States)

    Środa, Marcin; Szlósarczyk, Krzysztof; Różański, Marek; Sitarz, Maciej; Jeleń, Piotr

    2015-01-05

    Optically active glass-ceramics (GC) with the low-phonon phases of fluorides, doped with Er(3+) was studied. Glass based on SiO₂-Al₂O₃-Na₂F₂-Na₂O-GdF₃-BaO system was obtained. Dopant were introduced to the glass in an amount of 0.01 mol Er₂O₃ per 1 mol of glass. DTA/DSC study shows multi-stage crystallization. XRD identification of obtained phases did not confirm the presence of pure GdF₃ phase. Instead of that ceramization process led to formation of NaGdF₄ and BaGdF₅. The structural changes were studied using FT-IR spectroscopic method. The study of luminescence of the samples confirmed that optical properties of the obtained GC depend on crystallizing phases during ceramization. Time resolved spectroscopy of Er-doped glass showed the 3 and 8 times increase of lifetime of emission from (4)S₃/₂ and (4)F₉/₂ states, respectively. It confirms the erbium ions have ability to locate in the low phonon gadolinium-based crystallites. The results give possibility to obtain a new material for optoelectronic application.

  1. Fluoxetine and Norfluoxetine Revisited: New Insights into the Electrochemical and Spectroscopic Properties

    Science.gov (United States)

    Garrido, E. Manuela; Garrido, Jorge; Calheiros, Rita; Marques, M. Paula M.; Borges, Fernanda

    2009-08-01

    The extent to which humans and wildlife are exposed to the vast array of anthropogenic chemicals and their degradation products, along with related naturally occurring compounds, is nowadays an important issue. The study of the physical-chemical properties of the compounds and/or degradation products is an important subject because some of them are intrinsically related to its resistance to degradation and/or bioaccumulation. Accordingly, the study of the electrochemical behavior of the selective serotonin reuptake inhibitor fluoxetine and its main metabolite norfluoxetine was investigated. The identification of the oxidation processes was done via two fluoxetine analogues, 1-(benzyloxy)-4-(trifluoromethyl)benzene and N-methyl-3-phenylpropan-1-amine hydrochloride. The oxidative processes occurring in fluoxetine are pH-dependent and were ascribed to the chemical moieties present in the molecule: the secondary amine group and the substituted aromatic nucleus. To perform an unequivocal ascription, the structural preferences of the drug and metabolite were also determined, by Raman spectroscopy coupled to quantum mechanical calculations (at the DFT level). The analytical data obtained in this work will allow the development of a rapid and unequivocal spectroscopic procedure suitable for fluoxetine identification, as well as to distinguish between the drug and its main metabolite.

  2. The Biophysical Probes 2-fluorohistidine and 4-fluorohistidine: Spectroscopic Signatures and Molecular Properties

    Science.gov (United States)

    Kasireddy, Chandana; Ellis, Jonathan M.; Bann, James G.; Mitchell-Koch, Katie R.

    2017-02-01

    Fluorinated amino acids serve as valuable biological probes, by reporting on local protein structure and dynamics through 19F NMR chemical shifts. 2-fluorohistidine and 4-fluorohistidine, studied here with DFT methods, have even more capabilities for biophysical studies, as their altered pKa values, relative to histidine, allow for studies of the role of proton transfer and tautomeric state in enzymatic mechanisms. Considering the two tautomeric forms of histidine, it was found that 2-fluorohistidine primarily forms the common (for histidine) τ-tautomer at neutral pH, while 4-fluorohistidine exclusively forms the less common π-tautomer. This suggests the two isomers of fluorohistidine can also serve as probes of tautomeric form within biomolecules, both by monitoring NMR chemical shifts and by potential perturbation of the tautomeric equilibrium within biomolecules. Fluorine also enables assignment of tautomeric states in crystal structures. The differences in experimental pKa values between the isomers was found to arise from solvation effects, providing insight into the polarization and molecular properties of each isomer. Results also encompass 13C and 19F NMR chemical shifts, from both tautomers of 2-fluorohistidine and 4-fluorohistidine in a number of different environments. This work can serve as a guide for interpretation of spectroscopic results in biophysical studies employing 2-fluorohistidine and 4-fluorohistidine.

  3. Synthesis and spectroscopic properties of homo- and heterobimetallic complexes of oxovanadium(V)

    Indian Academy of Sciences (India)

    Rajendra S Ghadwal; Anirudh Singh

    2006-03-01

    Equimolar interaction of VO(OPri)3 with N-phenyldiethanolamine (H2L) affords the dimeric complex [VO(L)(-OPri)]2 (1), which on reaction with different glycols yields a new class of oxovanadium(V) complexes of the type: VO(L)(OGOH) (where L = C6H5N(CH2CH2O-)2 and G = G1 (CMe2CH2CH2CMe2) 2, G2(CHMeCH2CMe2) 3, G3(CH2CMe2CH2) 4, G4(CH2CEt2CH2) 5, G5(CHMeCHMe) 6, G6(CMe2CMe2) 7), featuring N-phenyldiethanolaminate and glycolate moieties. Complexes (2)-(7) react with Al(OPri)3 to afford novel heterobimetallic coordination complexes of the type: VO(L){(OGO)Al(OPri)2} (G = G1-G6). All these complexes have been characterised by elemental analyses and molecular weight measurements. Spectroscopic (IR, UV-Vis and (1H, 27Al, 51V) NMR) properties of the new complexes have been investigated and their plausible structures suggested.

  4. The Spectr-W3 database on the spectroscopic properties of atoms and ions

    Science.gov (United States)

    Skobelev, I. Yu.; Loboda, P. A.; Gagarin, S. V.; Ivliev, S. V.; Kozlov, A. I.; Morozov, S. V.; Pikuz, S. A.; Pikuz, T. A.; Popova, V. V.; Faenov, A. Ya.

    2016-04-01

    The Spectr-W3 database was developed in 2001-2013 and is available online (http://spectrw3. snz.ru). The database contains information on various spectroscopic constants of atoms and ions such as the wavelengths and probabilities of radiative transitions, energy levels of atoms and ions, ionization potentials, autoionization rates, and the parameters of analytical approximation of cross sections and rates of collisional transitions in atoms and ions. Spectr-W3 presently contains around 450 thousand records and is the world's largest factual database on spectral properties of multicharged ions. A new stage of development of Spectr-W3, which involves adding a new section titled "Emission Spectrograms" to the database, commenced in 2014. In contrast to the already existing sections that contain tabulated data, this new section provides graphical data (with necessary explanatory notes) on the spectrograms of emission of atoms and ions excited in various plasma sources. The structure of sections of the Spectr-W3 database is characterized, and examples of queries and the corresponding search results are given.

  5. Spectroscopic properties of Er{sup 3+}-doped antimony oxide glass

    Energy Technology Data Exchange (ETDEWEB)

    Ouannes, K.; Soltani, M.T. [Laboratoire de Physique Photonique et Nanomatériaux Multifonctionnels, Université de Biskra, BP 145 RP, 07000 Biskra (Algeria); Poulain, M. [UMR 6226 – Verres et Céramiques – Campus de Beaulieu, Université' de Rennes 1, 35042 Rennes (France); Boulon, G.; Alombert-Goget, G.; Guyot, Y.; Pillonnet, A. [Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne (France); Lebbou, K., E-mail: kheireddine.lebbou@univ-lyon1.fr [Institut Lumière Matière, UMR 5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne (France)

    2014-08-01

    Highlight: • As a function of Er concentration, glasses corresponding to the 60Sb{sub 2}O{sub 3}–20WO{sub 3}–(19 − x) Na{sub 2}O–1Bi{sub 2}O{sub 3}, xEr{sub 2}O{sub 3} formula were prepared. The quantum efficiency shows that this glass could be promised for laser devices. - Abstract: Spectroscopic properties of Er{sup 3+} ions have been studied in the 60Sb{sub 2}O{sub 3}–20WO{sub 3}–19Na{sub 2}O–1Bi{sub 2}O{sub 3} (SWNB) glasses doped with 0.25 and 0.50 mol% Er{sub 2}O{sub 3} respectively. The Judd–Ofelt parameters measured from the absorption spectra have been used to calculate the radiative life-time (τ{sub r}) and the stimulated emission cross section. The low phonon energy, a reduced quenching effect and a high quantum efficiency of 90% for the 1.53 μm expected laser emission into pumping at 980 nm are in favor of promising material laser application.

  6. Spectroscopic mapping of the physical properties of supernova remnant N\\,49

    CERN Document Server

    Pauletti, Diogo

    2016-01-01

    Physical conditions inside a supernova remnant can vary significantly between different positions. However, typical observational data are integrated data or contemplate specific portions of the remnant. We study the spatial variation in the physical properties of the N\\,49 supernova remnant based on a spectroscopic mapping of the whole nebula. Long-slit spectra were obtained with the slit ($\\sim4\\arcmin \\times 1.03\\arcsec$) aligned along the east-west direction from 29 different positions spaced by $2\\arcsec$ in declination. A total of 3248 1D spectra were extracted from sections of $2\\arcsec$ of the 2D spectra. More than 60 emission lines in the range 3550\\,\\AA{} to 8920\\,\\AA{} were measured in these spectra. Maps of the fluxes and of intensity ratios of these emission lines were built with a spatial resolution of $2\\arcsec \\times 2\\arcsec$. An electron density map has been obtained using the [S\\,{\\sc ii}]\\,$\\lambda6716/\\lambda6731$ line ratio. Values vary from $\\sim$500\\,cm$^{-3}$ at the northeast region t...

  7. Effect of helium nanoclusters on the spectroscopic properties of embedded SF6: Ionization, excitation and vibration

    Science.gov (United States)

    Dehdashti-Jahromi, M.; Farrokhpour, H.

    2017-02-01

    Ionization and excitation energies, IR and Raman spectra of sulfur hexafluoride (SF6), located inside helium (He) nanoclusters with different sizes (SF6@Hen; n = 20, 40, 60), were calculated. The effect of the cluster size on the spectroscopic properties of the SF6 was investigated and found that the Hen-SF6 interaction in the He clusters with large number of atoms is small so that the ionization and absorption energies of SF6 are not affected while for small He nanoclusters the Hen-SF6 interaction is more important. The effect of Hen-SF6 interaction and deformation of the fragments on the photoelectron and absorption spectra of SF6@Hen were separated theoretically and discussed in details. It was deduced that the effect of the cluster size on the IR and Raman vibrational frequencies of the SF6 is negligible for the cluster size range considered in this work. Density functional theory (DFT) employing M06-2X functional and 6-31 + G(df) basis set were used for optimizing the structures of SF6@Hen. Symmetry adapted cluster-configuration interaction (SAC-CI) methodology, with the same basis set, were used to calculate the ionization and excitation energies of the SF6@Hen structures. Using the calculated ionization and absorption energies and their intensities, the photoelectron and absorption spectra of the considered SF6@Hen structures were simulated and compared with the experiment.

  8. Spectroscopic properties of doped and defective semiconducting oxides from hybrid density functional calculations.

    Science.gov (United States)

    Di Valentin, Cristiana; Pacchioni, Gianfranco

    2014-11-18

    CONSPECTUS: Very rarely do researchers use metal oxides in their pure and fully stoichiometric form. In most of the countless applications of these compounds, ranging from catalysis to electronic devices, metal oxides are either doped or defective because the most interesting chemical, electronic, optical, and magnetic properties arise when foreign components or defects are introduced in the lattice. Similarly, many metal oxides are diamagnetic materials and do not show a response to specific spectroscopies such as electron paramagnetic resonance (EPR) spectroscopy. However, doped or defective oxides may exhibit an interesting and informative paramagnetic behavior. Doped and defective metal oxides offer an expanding range of applications in contemporary condensed matter science; therefore researchers have devoted enormous effort to the understanding their physical and chemical properties. The interplay between experiment and computation is particularly useful in this field, and contemporary simulation techniques have achieved high accuracies with these materials. In this Account, we show how the direct comparison between spectroscopic experimental and computational data for some selected and relevant materials provides ways to understand and control these complex systems. We focus on the EPR properties and electronic transitions that arise from the presence of dopants and defects in bulk metal oxide materials. We analyze and compare the effect of nitrogen doping in TiO2 and ZnO (two semiconducting oxides) and MgO (a wide gap insulator) and examine the effect of oxygen deficiency in the semiconducting properties of TiO2-x, ZnO1-x, and WO3-x materials. We chose these systems because of their relevance in applications including photocatalysis, touch screens, electrodes in magnetic random access memories, and smart glasses. Density functional theory (DFT) provides the general computational framework used to illustrate the electronic structure of these systems. However

  9. Modulation of the spectroscopic property of Bodipy derivates through tuning the molecular configuration.

    Science.gov (United States)

    Chen, Yuting; Wan, Liang; Zhang, Daopeng; Bian, Yongzhong; Jiang, Jianzhuang

    2011-06-01

    A series of six Bodipy derivatives, namely 4,4-difluoro-8-(4-amidophenyl)-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (1), 4,4-difluoro-8-(4-methylphenyl)-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (2), 4,4-difluoro-8-(4-nitrylphenyl)-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (3), 4,4-difluoro-8-(4-amidophenyl)-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene (4), 4,4-difluoro-8-(4-methylphenyl)-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene (5), and 4,4-difluoro-8-(4-nitrylphenyl)-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene (6) were structurally characterized by single crystal X-ray diffraction analysis. Two methyl substituents attached at C-1 and C-7 positions of boron-dipyrromethene (Bodipy) moiety in compounds 1-3 were revealed to prevent the free rotation of the benzene moiety, resulting in a molecular configuration with an almost orthogonal dihedral angle between the Bodipy and benzene moieties with the dihedral angle in the range of 81.14-88.56°. This is obviously different from that for 4-6 with a free-rotating benzene moiety relative to the Bodipy core due to the lack of two methyl substituents in the latter series of compounds, leading to an enhanced interaction between the Bodipy and benzene moieties for 4-6 in comparison with 1-3. The resulting larger HOMO-LUMO gap for 1-3 than 4-6 results in a blue-shifted absorption band for 1-3 relative to that for 4-6. Comparative studies over their fluorescence properties also disclose the blue-shifted fluorescence emission band and corresponding higher fluorescence quantum yield for 1-3 relative to those of 4-6, revealing the effect of molecular configuration on the spectroscopic properties of Bodipy derivatives. Comparison of the redox behaviors of these two series of Bodipy compounds provides additional support for this point. In addition, the electron-donating/withdrawing property of the para substituent of the benzene moiety was shown to exhibit a slight influence on the electronic absorption and

  10. Imaging properties of small-pixel spectroscopic x-ray detectors based on cadmium telluride sensors.

    Science.gov (United States)

    Koenig, Thomas; Schulze, Julia; Zuber, Marcus; Rink, Kristian; Butzer, Jochen; Hamann, Elias; Cecilia, Angelica; Zwerger, Andreas; Fauler, Alex; Fiederle, Michael; Oelfke, Uwe

    2012-11-07

    Spectroscopic x-ray imaging by means of photon counting detectors has received growing interest during the past years. Critical to the image quality of such devices is their pixel pitch and the sensor material employed. This paper describes the imaging properties of Medipix2 MXR multi-chip assemblies bump bonded to 1 mm thick CdTe sensors. Two systems were investigated with pixel pitches of 110 and 165 μm, which are in the order of the mean free path lengths of the characteristic x-rays produced in their sensors. Peak widths were found to be almost constant across the energy range of 10 to 60 keV, with values of 2.3 and 2.2 keV (FWHM) for the two pixel pitches. The average number of pixels responding to a single incoming photon are about 1.85 and 1.45 at 60 keV, amounting to detective quantum efficiencies of 0.77 and 0.84 at a spatial frequency of zero. Energy selective CT acquisitions are presented, and the two pixel pitches' abilities to discriminate between iodine and gadolinium contrast agents are examined. It is shown that the choice of the pixel pitch translates into a minimum contrast agent concentration for which material discrimination is still possible. We finally investigate saturation effects at high x-ray fluxes and conclude with the finding that higher maximum count rates come at the cost of a reduced energy resolution.

  11. EuAu3Al2: Crystal and Electronic Structures and Spectroscopic, Magnetic, and Magnetocaloric Properties.

    Science.gov (United States)

    Schmiegel, Jan-Patrick; Block, Theresa; Gerke, Birgit; Fickenscher, Thomas; Touzani, Rachid St; Fokwa, Boniface P T; Janka, Oliver

    2016-09-06

    The intermetallic compound EuAu3Al2 has been prepared by reaction of the elements in tantalum ampules. The structure was refined from single-crystal data, indicating that the title compound crystallizes in the orthorhombic crystal system (a = 1310.36(4), b = 547.87(1), c = 681.26(2) pm) with space group Pnma (wR2 = 0.0266, 1038 F(2) values, 35 parameters) and is isostructural to SrAu3Al2 (LT-SrZn5 type). Full ordering of the gold and aluminum atoms was observed. Theoretical calculations confirm that the title compound can be described as a polar intermetallic phase containing a polyanionic [Au3Al2](δ-) network featuring interconnected strands of edge-sharing [AlAu4] tetrahedra. Magnetic measurements and (151)Eu Mössbauer spectroscopic investigations confirmed the divalent character of the europium atoms. Ferromagnetic ordering below TC = 16.5(1) K was observed. Heat capacity measurements showed a λ-type anomaly at T = 15.7(1) K, in line with the ordering temperature from the susceptibility measurements. The magnetocaloric properties of EuAu3Al2 were determined, and a magnetic entropy of ΔSM = -4.8 J kg(-1) K(-1) for a field change of 0 to 50 kOe was determined. Band structure calculations found that the f-bands of Eu present at the Fermi level of non-spin-polarized calculations are responsible for the ferromagnetic ordering in this phase, whereas COHP chemical bonding coupled with Bader charge analysis confirmed the description of the structure as covalently bonded polyanionic [Au3Al2](δ-) network interacting ionically with Eu(δ+).

  12. Soft X-ray properties of a spectroscopically selected sample of interacting and isolated Seyfert galaxies

    Science.gov (United States)

    Pfefferkorn, F.; Boller, Th.; Rafanelli, P.

    2001-03-01

    We present a catalogue of ROSAT detected sources in the sample of spectroscopically selected Seyfert 1 and Seyfert 2 galaxies of Rafanelli et al. (\\cite{Rafanelli95}). The catalogue contains 102 Seyfert 1 and 36 Seyfert 2 galaxies. The identification is based on X-ray contour maps overlaid on optical images taken from the Digitized Sky Survey. We have derived the basic spectral and timing properties of the X-ray detected Seyfert galaxies. For Seyfert 1 galaxies a strong correlation between photon index and X-ray luminosity is detected. We confirm the presence of generally steeper X-ray continua in narrow-line Seyfert 1 galaxies (NLS1s) compared to broad-line Seyfert 1 galaxies. Seyfert 2 galaxies show photon indices similar to those of NLS1s. Whereas a tendency for an increasing X-ray luminosity with increasing interaction strength is found for Seyfert 1 galaxies, such a correlation is not found for Seyfert 2 galaxies. For Seyfert 1 galaxies we found also a strong correlation for increasing far-infrared luminosity with increasing interaction strength. Both NLS1s and Seyfert 2 galaxies show the highest values of far-infrared luminosity compared to Seyfert 1 galaxies, suggesting that NLS1s and Seyfert 2 galaxies host strong (circumnuclear) star formation. For variable Seyfert galaxies we present the X-ray light curves obtained from the ROSAT All-Sky Survey and from ROSAT PSPC and HRI pointed observations. Besides the expected strong short- and long-term X-ray variability in Seyfert 1 galaxies, we find indications for X-ray flux variations in Seyfert 2 galaxies. All overlays can be retrieved via CDS anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)} or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/368/797

  13. Investigation of optical and spectroscopic properties of Sm3+ ions in CaBAl glasses

    Science.gov (United States)

    Brito, D. R. N.; Queiroz, M. N.; Barboza, M. J.; Steimacher, A.; Pedrochi, F.

    2017-02-01

    Samples of CaBAl glass with composition of (25-x)CaO-50B2O3-15Al2O3-10CaF2-xSm2O3, with Sm2O3 concentration varying from 0.5 to 7 wt%, were prepared by using melt-quenching method in air atmosphere. The samples were prepared with different concentrations of Sm2O3, aiming to understand how the dopant changes the optical and spectroscopic properties of the glass. The doped CaBAl glasses were studied by means of volumetric density measurements, refractive index, optical absorption, luminescence at room temperature, luminescence as function of the temperature and radiative lifetime. All results were discussed in function of Sm2O3 concentration. The measured volumetric density and polarizability showed an increase with Sm2O3 doping. The refractive index showed a small increase due to RE doping, although within the errors. The absorption bands were attributed to Sm3+ transitions from the ground state 6H5/2 to the various excited states. The luminescence spectra present emission bands assigned to the appropriate electronic f-f transitions of Sm3+ ions; there are four emission bands at 565, 602, 649 and 710 nm. The luminescence quenching was observed up to 2 wt% of Sm2O3. The O/R ratio as function of the Sm2O3 concentration showed changes in the symmetry site with addition of Sm2O3. The CIE 1931 diagram presented a reddish-orange shift color with Sm2O3 doping. The luminescence intensity presents a decrease with temperature increase for all studied samples. The experimental lifetime decreases with the increase of Sm2O3, mainly due to ion-ion interaction.

  14. Effects of spin-orbit coupling on the electronic states and spectroscopic properties of diatomic SeS

    Science.gov (United States)

    Chattopadhyaya, Surya; Nath, Abhijit; Das, Kalyan Kumar

    2016-03-01

    The electronic states and spectroscopic properties of selenium monosulfide (78Se32S) have been studied using relativistic configuration interaction methodology that includes effective core potentials of the constituent atoms. Potential energy curves of several spin-excluded (Λ-S) electronic states have been constructed and spectroscopic constants of low-lying bound Λ-S states within 5.1 eV are reported in the first stage of the calculations. In the next stage, the spin-orbit interaction has been incorporated and its effects on the potential energy curves and spectroscopic properties of the species have been investigated in detail. After the inclusion of spin-orbit coupling, the {{{{X}}}{{1}}}{{3}}{Σ }{0+}- is identified as the spin-orbit (Ω) ground state of the species. The transition moments of several important dipole-allowed and spin-forbidden transitions are calculated and the radiative lifetimes of the excited states involved in the respective transitions are computed. Electric dipole moments (μ z) for some low-lying bound Λ-S states as well as a few low-lying spin-orbit states (Ω-states) are also calculated in the present study.

  15. The 67P/Churyumov-Gerasimenko nucleus spectroscopic properties and their evolution over time

    Science.gov (United States)

    Fornasier, S.

    2016-11-01

    different regions of the comet (Pommerol et al., 2015; De Sanctis et al., 2015; Filacchione et al., 2016; Barucci et al. 2016). Thanks to the unprecedented spatial resolution, VIRTIS and OSIRIS instruments have detected the occurrence of water frost close to the morning shadows, putting in evidence the diurnal cycle of water. Seasonal color and spectral variations have also been observed when the comet approached perihelion, indicating that the increasing activity had progressively shed the surface dust, partially showing the underlying ice-rich layer. I will present an overview of the spectroscopic properties of the 67P nucleus and of their diurnal and seasonal variations over time and heliocentric distance.

  16. Investigation of luminescence and spectroscopic properties of Nd3+ions in cadmium alkali borate glasses

    Science.gov (United States)

    Mohan, Shaweta; Thind, Kulwant Singh

    2016-07-01

    Neodymium doped cadmium alkali borate glasses having composition 20CdOsbnd 20R2Osbnd 59.5H3BO3sbnd 0.5Nd2O3; (R = Li, Na and K) were prepared by conventional melt-quenching technique. The amorphous nature of the glasses was confirmed by X-ray diffraction studies. The physical properties such as density, refractive index, molar volume, rare earth ion concentration etc. were determined. Optical absorption and fluorescence spectra were recorded. The Judd-Ofelt theory was applied on the optical absorption spectra of the glasses to evaluate the three phenomenological intensity parameters Ω2, Ω4 and Ω6. These parameters were in turn used to predict the radiative properties such as the radiative transition probability (A), radiative lifetime (τR) and branching ratio (βR) for the fluorescent levels of Nd3+ ion in the present glass series. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Ω4/Ω6), the value of which is in the range of 0.2-1.5, typical for Nd3+ in different laser hosts. The variation of Ω2 with the change in alkali oxide has been attributed to the changes in the asymmetry of the ligand field at the rare earth ion site. The shift of the hypersensitive bands, study of the oscillator strengths and the variation of the spectral profile of the transition 4I9/2 → 4F7/2 + 4S3/2 indicate a maximum covalency of Ndsbnd O bond for glass with potassium ions. From the fluorescence spectra, peak wavelength (λp), effective line widths (Δλeff) and stimulated emission cross-section (σp) have been obtained for the three transitions 4F3/2 → 4I9/2,4F3/2 → 4I11/2 and4F3/2 → 4I13/2 of Nd3+ ion. The relatively high values of σp obtained for Nd3+ in present glass system suggest that these materials can be considered as suitable candidates for laser applications. The glass with potassium ions shows the highest value of the stimulated emission cross-section.

  17. Alkynyl functionalized iminopyridine copper(I) phosphine complexes: Synthesis, spectroscopic characterization and photophysical properties

    Energy Technology Data Exchange (ETDEWEB)

    Jadhav, A.N.; Chavan, S.S., E-mail: sanjaycha2@rediffmail.com

    2014-04-15

    Some copper(I) complexes of type [Cu(L{sub 1})(PPh{sub 3}){sub 2}/(dppe)]X (1a–6a) and [Cu(L{sub 2})(PPh{sub 3}){sub 2}/(dppe)]X (1b–6b) [where L{sub 1}=N-(2-pyridylmethylene)-4-(trimethylsilylethynyl)aniline, L{sub 2}=N-(2-pyridylmethylene)-4-(phenylethynyl)aniline, PPh{sub 3}=triphenylphosphine, dppe=1,2-bis(diphenylphosphino)ethane, and X=ClO{sub 4}{sup −}, BF{sub 4}{sup −} and PF{sub 6}{sup −}] have been prepared and characterized on the basis of their elemental analyses and spectroscopic studies (IR, UV–visible, {sup 1}H NMR and {sup 31}P NMR). The representative complex of the series [Cu(L{sub 2})(PPh{sub 3}){sub 2}]ClO{sub 4}{sup −} (1b) has been characterized by single crystal X-ray diffraction which reveals that in the complex the central copper(I) ion assumes highly distorted-tetrahedral geometry. The UV–visible spectra indicate that the ancillary phosphine ligands significantly perturb the MLCT state of copper(I) complexes. Room temperature luminescence is observed for all copper(I) complexes in dichloromethane solution, indicating that alkynyl functionality on iminopyridine ligands enhances the emission property of copper(I) complexes and varies considerably with ancillary phosphine ligands. The thermal behavior of complexes revealed that copper(I) complexes with dppe ligand are thermally more stable than PPh{sub 3} complexes. All the complexes exhibit a quasireversible redox behavior corresponding to Cu(I)/Cu(II) couple and are sensitive to phosphine ligand. -- Highlights: • Synthesis of copper(I) complexes of alkynyl functionalized Schiff base. • Characterization by elemental analyses, IR, {sup 1}H NMR and {sup 31}P NMR spectral studies. • Electrochemical properties indicate a quasireversible redox behavior for all copper(I) complexes • All the copper(I) complexes exhibit intraligand (π→π{sup ⁎}) luminescence in dichloromethane.

  18. Fabrication and spectroscopic properties of transparent Nd3+:MgO and Er3+:MgO ceramics

    Science.gov (United States)

    Sanamyan, T.; Cooper, C.; Gilde, G.; Sutorik, A. C.; Dubinskii, M.

    2014-06-01

    We present the results of the development and comprehensive characterization of fully densified Er3+:MgO and Nd3+:MgO transparent ceramics fabricated from specially formulated nanopowders. Also presented are the spectroscopic characterization results (absorption, fluorescence and emission lifetimes) of Er3+ and Nd3+ dopant ions in MgO in the temperature range 10 to 300 K. To the best of our knowledge, this is the first reported successful demonstration of bulk MgO host material doped with rare earth (RE) ions. Spectroscopic results are indicative of a single-site RE ion incorporation with a nearly perfect single crystalline environment within the MgO ceramic grains. The results are presented with major emphasis on potential laser application and the outlook for substantially improved laser power scaling at room temperature based on the unique thermal properties of the host material.

  19. Composition dependent phase transition and its induced hysteretic effect in the thermal conductivity of WxMo1-xTe2

    Science.gov (United States)

    Yan, Xue-Jun; Lv, Yang-Yang; Li, Lei; Li, Xiao; Yao, Shu-Hua; Chen, Yan-Bin; Liu, Xiao-Ping; Lu, Hong; Lu, Ming-Hui; Chen, Yan-Feng

    2017-05-01

    Recently, transition metal dichalcogenide (TMD) materials have shown promise in electronics and optoelectronics applications. Most of their properties are closely related to their abundant structural phases and phase transitions. For more practical applications in the future, it is necessary to tune the phase transitions in this material system. Here, we demonstrate the modulation of phase transitions in miscible WxMo1-xTe2 samples by appropriate alloying. The temperature dependent thermal conductivity along the c-axis, which strongly relates to the phase structures and the defect level, has been measured using the time-domain thermoreflectance method. In addition, a tunable hysteretic effect, induced by phase transitions, is observed in both thermal and electrical transport properties and confirmed by the consistent hysteresis in the Raman spectroscopic study. This hysteretic effect can be applied to realize phase-change storage devices. Furthermore, we provide a phase diagram to illustrate the composition dependent phase transition in WxMo1-xTe2. This work demonstrates an approach to modulate phase transition and thermal hysteresis in such a TMD material system by alloying engineering.

  20. Spectroscopic properties of Er{sup 3+} ions in multicomponent tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sajna, M.S.; Thomas, Sunil; Ann Mary, K.A.; Joseph, Cyriac; Biju, P.R.; Unnikrishnan, N.V., E-mail: nvu100@yahoo.com

    2015-03-15

    In the present work, multicomponent tellurite glasses were elaborated by the melt quench technique with different concentrations of Er{sup 3+} ions. Amorphous nature of all the glasses was confirmed using X-ray diffraction patterns. The thermal parameters, such as glass transition temperature (T{sub g}) and the onset of crystallization temperature (T{sub X}), were determined by the differential scanning calorimetry. Judd–Ofelt parameters were derived for 0.5 mol% Er{sup 3+}-doped glass from the absorption measurements, and in turn, used to find the radiative properties of {sup 4}S{sub 3/2}, {sup 2}H{sub 11/2} and {sup 4}I{sub 11/2} levels of Er{sup 3+} ion. A green emission corresponding to {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} and {sup 2}H{sub 11/2}→{sup 4}I{sub 15/2} transitions of Er{sup 3+} ions was observed in the glasses under investigation. Efficient green upconversion luminescence was observed under 976 nm excitation. The emission bands centered at 529 and 543 nm confirmed that two photons contribute to the upconversion processes. We have also analyzed the dependence of downconversion as well as upconversion as a function of Er{sup 3+} ion concentration, which shows quenching of photoluminescence intensity above 0.5 mol% doping. From the emission spectra, CIE color coordinates of 0.5 mol% Er{sup 3+}-doped glass was examined. Fluorescence decay curves for the {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} transition for all the doped glasses have been measured and analyzed. Absorption cross-section and calculated emission cross-section, using the McCumber method, for the {sup 4}I{sub 13/2}↔{sup 4}I{sub 15/2} transitions were evaluated and discussed. - Highlights: • Multicomponent tellurite glasses were fabricated for laser applications. • Spectroscopic parameters were evaluated using Judd–Ofelt theory. • Effects of Er{sup 3+} concentration on luminescence of the glasses were studied. • Efficient green upconversion mechanism was discussed. • CIE

  1. Spectroscopic properties of Sm3 + ions doped Alkaliborate glasses for photonics applications

    Science.gov (United States)

    Nagaraj, R.; Suthanthirakumar, P.; Vijayakumar, R.; Marimuthu, K.

    2017-10-01

    A new series of Sm3 + doped alkaliborate glasses have been prepared by melt quenching technique and their structural and spectroscopic properties were analysed employing XRD, FTIR, optical absorption, photoluminescence and decay spectral measurements in order to explore their suitability for photonic applications. The amorphous nature have been confirmed through XRD analysis and the FTIR spectra reveal the presence of fundamental stretching and bending vibrations of the borate networks in the prepared glasses. From the absorption peak positions, bonding parameter (δ) values were calculated to examine the nature of the metal-ligand bond. The optical band gap (Eopt) corresponds to the direct and indirect allowed transitions and the Urbach energies (ΔE) were calculated from the absorption spectra to understand the electronic band structure of the studied glasses. The Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4 and 6) were determined to explore the symmetry of the ligand environment around the Sm3 + ions in the studied glasses. The luminescence spectra exhibit four emission bands in the visible region due to the 4G5/2 → 6H5/2, 6H7/2, 6H9/2 and 6H11/2 transitions. The radiative parameters such as transition probability (A), stimulated emission cross-section (σPE), branching ratios (βR) and radiative lifetime (τR) have been determined from the luminescence spectra using JO theory to ensure the suitability of the studied glasses for optoelectronic applications. The luminescence spectra were characterized through CIE 1931 chromaticity diagram to examine the dominant emission color of the studied glasses. The lifetime values of the Sm3 + doped studied glasses pertaining to the 4G5/2 excited level have been determined through decay curve measurements and the non-exponential decay curves were fitted to the Inokuti-Hirayama model to analyze the energy transfer mechanism between the nearby Sm3 + ions. The obtained results were discussed and compared with the

  2. Photoelectrochemical sensitization and spectroscopic properties of reduced and oxidized forms of a chlorophyll analogue

    Energy Technology Data Exchange (ETDEWEB)

    Kamat, P.V. (Notre Dame Univ., IN (USA). Radiation Lab.); Chauvet, J.-P. (Notre Dame Univ., IN (USA). Radiation Lab. Ecole Normale Superieure, Lyon (France))

    1991-01-01

    The photoelectrochemical sensitization of a large bandgap semiconductor has been achieved via excitation of a sensitizer, chlorophyllin (CPLN). The redox states that control the net charge transfer are characterized by pulse radiolysis. The spectroscopic and kinetic details of the pulse radiolytically generated CPLN{sup .+} and CPLN{sup .-} are reported. (author).

  3. Composition dependent room temperature structure, electric and magnetic properties in magnetoelectric Pb(Fe{sub 1/2}Nb{sub 1/2})O{sub 3}−Pb(Fe{sub 2/3}W{sub 1/3})O{sub 3} solid-solutions

    Energy Technology Data Exchange (ETDEWEB)

    Matteppanavar, Shidaling [Department of Physics, Jnanabharathi Campus, Bangalore University, Bangalore, 560056 (India); Rayaprol, Sudhindra [UGC-DAE-Consortium for Scientific Research, Mumbai Centre, B A R C Campus, Mumbai, 400085 (India); Angadi, Basavaraj, E-mail: brangadi@gmail.com [Department of Physics, Jnanabharathi Campus, Bangalore University, Bangalore, 560056 (India); Sahoo, Balaram [Materials Research Centre, Indian Institute of Science, Bangalore, 560012 (India)

    2016-08-25

    Fe in 3+ state and on increasing x, the spectra changes from doublet to sextet. The ferroelectric (P-E) study confirms the existence of ferroelectric ordering with leaky behaviour. The reasonable ferroelectric loops with antiferromagnetic properties indicate samples with x = 0.2–0.6 show good magnetoelectric characteristics and may find applications in multiferroics. - Highlights: • RT neutron diffraction studies on PFN{sub 1−x}-PFW{sub x} (x = 0.0 to1.0) multiferroics. • Composition dependent changes in nuclear and magnetic structure. • On increasing x, system exhibit a gradual phase transition from monoclinic to cubic. • Supporting Raman, magnetic, Mössbauer and ferroelectric studies. • Augmentation of Néel temperature (T{sub N}) from 155 K to 350 K on increasing x.

  4. Spectroscopic and laser properties of SrMoO4:Tm3+ crystal under 1700-nm laser diode pumping

    Science.gov (United States)

    Doroshenko, M. E.; Papashvili, A. G.; Dunaeva, E. E.; Ivleva, L. I.; Osiko, V. V.; Jelinkova, H.; Sulc, J.; Nemec, M.

    2016-10-01

    Spectroscopic and laser properties of Tm3+ ions under 1700 nm excitation in SrMoO4 crystal are investigated. Negligible effect of cross-relaxation process (3H4sbnd 3F4, 3H6sbnd 3F4) on population of 3F4 level for thulium concentrations up to 0.25 at.% was demonstrated. Efficient lasing with slope efficiency up to 18% and broadband (over 100 nm) tuning at room temperature under 1700 nm diode pumping were obtained.

  5. Theoretical studies on the spectroscopic properties and the substituent effects of pyridyl triazole Os(Ⅱ) complexes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    To explore the spectroscopic properties of pyridyl triazole Os(Ⅱ) complexes and how the substituent effects affect the spectroscopic properties of [Os(ptz)2L2] (L=PH3; ptzH=(2-pyridyl)-1,2,4-triazole) (1), [Os(bptz)2L2] (bptzH=3-tert-butyl-5-(2-pyridyl)-1,2,4-triazole) (2), [Os(fptz)2L2] (fptzH=3- (trifluoreomethyl)- 5-(2-pyridyl)-1,2,4-triazole) (3), and [Os(fbtz)2L2] (fbtzH=3-(trifluoreomethyl)-5-(4-tert-butyl- 2-pyridyl)-1,2, 4-triazole) (4), the density functional theory (DFT) method at the B3LYP level was used to optimize the geometrical structures in the ground and excited state. The absorption and emission properties of the dichloromethane solution were predicted at the time-dependent density functional theory (TD-DFT, B3LYP) level associated with the PCM solvent effect model, the transitions characters of them were assigned. Important correlations between substituent effects and emission spectra and the quantum yield have been obtained by comparing and analyzing the calculated results.

  6. Theoretical studies on the spectroscopic properties and the substituent effects of pyridyl triazole Os(Ⅱ)complexes

    Institute of Scientific and Technical Information of China (English)

    WU Yu-Hui; ZHOU Xin; ZHANG Hong-Xing

    2009-01-01

    To explore the spectroscopic properties of pyridyl triazole Os(Ⅱ) complexes and how the substituent effects affect the spectroscopic properties of [Os(ptz)2L2] (L=PH3; ptzH=(2-pyridyl)-1,2,4-triazole) (1), [Os(bptz)2L2] (bptzH=3-tert-butyl-5-(2-pyridyl)-1,2,4-triazole) (2), [Os(fpt2)L2] (fptzH=3-(trifluoreomethyl)-5-(2-pyridyl)-1,2,4-triazole) (3), and [Os(fbtz)2L2] (fbtzH=3-(trifluoreomethyl)-5-(4-tert-butyl- 2-pyridyl)-1,2, 4-triazole) (4), the density functional theory (DFT) method at the B3LYP level was used to optimize the geometrical structures in the ground and excited state. The absorption and emission properties of the dichloromethane solution were predicted at the time-dependent density functional theory (TD-DFT, B3LYP) level associated with the PCM solvent effect model, the transitions characters of them were assigned. Important correlations between substituent effects and emission spectra and the quantum yield have been obtained by comparing and analyzing the calculated results.

  7. Structural and spectroscopic properties of the peroxodiferric intermediate of Ricinus communis soluble Δ9 desaturase.

    Science.gov (United States)

    Srnec, Martin; Rokob, Tibor András; Schwartz, Jennifer K; Kwak, Yeonju; Rulíšek, Lubomír; Solomon, Edward I

    2012-03-05

    Large-scale quantum and molecular mechanical methods (QM/MM) and QM calculations were carried out on the soluble Δ(9) desaturase (Δ(9)D) to investigate various structural models of the spectroscopically defined peroxodiferric (P) intermediate. This allowed us to formulate a consistent mechanistic picture for the initial stages of the reaction mechanism of Δ(9)D, an important diferrous nonheme iron enzyme that cleaves the C-H bonds in alkane chains resulting in the highly specific insertion of double bonds. The methods (density functional theory (DFT), time-dependent DFT (TD-DFT), QM(DFT)/MM, and TD-DFT with electrostatic embedding) were benchmarked by demonstrating that the known spectroscopic effects and structural perturbation caused by substrate binding to diferrous Δ(9)D can be qualitatively reproduced. We show that structural models whose spectroscopic (absorption, circular dichroism (CD), vibrational and Mössbauer) characteristics correlate best with experimental data for the P intermediate correspond to the μ-1,2-O(2)(2-) binding mode. Coordination of Glu196 to one of the iron centers (Fe(B)) is demonstrated to be flexible, with the monodentate binding providing better agreement with spectroscopic data, and the bidentate structure being slightly favored energetically (1-10 kJ mol(-1)). Further possible structures, containing an additional proton or water molecule are also evaluated in connection with the possible activation of the P intermediate. Specifically, we suggest that protonation of the peroxide moiety, possibly preceded by water binding in the Fe(A) coordination sphere, could be responsible for the conversion of the P intermediate in Δ(9)D into a form capable of hydrogen abstraction. Finally, results are compared with recent findings on the related ribonucleotide reductase and toluene/methane monooxygenase enzymes.

  8. The K20 survey. VII. The spectroscopic catalogue: spectral properties and evolution of the galaxy population

    CERN Document Server

    Mignoli, M; Zamorani, G; Pozzetti, L; Daddi, E; Renzini, A; Broadhurst, T J; Cristiani, S; D'Odorico, S; Fontana, A; Giallongo, E; Gilmozzi, R; Menci, N; Saracco, P

    2005-01-01

    The K20 survey is a near infrared-selected, deep (Ks < 20) redshift survey targeting galaxies in two independent regions of the sky, the CDFS and the q0055-2659 field. The total Ks-selected sample includes 545 objects. Optical spectra for 525 of them have been obtained, providing 501 spectroscopic identifications (including 12 type-1 AGN and 45 stars). This paper describes the final K20 spectroscopic catalogue, along with the technique used to determine redshifts, measure the spectral features and characterize the spectra. The classification of the galaxy spectra has been performed according to a simple parametric recipe that uses the equivalent widths of the two main emission lines (O[II] and Halpha+[N II]) and two continuum indices (the 4000A break index, and a near-UV color index, C(28-39)). We defined three main spectroscopic classes: red early-type galaxies, blue emission-line galaxies and the intermediate galaxies, which show emission lines but a red continuum. More than 95% of the examined galaxies ...

  9. Spectroscopic and second-order nonlinear optical properties of Ruthenium(ii) complexes: a DFT/MRCI and ADC(2) study.

    Science.gov (United States)

    Escudero, Daniel; Thiel, Walter; Champagne, Benoît

    2015-07-15

    In this communication we use the density functional theory-based multi-reference configuration interaction (DFT/MRCI) and the second-order algebraic diagrammatic construction (ADC(2)) methods to compute the spectroscopic and second-order nonlinear optical (NLO) properties of Ru(ii)-based NLO-phores. For some of the complexes, an appropriate treatment of doubly excited states is essential to correctly describe their spectroscopic and photochemical properties. Geometrical and solvent relaxation effects are also assessed. An adequate treatment of solvent effects seems critical for an accurate description of the NLO properties of these complexes.

  10. Spectroscopic mapping of the physical properties of supernova remnant N 49

    Science.gov (United States)

    Pauletti, D.; Copetti, M. V. F.

    2016-10-01

    Context. Physical conditions inside a supernova remnant can vary significantly between different positions. However, typical observational data of supernova remnants are integrated data or contemplate specific portions of the remnant. Aims: We study the spatial variation in the physical properties of the N 49 supernova remnant based on a spectroscopic mapping of the whole nebula. Methods: Long-slit spectra were obtained with the slit (~4' × 1.03″) aligned along the east-west direction from 29 different positions spaced by 2″ in declination. A total of 3248 1D spectra were extracted from sections of 2″ of the 2D spectra. More than 60 emission lines in the range 3550 Å to 8920 Å were measured in these spectra. Maps of the fluxes and of intensity ratios of these emission lines were built with a spatial resolution of 2″ × 2″. Results: An electron density map has been obtained using the [S II] λ6716 /λ6731 line ratio. Values vary from ~500 cm-3 at the northeast region to more than 3500 cm-3 at the southeast border. We calculated the electron temperature using line ratio sensors for the ions S+, O++, O+, and N+. Values are about 3.6 × 104 K for the O++ sensor and about 1.1 × 104 K for other sensors. The Hα/Hβ ratio map presents a ring structure with higher values that may result from collisional excitation of hydrogen. We detected an area with high values of [N II] λ6583/Hα extending from the remnant center to its northeastern border, which may be indicating an overabundance of nitrogen in the area due to contamination by the progenitor star. We found a radial dependence in many line intensity ratio maps. We observed an increase toward the remnant borders of the intensity ratio of any two lines in which the numerator comes before in the sequence [O III] λ5007, [O III] λ4363, [Ar III] λ7136, [Ne III] λ3869, [O II] λ7325, [O II] λ3727, He II λ4686, Hβ λ4861, [N II] λ6583, He I λ6678, [S II] λ6731, [S II] λ6716, [O i] λ6300, [Ca II]

  11. Luminescence and spectroscopic properties of Sm{sup 2+} and Er{sup 3+} doped SrI{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Alekhin, Mikhail S.; Awater, Roy H.P. [Faculty of Applied Sciences, Department RST-FAME, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Biner, Daniel A.; Krämer, Karl W. [Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern (Switzerland); Haas, Johan T.M. de [Faculty of Applied Sciences, Department RST-FAME, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Dorenbos, Pieter, E-mail: P.Dorenbos@tudelft.nl [Faculty of Applied Sciences, Department RST-FAME, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

    2015-11-15

    The scintillation and luminescence properties of SrI{sub 2}:1% Sm{sup 2+} and SrI{sub 2}:1% Er{sup 3+} are reported. Single crystals were grown by the vertical Bridgman technique. Broad band Sm{sup 2+} 5d–4f emission was observed centered at 750 nm with a radiative lifetime of 1.25 µs. The photoluminescence decay time increases with temperature due to self-absorption. With Er{sup 3+} a clear charge transfer band was identified at 295 nm. The spectroscopic properties of Sm{sup 2+} and Er{sup 3+} are compared with those of Eu{sup 2+}, Yb{sup 2+}, Ce{sup 3+}, and Nd{sup 3+} doped in SrI{sub 2}. The results are combined to construct a diagram with the vacuum referred electron binding energies for all divalent and trivalent lanthanide ions in SrI{sub 2} which is fully consistent with the spectroscopic observations. - Highlights: • 750nm 5d–4f emission has been observed for Sm{sup 2+} in SrI{sub 2}. • A valence band to Er{sup 3+} charge band has been observed for Er{sup 3+} in SrI{sub 2}. • A binding energy diagram has been constructed from data on lanthanides in SrI{sub 2}.

  12. Optical properties of monolayer transition metal dichalcogenides probed by spectroscopic ellipsometry

    KAUST Repository

    Liu, Hsiang-Lin

    2014-11-17

    Spectroscopic ellipsometry was used to characterize the complex refractive index of chemical-vapor-deposited monolayer transition metal dichalcogenides (TMDs). The extraordinary large value of the refractive index in the visible frequency range is obtained. The absorption response shows a strong correlation between the magnitude of the exciton binding energy and band gap energy. Together with the observed giant spin-orbit splitting, these findings advance the fundamental understanding of their novel electronic structures and the development of monolayer TMDs-based optoelectronic and spintronic devices.

  13. Spectroscopic properties in Er3+-doped germanotellurite glasses and glass ceramics for mid-infrared laser materials

    Science.gov (United States)

    Kang, Shiliang; Xiao, Xiudi; Pan, Qiwen; Chen, Dongdan; Qiu, Jianrong; Dong, Guoping

    2017-03-01

    Transparent Er3+-doped germanotellurite glass ceramics (GCs) with variable Te/Ge ratio were prepared by controllable heat-treated process. X-ray diffraction (XRD) and transmission electron microscope (TEM) confirmed the formation of nanocrystals in glass matrix. Raman spectra were used to investigate the evolution of glass structure and photon energy. Fourier transform infrared (FTIR) spectra were introduced to characterize the change of hydroxyl group (OH‑) content. Enhanced 2.7 μm emission was achieved from Er3+-doped GCs upon excitation with a 980 nm laser diode (LD), and the influence of GeO2 concentration and heat-treated temperature on the spectroscopic properties were also discussed in detail. It is found that the present Er3+-doped GC possesses large stimulated emission cross section at around 2.7 μm (0.85 × 10‑20 cm2). The advantageous spectroscopic characteristics suggest that the obtained GC may be a promising material for mid-infrared fiber lasers.

  14. Spectroscopic properties in Er3+-doped germanotellurite glasses and glass ceramics for mid-infrared laser materials

    Science.gov (United States)

    Kang, Shiliang; Xiao, Xiudi; Pan, Qiwen; Chen, Dongdan; Qiu, Jianrong; Dong, Guoping

    2017-01-01

    Transparent Er3+-doped germanotellurite glass ceramics (GCs) with variable Te/Ge ratio were prepared by controllable heat-treated process. X-ray diffraction (XRD) and transmission electron microscope (TEM) confirmed the formation of nanocrystals in glass matrix. Raman spectra were used to investigate the evolution of glass structure and photon energy. Fourier transform infrared (FTIR) spectra were introduced to characterize the change of hydroxyl group (OH−) content. Enhanced 2.7 μm emission was achieved from Er3+-doped GCs upon excitation with a 980 nm laser diode (LD), and the influence of GeO2 concentration and heat-treated temperature on the spectroscopic properties were also discussed in detail. It is found that the present Er3+-doped GC possesses large stimulated emission cross section at around 2.7 μm (0.85 × 10−20 cm2). The advantageous spectroscopic characteristics suggest that the obtained GC may be a promising material for mid-infrared fiber lasers. PMID:28266570

  15. Synthesis, spectroscopic characterisation, biological and DNA cleavage properties of complexes of nicotinamide

    Directory of Open Access Journals (Sweden)

    C. Surendra Dilip

    2016-09-01

    Full Text Available Transition metal complexes of nicotinamide with metal precursors such as Cr(III, Mn(II, Fe(III, Co(II, Ni(II, Cu(II and Cd(II, were synthesized and characterised by physico-chemical and spectroscopic techniques. Based on analytical, spectral and magnetic moments, all the complexes are identified as distorted octahedral in structure. All the complexes are of the ML14L22 type. The shifts of the ν (CN (azomethine and ν (CO (amide stretches have been monitored in order to find out the donor sites of the ligands. Antibacterial and antifungal activities of the complexes were studied and the complexes were screened against bacteria and fungi. The activity data show that the metal complexes are more potent than the parent nicotinamide.

  16. Dissecting the morphological and spectroscopic properties of galaxies in the local Universe: I. Elliptical galaxies

    CERN Document Server

    Aguerri, J A L; Almeida, J Sánchez; Munoz-Tunon, C

    2012-01-01

    We revisit the scaling relations and star-forming histories of local elliptical galaxies using a novel selection method applied to the Sloan Digital Sky Survey DR7. We combine two probability-based automated spectroscopic and morphological classifications of about 600000 galaxies with z<0.25 to isolate true elliptical galaxies. Our sample selection method does not introduce artificial cuts in the parameters describing the galaxy but instead it associates to every object a weight measuring the probability of being in a given spectro-morphological class. Thus the sample minimizes the selection biases. We show that morphologically defined ellipticals are basically distributed in 3 spectral classes, which dominate at different stellar masses. The bulk of the population (about 50%) is formed by a well defined class of galaxies with old stellar populations that formed their stars at very early epochs in a short episode of star formation. They dominate the scaling relations of elliptical galaxies known from previ...

  17. Temperature dependence of spectroscopic and electrical properties of Cr(Fe):ZnSe laser active materials

    Science.gov (United States)

    Gafarov, Ozarfar; Watkins, Rick; Bernard, Chandler; Fedorov, Vladimir; Mirov, Sergey

    2017-02-01

    Temperature influence on spectroscopic characteristics is crucial for many aspects of laser engineering including output noise, single frequency oscillation, and thermal bistability. We report on the spectroscopic characterization of chromium and iron doped ZnSe gain element media at temperatures ranging from 77K to 389K. Heating of Cr:ZnSe resulted in the absorption peak shifting to a shorter wavelength from 1.806 μm at 77K to 1.753 μm at 389K. It also resulted in broadening of the absorption band from Δλ=260 cm-1nm to Δλ=373 cm-1nm and decreasing of the absorption cross section by 69%. Similar characterization was done for Fe:ZnSe laser material. The cooling of the Fe:ZnSe crystal from room temperature to 77K resulted in a 32% increase of the absorption coefficient at 2.94 μm which is usually used as a pump source. We also studied the absorption of the electrical free-carriers in n-type Al:ZnSe crystals in visible and mid- IR absorption spectral ranges. Diffusion of Al into ZnSe samples was achieved by annealing at 1000°C during 4 days in Al vapors. It was demonstrated that free-carriers absorption of Al:ZnSe samples with resistivity σ=100-150 Ω×cm resulted in an increase of the absorption coefficient at 2.4 μm up to 2.5 cm-1.

  18. Thermal stability and spectroscopic properties of erbium-doped niobic-tungsten-tellurite glasses for laser and amplifier devices

    Energy Technology Data Exchange (ETDEWEB)

    Boetti, Nadia G., E-mail: nadia.boetti@polito.it [PhotonLab, Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Lousteau, Joris [PhotonLab, Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Chiasera, Alessandro; Ferrari, Maurizio [CNR-IFN, Istituto di Fotonica e Nanotecnologie, CSMFO Lab. via alla Cascata 56/C, Povo, 38123 Trento (Italy); Mura, Emanuele; Scarpignato, Gerardo C. [PhotonLab, Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Abrate, Silvio [PhotonLab, Istituto Superiore Mario Boella, Via P.C. Boggio, 61, 10138 Torino (Italy); Milanese, Daniel [PhotonLab, Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2012-05-15

    Er{sup 3+} doped niobic-tungsten-tellurite glasses doped with concentration of Er{sup 3+} ion up to 3 wt% were fabricated. The effect of Er{sup 3+} doping concentration on thermal stability and optical properties was investigated in order to obtain the most suitable rare earth content for developing 1.5 {mu}m compact fiber amplifier pumped with a commercial telecom 980 nm laser diode. The maximum doping concentration allowed was found to be around 1.77 Multiplication-Sign 10{sup 20} ions/cm{sup 3}, for which a broad 1.5 {mu}m emission spectra of 65 nm FWHM and a lifetime of 3.4 ms for the {sup 4}I{sub 13/2} level was measured. - Highlights: Black-Right-Pointing-Pointer Thermal and optical properties of Er{sup 3+} doped niobic-tungsten-tellurite glasses. Black-Right-Pointing-Pointer Spectroscopic properties measured when pumped by commercial telecom 980 nm LD. Black-Right-Pointing-Pointer Investigation of the effect of Er{sup 3+}doping level on glass properties. Black-Right-Pointing-Pointer Present glass is a good candidate for efficient 1.5 {mu}m compact fiber amplifier or laser.

  19. Modulation of physicochemical and spectroscopic properties of l-serine and l-proline by propionate based food preservatives.

    Science.gov (United States)

    Banipal, Tarlok S; Kaur, Navalpreet; Kaur, Jaspreet; Komal; Banipal, Parampaul K

    2016-10-15

    To have an insight into the effect of preservatives on various ingredients of processed items, it is important to study their thermodynamic, transport and spectroscopic properties in aqueous solutions to elucidate various solute-co-solute interactions. The densities, viscosities and enthalpies of dilution of l-serine and l-proline have been determined in water and in aqueous solutions of sodium propionate and calcium propionate at different temperatures. The derived parameters elucidate the changes in taste quality and hydration number of l-serine and l-proline in the presence of the studied preservatives. Predominance of dehydration effect has been observed from calorimetry and changes in chemical shifts from nuclear magnetic resonance spectroscopy also support the above results.

  20. Global Properties of the Rich Cluster ABCG 209 at z~0.2. Spectroscopic and Photometric Catalogue

    CERN Document Server

    Mercurio, A; Haines, C P; Merluzzi, P; Busarello, G; Capaccioli, M

    2008-01-01

    This paper is aimed at giving an overview of the global properties of the rich cluster of galaxies ABCG 209. This is achieved by complementing the already available data with new medium resolution spectroscopy and NIR photometry which allow us to i) analyse in detail the cluster dynamics, distinguishing among galaxies belonging to different substructures and deriving their individual velocity distributions, using a total sample of 148 galaxies in the cluster region, of which 134 belonging to the cluster; ii) derive the cluster NIR luminosity function; iii) study the Kormendy relation and the photometric plane of cluster early-type galaxies (ETGs). Finally we provide an extensive photometric (optical and NIR) and spectroscopic dataset for such a complex system to be used in further analyses investigating the nature, formation and evolution of rich clusters of galaxies. The observational scenario confirms that ABCG 209 is presently undergoing strong dynamical evolution with the merging of two or more subclumps....

  1. Spectroscopic and Neutron Detection Properties of Rare Earth and Titanium Doped LiAlO2 Single Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Dickens, Peter T.; Marcial, Jose; McCloy, John S.; McDonald, Benjamin S.; Lynn, Kelvin G.

    2017-10-02

    In this study, LiAlO2 crystals doped with rare-earth elements and Ti were produced by the CZ method and spectroscopic and neutron detection properties were investigated. Photoluminescence revealed no clear luminescent activation of LiAlO2 by the rare-earth dopants though some interesting luminescence was observed from secondary phases within the crystal. Gamma-ray pulse height spectra collected using a 137Cs source exhibited only a Compton edge for the crystals. Neutron modeling using Monte Carlo N-Particle Transport Code revealed most neutrons used in the detection setup are thermalized, and while using natural lithium in the crystal growth, which contains 7.6 % 6Li, a 10 mm Ø by 10 mm sample of LiAlO2 has a 70.7 % intrinsic thermal neutron capture efficiency. Furthermore, the pulse height spectra collected using a 241Am-Be neutron source demonstrated a distinct neutron peak.

  2. Thioflavin T and its photoirradiative derivatives: exploring their spectroscopic properties in the absence and presence of amyloid fibrils.

    Science.gov (United States)

    Hsu, Jack C-C; Chen, Eric H-L; Snoeberger, Robert C; Luh, Frederick Y; Lim, T-S; Hsu, C-P; Chen, Rita P-Y

    2013-04-04

    In this work, we found that, during storage or after UV irradiation, ThT is demethylated or oxidized, forming three derivatives. These three derivatives were purified by high performance liquid chromatography and characterized by mass and nuclear magnetic resonance spectroscopy and the spectroscopic properties of pure ThT and the derivatives carefully compared. Our results show that the emission peak at 450 nm results from oxidized ThT and not from the monomeric form of ThT, as previously proposed. The partial conversion of ThT into oxidized and demethylated derivatives has an effect on amyloid detection using ThT assay. Irradiated ThT has the same lag time as pure ThT in the amyloidogenesis of insulin, but the intensity of the emitted fluorescence is significantly decreased.

  3. Potential of a spectroscopic measurement method using adding-doubling to retrieve the bulk optical properties of dense microalgal media.

    Science.gov (United States)

    Bellini, Sarah; Bendoula, Ryad; Latrille, Eric; Roger, Jean-Michel

    2014-01-01

    In the context of algal mass cultivation, current techniques used for the characterization of algal cells require time-consuming sample preparation and a large amount of costly, standard instrumentation. As the physical and chemical properties of the algal cells strongly affect their optical properties, the optical characterization is seen as a promising method to provide an early diagnosis in the context of mass cultivation monitoring. This article explores the potential of a spectroscopic measurement method coupled with the inversion of the radiative transfer theory for the retrieval of the bulk optical properties of dense algal samples. Total transmittance and total reflectance measurements were performed over the 380-1020 nm range on dense algal samples with a double integrating sphere setup. The bulk absorption and scattering coefficients were thus extracted over the 380-1020 nm range by inverting the radiative transfer theory using inverse-adding-doubling computations. The experimental results are presented and discussed; the configuration of the optical setup remains a critical point. The absorption coefficients obtained for the four samples of this study appear not to be more informative about pigment composition than would be classical methods in analytical spectroscopy; however, there is a real added value in measuring the reduced scattering coefficient, as it appears to be strongly correlated to the size distribution of the algal cells.

  4. Effect of B2O3 content on structure and spectroscopic properties of neodymium-doped calcium aluminate glasses

    Science.gov (United States)

    Kang, Shuai; Wang, Xue; Xu, Wenbin; Wang, Xin; He, Dongbing; Hu, Lili

    2017-04-01

    Nd2O3-doped calcium aluminate glasses was synthesized with the following compositions: (100-x)(33Al2O3-62CaO-2MgO-3BaO)-xB2O3-0.5Nd2O3 (x = 0, 2.5, 5, 7.5, 10). The Raman, absorption, and emission spectra were measured to characterize the structure and spectroscopic properties of these glasses. The glass thermal stability was studied using differential scanning calorimetry (DSC) tests. Both the Raman spectra and DSC results indicated a decrease in the non-bridging oxygens (NBOs) in the [AlO4]- network with an increase in the B2O3 content. The J-O intensity parameter Ω2, covalency degree of the Nd-O bond, and emission bandwidth of the Nd3+ ions decreased with the B2O3 content. The stimulated emission cross-section and optical gain property increased with an increase in the B2O3 content. The tunable gain property and broadband emission feature of the Nd3+-doped CaO-Al2O3-B2O3-MgO-BaO calcium aluminate glass suggested a potential application to a high-energy ultra-short-pulse laser.

  5. An Efficient Preparation, Spectroscopic Properties, and Crystal Structure of 1,1-Bis(4-[2-(dimethylaminoethoxy]phenyl-2-(3-guaiazulenylethylene

    Directory of Open Access Journals (Sweden)

    Shin-ichi Takekuma

    2009-01-01

    Full Text Available Reaction of 2-(3-guaiazulenyl-1,1-bis(4-hydroxyphenylethylene with 2-chloroethyldimethylammonium chloride in acetone in the presence of K2CO3 at reflux temperature for 24 hours gives a new title compound in 89% yield. Spectroscopic properties and crystal structure of the target molecule are reported.

  6. Dipodal quinoline-tethered fluorescent probe synthesis and investigation of spectroscopic properties

    Science.gov (United States)

    Obalı, Aslıhan Yılmaz; Yilmaz, Menzeher Serkan; Uçan, Halil İsmet

    2017-10-01

    Novel quinoline-tethered fluorescent probe was designed and synthesized as multidentate ligand. Their sensing actions were confirmed by UV-Vis absorbance and emission spectroscopic studies in presence of perchlorate salts of Co2+, Li+, Fe2+, K+, Pb2+, Cu2+, Zn2+, Ni2+, Hg2+, Ag+ cations in acetonitrile (1 × 10-5 M for absorption studies, 1 × 10-7 M for fluorescence studies). It was found that the dipodal compounds can selectively bind to Cu2+ and Ag+ metal ions with a significant quenching in their emissions. The capture of Cu2+ and Ag+ by the probe resulted in deprotonation of the secondary amine conjugated to the quinoline-tethered probe, so that the electron-donation ability of the 'N' atom would be greatly enhanced and the probe (2) showed blue-shift in emission and exhibited an on-off fluorescent response. The binding study was explored by using fluorescence spectroscopy with Job plot method.

  7. Synthesis, structure, spectroscopic and electrochemical properties of bis(histamine-saccharinate) copper(II) complex

    Science.gov (United States)

    Bulut, İclal; Uçar, İbrahim; Karabulut, Bünyamin; Bulut, Ahmet

    2007-05-01

    Crystal structure of [Cu(hsm) 2(sac) 2] (hsm is histamine and sac is saccharinate) complex has been determined by X-ray diffraction analyses and its magnetic environment has been identified by electron paramagnetic resonance (EPR) technique. The title complex crystallizes in the monoclinic system, space group P 21/ c with a = 7.4282(4), b = 22.5034(16), c = 8.3300(5) Å, β = 106.227(4)°, V = 1336.98(14) Å 3, and Z = 2. The structure consist of discrete [Cu(hsm) 2(sac) 2] molecules in which the copper ion is centrosymmetrically coordinated by two histamine ligands forming an equatorial plane [Cu-N hsm = 2.024(2) and Cu-N hsm = 2.0338(18) Å]. Two N atoms from the saccharinate ligands coordinate on the elongated axial positions with Cu-N sac being 2.609(5) Å. The complex is also characterized by spectroscopic (IR, UV/Vis) and thermal (TG, and TDA) methods. The cyclic voltammogram of the title complex investigated in DMSO (dimethylsulfoxide) solution exhibits only metal centred electroactivity in the potential range - 1.25-1.5 V versus Ag/AgCl reference electrode. The molecular orbital bond coefficients of Cu(II) ion in d 9 state is also calculated by using EPR and optical absorption parameters.

  8. Spectroscopic properties of Young Stellar Objects in the Lupus Molecular Clouds

    CERN Document Server

    Mortier, Annelies; van Dishoeck, Ewine F

    2011-01-01

    The results of an optical spectroscopic survey of a sample of young stellar objects (YSOs) and pre-main sequence (PMS) stars in the Lupus Clouds are presented. 92 objects were observed with VLT/FLAMES. All of those objects show IR excess as discovered by the Spitzer Legacy Program "From Molecular Cores to Planet-Forming Disks" (c2d). After reduction, 54 spectra with good signal-to-noise ratio are spectrally classified. Effective temperatures and luminosities are derived for these objects, and used to construct H-R diagrams for the population. The sample consists mostly of M-type stars, with 10% K-type stars. Individual ages and masses are inferred for the objects according to theoretical evolutionary models. The mean population age is found to be between 3.6 and 4.4 Myr, depending on the model, while the mean mass is found to be ~0.3 M for either model. Together with literature data, the distribution of spectral types is found to be similar to that in Chamaeleon I and IC348. The H{\\alpha} line in emission, fo...

  9. Prompt and Afterglow Emission Properties of Gamma-Ray Bursts with Spectroscopically Identified Supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Yuki; Ramirez-Ruiz, E.; Granot, J.; Kouveliotou, C.; Woosley, S.E.; Patel, S.K.; Rol, E.; Zand, J.J.M.in' t; a; Wijers, R.A.M.J.; Strom, R.; /USRA, Huntsville

    2006-07-12

    We present a detailed spectral analysis of the prompt and afterglow emission of four nearby long-soft gamma-ray bursts (GRBs 980425, 030329, 031203, and 060218) that were spectroscopically found to be associated with type Ic supernovae, and compare them to the general GRB population. For each event, we investigate the spectral and luminosity evolution, and estimate the total energy budget based upon broadband observations. The observational inventory for these events has become rich enough to allow estimates of their energy content in relativistic and sub-relativistic form. The result is a global portrait of the effects of the physical processes responsible for producing long-soft GRBs. In particular, we find that the values of the energy released in mildly relativistic outflows appears to have a significantly smaller scatter than those found in highly relativistic ejecta. This is consistent with a picture in which the energy released inside the progenitor star is roughly standard, while the fraction of that energy that ends up in highly relativistic ejecta outside the star can vary dramatically between different events.

  10. Synthesis, crystal structure, spectroscopic characterization and optical properties of bis(4-acetylanilinium) tetrachlorocobalt (II)

    Science.gov (United States)

    Abkari, A.; Chaabane, I.; Guidara, K.

    2017-02-01

    The chemical preparation, crystal structure, spectroscopic investigations and optical features are given for a novel organic-inorganic hybrid material [C8H10NO]2CoCl4.The compound is crystallized in the orthorhombic space group Cmca, with the following unit cell parameters: a=19.461(2) Å, b=15.523(2) Å, c=13.7436(15) Å, and Z=8. The atomic arrangement shows an alternation of organic and inorganic layers along the b-axis. The cohesion between these entities is performed by N-H…Cl and N-H…O hydrogen bonds and π-π stacking interactions. Infrared and Raman spectra at room temperature are recorded in the 4000-400 and 4000-0 cm-1 frequency regions, respectively and analyzed on the basis of literature data. This study confirms the presence of the organic cation [C8H10NO]+ and of the [CoCl4]2- anion. UV-vis spectroscopy results showed the indirect transition with band gap energy 2.98 eV.

  11. Some Lower Valence Vanadium Fluorides: Their Crystal Distortions, Domain Structures, Modulated Structures, Ferrimagnetism, and Composition Dependence.

    Science.gov (United States)

    Hong, Y. S.; And Others

    1980-01-01

    Describes some contemporary concepts unique to the structure of advanced solids, i.e., their crystal distortions, domain structures, modulated structures, ferrimagnetism, and composition dependence. (Author/CS)

  12. Configuration interaction studies on the spectroscopic properties of PbO including spin orbit coupling

    Institute of Scientific and Technical Information of China (English)

    罗旺; 李瑞; 盖志强; 艾瑞波; 张宏民; 张晓美; 闫冰

    2016-01-01

    Lead oxide (PbO), which plays the key roles in a range of research fields, has received a great deal of attention. Owing to the large density of electronic states and heavy atom Pb including in PbO, the excited states of the molecule have not been well studied. In this work, high level multireference configuration interaction calculations on the low-lying states of PbO have been carried out by utilizing the relativistic effective core potential. The effects of the core-valence correlation correction, the Davidson modification, and the spin–orbital coupling on the electronic structure of the PbO molecule are estimated. The potential energy curves of 18Λ-S states correlated to the lowest dissociation limit (Pb (3Pg)+O(3Pg)) are reported. The calculated spectroscopic parameters of the electronic states below 30000 cm−1, for instance, X1Σ+, 13Σ+, and 13Σ−, and their spin–orbit coupling interaction, are compared with the experimental results, and good agreements are derived. The dipole moments of the 18Λ-S states are computed with the configuration interaction method, and the calculated dipole moments of X1Σ+and 13Σ+are consistent with the previous experimental results. The transition dipole moments from 11Π, 21Π, and 21Σ+to X1Σ+and other singlet excited states are estimated. The radiative lifetime of several low-lying vibrational levels of 11Π, 21Π, and 21Σ+states are evaluated.

  13. Configuration interaction studies on the spectroscopic properties of PbO including spin-orbit coupling

    Science.gov (United States)

    Wang, Luo; Rui, Li; Zhiqiang, Gai; RuiBo, Ai; Hongmin, Zhang; Xiaomei, Zhang; Bing, Yan

    2016-07-01

    Lead oxide (PbO), which plays the key roles in a range of research fields, has received a great deal of attention. Owing to the large density of electronic states and heavy atom Pb including in PbO, the excited states of the molecule have not been well studied. In this work, high level multireference configuration interaction calculations on the low-lying states of PbO have been carried out by utilizing the relativistic effective core potential. The effects of the core-valence correlation correction, the Davidson modification, and the spin-orbital coupling on the electronic structure of the PbO molecule are estimated. The potential energy curves of 18 Λ-S states correlated to the lowest dissociation limit (Pb (3Pg) + O(3Pg)) are reported. The calculated spectroscopic parameters of the electronic states below 30000 cm-1, for instance, X1Σ+, 13Σ+, and 13Σ-, and their spin-orbit coupling interaction, are compared with the experimental results, and good agreements are derived. The dipole moments of the 18 Λ-S states are computed with the configuration interaction method, and the calculated dipole moments of X1Σ+ and 13Σ+ are consistent with the previous experimental results. The transition dipole moments from 11Π, 21Π, and 21Σ+ to X1Σ+ and other singlet excited states are estimated. The radiative lifetime of several low-lying vibrational levels of 11Π, 21Π, and 21Σ+ states are evaluated. Project supported by the National Natural Science Foundation of China (Grant Nos. 11404180 and 11574114), the Natural Science Foundation of Heilongjiang Province, China (Grant No. A2015010), the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province, China (Grant No. UNPYSCT-2015095), and the Natural Science Foundation of Jilin Province, China (Grant No. 20150101003JC).

  14. Effect of cryogenic temperature on spectroscopic and laser properties of Er, Yb-doped potassium-lanthanum phosphate glass

    Science.gov (United States)

    Švejkar, Richard; Šulc, Jan; Němec, Michal; Jelínková, Helena; Nitsch, Karel; Cihlář, Antonín.; Král, Robert; Nejezchleb, Karel; Nikl, Martin

    2017-05-01

    Glass matrix doped with rare-earth ions is a promising laser active medium for high power laser systems. Due to amorphous structure of glasses the absorption and emission spectra lines are broader in comparison with crystalline materials thus pumping radiation can be absorbed efficiently, moreover much broader gain bandwidth is suitable for generation of ultra-short pulses. Another advantage of the glass matrix is the possibility to fabricate large volume ingots and simultaneously preservation of sufficient optical quality. The lower thermal conductivity of glasses can be compensated by geometry of the active medium for instance shaped into fibres or discs. We present temperature dependence of spectroscopic and laser properties of newly developed Er, Yb - doped potassium-lanthanum phosphate glass, which is appropriate for generation of radiation at 1.53 μm. The sample of Er,Yb:KLaP glassy mixture was cut into disc shape with dimensions of 2.5 mm (thickness) and 5 mm (diameter) and its faces were polished plan-parallelly without being anti-reflection coated. The temperature dependence of the transmission and emission spectra Er,Yb:KLaP together with the fluorescence decay time were measured the temperature range from 80 to 400 K. The fluorescence lifetime of manifold 4I13/2 (upper laser level) prolonged and the intensity of up-conversion radiation decreased with decreasing temperature. The longitudinal excitation of Er,Yb:KLaP was carried out by a fibre-coupled laser diode (pulse duration 2 ms, repetition rate 10 Hz, pump wavelength 969 nm). Laser resonator was hemispherical, with flat pumping mirror (HR @ 1.5 μm) and spherical output coupler (R = 98 % @ 1.5 - 1.6 μm). The Er,Yb:KLaP glass laser properties were investigated in the temperature range 80 - 300 K. The highest slope efficiency with respect to absorbed pumped power was 6.1 % at 80 K. The maximum output of peak amplitude power was 0.71 W at 80 K, i.e. 1.2 times higher than at 300 K. Tunability of laser

  15. Effects of humic substances on the bioconcentration of polycyclic aromatic hydrocarbons: Correlations with spectroscopic and chemical properties of humic substances

    Science.gov (United States)

    Haitzer, M.; Abbt-Braun, G.; Traunspurger, W.; Steinberg, C.E.W.

    1999-01-01

    The presence of dissolved humic substances (HS, fulvic and humic acids) generally reduces the uptake of hydrophobic organic compounds into aquatic organisms. The extent of this effect depends both on the concentration and on the origin of the HS. The aim of this study was to investigate the role of qualitative differences between HS from different origins. The effects of seven different HS on the bioconcentration of pyrene and benzo[a]pyrene (BaP) in the nematode Caenorhabditis elegans were related to the spectroscopic and chemical properties of the HS. The effect of each humic material on the bioconcentration of pyrene or BaP was quantified as a 'biologically determined' partition coefficient K(DOC). We observed significant linear relationships between K(DOC) and the atomic H/C ratio, the specific absorptivity at 254 nm, the content of aromatic carbons (as determined by 13C nuclear magnetic resonance spectroscopy, the copper-complexing capacity, the content of phenolic OH groups, and the molecular weight of the HS. There was no discernible relationship of K(DOC) with the atomic (N + O)/C ratio, an indicator of the polarity of HS. Taken together, our results show that the variability in the effects of HS from different origins could be related to variations in bulk properties of the HS. Parameters describing the aromaticity of the humic materials seemed to be most useful for estimating effects of HS on the bioconcentration of pyrene and BaP.

  16. Parametrization of optical properties of indium-tin-oxide thin films by spectroscopic ellipsometry: Substrate interfacial reactivity

    Science.gov (United States)

    Losurdo, M.; Giangregorio, M.; Capezzuto, P.; Bruno, G.; de Rosa, R.; Roca, F.; Summonte, C.; Plá, J.; Rizzoli, R.

    2002-01-01

    Indium-tin-oxide (ITO) films deposited by sputtering and e-gun evaporation on both transparent (Corning glass) and opaque (c-Si, c-Si/SiO2) substrates and in c-Si/a-Si:H/ITO heterostructures have been analyzed by spectroscopic ellipsometry (SE) in the range 1.5-5.0 eV. Taking the SE advantage of being applicable to absorbent substrate, ellipsometry is used to determine the spectra of the refractive index and extinction coefficient of the ITO films. The effect of the substrate surface on the ITO optical properties is focused and discussed. To this aim, a parametrized equation combining the Drude model, which considers the free-carrier response at the infrared end, and a double Lorentzian oscillator, which takes into account the interband transition contribution at the UV end, is used to model the ITO optical properties in the useful UV-visible range, whatever the substrate and deposition technique. Ellipsometric analysis is corroborated by sheet resistance measurements.

  17. Spectroscopic Evaluation of Effects of Heat Treatments on the Structures and Emulsifying Properties of Caseins

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao; WANG Peng-jie; LEI Xin-gen; YANG Hong-ju; ZHANG Lu-da; REN Fa-zheng; ZHENG Li-min

    2013-01-01

    The effects of heat treatment(heating temperature and pH) on the structures and emulsifying properties of caseins were systematically studied by spectroscopy.Heat treatment from 60 to 100 ℃ resulted in an increase in their fluorescence intensity,hydrodynamic diameter,turbidity and emulsifying activity index,but decreased the size polydispersity of caseins.In the pH range of 5.5 to 7.0,the fluorescence intensity,hydrodynamic diameter,turbidity and emulsifying properties decreased with increased heating pH,but the size polydispersity of caseins increased with increased pH.The relationship between the surface fluorescence intensity and emulsifying activity was also investigated,revealing a correlation coefficient of 0.90.These results suggested that heat treatment could be used to modify the structures and emulsifying properties of caseins by appropriately selecting heating conditions.

  18. Reduction of 4-azidonaphthalimide with different phosphine ligands and exploration of their spectroscopic properties

    Science.gov (United States)

    Xu, Shou De; Fang, Cheng Hui; Tian, Guang Xuan; Chen, Yi; Dou, Ye Hong; Kou, Jun Feng; Wu, Xiang Hua

    2015-12-01

    A convenient, high efficient method for the reduction of 4-azidonaphthalimide to 4-aminonaphthalimide (1) by using PMe3 has been developed. Several 4-substituted 1,8-naphthalimide iminophosphoranes were also successfully synthesized. Their structures were characterized by NMR and MS analyses. The structures of compounds 2 and 3 were also confirmed by single crystal X-ray diffraction analysis. Their optoelectronic properties of these naphthalimides were investigated. The results indicated that their optical properties could be tuned by different phosphine ligands, which make them novel potential organic luminescent materials.

  19. Effects of alkali ions on thermal stability and spectroscopic properties of Er{sup 3+}-doped gallogermanate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Shi, D.M.; Zhao, Y.G.; Wang, X.F.; Liao, G.H. [Department of Materials Science and Engineering, Luoyang Institute of Science and Technology, Luoyang 471023 (China); Zhao, C. [Department of Physics, South China University of Technology, Guangzhou 510641 (China); MOE Key Lab of Specially Functional Materials and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China); Peng, M.Y. [MOE Key Lab of Specially Functional Materials and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China); Zhang, Q.Y., E-mail: qyzhang@scut.edu.c [MOE Key Lab of Specially Functional Materials and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641 (China)

    2011-02-01

    Since information transportation capacity of optical communication network increases rapidly, new optical materials are always demanded with gain bandwidth desirably much broader than traditional erbium-doped silica fiber amplifier (EDFA). We show here in this paper the erbium-doped gallogermanate glasses with a full-width at half-maximum (FWHM) more than 50 nm. Incorporation of alkali ions such as Li{sup +}, Na{sup +}, K{sup +} into the system can on the one hand improve the thermal stability of the glasses, and on the other hand enhance the emission at 1.5 {mu}m due to the {sup 4}I{sub 13/2{yields}}{sup 4}I{sub 15/2} transition of Er{sup 3+} and suppress the upconversion process at the same time. This particularly works best for the case of K{sup +} inclusion. This work might give a general idea on controlling the Er{sup 3+} luminescence by simply adjusting the glass component and find a potential laser glass applicable to developing new broadband fiber amplifier. -- Research highlights: {yields} We report on spectroscopic properties of Er{sup 3+}-doped Ga{sub 2}O{sub 3}-GeO{sub 2}-R{sub 2}O (GGR, R=Li, Na and K) glasses for 1.53 {mu}m fiber amplifier. Effects of alkali metal ions on the thermal stability and spectroscopic properties of Er{sup 3+}-doped GGR glasses have been investigated. {yields} Incorporation of alkali ions such as Li{sup +}, Na{sup +}, K{sup +} into the system can on the one hand improve the thermal stability of the glasses, and on the other hand enhance the emission at 1.5 {mu}m due to the {sup 4}I{sub 13/2{yields}}{sup 4}I{sub 15/2} transition of Er{sup 3+} and suppress the upconversion process at the same time. This particularly works best for the case of K{sup +} inclusion. This work might give a general idea on controlling the Er{sup 3+} luminescence by simply adjusting the glass component and find a potential laser glass applicable to developing new broadband fiber amplifier.

  20. Anomalous composition-dependent dynamics of nanoconfined water in the interlayer of disordered calcium-silicates.

    Science.gov (United States)

    Qomi, Mohammad Javad Abdolhosseini; Bauchy, Mathieu; Ulm, Franz-Josef; Pellenq, Roland J-M

    2014-02-07

    With shear interest in nanoporous materials, the ultraconfining interlayer spacing of calcium-silicate-hydrate (C-S-H) provides an excellent medium to study reactivity, structure, and dynamic properties of water. In this paper, we present how substrate composition affects chemo-physical properties of water in ultraconfined hydrophilic media. This is achieved by performing molecular dynamics simulation on a set of 150 realistic models with different compositions of calcium and silicon contents. It is demonstrated that the substrate chemistry directly affects the structural properties of water molecules. The motion of confined water shows a multi-stage dynamics which is characteristic of supercooled liquids and glassy phases. Inhomogeneity in that dynamics is used to differentiate between mobile and immobile water molecules. Furthermore, it is shown that the mobility of water molecules is composition-dependent. Similar to the pressure-driven self-diffusivity anomaly observed in bulk water, we report the first study on composition-driven diffusion anomaly, the self diffusivity increases with increasing confined water density in C-S-H. Such anomalous behavior is explained by the decrease in the typical activation energy required for a water molecule to escape its dynamical cage.

  1. Spectroscopic properties of second generation photosensitizers for photo-diagnostics and photo-dynamic therapy

    Science.gov (United States)

    Naurecka, Magdalena Ligia; Sierakowski, Bartosz Michał; Kwaśny, Mirosław

    2016-12-01

    The aim of the study was to investigate and compare photophysical properties of the most modern formulations used in the world - derivatives of: porphyrin, chlorines, bacteriochlorins, phthalocyanines and phenothiazines. Useful parameters of comparing the emission properties of various sensitizers groups are quantum yield of singlet oxygen generation (ΦT) and quantum yields of fluorescence (ΦF). The emission and excitation characteristics were appointed and shown as excitation - emission matrices (EX - EM). The influence of the monomerization degree of the pure hematoporphyrin (HP) on the quantum yield was also measured. Received quantum yield values of commonly used sensitizers are in the range 0.05 - 0.3 and efficiency values of singlet oxygen generation are 0.3 - 0.7. These values depend not only on the chemical structure of the compounds, but also on solvent polarity, temperature and concentration which is decisive for the monomerization degree.

  2. Dielectric Properties of Bi4Ti3O12 Ceramics by Impedance Spectroscopic Method

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong; SU Huyin; XUE Simin; LI Zhaozhi; ZHANG Cancan; CHEN Qi; XU Lingfang; CAO Wanqiang; HUANG Zhaoxiang

    2016-01-01

    Various lead-free ceramics have been investigated in search for new high-temperature dielectrics. In particular, Bi4Ti3O12 is a type of ferroelectric ceramics, which is supposed to replace lead-containing ceramics for its outstanding dielectric properties in the near future. Ferroelectric ceramics of Bi4Ti3O12 made by conventional mixed oxide route have been studied by impedance spectroscopy in a wide range of temperature. X-ray diffraction patterns show that Bi4Ti3O12 ceramics are a single-phase of ferroelectric Bi-layered perovskite structure whether it is calcined at 800℃ or after sintering production. This study focused on the effect of the grain size on the electric properties of BIT ceramics. The BIT ceramics with different grain sizes were prepared at different sintering temperatures. Grain becomes coarser with the sintering temperature increasing by 50℃, relative permittivity and dielectric loss also change a lot. When sintered at 1 100℃, r values peak can reach 205.40 at a frequency of 100 kHz, the minimum dielectric losses of four different frequencies make no difference, all close to 0.027. The values ofEa range from 0.52 to 0.68 eV. The dielectric properties of the sample sintered at 1 100℃ are relatively better than those of the other samples by analyzing the relationship of the grain, the internal stresses, the homogeneity and the dielectric properties. SEM can better explain the results of the dielectric spectrum at different sintering temperatures. The results show that Bi4Ti3O12 ceramics are a kind of dielectrics. Thus, Bi4Ti3O12 can be used in high-temperature capacitors and microwave ceramics.

  3. Spectroscopic studies on the lanthanide sensitized luminescence and chemiluminescence properties of fluoroquinolone with different structure

    Science.gov (United States)

    Sun, Chunyan; Ping, Hong; Zhang, Minwei; Li, Hongkun; Guan, Fengrui

    2011-11-01

    Lanthanide sensitized luminescence and chemiluminescence (CL) are of great importance because of the unique spectral properties, such as long lifetime, large Stokes shifts, and narrow emission bands characteristic to lanthanide ions (Ln 3+). With the fluoroquinolone (FQ) compounds including enoxacin (ENX), norfloxacin (NFLX), lomefloxacin (LMFX), fleroxacin (FLRX), ofloxacin (OFLX), rufloxacin (RFX), gatifloxacin (GFLX) and sparfloxacin (SPFX), the luminescence and CL properties of Tb 3+-FQ and Eu 3+-FQ complexes have been investigated in this contribution. Ce 4+-SO 32- in acidic conditions was taken as the CL system and sensitized CL intensities of Tb 3+-FQ and Eu 3+-FQ complexes were determined by flow-injection analysis. The luminescence and CL spectra of Tb 3+-FQ complexes show characteristic peaks of Tb 3+ at 490 nm, 545 nm, 585 nm and 620 nm. Complexes of Tb 3+-ENX, Tb 3+-NFLX, Tb 3+-LMFX and Tb 3+-FLRX display relatively strong emission intensity compared with Tb 3+-OFLX, Tb 3+-RFX, Tb 3+-GFLX and Tb 3+-SPFX. Quite weak peaks with unique characters of Eu 3+ at 590 nm and 617 nm appear in the luminescence and CL spectra of Eu 3+-ENX, but no notable sensitized luminescence and CL of Eu 3+ could be observed when Eu 3+ is added into other FQ. The distinct differences on emission intensity of Tb 3+-FQ and Eu 3+-FQ might originate from the different energy gap between the triplet levels of FQ and the excited levels of the Ln 3+. The different sensitized luminescence and CL signals among Tb 3+-FQ complexes could be attributed to different optical properties and substituents of these FQ compounds. The detailed mechanism involved in the luminescence and CL properties of Tb 3+-FQ and Eu 3+-FQ complexes has been investigated by analyzing the luminescence and CL spectra, quantum yields, and theoretical calculation results.

  4. Physicotechnical, spectroscopic and thermogravimetric properties of powdered cellulose and microcrystalline cellulose derived from groundnut shells

    OpenAIRE

    Chukwuemeka P. Azubuike; Jimson O. Odulaja; Augustine O Okhamafe

    2012-01-01

    α-Cellulose and microcrystalline cellulose powders, derived from agricultural waste products, that have for thepharmaceutical industry, desirable physical (flow) properties were investigated. α–Cellulose (GCN) wasextracted from groundnut shell (an agricultural waste product) using a non-dissolving method based oninorganic reagents. Modification of this α -cellulose was carried out by partially hydrolysing it with 2Nhydrochloric acid under reflux to obtain microcrystalline cellulose (MCGN). Th...

  5. Access to a CuII–O–CuII Motif: Spectroscopic Properties, Solution Structure, and Reactivity

    Science.gov (United States)

    Haack, Peter; Kärgel, Anne; Greco, Claudio; Dokic, Jadranka; Braun, Beatrice; Pfaff, Florian F.; Mebs, Stefan; Ray, Kallol; Limberg, Christian

    2013-01-01

    We report a complex with a rare CuII–O–CuII structural motif that is stable at room temperature, which allows its in-depth characterization by a variety of spectroscopic methods. Interest in such compounds is fueled by the recent discovery that a CuII–O–CuII species on the surface of Cu-ZSM-5 is capable of oxidizing methane to methanol and this in turn ties into mechanistic discussions on the methane oxidation at the dicopper site within the particulate methane monooxygenase. For the synthesis of our Cu2O complex we have developed a novel, neutral ligand system, FurNeu, exhibiting two N-(N',N'-dimethylaminoethyl)(2-pyridylmethyl)amino binding pockets connected by a dibenzofuran spacer. The reaction of FurNeu with CuCl yielded [FurNeu](Cu2(μ-Cl))(CuCl2), 1, demonstrating the geometric potential of the ligand to stabilize Cu–X–Cu moieties. A CuI precursor with weakly coordinating anions was chosen in the next step, namely [Cu(NCCH3)4]OTf, which led to the formation of [FurNeu](Cu(NCCH3))2(OTf)2, 3. Treatment of 3 with O2 or PhIO led to identical green solutions, whose UV/Vis spectra were markedly different from the one displayed by [FurNeu](Cu)2(OTf)4, 4, prepared independently from FurNeu and Cu(OTf)2. Further investigations including PhIO consumption experiments, NMR and UV/Vis spectroscopy, HR-ESI mass spectrometry and protonation studies led to the identification of the green product as [FurNeu](Cu2(μ-O))(OTf)2, 5. DOSY NMR spectroscopy confirmed its monomeric character. Over longer periods of time 5 decomposes to give [Cu(picoloyl)2], formed through an oxidative N-dealkylation reaction followed by further oxidation of the ligand. Due to its slow decomposition reaction all attempts to crystallize 5 failed. However, its structure in solution could be determined by EXAFS analysis in combination with DFT calculations, which revealed a Cu–O–Cu angle that amounts to 105.17°. Moreover, TDDFT calculations helped to rationalize the UV/Vis absorptions

  6. Spectroscopic and luminescent properties of Co2+ doped tin oxide thin films by spray pyrolysis

    Directory of Open Access Journals (Sweden)

    K. Durga Venkata Prasad

    2016-07-01

    Full Text Available The wide variety of electronic and chemical properties of metal oxides makes them exciting materials for basic research and for technological applications alike. Oxides span a wide range of electrical properties from wide band-gap insulators to metallic and superconducting. Tin oxide belongs to a class of materials called Transparent Conducting Oxides (TCO which constitutes an important component for optoelectronic applications. Co2+ doped tin oxide thin films were prepared by chemical spray pyrolysis synthesis and characterized by powder X-ray diffraction, SEM, TEM, FT-IR, optical, EPR and PL techniques to collect the information about the crystal structure, coordination/local site symmetry of doped Co2+ ions in the host lattice and the luminescent properties of the prepared sample. Powder XRD data revealed that the crystal structure belongs to tetragonal rutile phase and its lattice cell parameters are evaluated. The average crystallite size was estimated to be 26 nm. The morphology of prepared sample was analyzed by using SEM and TEM studies. Functional groups of the prepared sample were observed in the FT-IR spectrum. Optical absorption and EPR studies have shown that on doping, Co2+ ions enter in the host lattice as octahedral site symmetry. PL studies of Co2+ doped SnO2 thin films exhibit blue and yellow emission bands. CIE chromaticity coordinates were also calculated from emission spectrum of Co2+ doped SnO2 thin films.

  7. Spectroscopic characterization of changes of DOM deprotonation-protonation properties in water treatment processes.

    Science.gov (United States)

    Yan, Mingquan; Dryer, Deborah; Korshin, Gregory V

    2016-04-01

    The deprotonation-protonation properties of dissolved organic matter (DOM) in drinking water produced at critical treatment points were quantified using absorbance spectra in combination with DOM fractionation data. Analysis of differential spectra of DOM present in inlet, settled and filtered waters from two large treatment plants and their fractions were obtained. The data demonstrated the presence of six Gaussian bands largely associated with carboxylic and phenolic DOM functionalities. Properties of the protonation-active groups of DOM in raw and treated waters were further examined based on data of potentiometric titrations at pH from 2.5 to 10. Interpretation of the differential log-transformed absorbance at wavelength 350 nm (DlnA350) based on the NICA-Donnan model showed that the normalized concentrations of low- and high-affinity protonation-active groups in residual DOMs increases as a result of water treatment. This was consistent with the results of DOM fractionation. This study demonstrates that changes of the composition and reactivity of DOM found in drinking water treatment sequences can be quantified based on the examination of their optical properties.

  8. Spectroscopic properties of Nd3+ ion in several types of phosphate materials

    Science.gov (United States)

    Godlewska, P.; Bandrowski, Sz.; Macalik, L.; Lisiecki, R.; Ryba-Romanowski, W.; Szczygieł, I.; Ropuszyńska-Robak, P.; Hanuza, J.

    2012-05-01

    Neodymium phosphate materials were considered as possible laser media. NaNdP2O7, NaNd(PO3)4, Na3Nd(PO4)2 and Nd3(PO4)O3 phosphates have been synthesized in the solid state reaction protecting the proper conditions characteristic for the each synthesis. Structure, optical properties and vibrational characteristics for the obtained samples have been analyzed taking into account the relations between them. Considering the structure influence of the studied phosphates on their optical properties it was found that the emission efficiency, in that the lifetime in investigated phosphates was not clearly dependent on the type of structure of these materials. Significant improvement of the emission properties is observed only for the NaNd(PO3)4 metaphosphate where the longest Nd-Nd distance appears and the luminescence lifetime of the 4F3/2 level in this material was measured to be 112 μs. It means that among investigated compounds solely NaNd(PO3)4 metaphosphate can be considered as promising stoichiometric laser active material.

  9. Spectroscopic properties and energy transfer parameters of Er3+- doped fluorozirconate and oxyfluoroaluminate glasses

    Science.gov (United States)

    Huang, Feifei; Liu, Xueqiang; Hu, Lili; Chen, Danping

    2014-05-01

    Er3+- doped fluorozirconate (ZrF4-BaF2-YF3-AlF3) and oxyfluoroaluminate glasses are successfully prepared here. These glasses exhibit significant superiority compared with traditional fluorozirconate glass (ZrF4-BaF2-LaF3-AlF3-NaF) because of their higher temperature of glass transition and better resistance to water corrosion. Judd-Ofelt (J-O) intensity parameters are evaluated and used to compute the radiative properties based on the VIS-NIR absorption spectra. Broad emission bands located at 1535 and 2708 nm are observed, and large calculated emission sections are obtained. The intensity of 2708 nm emission closely relates to the phonon energy of host glass. A lower phonon energy leads to a more intensive 2708 nm emission. The energy transfer processes of Er3+ ions are discussed and lifetime of Er3+: 4I13/2 is measured. It is the first time to observe that a longer lifetime of the 4I13/2 level leads to a less intensive 1535 nm emission, because the lifetime is long enough to generate excited state absorption (ESA) and energy transfer (ET) processes. These results indicate that the novel glasses possess better chemical and thermal properties as well as excellent optical properties compared with ZBLAN glass. These Er3+- doped ZBYA and oxyfluoroaluminate glasses have potential applications as laser materials.

  10. A spectroscopic study of the chromatic properties of GafChromic™EBT3 films

    Energy Technology Data Exchange (ETDEWEB)

    Callens, M., E-mail: maarten.callens@kuleuven-kulak.be; Van Den Abeele, K. [Wave Propagation and Signal Processing, KU Leuven–KULAK, Kortrijk 8500 (Belgium); Crijns, W.; Depuydt, T.; Haustermans, K. [Department of Radiation Oncology, University Hospitals Leuven, Leuven 3000 (Belgium); Simons, V. [imec, Kapeldreef 75, Leuven 3001 (Belgium); De Wolf, I. [imec, Kapeldreef 75, Leuven 3001, Belgium and Department of Materials Engineering, KU Leuven, Leuven 3001 (Belgium); Maes, F. [Department of Electrical Engineering, ESAT/PSI, KU Leuven, Leuven 3001 (Belgium); D’hooge, J. [Department of Cardiovascular Sciences, KU Leuven, Leuven 3000 (Belgium); D’Agostino, E. [DoseVue NV, Hasselt 3500 (Belgium); Wevers, M.; Pfeiffer, H. [Department of Materials Engineering, KU Leuven, Leuven 3001 (Belgium)

    2016-03-15

    Purpose: This work provides an interpretation of the chromatic properties of GafChromic™EBT3 films based on the chemical nature of the polydiacetylene (PDA) molecules formed upon interaction with ionizing radiation. The EBT3 films become optically less transparent with increasing radiation dose as a result of the radiation-induced polymerization of diacetylene monomers. In contrast to empirical quantification of the chromatic properties, less attention has been given to the underlying molecular mechanism that induces the strong decrease in transparency. Methods: Unlaminated GafChromic™EBT3 films were irradiated with a 6 MV photon beam to dose levels up to 20 Gy. The optical absorption properties of the films were investigated using visible (vis) spectroscopy. The presence of PDA molecules in the active layer of the EBT3 films was investigated using Raman spectroscopy, which probes the vibrational modes of the molecules in the layer. The vibrational modes assigned to PDA’s were used in a theoretical vis-absorption model to fit our experimental vis-absorption spectra. From the fit parameters, one can assess the relative contribution of different PDA conformations and the length distribution of PDA’s in the film. Results: Vis-spectroscopy shows that the optical density increases with dose in the full region of the visible spectrum. The Raman spectrum is dominated by two vibrational modes, most notably by the ν(C≡C) and the ν(C=C) stretching modes of the PDA backbone. By fitting the vis-absorption model to experimental spectra, it is found that the active layer contains two distinct PDA conformations with different absorption properties and reaction kinetics. Furthermore, the mean PDA conjugation length is found to be 2–3 orders of magnitude smaller than the crystals PDA’s are embedded in. Conclusions: Vis- and Raman spectroscopy provided more insight into the molecular nature of the radiochromic properties of EBT3 films through the identification of

  11. Determination of human skin optical properties in vivo from reflectance spectroscopic measurements

    Institute of Scientific and Technical Information of China (English)

    Hongqin Yang; Shusen Xie; Hui Li; Zukang Lu

    2007-01-01

    A novel approach has been proved to quickly and non-invasively determine the optical properties of human skin in vivo. It is based on the diffuse reflectance approximation model and subjected to the well established library of absorption spectra of water and hemoglobin. Under the nonlinear least-square algorithm, fitting the measured spectra in the range of 400-1000 nm to the diffusion approximation model, the reduced scattering coefficient and absorption coefficient of skin tissue can be quickly determined in vivo. The results show that this method is convenient and suitable for the real-time clinical application.

  12. Spectroscopic properties of erbium-doped yttria-stabilised zirconia crystals

    Energy Technology Data Exchange (ETDEWEB)

    Ryabochkina, P A; Sidorova, N V [N.P. Ogarev Mordovian State University, Saransk (Russian Federation); Ushakov, S N; Lomonova, E E [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2014-02-28

    Yttria-stabilised zirconia crystals ZrO{sub 2} – Y{sub 2}O{sub 3} (6 mol %) – Er{sub 2}O{sub 3} (5.85 mol %) are grown by directional crystallisation in a cold container using direct RF melting. The spectral and luminescent properties of these crystals are studied in order to use them as active media of solid state lasers emitting in the wavelength range 1.5 – 1.7 μm. (active media)

  13. Comparison of spectroscopic properties of Yb:YAP and Yb:YAG crystals

    Institute of Scientific and Technical Information of China (English)

    Xiaoming He; Guangjun Zhao; Xiaodong Xu; Xionghui Zeng; Jun Xu

    2007-01-01

    The Yb:YAG and Yb:YAP crystals have been grown by Czochralski method. The absorption spectra and the fluorescence spectra of Yb:YAG and Yb:YAP crystals have been investigated. It is shown that the Yb:YAG crystal has better laser properties and smaller threshold power than Yb:YAP crystal. In addition, the absorption cross-section of the Yb:YAP crystal is 2.16 times of that of the Yb:YAG crystal,so laser diode pumped Yb:YAG lasing can be easily realized. Because YAP single crystal is anisotropic, it is provided with polarization characteristics.

  14. Synthesis and Spectroscopic Properties of a Series of New tetra-Substituted Metal Phthalocyanines

    Institute of Scientific and Technical Information of China (English)

    YU Hai-ling; YANG Jin; FU Qiang; MA Ji-cheng; LI Wei-li

    2008-01-01

    A new class of metal phthalocyanines(MPcs)containing four 8-quinolinol(8-QH) derivative moieties were successfully synthesized and characterized by mass spectroscopy,IR, UV-Vis and element analysis,the results of which were consistent with the proposed structures.All of them can dissolve in common organic solvents.such as dichloromethane,chloroform,and acetone.The effect of metal ion on the absorption of Q band was studied with UV-Vis spectra.The fluorescent properties for those complexes were also investigated.

  15. Optical properties of Cd1-xZnxTe films in a device structure using variable angle spectroscopic ellipsometry

    Science.gov (United States)

    Paulson, P. D.; McCandless, B. E.; Birkmire, R. W.

    2004-03-01

    The optical properties of polycrystalline Cd1-xZnxTe alloy thin films in device structures are reported for energy from 0.8 to 4.6 eV. Cd1-xZnxTe alloy thin films with x from 0 to 1 were deposited on glass/indium-tin-oxide (ITO)/CdS substrates by coevaporation from CdTe and ZnTe sources and were characterized by variable angle spectroscopic ellipsometry, energy dispersive x-ray spectroscopy, and x-ray diffractometry. The Cd1-xZnxTe films are single phase with a zincblende crystal structure over the entire alloy range. The Cd1-xZnxTe optical constants were determined using a multilayer optical model incorporating the optical constants of glass, ITO and CdS, determined independently from glass, glass/ITO, and glass/ITO/CdS specimens. The optical constants of the Cd1-xZnxTe thin films are comparable to literature values reported for single crystals, indicating that the polycrystalline nature of the films does not measurably alter the optical constants. A semiconductor alloy model for determining the composition of CdxZn1-xTe alloy films is developed using the optical data obtained from the analysis. This alloy model can be used to evaluate compositional grading and the effects of Cd1-xZnxTe film processing.

  16. Investigation of role of silver nanoparticles on spectroscopic properties of biologically active coumarin dyes 4PTMBC and 1IPMBC.

    Science.gov (United States)

    Raghavendra, U P; Basanagouda, Mahantesha; Thipperudrappa, J

    2015-01-01

    The role of silver nanoparticles on spectroscopic properties of biologically active coumarin dyes 4-p-tolyloxymethyl-benzo[h]coumarin (4PTMBC) and 1-(4-iodophenoxymethyl)-benzo[f]coumarin (1IPMBC) has been investigated using absorption and fluorescence spectroscopy. Silver nanoparticles are synthesized by chemical reduction method and the estimated size by Mie theory is 12 nm. The absorption spectral changes of dyes in the presence of silver nanoparticles suggest their possible interaction with silver nanoparticles. The apparent association constants of the interaction are estimated using Benesi-Hildebrand model. Fluorescence quenching has been observed in both the dyes with the addition of silver nanoparticles. The Stern-Volmer plots of fluorescence quenching are found to be nonlinear showing positive deviation. The magnitudes of quenching rate parameter and fluorescence lifetime measurements indicate the presence of both collisional and static quenching mechanisms. The binding constants and the number of binding sites for the static type of quenching have been estimated from the fluorescence data. The role of diffusion, energy transfer and electron transfer processes in fluorescence quenching mechanism has been discussed.

  17. Physical and spectroscopic properties of pure C2H4 and CH4:C2H4 ices

    Science.gov (United States)

    Molpeceres, Germán; Satorre, Miguel Angel; Ortigoso, Juan; Zanchet, Alexandre; Luna, Ramón; Millán, Carlos; Escribano, Rafael; Tanarro, Isabel; Herrero, Víctor J.; Maté, Belén

    2017-04-01

    Physical and spectroscopic properties of ices of C2H4 and CH4:C2H4 mixtures with 3:1, 1:1 and 1:3 ratios have been investigated at 30 K. Two laboratories are involved in this work. In one of them, the density and refractive index of the samples have been measured by using a cryogenic quartz microbalance and laser interferometric techniques. In the other one, IR spectra have been recorded in the near- and mid-infrared regions, and band shifts with respect to the pure species, band strengths of the main bands, and the optical constants in both regions have been determined. Previous data on ethylene and the mixtures studied here were scarce. For methane, both the wavenumbers and band strengths have been found to follow a regular pattern of decrease with increasing dilution, but no pattern has been detected for ethylene vibrations. The method employed for the preparation of the samples, by vapour deposition under vacuum, is thought to be adequate to mimic the structure of astrophysical ices. Possible astrophysical implications, especially by means of the optical constants reported here, have been discussed.

  18. Crystal structure characterization as well as theoretical study of spectroscopic properties of novel Schiff bases containing pyrazole group.

    Science.gov (United States)

    Guo, Jia; Ren, Tiegang; Zhang, Jinglai; Li, Guihui; Li, Weijie; Yang, Lirong

    2012-09-01

    A series of novel Schiff bases containing pyrazole group were synthesized using 1-aryl-3-methyl-4-benzoyl-5-pyrazolone and phenylenediamine as the starting materials. All as-synthesized Schiff bases were characterized by means of NMR, FT-IR, and MS; and the molecular geometries of two Schiff bases as typical examples were determined by means of single crystal X-ray diffraction. In the meantime, the ultraviolet-visible light absorption spectra and fluorescent spectra of various as-synthesized products were also measured. Moreover, the B3LYP/6-1G(d,p) method was used for the optimization of the ground state geometry of the Schiff bases; and the spectroscopic properties of the products were computed and compared with corresponding experimental data based on cc-pVTZ basis set of TD-B3LYP method. It has been found that all as-synthesized Schiff bases show a remarkable absorption peak in a wavelength range of 270-370 nm; and their maximum emission peaks are around 344 nm and 332 nm, respectively.

  19. Theoretical modeling of the spectroscopic absorption properties of luciferin and oxyluciferin: A critical comparison with recent experimental studies

    Energy Technology Data Exchange (ETDEWEB)

    Anselmi, Massimiliano, E-mail: m.anselmi@caspur.it [Department of Chemistry, University of Rome ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy); Marocchi, Simone [Department of Chemistry, University of Rome ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy); Aschi, Massimiliano [Department of Chemistry, Chemical Engineering and Materials, University of L' Aquila, Via Vetoio (Coppito 1), 67100 Coppito, L' Aquila (Italy); Amadei, Andrea [Department of Chemistry, University of Rome ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Rome (Italy)

    2012-01-02

    Highlights: Black-Right-Pointing-Pointer The calculated absorption spectra were compared with experimental data. Black-Right-Pointing-Pointer Shapes and absorption maxima were reproduced for luciferin and oxyluciferin spectra. Black-Right-Pointing-Pointer The effect of the solvent largely changes the electronic transition probabilities. Black-Right-Pointing-Pointer Higher excitations provide an important contribution to the main absorption peak. - Abstract: Firefly luciferin and its oxidated form, oxyluciferin, are two heterocyclic compounds involved in the enzymatic reaction, catalyzed by redox proteins called luciferases, which provides the bioluminescence in a wide group of arthropods. Whereas the electronic absorption spectra of D-luciferin in water at different pHs are known since 1960s, only recently reliable experimental electronic spectra of oxyluciferin have become available. In addition oxyluciferin is involved in a triple chemical equilibria (deprotonation of the two hydroxyl groups and keto-enol tautomerism of the 4-hydroxythiazole ring), that obligates to select during an experiment a predominant species, tuning pH or solvent polarity besides introducing chemical modifications. In this study we report the absorption spectra of luciferin and oxyluciferin in each principal chemical form, calculated by means of perturbed matrix method (PMM), which allowed us to successfully introduce the effect of the solvent on the spectroscopic absorption properties, and compare the result with available experimental data.

  20. An investigation of the photophysical properties of minor groove bound and intercalated DAPI through quantum-mechanical and spectroscopic tools.

    Science.gov (United States)

    Biancardi, Alessandro; Biver, Tarita; Secco, Fernando; Mennucci, Benedetta

    2013-04-07

    The fluorescent probe 4',6-diamidino-2-phenylindole (DAPI) is a dye known to interact with polynucleotides in a non-univocal manner, both intercalation and minor groove binding modes being possible, and to specifically change its photophysical properties according to the different environments. To investigate this behavior, quantum-mechanical calculations using time-dependent density functional theory (TDDFT), coupled with polarizable continuum and/or atomistic models, were performed in combination with spectroscopic measurements of the probe in the different environments, ranging from a homogeneous solution to the minor groove or intercalation pockets of double stranded nucleic acids. According to our simulation, the electronic transition involves a displacement of the electron charge towards the external amidine groups and this feature makes the absorption energies very environment-sensitive while a much smaller sensitivity is seen in the fluorescence energies. Moreover, the calculations show that the DAPI molecule, when minor groove bound to the nucleic acid, presents both a reduced geometrical flexibility because of the rigid DNA pocket and a reduced polarization due to the very "apolar" microenvironment. All these effects can be used to better understand the observed enhancement of the fluorescence, which makes it an excellent marker for DNA.

  1. Thermal and spectroscopic properties of the nano-system (ZnO(1-x)SiO2(x))

    Science.gov (United States)

    El-Kabbany, F.; Taha, S.; Hafez, M.; Yahia, I. S.

    2016-05-01

    Structural and thermal properties of the investigated nano-matrix ZnO(1-x)SiO2(x) samples were characterized by various techniques such as X-ray analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). IR spectroscopic analysis in the frequency range 400-4000 cm-1 is used here to investigate the new nano-system at room temperature. The variation of enthalpy (ΔH) with the concentration of SiO2 nanoparticles for the five systems of the ZnO(1-x)SiO2(x) matrix is determined. Seven different fundamental modes have been investigated. All of the vibrations of the investigated nano-system (ZnO(1-x)SiO2(x)) were found to be 449 cm-1, 469 cm-1, 798 cm-1, 959 cm-1, 1096 cm-1, 1630 cm-1 and 3447 cm-1 correspond to normal vibrations of stretching mode of ZnO, Si - O - Si or O - Si - O bending mode, Si - O - Si symmetric stretching, vibrational mode of Si-O - Zn, Si - O - Si asymmetric stretching, bending vibration mode of adsorbed water and stretching vibration of OH group respectively in which the variations strongly support the variation of ZnO and SiO2 nanoparticles concentration in the studied matrix. Measurements and interpretation of IR spectra as a function of ZnO and SiO2 nanoparticles concentration is reported.

  2. Kinematics and stellar population properties of the Andromeda galaxy by using the spectroscopic observations of the Guoshoujing Telescope

    Institute of Scientific and Technical Information of China (English)

    Hu Zou; Yan-Bin Yang; Tian-Meng Zhang; Jun Ma; Xu Zhou; Ali Luo; Hao-Tong Zhang; Zhong-Rui Bai; Yong-Heng Zhao

    2011-01-01

    The Andromeda galaxy was observed by the Guoshoujing Telescope (formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope ——LAMOST),during the 2009 commissioning phase.Due to the absence of standard stars for flux calibration,we use the photometric data of 15 intermediate bands in the Beijing-Arizona-Taipei-Connecticut (BATC) survey to calibrate the spectra.In total,59 spectra located in the bulge and disk of the galaxy are obtained.Kinematic and stellar population properties of the stellar content are derived with these spectra.We obtain the global velocity field and calculate corresponding rotation velocities out to about 7 kpc along the major axis.These rotation velocity measurements complement those of the gas content,such as the H I and CO.The radial velocity dispersion shows that the stars in the bulge are more dynamically thermal and the disk is more rotationally-supported.The age distribution shows that the bulge was formed about 12 Gyr ago,the disk is relatively younger and the ages of some regions along the spiral arms can reach as young as about 1 Gyr.These young stellar populations have a relatively richer abundance and larger reddening.The overall average metallicity of the galaxy approximates the solar metallicity and a very weak abundance gradient is gained.The reddening map gives a picture of a dust-free bulge and a distinct dusty ring in the disk.

  3. Effect of Bi2O3 on spectroscopic and structural properties of Er3+ doped cadmium bismuth borate glasses.

    Science.gov (United States)

    Sanghi, S; Pal, I; Agarwal, A; Aggarwal, M P

    2011-12-01

    Glasses with composition 20CdO·xBi(2)O(3)·(79.5-x)B(2)O(3) (15≤x≤35, x in mol%) containing 0.5 mol% of Er(3+) ions were prepared by melt-quench technique (1150°C in air). The amorphous nature of the glasses was confirmed by X-ray diffraction. The spectroscopic properties of the glasses were investigated using optical absorption spectra and fluorescence spectra. The phenomenological Judd-Ofelt intensity parameters Ω(λ) (λ=2, 4, 6) were determined from the spectral intensities of absorption bands in order to calculate the radiative transition probability (A(R)), radiative life time (τ(R)), branching ratios (β(R)) for various excited luminescent states. Using the near infrared emission spectra, full width at half maxima (FWHM), stimulated emission cross-section (σ(e)) and figure of merit (FOM) were evaluated and compared with other hosts. Especially, the numerical values of these parameters indicate that the emission transition (4)I(13/2)→(4)I(15/2) at 1.506 μm in Er(3+)-doped cadmium bismuth borate glasses may be useful in optical communication.

  4. Spectroscopic properties of Nd-doped phosphate glass with a high emission cross section

    Institute of Scientific and Technical Information of China (English)

    毛艳丽; 孙真荣; 蒋秀丽; 邓佩珍; 干福熹

    2002-01-01

    Neodymium doped phosphate glasses have been prepared by the semi-continuous melting technique. Their ab-sorption and emission spectra have been recorded at room temperature. The Judd-Ofelt theory has been applied to ewluate the stimulated emission cross sections of 4F3/2→4I11/2 transition for Nd3+. The higher stimulated emission cross section, 4.0×10-20cm2, is obtained. The fluorescence decays of the 4F3/2→411/2 transition of Nd3+ are mea-sured for the samples doped (0.7-10) wt% of Nd2O3 at room temperature. The concentration quenching of Nd-doped phosphate glass is mainly attributed to cross-relaxation and energy migration. The site-dependent properties of fluores-cence spectra and the fluorescence lifetime of the Nd3+-doped phosphate glass (with 2.2wt% Nd2O3) are studied using laser-induced fluorescence line narrowing techniques, and the site-to-site variations of optical properties are observed at low temperature.

  5. Copper(i) complexes with phosphine derived from sparfloxacin. Part I - structures, spectroscopic properties and cytotoxicity.

    Science.gov (United States)

    Komarnicka, Urszula K; Starosta, Radosław; Kyzioł, Agnieszka; Jeżowska-Bojczuk, Małgorzata

    2015-07-28

    In this paper we present new copper(i) iodide or copper(i) thiocyanate complexes with hydroxymethyldiphenylphosphine (PPh2(CH2OH)) or phosphine derivatives of sparfloxacin, a 3(rd) generation fluoroquinolone antibiotic agent (PPh2(CH2-Sf)) and 2,9-dimethyl-1,10-phenanthroline (dmp) or 2,2'-biquinoline (bq) auxiliary ligands. The synthesised complexes were fully characterised by NMR and UV-Vis spectroscopy as well as by mass spectrometry. Selected structures were additionally analysed using X-ray and DFT methods. All complexes proved to be stable in solution in the presence of water and atmospheric oxygen for several days. The cytotoxic activity of the complexes was tested against two cancer cell lines (CT26 - mouse colon carcinoma and A549 - human lung adenocarcinoma). Applying two different incubation times, the studies enabled a preliminary estimation of the dependence of the selectivity and the mechanism of action on the type of diimine and phosphine ligands. The results obtained showed that complexes with PPh2(CH2-Sf) are significantly more active than those with PPh2(CH2OH). On the other hand, the relative impact of diimine on cytotoxicity is less pronounced. However, the dmp complexes are characterised by strong inhibitory properties, while the bq ones are rather not. This confirms the interesting and promising biological properties of the investigated group of copper(i) complexes, which undoubtedly are worthy of further biological studies.

  6. Structural and spectroscopic properties of high temperature prepared ZrO₂–TiO₂ mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Gionco, Chiara [Dipartimento di Chimica and NIS (Nanostructured Surfaces and Interfaces), Università degli Studi di Torino, Via Giuria 7, 10125 Torino (Italy); Battiato, Alfio; Vittone, Ettore [Dipartimento di Fisica, Università degli Studi di Torino, Via Giuria 1, 10125 Torino (Italy); Paganini, Maria Cristina, E-mail: mariacristina.paganini@unito.it [Dipartimento di Chimica and NIS (Nanostructured Surfaces and Interfaces), Università degli Studi di Torino, Via Giuria 7, 10125 Torino (Italy); Giamello, Elio [Dipartimento di Chimica and NIS (Nanostructured Surfaces and Interfaces), Università degli Studi di Torino, Via Giuria 7, 10125 Torino (Italy)

    2013-05-01

    ZrO₂-TiO₂ mixed oxides of various composition, with the molar fraction of TiO₂ ranging from 0.1% to 15%, have been prepared via sol-gel synthesis and then calcined at 1273 K to check both their thermal stability and physicochemical properties. These solids are usually employed in photocatalytic processes and as active phase supports in heterogeneous catalysis. As indicated by X-ray diffraction and Raman spectroscopy, solid solutions based on Ti ions diluted in the ZrO₂ matrix are formed in the whole range of Ti molar fraction examined. Materials with low Ti loading (0.1%–1%) are basically constituted by the monoclinic phase of ZrO₂ while the tetragonal phase becomes prevalent at 15% of TiO₂ molar fraction. The presence of Ti ions modify the electronic structure of the solid as revealed by investigation of the optical properties. The typical band gap transition of ZrO₂ undergoes, in fact, a red shift roughly proportional to the Ti loading which reach the remarkable value of 1.6 eV for the sample with 10% of molar Ti concentration. Comparing chemical analysis of the solids with XPS data it has been put into evidence that the titanium ions distribution into the solid is not uniform and the concentration of Ti⁴⁺ tend to be higher in subsurface layers than in the crystal bulk. The introduction of titanium ions in the structure increases the reducibility of the solid. Annealing under vacuum at various temperatures causes oxygen depletion with consequent reduction of the solid which shows up mainly in terms of formation of Ti³⁺ reduced centres which are characterized by a typical EPR signal. Ti³⁺ defects forms, as also forecast by theoretical modelling of the solid, as their energy is lower than that of other possible reduced defective centers. The reduced solids are able to transfer electrons to adsorbed oxygen molecules in mild condition resulting in the formation of surface superoxide anions (O₂⁻) which are stabilized on surface Zr

  7. Spectroscopic study on the photophysical properties of chlorine substituted tetraphenylporphyrinhistidine and its zinc (Ⅱ) complexes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Huijuan; FENG Juan; AI Xicheng; ZHANG Xingkang; YU Zhongheng; ZHANG Jianping

    2003-01-01

    The photophysical properties of ortho-Cl, meta-Cl and para-Cl substituted tetraphenylporphyrin-histidine and their zinc (Ⅱ) complexes have been studied by means of steady-state absorption and fluorescence spectroscopies, as well as time-resolved fluorescence spectroscopy. For the cases of both free-base and zinc complexes, it was found that the ortho-chlorine substitution onto the phenyl rings significantly altered the fluorescence quantum yield, the fluorescence lifetime and the ratio between radiative and nonradiative deactivation rates of the porphyrin chromophore, i.e. the photophysical parameters were quite differentfrom those of meta- and para-substi- tuted compounds. On the other hand, however, the introduction of covalently-linked histidine did not exert much effects onthe photophysical behavior of the porphyrin chromophore. The results are interpreted in terms of the steric effect and the heavy-atom effect from the chlorine atoms substituted onto the phenyl rings.

  8. Transition metal impurities in fluorides: Role of electronic structure of fluorine on spectroscopic properties

    DEFF Research Database (Denmark)

    Trueba, A.; Garcia-Fernandez, P.; García Lastra, Juan Maria

    2011-01-01

    This work examines the relation between optical properties of a MF6q− complex (M=transition–metal cation) and the chemical bonding paying especial attention to the role played by the electronic structure of fluorine. A main goal of the present study is to understand why if the effective Racah...... that the reduction of Racah parameters essentially reflects the global covalency in the bonding. The way of measuring the 2p(F) and 2s(F) admixtures into the mainly 3d(Cr) level through Electron Paramagnetic Resonance data for MF6q− complexes with unpaired σ electrons in the ground state is also explained in some...... detail. At the same time the reasons avoiding its measurement from optical spectra are pointed out as well. The present results stress that the microscopic origin of an optical parameter like 10Dq can certainly be very subtle....

  9. The WHIQII Survey: Metallicities and Spectroscopic Properties of Luminous Compact Blue Galaxies

    CERN Document Server

    Tollerud, Erik J; van Zee, Liese; Cooke, Jeff

    2009-01-01

    As part of the WIYN High Image Quality Indiana Irvine (WHIQII) survey, we present 123 spectra of emission-line galaxies, selected on intermediate redshift (.4properties and state of star formation. Some LCBG metallicities are consistent with a "bursting dwarf" scenario, while a substantial fraction of others are not, further confirming that LCBGs are a highly heterogeneous population but are broadly consistent with the intermediate redshift field. In agreement with previous studies, we observe overall evolution ...

  10. Measurement of the optical properties of skin using terahertz time-domain spectroscopic techniques

    Science.gov (United States)

    Wilmink, Gerald J.; Ibey, Bennett L.; Tongue, Thomas; Schulkin, Brian; Peralta, Xomalin; Rivest, Benjamin D.; Haywood, Eric C.; Roach, William P.

    2010-02-01

    Terahertz (THz) radiation is increasingly being used in biomedical imaging and spectroscopy applications. These techniques show tremendous promise to provide new sophisticated tools for the improved detection of skin cancer. However, despite recent efforts to develop these applications, few studies have been conducted to characterize the optical properties of skin at THz frequencies. Such information is required to better understand THz-tissue interactions, and is critical for determining the feasibility of proposed applications. In this study, we have developed and tested a THz time-domain spectroscopy system. We used this system to acquire the optical properties for fresh and frozen/thawed excised porcine skin from 0.1 to 2.0 THz. Results show that the index of refraction (n) for both frozen and fresh skin decreases with frequency. For frozen skin, n equals 2.5 at 0.1 THz and 2.0 at 2.0 THz, and for fresh skin equals 2.0 at 0.1 THz and 1.7 at 2.0 THz. Values for the absorption coefficient (μa) increase with frequency for both frozen and fresh skin. Frozen skin exhibits μa values equal to 56 cm-1 at 0.1 THz and 550 cm-1 at 2.0 THz, whereas fresh skin exhibits values of 56 cm-1 at 0.1 THz and 300 cm-1 at 2.0 THz. Assuming the optical penetration depth (δ) is inversely proportional to μa (absorption-dominated interactions), THz radiation has limited δ in skin (200 μm at 0.1 THz to 40 μm at 2.0 THz). These results suggest that applications exploiting THz radiation show the most promise for investigating superficial tissues.

  11. Structural and spectroscopic properties of pure and doped LiCe(PO{sub 3}){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Abdelhedi, M., E-mail: m_abdelhedi2002@yahoo.fr [Laboratoire de Chimie Inorganique, Université de Sfax, Faculté des Sciences de Sfax, BP 1171, 3000 Sfax (Tunisia); Horchani-Naifer, K. [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, Technopole de Borj Cedria, 6 BP 73, 8027 Soliman (Tunisia); Dammak, M. [Laboratoire de Chimie Inorganique, Université de Sfax, Faculté des Sciences de Sfax, BP 1171, 3000 Sfax (Tunisia); Ferid, M. [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, Technopole de Borj Cedria, 6 BP 73, 8027 Soliman (Tunisia)

    2015-10-15

    Graphical abstract: Emission and excitation and spectra of Eu{sup 3+} doped LiCe(PO{sub 3}){sub 4} host lattice with 1, 2, 3 and 4 mol%. - Highlights: • Europium–doped LiCe(PO{sub 3}){sub 4} were prepared by flux method. • It was analyzed by infrared and Raman spectroscopy, and luminescence spectroscopy. • LiCe(PO{sub 3}){sub 4} doped with Eu{sup 3+} ions as luminophore host materials to produce an intense red. - Abstract: Single crystals of LiCe(PO{sub 3}){sub 4} polyphosphate have been synthesized by the flux method and its structural and luminescence properties have been investigated. This compound crystallizes in the space group C2/c with unit cell dimensions a = 16.52(7) Å, b = 7.09(4) Å, c = 9.83 (4)Å, β = 126.29(4)°, Z = 8 and V = 927.84(3) Å{sup 3}. The obtained polytetraphosphate exhibits very small crystals and the dopant Eu{sup 3+} ions were successfully incorporated into the sites of Ce{sup 3+} ions of the host lattice. The spectroscopy properties confirm the potentiality of present LiCe(PO{sub 3}){sub 4} doped with Eu{sup 3+} ions as luminophore host materials to produce an intense red luminescence at 628 nm corresponding to {sup 5}D{sub 0} → {sup 7}F{sub 2} emission level and have significant importance in the development of emission optical systems.

  12. [Study on spectroscopic characterization and property of PES/ micro-nano cellulose composite membrane material].

    Science.gov (United States)

    Tang, Huan-Wei; Zhang, Li-Ping; Li, Shuai; Zhao, Guang-Jie; Qin, Zhu; Sun, Su-Qin

    2010-03-01

    In the present paper, the functional groups of PES/micro-nano cellulose composite membrane materials were characterized by Fourier transform infrared spectroscopy (FTIR). Also, changes in crystallinity in composite membrane materials were analyzed using X-ray diffraction (XRD). The effects of micro-nano cellulose content on hydrophilic property of composite membrane material were studied by measuring hydrophilic angle. The images of support layer structure of pure PES membrane material and composite membrane material were showed with scanning electron microscope (SEM). These results indicated that in the infrared spectrogram, the composite membrane material had characteristic peaks of both PES and micro-nano cellulose without appearance of other new characteristics peaks. It revealed that there were no new functional groups in the composite membrane material, and the level of molecular compatibility was achieved, which was based on the existence of inter-molecular hydrogen bond association between PES and micro-nano cellulose. Due to the existence of micro-nano cellulose, the crystallinity of composite membrane material was increased from 37.7% to 47.9%. The more the increase in micro-nano cellulose mass fraction, the better the van de Waal force and hydrogen bond force between composite membrane material and water were enhanced. The hydrophilic angle of composite membrane material was decreased from 55.8 degrees to 45.8 degrees and the surface energy was raised from 113.7 to 123.5 mN x m(-2). Consequently, the hydrophilic property of composite membrane material was improved. The number of pores in the support layer of composite membrane material was lager than that of pure PES membrane. Apparently, pores were more uniformly distributed.

  13. Polarized spectroscopic properties of Er{sup 3+}:Ca{sub 9}Y(VO{sub 4}){sub 7} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Feifei [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou 350002 (China); University of Chinese Academy of Science, Beijing 100049 (China); Zhao, Wang [Anhui Key Laboratory of Low Temperature Co-fired Materials, Department of Physics, Huainan Normal University, Huainan, Anhui 232038 (China); Sun, Shijia; Zhang, Lizhen; Huang, Yisheng [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou 350002 (China); Lin, Zhoubin, E-mail: lzb@fjirsm.ac.cn [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou 350002 (China); Wang, Guofu [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou 350002 (China)

    2014-10-15

    An Er{sup 3+}-doped Ca{sub 9}Y(VO{sub 4}){sub 7} single crystal with dimensions of Ø 27×30 mm{sup 3} was grown successfully by Czochralski method. Its spectroscopic properties were investigated in detail. The absorption spectra show weak polarization effect, the absorption cross-sections at 801 nm are 6.36×10{sup −21} cm{sup 2} and 9.24×10{sup −21} cm{sup 2} for σ- and π-polarization, respectively. The emission cross sections at 1533 nm are 9.43×10{sup −21} cm{sup 2} for σ-polarization and 13.46×10{sup −21} cm{sup 2} for π-polarization. The fluorescence lifetime of the {sup 4}I{sub 13/2} manifold is 3.84 ms. When the population inversion parameter β≥0.2, laser emission will be realized in the tuning range of 1575 to 1615 nm for σ-polarization. The results show that Er{sup 3+}:Ca{sub 9}Y(VO{sub 4}){sub 7} crystal is a promising laser material for producing 1.5 μm laser. - Highlights: • Er{sup 3+}:Ca{sub 9}Y(VO{sub 4}){sub 7} crystal was grown successfully by the Czochralski method. • The spectral properties of the Er{sup 3+}:Ca{sub 9}Y(VO{sub 4}){sub 7} crystal was investigated. • Laser emission will be realized in the tuning range of 1505–1643 nm. • The results show that Er{sup 3+}:Ca{sub 9}Y( VO{sub 4}){sub 7} is a promising material for 1.5 μm laser.

  14. Deformed shell model studies of spectroscopic properties of 64Zn and 64Ni and the positron double beta decay of 64Zn

    Indian Academy of Sciences (India)

    R Sahu; V K B Kota

    2014-04-01

    The spectroscopic properties of 64Zn and 64Ni are calculated within the framework of the deformed shell model (DSM) based on Hartree–Fock states. GXPF1A interaction in 1 $f_{7/2}$, 2$p_{3/2}$, 1$f_{5/2}$ and 2$p_{1/2}$ space with 40Ca as the core is employed. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these two nuclei considered, nuclear transition matrix elements (NTME) for the neutrinoless positron double beta decay (0 + and 0 +EC) of 64Zn are calculated. The two-neutrino positron double beta decay halflife is also calculated for this nucleus.

  15. Reliable structural, thermodynamic, and spectroscopic properties of organic molecules adsorbed on silicon surfaces from computational modeling: the case of glycine@Si(100).

    Science.gov (United States)

    Carnimeo, Ivan; Biczysko, Malgorzata; Bloino, Julien; Barone, Vincenzo

    2011-10-06

    Chemisorption of glycine on Si(100) has been studied by an integrated computational strategy based on perturbative anharmonic computations employing geometries and harmonic force fields evaluated by hybrid density functionals coupled to purposely tailored basis sets. It is shown that such a strategy allows the prediction of spectroscopic properties of isolated and chemisorbed molecules with comparable accuracy, paving the route toward a detailed analysis of surface-induced changes of glycine vibrational spectra.

  16. Free base tetraazaporphine isolated in inert gas hosts: Matrix influence on its spectroscopic and photochemical properties

    Science.gov (United States)

    Henchy, Chris; McCaffrey, John G.; Arabei, Serguei; Pavich, Tatiana; Galaup, Jean-Pierre; Shafizadeh, Niloufar; Crépin, Claudine

    2014-09-01

    The absorption, fluorescence, and excitation spectra of free base tetraazaporphine (H2TAP) trapped in Ne, N2, and Ar matrices have been recorded at cryogenic temperatures. Normal Raman spectra of H2TAP were recorded in KBr discs and predicted with density functional theory (DFT) using large basis sets calculations. The vibrational frequencies observed in the Raman Spectrum exhibit reasonable agreement with those deduced from the emission spectra, as well as with frequencies predicted from large basis set DFT computations. The upper state vibrational frequencies, obtained from highly resolved, site selected excitation spectra, are consistently lower than the ground state frequencies. This contrasts with the situation in free base phthalocyanine, where the upper state shows little changes in vibrational frequencies and geometry when compared with the ground state. Investigations of the photochemical properties of H2TAP isolated in the three matrices have been performed using the method of persistent spectral hole-burning (PSHB). This technique has been used to reveal sites corresponding to distinct N-H tautomers which were not evident in the absorption spectra. An analysis of the holes and antiholes produced with PSHB in the Qx (0-0) absorption band made it possible to identify inter-conversion of distinct host sites.

  17. CALIBRATIONS BASED ON NEAR INFRARED SPECTROSCOPIC DATA TO ESTIMATE WOOD-CEMENT PANEL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Paulo Ricardo Gherardi Hein

    2009-11-01

    Full Text Available Some scientific contributions have used near infrared (NIR spectroscopy as a rapid and reliable tool for characterizing engineered wood products. However, to our knowledge, there are no published papers that used this technique in order to evaluate wood-cement panels. The main objective of this paper was to evaluate the ability of NIR spectroscopy to estimate physical and mechanical properties in wood-cement panels. The wood-cement panels were produced using Eucalyptus grandis x E. urophylla, Pinus taeda, and Toona ciliata woods with Portland cement under different manufacturing conditions. Wood-cement panels were characterized by traditional methods, and Partial Least Squares regressions were used to build calibrations. Our cross-validated models for MOR, IB, and TS24h of the panels yielded good coefficients of determination (0.80, 0.82, and 0.91, respectively. Based on the significant absorption bands and regression coefficients of the PLS models, our results indicate that cellulose and aromatic groups in lignin are components that play an important role in the calibrations.

  18. Crystal growth and spectroscopic properties of Cr3+-doped CaGdAlO4

    Science.gov (United States)

    Zhang, Zhu; Huang, Yisheng; Zhang, Lizhen; Sun, Shijia; Yuan, Feifei; Lin, Zhoubin

    2017-04-01

    A Cr3+:CaGdAlO4 single crystal with dimensions of ∅21 × 33 mm3 was grown successfully by Czochralski method for the first time. Its spectral properties including polarized absorption spectra, polarized fluorescence spectra, excitation spectrum and fluorescence decay curves were investigated in detail. The absorption cross-sections at around 573 nm corresponding to the 4A2 → 4T2 transition of Cr3+ ions are 4.75 × 10-20 and 2.56 × 10-20 cm2 for σ- and π-polarizations, respectively. The excitation spectrum shows two broad and intense absorption bands at about 390 nm and 570 nm, which are associated with the 4A2 → 4T1 and 4A2 → 4T2 transitions of Cr3+ ions, respectively. The emission band with peak at around 744 nm is ascribed to the 2E → 4A2 transition of Cr3+ ions, with the emission cross-sections of 5.55 × 10-22 and 5.41 × 10-22 cm2 for σ- and π-polarizations, respectively. The fluorescence lifetime is 4.35 ms at room temperature. The Dq/B value is 2.72, which means that Cr3+ ions occupy the lattice sites with strong crystal field strength. The results show that Cr3+:CaGdAlO4 crystal can be regarded as a potential laser gain medium.

  19. Spectroscopic studies of the electronic properties of regularly arrayed two-dimensional protein layers

    Energy Technology Data Exchange (ETDEWEB)

    Vyalikh, D V [Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden (Germany); Kirchner, A [BioNanotechnology and Structure Formation Group, Max Bergmann Centre of Biomaterials, Dresden University of Technology, D-01062 Dresden (Germany); Kade, A [Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden (Germany); Danzenbaecher, S [Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden (Germany); Dedkov, Yu S [Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden (Germany); Mertig, M [BioNanotechnology and Structure Formation Group, Max Bergmann Centre of Biomaterials, Dresden University of Technology, D-01062 Dresden (Germany); Molodtsov, S L [Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden (Germany)

    2006-04-05

    Photoemission (PE) and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy were applied to characterize electronic properties of the regular two-dimensional bacterial surface protein layer (S layer) of Bacillus sphaericus NCTC 9602, which is widely used as a protein template for the bottom-up fabrication of advanced metallic and hybrid nanostructures. PE and NEXAFS at the C 1s, O 1s, and N 1s core levels show similar chemical states for each oxygen atom and also for each nitrogen atom, while carbon atoms exhibit a range of chemical environments in different functional groups of the amino acids. A series of characteristic NEXAFS peaks were assigned to particular molecular orbitals of the amino acids by applying a phenomenological building-block model. It was found that the {pi} clouds of aromatic rings make the main contribution to both the lowest unoccupied and highest occupied molecular orbitals. The two-dimensional protein crystal shows a semiconductor-like behaviour with a gap value of {approx}3.0 eV and the Fermi energy close to the bottom of the LUMO.

  20. Synthesis, crystal structure, spectroscopic, thermal and dielectric properties of a novel semi-organic pentachloroantimonate (III)

    Science.gov (United States)

    Lahbib, Ikram; Rzaigui, Mohamed; Smirani, Wajda

    2016-09-01

    A new organic-inorganic hybrid material of formula (C10H15N2F)5(SbCl5)5.2H2O was synthesized and characterized by X-Ray diffraction analysis. It crystallizes in the monoclinic space group P21/c with the following unit cell parameters a = 15.819(4) Å, b = 17.685(3) Å, c = 30.529(4) Å, Z = 4 and V = 8540(3) Å3. The examination of the structure shows that the three-dimensional frameworks are produced by Nsbnd H⋯Cl, Nsbnd H⋯O, Csbnd H⋯Cl and Nsbnd H⋯F, Csbnd H⋯F hydrogen bonding and Cl⋯Cl interactions. IR, Raman and UV-Visible spectroscopies were also used to characterize this compound. In addition, the fluorescent properties of this compound have been investigated in the liquid state at room temperature. Differential scanning calorimetry (DSC) has revealed a structural phase transition of the order-disorder type around 370 K. Dielectric investigations revealed a step-wise change of the electric permittivity at Ttr characteristic of the crystal in the high-temperature phase. The evolution of dielectric constant as a function of temperature of the sample has been investigated in order to determine some related parameters. Measurements of AC conductivity as a function of frequency at different temperatures indicated a hopping conduction mechanism and/or reorientational motion.

  1. Spectroscopic properties and amplified spontaneous emission of fluorescein laser dye in ionic liquids as green media

    Science.gov (United States)

    AL-Aqmar, Dalal M.; Abdelkader, H. I.; Abou Kana, Maram T. H.

    2015-09-01

    The use of ionic liquids (ILs) as milieu materials for laser dyes is a promising field and quite competitive with volatile organic solvents and solid state-dye laser systems. This paper investigates some photo-physical parameters of fluorescein dye incorporated into ionic liquids; 1-Butyl-3-methylimidazolium chloride (BMIM Cl), 1-Butyl-3-methylimidazolium tetrachloroaluminate (BMIM AlCl4) and 1-Butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4) as promising host matrix in addition to ethanol as reference. These parameters are: absorption and emission cross-sections, fluorescence lifetime and quantum yield, in addition to the transition dipole moment, the attenuation length and oscillator strength were also investigated. Lasing characteristics such as amplified spontaneous emission (ASE), the gain, and the photostability of fluorescein laser dye dissolved in different host materials were assessed. The composition and properties of the matrix of ILs were found that it has great interest in optimizing the laser performance and photostability of the investigated laser dye. Under transverse pumping of fluorescein dye by blue laser diode (450 nm) of (400 mW), the initial ASE for dye dissolved in BMIM AlCl4 and ethanol were decreased to 39% and 36% respectively as time progressed 132 min. Relatively high efficiency and high fluorescence quantum yield (11.8% and 0.82% respectively) were obtained with good photostability in case of fluorescein in BMIM BF4 that was decreased to ∼56% of the initial ASE after continuously pumping with 400 mW for 132 min.

  2. Synthesis, spectroscopic and electrochemical studies of phosphoryl and carbomethoxyphenyl substituted corroles, and their anion detection properties.

    Science.gov (United States)

    Yadav, Pinky; Sankar, Muniappan

    2014-10-21

    The synthesis, electrochemical studies and anion detection properties of triphosphoryl () and triester corroles () are reported and compared with triphenylcorrole (). These corroles exhibited typical acid-base binding behaviour in CH3CN and were converted to monoprotonated and dianionic species, respectively. has shown a ∼30 fold lower Keq value for monoprotonation than that of in a TFA-CH3CN medium. The detection ability of these corroles was also tested in acetonitrile towards various anions. The observed spectral changes in free-base corroles () are due to anion-induced deprotonation rather than the hydrogen bonding interaction between the imino protons of the corrole moiety with anions. and have shown higher equilibrium constants with F(-) ions (4.7 × 10(3) fold higher for and 9.7 × 10(3) fold higher for ) as compared to and are able to detect 0.06 μM of F(-) ions. The Cu(iii) and Ag(iii) complexes of and exhibited an anodic shift of ∼250 mV in first ring oxidation and ∼100-150 mV in metal centred reduction as compared to the Cu(iii) and Ag(iii) complexes of . The anodic shift in the redox potentials, lower protonation constants and lower detection limit of anions have been explained in terms of the electron-withdrawing nature of the diethylphosphite and carbomethoxy substituents at the meso-phenyl positions of the corrole ring.

  3. Spectroscopic properties of nearby late-type stars, members of stellar kinematic groups

    CERN Document Server

    Maldonado, J; Eiroa, C; Montes, D; Montesinos, B

    2010-01-01

    Nearby late-type stars are excellent targets to look for young objects in stellar associations and moving groups. The study of these groups goes back more than one century ago however, their origin is still misunderstood. Although their existence have been confirmed by statistical studies of large sample of stars, the identification of a group of stars as member of moving groups, is not an easy task, list of members often change with time and most members have been identified by means of kinematics criteria which is not sufficient since many old stars can share the same spatial motion of those stars in moving groups. In this contribution we attempt to identify unambiguous moving groups members, among a sample of nearby-late type stars. High resolution echelle spectra is used to i) derive accurate radial velocities which allow us to study the stars' kinematics and make a first selection of moving groups members; and ii) analyze several age-related properties for young late-type stars (i.e., lithium LiI 6707.8 ...

  4. Spectroscopic study of terahertz reflection and transmission properties of carbon-fiber-reinforced plastic composites

    Science.gov (United States)

    Zhang, Jin; Shi, Changcheng; Ma, Yuting; Han, Xiaohui; Li, Wei; Chang, Tianying; Wei, Dongshan; Du, Chunlei; Cui, Hong-Liang

    2015-05-01

    Carbon-fiber-reinforced plastic (CFRP) composites are widely used in aerospace and concrete structure reinforcement due to their high strength and light weight. Terahertz (THz) time-domain spectroscopy is an attractive tool for defect inspection in CFRP composites. In order to improve THz nondestructive testing of CFRP composites, we have carried out systematic investigations of THz reflection and transmission properties of CFRP. Unidirectional CFRP composites with different thicknesses are measured with polarization directions 0 deg to 90 deg with respect to the fiber direction, in both reflection and transmission modes. As shown in the experiments, CFRP composites are electrically conducting and therefore exhibit a high THz reflectivity. In addition, CFRP composites have polarization-dependent reflectivity and transmissivity for THz radiation. The reflected THz power in the case of parallel polarization is nearly 1.8 times higher than for perpendicular polarization. At the same time, in the transmission of THz wave, a CFRP acts as a Fabry-Pérot cavity resulting from multiple internal reflections from the CFRP-air interfaces. Moreover, from the measured data, we extract the refractive index and absorption coefficient of CFRP composites in the THz frequency range.

  5. Dirty H2 Molecular Clusters as the DIB Sources: Spectroscopic and Physical Properties

    Science.gov (United States)

    Bernstein, L. S.; Clark, F. O.; Lynch, D. K.

    2014-02-01

    We propose that the diffuse interstellar bands (DIBs) arise from absorption lines of electronic transitions in molecular clusters primarily composed of a single molecule, atom, or ion (``seed''), embedded in a single-layer shell of H2 molecules (Bernstein et al. 2013). Less abundant variants of the cluster, including two seed molecules and/or a two-layer shell of H2 molecules may also occur. The lines are broadened, blended, and wavelength-shifted by interactions between the seed and surrounding H2 shell. We refer to these clusters as CHCs (Contaminated H2 Clusters). CHC spectroscopy matches the diversity of observed DIB spectral profiles, and provides good fits to several DIB profiles based on a rotational temperature of 10 K. CHCs arise from ~cm-sized, dirty H2 ice balls, called CHIMPs (Contaminated H2 Ice Macro-Particles), formed in cold, dense, Giant Molecular Clouds (GMCs), and later released into the interstellar medium (ISM) upon GMC disruption. Attractive interactions, arising from Van der Waals and ion-induced dipole potentials, between the seeds and H2 molecules enable CHIMPs to attain cm-sized dimensions. When an ultraviolet (UV) photon is absorbed in the outer layer of a CHIMP, it heats the icy matrix and expels CHCs into the ISM. While CHCs are quickly destroyed by absorbing UV photons, they are replenished by the slowly eroding CHIMPs. Since CHCs require UV photons for their release, they are most abundant at, but not limited to, the edges of UV-opaque molecular clouds, consistent with the observed, preferred location of DIBs. An inherent property of CHCs, which can be characterized as nanometer size, spinning, dipolar dust grains, is that they emit in the radio-frequency region. Thus, CHCs offer a natural explanation to the anomalous microwave emission (AME) feature in the ~10-100 GHz spectral region.

  6. Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of Co(II)- picolinate complex

    Energy Technology Data Exchange (ETDEWEB)

    Tamer, Ömer, E-mail: omertamer@sakarya.edu.tr; Avcı, Davut; Atalay, Yusuf

    2015-11-15

    A cobalt(II) complex of picolinate was synthesized, and its structure was fully characterized by the applying of X-ray diffraction method as well as FT-IR, FT-Raman and UV–vis spectroscopies. In order to both support the experimental results and convert study to more advanced level, density functional theory calculations were performed by using B3LYP level. Single crystal X-ray structural analysis shows that cobalt(II) ion was located to the center of distorted octahedral geometry. The C=O, C=C and C=N stretching vibrations were found as highly active and strong peaks, inducing the molecular charge transfer within Co(II) complex. The small energy gap between frontier molecular orbital energies was another indicator of molecular charge transfer interactions within Co(II) complex. The nonlinear optical properties of Co(II) complex were investigated at DFT/B3LYP level, and the hypepolarizability parameter was found to be decreased due to the presence of inversion symmetry. The natural bond orbital (NBO) analysis was performed to investigate molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength for Co(II) complex. Finally, molecular electrostatic potential (MEP) and spin density distributions for Co(II) complex were evaluated. - Highlights: • Co(II) complex of picolinate was prepared. • Its FT-IR, FT-Raman and UV–vis spectra were measured. • DFT calculations were performed to support experimental results. • Small HOMO-LUMO energy gap is an indicator of molecular charge transfer. • Spin density localized on Co(II) as well as O and N atoms.

  7. Spectroscopic properties and luminescence behaviour of europium doped lithium borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Anjaiah, J., E-mail: anjaiah.juluru@gmail.com [Department of Physics, The University of Dodoma, Tanzania, East Africa (Tanzania, United Republic of); Department of Physics, Geethanjali College of Engineering and Technology, Keesara, RR Dist., Hyderabad 501 301 (India); Laxmikanth, C. [Department of Physics, The University of Dodoma, Tanzania, East Africa (Tanzania, United Republic of); Veeraiah, N. [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar, Guntur 522 510, AP. (India)

    2014-12-01

    Li{sub 2}O–MO–B{sub 2}O{sub 3} (MO=ZnO, CaO and CdO) glasses doped with europium are prepared by using the melt quenching technique to study their absorption and luminescence properties to understand their lasing potentialities. The XRD pattern of the glasses confirmed the amorphous nature and the IR spectra reveal the presence of BO{sub 3} and BO{sub 4} units in the glass network. Judd–Ofelt intensity parameters Ω{sub λ} (λ=2, 4, 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. The J–O parameters have been used to calculate transition probabilities (A), lifetime (τ{sub R}), branching ratios (β{sub R}) and stimulated emission cross-section (σ{sub P}) for the {sup 5}D{sub 0}→{sup 7}F{sub J} (J=1–4) transitions of the Eu{sup 3+} ions. The decay from the {sup 5}D{sub 0} level of Eu{sup 3+} ions in these glasses has been measured and analysed. Branching ratios and stimulated emission cross-sections measured for all these glasses show that the {sup 5}D{sub 0}→{sup 7}F{sub 1} transition under investigation has the potential for laser applications. The high stimulated emission cross-section and branching ratios from the present glasses suggests their potential for infra red lasers. The study of the thermoluminescence is also carried out and the data suggests that the CdBEu glass is suitable for thermoluminescence emission output among the three Eu{sup 3+} doped glasses.

  8. Spectroscopic and laser properties of Er{sup 3+} doped fluoro-phosphate glasses as promising candidates for broadband optical fiber lasers and amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Babu, S. [Department of Physics, Sri Venkateswara University, Tirupati 517 502, A.P. (India); Seshadri, M. [Institute of Physics, University of Campinas, UNICAMP, P.O. Box 6165, Campinas 13083-970 (Brazil); Reddy Prasad, V. [Department of Physics, Sri Venkateswara University, Tirupati 517 502, A.P. (India); Ratnakaram, Y.C., E-mail: ratnakaramsvu@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati 517 502, A.P. (India)

    2015-10-15

    Highlights: • Erbium doped different fluoro-phosphate glasses are prepared and characterized. • Spectroscopic properties have been determined using Judd–Ofelt and Mc-Cumber theory. • Prominent laser transition Er{sup 3+}:{sup 4}I{sub 13/2} → {sup 4}I{sub 15/2} is observed at 1.53 μm. - Abstract: Different fluoro-phosphate glasses doped with 0.5 mol% Er{sup 3+} doped are prepared by melt quenching method. Both structural and spectroscopic properties have been characterized in order to evaluate their potential as both laser source and amplifier materials. Optical absorption measurements are carried out and analyzed through Judd–Ofelt and Mc-Cumber theories where spectroscopic parameters such as intensity parameters Ω{sub l} (λ = 2,4,6), transition probabilities, radiative lifetimes, stimulated absorption cross-sections and emission cross-sections at 1.5 μm have been evaluated for Er{sup 3+} doped different fluorophosphate glasses. The various luminescence and gain properties are explained from photoluminescence studies. The decay curve analysis have been done for obtaining the decay time constants of Er{sup 3+} excited level {sup 4}I{sub 13/2} in all the fluoro-phosphate glasses. The obtained results of each glass matrix are compared with the equivalent parameters for several other host glasses. These fluoro-phosphate glasses are found to be suitable candidates for laser and amplifier applications.

  9. Spectroscopic and Mechanical Properties of a New Generation of Bulk Fill Composites

    Science.gov (United States)

    Monterubbianesi, Riccardo; Orsini, Giovanna; Tosi, Giorgio; Conti, Carla; Librando, Vito; Procaccini, Maurizio; Putignano, Angelo

    2016-01-01

    Objectives: The aims of this study were to in vitro evaluate the degree of conversion and the microhardness properties of five bulk fill resin composites; in addition, the performance of two curing lamps, used for composites polymerization, was also analyzed. Materials and Methods: The following five resin-based bulk fill composites were tested: SureFil SDR®, Fill Up!™, Filtek™, SonicFill™, and SonicFill2™. Samples of 4 mm in thickness were prepared using Teflon molds filled in one increment and light-polymerized using two LED power units. Ten samples for each composite were cured using Elipar S10 and 10 using Demi Ultra. Additional samples of SonicFill2, (3 and 5 mm-thick) were also tested. The degree of conversion (DC) was determined by Raman spectroscopy, while the Vickers microhardness (VMH) was evaluated using a microhardness tester. The experimental evaluation was carried out on top and bottom sides, immediately after curing (t0), and, on bottom, after 24 h (t24). Two-ways analysis of variance was applied to evaluate DC and VMH-values. In all analyses, the level of significance was set at p < 0.05. Results: All bulk fill resin composites recorded satisfactory DCs on top and bottom sides. At t0, the top of SDR and SonicFill2 showed the highest DCs-values (85.56 ± 9.52 and 85.47 ± 1.90, respectively), when cured using Elipar S10; using Demi Ultra, SonicFill2 showed the highest DCs-values (90.53 ± 2.18). At t0, the highest DCs-values of bottom sides were recorded by SDR (84.64 ± 11.68), when cured using Elipar S10, and Filtek (81.52 ± 4.14), using Demi Ultra. On top sides, Demi Ultra lamp showed significant higher DCs compared to the Elipar S10 (p < 0.05). SonicFill2 reached suitable DCs also on bottom of 5 mm-thick samples. At t0, VMH-values ranged between 24.4 and 69.18 for Elipar S10, and between 26.5 and 67.3 for Demi Ultra. Using both lamps, the lowest VMH-values were shown by SDR, while the highest values by SonicFill2. At t24, all DC and VMH

  10. Influence of annealing temperature and Sn doping on the optical properties of hematite thin films determined by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Lígia P. de; Chaves, Rodrigo O. G.; Malachias, Angelo; Paniago, Roberto; Ferlauto, Andre S. [Department of Physics, Federal University of Minas Gerais, Belo Horizonte 31270-901 (Brazil); Ferreira, Sukarno O. [Department of Physics, Federal University of Viçosa, Viçosa 36570-900 (Brazil)

    2016-06-28

    Hematite (α-Fe{sub 2}O{sub 3}) thin films were prepared by sol-gel route and investigated for application in H{sub 2} generation by photo-assisted water splitting. The photoelectrochemical (PEC) performance was shown to increase significantly for films deposited on SnO{sub 2}:F/glass subjected to high temperature (T) annealing (>750 °C). Strong correlation was found between photogenerated current, donor concentration, and Sn concentration as determined by Mott-Schottky analysis and X-ray photoelectron spectroscopy. The effects of thermal annealing and Sn addition in the resulting microstructure and optical properties of hematite films deposited on fused silica substrates were determined by a combination of structural characterization techniques and spectroscopic ellipsometry. Thermal annealing (>600 °C) induces a higher optical absorption that is associated directly to film densification and grain growth; however, it promotes no changes in the energy positions of the main Fe{sub 2}O{sub 3} electronic transitions. The band gap energy was found to be 2.21 eV and independent of microstructure and of Sn concentration for all studied films. On the other hand, Sn can be incorporated in the Fe{sub 2}O{sub 3} lattice for concentration up to Sn/Fe ∼2%, leading to an increase in energy split of the main absorption peak, attributed to a distortion of the Fe{sub 2}O{sub 3} lattice. For higher concentrations, Sn incorporation leads to a reduction in absorption, associated with higher porosity and the formation of a secondary Sn-rich phase. In summary, the variation in the optical properties induced by thermal annealing and Sn addition cannot account for the order of magnitude increase of the current density generated by photoanodes annealed at high T (>750 °C); thus, it is concluded that the major contribution for the enhanced PEC performance comes from improved electronic properties induced by the n-type doping caused by Sn diffusion from the SnO{sub 2}:F

  11. Effects of mutations in active site heme ligands on the spectroscopic and catalytic properties of SoxAX cytochromes.

    Science.gov (United States)

    Kilmartin, James R; Bernhardt, Paul V; Dhouib, Rabeb; Hanson, Graeme R; Riley, Mark J; Kappler, Ulrike

    2016-09-01

    By attaching a sulfur substrate to a conserved cysteine of the SoxYZ carrier protein SoxAX cytochromes initiate the reaction cycle of the Sox (sulfur oxidation) multienzyme complex, which is the major pathway for microbial reoxidation of sulfur compounds in the environment. Despite their important role in this process, the reaction mechanism of the SoxAX cytochromes has not been fully elucidated. Here we report the effects of several active site mutations on the spectroscopic and enzymatic properties of the type II SoxAX protein from Starkeya novella, which in addition to two heme groups also contains a Cu redox centre. All substituted proteins contained these redox centres except for His231Ala which was unable to bind Cu(II). Substitution of the SoxA active site heme cysteine ligand with histidine resulted in increased microheterogeneity around the SoxA heme as determined by CW-EPR, while a SnSoxAX(C236A) substituted protein revealed a completely new, nitrogenous SoxA heme ligand. The same novel ligand was present in SnSoxAX(H231A) CW-EPR spectra, the first time that a ligand switch of the SoxA heme involving a nearby amino acid has been demonstrated. Kinetically, SnSoxAX(C236A) and SnSoxAX(C236H) showed reduced turnover, and in assays containing SoxYZ these mutants retained only ~25% of the wildtype activity. Together, these data indicate that the Cu redox centre can mediate a low level of activity, and that a possible ligand switch can occur during catalysis. It also appears that the SoxA heme cysteine ligand (and possibly the low redox potential) is important for an efficient reaction with SnSoxYZ/thiosulfate. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Synthesis, spectroscopic characterization and catalytic oxidation properties of ONO/ONS donor Schiff base ruthenium(III) complexes containing PPh3/AsPh3

    Indian Academy of Sciences (India)

    Priyarega; M Muthu Tamizh; R Karvembu; R Prabhakaran; K Natarajan

    2011-05-01

    Six different ruthenium(III) complexes of Schiff bases derived from 2-hydroxy-1-naphthaldehyde and -aminophenol/-aminothiophenol have been synthesized. The compounds with the general formula [RuX(EPh3)2(L)] (X = Cl or Br; E = P or As; L = bifunctional tridentate ONO/ONS donor Schiff base ligand) were characterized by infrared, electronic, electron paramagnetic resonance spectroscopy and elemental analyses. Spectroscopic investigation reveals coordination of Schiff base ligand through ONO/ONS donor atoms and octahedral geometry around ruthenium metal. Redox property of complexes has been examined by using cyclic voltammetry. The catalytic oxidation property of ruthenium(III) complexes were also investigated.

  13. Spectroscopic properties of tellurite glasses co-doped with Er{sup 3+} and Yb{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Leal, J.J. [Instituto Politécnico Nacional CICATA-Unidad Altamira, Tamaulipas 89600 (Mexico); Narro-García, R., E-mail: roberto.narro@gmail.com [Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-1010, Querétaro 76000, Querétaro México (Mexico); Desirena, H. [Centro de Investigaciones en Óptica, A.P. 1-948, León, Gto. 37150 (Mexico); Marconi, J.D. [Universidade Federal do ABC, SP (Brazil); Rodríguez, E. [Instituto Politécnico Nacional CICATA-Unidad Altamira, Tamaulipas 89600 (Mexico); Linganna, K. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); De la Rosa, E. [Centro de Investigaciones en Óptica, A.P. 1-948, León, Gto. 37150 (Mexico)

    2015-06-15

    Spectroscopic characterization of Er{sup 3+}/Yb{sup 3+} co-doped tellurite glasses 70.8TeO{sub 2}–5Al{sub 2}O{sub 3}–13K{sub 2}O–(11−x)–BaO–0.2Er{sub 2}O{sub 3}–xYb{sub 2}O{sub 3}, where x=0, 0.4, 0.8, 1.2 and 2 mol% has been carried out through X-ray diffraction, Raman, absorption and luminescence spectra. The Judd–Ofelt intensity parameters were calculated for 0.2 mol% Er{sup 3+}-doped glass and are used to evaluate radiative properties such as transition probabilities, branching ratios and radiative lifetime. The emission cross-section of the {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} transition has been calculated from the absorption data using McCumber's theory. The emission intensity of both, visible and infrared signals as a function of Yb{sub 2}O{sub 3}, have been studied under 980 nm and 375 nm laser excitation. The physical mechanisms responsible for both, visible and infrared signals in the tellurite samples have been explained in terms of the energy transfer and excited state absorption process. The FWHM of the {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} transition as a function of Yb{sub 2}O{sub 3} mol% and distance (δ) between the laser focusing point and the end-face of the glass has been reported. It was observed both, experimentally and numerically, a change in the FWHM with variations of δ less than 8 mm. The latter was attributed to the radiation trapping effect. - Highlights: • Er{sup 3+}/Yb{sup 3+} co-doped tellurite glasses were fabricated by the melt-quenching technique. • The structural, thermal and optical properties of the tellurite glasses were studied. • The radiation trapping effect has been observed in small tellurite glass samples. • Tellurite glasses could be a potential material for fiber fabrication.

  14. Optical properties and spectroscopic study of different modifier based Pr(3+):LiFB glasses as optical amplifiers.

    Science.gov (United States)

    Balakrishna, A; Babu, S; Kumar, Vinod; Ntwaeaborwa, O M; Ratnakaram, Y C

    2017-01-05

    In this paper, we report the preparation and optical characterization of Pr(3+) doped lithium fluoro borate (LiFB) glasses for six different chemical compositions of Li2B4O7-BaF2-NaF-MO (where M=Mg, Ca, Cd and Pb), Li2B4O7-BaF2-NaF-MgO-CaO and Li2B4O7-BaF2-NaF-CdO-PbO. The structural and optical properties of these glasses were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), optical absorption and photoluminescence techniques. The optical absorption spectra of Pr(3+) ions in LiFB glasses have been recorded in the UV-VIS-NIR region. The optical absorption data are used to calculate various spectroscopic parameters such as Racah (E(1), E(2), E(3)) and spin-orbit interaction (ξ4f) parameters. Judd-Ofelt (J-O) (Ωλ where λ=2, 4 and 6) intensity parameters were determined by applying J-O theory, which in turn used to calculate the radiative properties such as radiative transition probabilities (A), radiative lifetimes (τR), integrated absorption cross-sections (Σ) and branching ratios (βr) for all emission levels of Pr(3+) ion in different LiFB glass matrices. By using the J-O theory and luminescence parameters, stimulated emission cross sections (σp) of prominent transitions, (3)P0→(3)H4 and (1)D2→(3)H4 of Pr(3+) ion in all LiFB glasses were calculated. (3)P0→(3)H4 possesses higher branching ratios and stimulated emission cross-sections for the Pr(3+):LiFB(Mg-Ca) glass, which can be used as a best laser excitation. The optical gain parameter (σpxτR) was noticed higher in Pr(3+):LiFB(Mg-Ca) and Pr(3+):LiFB(Cd-Pb) glasses for the transition (3)P0→(3)H4 transition, and these glasses have potential for optical amplification at 488 nm wavelength.

  15. Optical properties and spectroscopic study of different modifier based Pr3 +:LiFB glasses as optical amplifiers

    Science.gov (United States)

    Balakrishna, A.; Babu, S.; Kumar, Vinod; Ntwaeaborwa, O. M.; Ratnakaram, Y. C.

    2017-01-01

    In this paper, we report the preparation and optical characterization of Pr3 + doped lithium fluoro borate (LiFB) glasses for six different chemical compositions of Li2B4O7-BaF2-NaF-MO (where M = Mg, Ca, Cd and Pb), Li2B4O7-BaF2-NaF-MgO-CaO and Li2B4O7-BaF2-NaF-CdO-PbO. The structural and optical properties of these glasses were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), optical absorption and photoluminescence techniques. The optical absorption spectra of Pr3 + ions in LiFB glasses have been recorded in the UV-VIS-NIR region. The optical absorption data are used to calculate various spectroscopic parameters such as Racah (E1, E2, E3) and spin-orbit interaction (ξ4f) parameters. Judd-Ofelt (J-O) (Ωλ where λ = 2, 4 and 6) intensity parameters were determined by applying J-O theory, which in turn used to calculate the radiative properties such as radiative transition probabilities (A), radiative lifetimes (τR), integrated absorption cross-sections (Σ) and branching ratios (βr) for all emission levels of Pr3 + ion in different LiFB glass matrices. By using the J-O theory and luminescence parameters, stimulated emission cross sections (σp) of prominent transitions, 3P0 → 3H4 and 1D2 → 3H4 of Pr3 + ion in all LiFB glasses were calculated. 3P0 → 3H4 possesses higher branching ratios and stimulated emission cross-sections for the Pr3 +:LiFB(Mg-Ca) glass, which can be used as a best laser excitation. The optical gain parameter (σpxτR) was noticed higher in Pr3 +:LiFB(Mg-Ca) and Pr3 +:LiFB(Cd-Pb) glasses for the transition 3P0→ 3H4 transition, and these glasses have potential for optical amplification at 488 nm wavelength.

  16. Spectroscopic and computational studies of a Ru(II) terpyridine complex: the importance of weak intermolecular forces to photophysical properties.

    Science.gov (United States)

    Garino, Claudio; Gobetto, Roberto; Nervi, Carlo; Salassa, Luca; Rosenberg, Edward; Ross, J B Alexander; Chu, Xi; Hardcastle, Kenneth I; Sabatini, Cristiana

    2007-10-15

    The complex [Ru(tpy)(CO)(2)TFA]+[PF(6)]- (where tpy = 2,2':6',2' '-terpyridine and TFA = CF(3)CO(2)-) (1) has been synthesized and fully characterized spectroscopically. The X-ray structure of the complex has been determined. The photopysical properties of the ruthenium complex and the free ligand tpy have been investigated at room temperature and at 77 K in acetonitrile solution and in the solid state. Their electronic spectra are highly influenced by intermolecular stacking interactions, both in solution and in the solid state. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations have been performed to characterize the electronic structure and the excited states of [Ru(tpy)(CO)(2)TFA]+[PF(6)]- and tpy. TDDFT calculations on three different conformations of free ligand have been performed as well. Absorption and emission spectra of tpy have been studied at different temperatures and concentrations in order to have a better understanding of this ruthenium derivative's properties. The absorption spectrum of 1 is characterized by metal-perturbed ligand-centered (LC) bands in the UV region. No metal-to-ligand charge transfer (MLCT) bands are observed in the visible for the complex. Only at high concentrations (10(-4) M) does a very weak band appear at 470 nm. At 77 K and low concentrations, solutions of 1 exhibit a major 3LC emission band centered at 468 nm (21.4 x 10(-3) cm(-1)). When the concentration of the complex is increased, an unstructured narrow emission at 603 nm (16.6 x 10(-3) cm(-1)), with a lifetime of 10 micros, dominates the emission spectrum in glassy acetonitrile. This emission originates from a pi-pi stacked dimeric (or oligomeric) species. TDDFT calculations performed on a tail-to-tail dimer structure, similar to that seen in the solid state, ascribe the transition to a triplet excited state, where intermolecular metal (d) --> ligand (pi*, polypyridine) charge transfer occurs. A good estimate of the transition energy is also

  17. Synthesis, Spectroscopic Properties and DFT Calculation of Novel Pyrrolo[1',5'-a]-1,8-naphthyridine Derivatives through a Facile One-pot Process

    Indian Academy of Sciences (India)

    GAO-ZHANG GOU; BO ZHOU; HE-PING YAN; YONG HONG; WEI LIU; SHAO-MING CHI; CHAO-YONG MANG

    2016-11-01

    Novel pyrrolo[1',5'-a]-1,8-naphthyridine compounds (L1-L4) have been synthesized through a facile one-pot process by the reaction of the corresponding 1,8-naphthyridines with aliphatic anhydride. The structures were established by spectroscopic data. Further, X-ray crystal analysis of 7-diacetamino-2,4-dimethy-1,8-naphthyridine (L1) identifies its molecular structure and reveals π-π stacking. The synthetic mechanisms for L2, L3 were studied by density functional theory calculations. And a comprehensive study of spectroscopic properties involving experimental data and theoretical studies is presented. L1 exhibited electronic absorption spectrum with λmax at ∼320 nm. L2-L4 exhibited similar electronic absorption spectra with λmax at ∼390 nm that is tentatively assigned to π→π* transition. The assignment was further supported by density functional theory (DFT) calculations.

  18. Quantum Chemical Study of the Solvent Effect on the Anticancer Active Molecule of Iproplatin: Structural, Electronic, and Spectroscopic Properties (IR, 1H NMR, UV)

    Science.gov (United States)

    Sadeghi, N.; Ghiasi, R.; Fazaeli, R.; Jamehbozorgi, S.

    2017-01-01

    The structural, electronic, and spectroscopic properties of the anticancer active molecule of iproplatin were investigated in the gas and liquid phases. Based on the polarizable continuum model (PCM), the solvent effect on the structural parameters, frontier orbitals, and spectroscopic parameters of the complex was investigated. The results indicate that the polarity of solvents plays a significant role in the structure and pro perties of the complex. 1H and 13C NMR chemical shifts were calculated using the Gauge-invariant atomic orbital (GIAO) method. Pt-Cl and Pt-OH bonds were investigated through a vibrational analysis. Moreover, time dependent density functional theory (TD-DFT) was used to calculate the energy, oscillatory strength, and wavelength absorption maximum (λmax) of electronic transitions and its nature within the complex.

  19. Harnessing the flexibility of peptidic scaffolds to control their copper(II)-coordination properties: a potentiometric and spectroscopic study.

    Science.gov (United States)

    Fragoso, Ana; Lamosa, Pedro; Delgado, Rita; Iranzo, Olga

    2013-02-04

    Designing small peptides that are capable of binding Cu(2+) ions mainly through the side-chain functionalities is a hard task because the amide nitrogen atoms strongly compete for Cu(2+) ion coordination. However, the design of such peptides is important for obtaining biomimetic small systems of metalloenyzmes as well as for the development of artificial systems. With this in mind, a cyclic decapeptide, C-Asp, which contained three His residues and one Asp residue, and its linear derivative, O-Asp, were synthesized. The C-Asp peptide has two Pro-Gly β-turn-inducer units and, as a result of cyclization, and as shown by CD spectroscopy, its backbone is constrained into a more defined conformation than O-Asp, which is linear and contains a single Pro-Gly unit. A detailed potentiometric, mass spectrometric, and spectroscopic study (UV/Vis, CD, and EPR spectroscopy) showed that at a 1:1 Cu(2+)/peptide ratio, both peptides formed a major [CuHL](2+) species in the pH range 5.0-7.5 (C-Asp) and 5.5-7.0 (O-Asp). The corrected stability constants of the protonated species (log K*(CuH(O-Asp))=9.28 and log K*(CuH(C-Asp))=10.79) indicate that the cyclic peptide binds Cu(2+) ions with higher affinity. In addition, the calculated value of K(eff) shows that this higher affinity for Cu(2+) ions prevails at all pH values, not only for a 1:1 ratio but even for a 2:1 ratio. The spectroscopic data of both [CuHL](2+) species are consistent with the exclusive coordination of Cu(2+) ions by the side-chain functionalities of the three His residues and the Asp residue in a square-planar or square-pyramidal geometry. Nonetheless, although these data show that, upon metal coordination, both peptides adopt a similar fold, the larger conformational constraints that are present in the cyclic scaffold results in different behaviour for both [CuHL](2+) species. CD and NMR analysis revealed the formation of a more rigid structure and a slower Cu(2+)-exchange rate for [CuH(C-Asp)](2+) compared

  20. Computational study of influence of diffuse basis functions on geometry optimization and spectroscopic properties of losartan potassium

    Science.gov (United States)

    Mizera, Mikołaj; Lewadowska, Kornelia; Talaczyńska, Alicja; Cielecka-Piontek, Judyta

    2015-02-01

    The work was aimed at investigating the influence of diffusion of basis functions on the geometry optimization of molecule of losartan in acidic and salt form. Spectroscopic properties of losartan potassium were also calculated and compared with experiment. Density functional theory method with various basis sets: 6-31G(d,p) and its diffused variations 6-31G(d,p)+ and 6-31G(d,p)++ was used. Application of diffuse basis functions in geometry optimization resulted in significant change of total molecule energy. Total molecule energy of losartan potassium decreased by 112.91 kJ/mol and 114.32 kJ/mol for 6-31G(d,p)+ and 6-31G(d,p)++ basis sets, respectively. Almost the same decrease was observed for losartan: 114.99 kJ/mol and 117.08 kJ/mol respectively for 6-31G(d,p)+ and 6-31G(d,p)++ basis sets. Further investigation showed significant difference within geometries of losartan potassium optimized with investigated basis sets. Application of diffused basis functions resulted in average 1.29 Å difference in relative position between corresponding atoms of three obtained geometries. Similar study taken on losartan resulted in only average 0.22 Å of dislocation. Extensive analysis of geometry changes in molecules obtained with diffused and non-diffuse basis functions was carried out in order to elucidate observed changes. The analysis was supported by electrostatic potential maps and calculation of natural atomic charges. UV, FT-IR and Raman spectra of losartan potassium were calculated and compared with experimental results. No crucial differences between Raman spectra obtained with different basis sets were observed. However, FT-IR spectra of geometry of losartan potassium optimized with 6-31G(d,p)++ basis set resulted in 40% better correlation with experimental FT-IR spectra than FT-IR calculated with geometry optimized with 6-31G(d,p) basis set. Therefore, it is highly advisable to optimize geometry of molecules with ionic interactions using diffuse basis functions

  1. Synthesis, Crystal Structure, Spectroscopic Properties and Potential Biological Activities of Salicylate‒Neocuproine Ternary Copper(II Complexes

    Directory of Open Access Journals (Sweden)

    Lenka Kucková

    2015-01-01

    Full Text Available Mixed ligand copper(II complexes containing derivatives of salicylic acid and heterocyclic ligands with nitrogen donor atoms have been the subject of various studies and reviews. In this paper, synthesis and characterization of the ternary copper(II complexes of neocuproine (2,9-dimethyl-1,10-phenanthroline, Neo and salicylate ligands (Sal are reported. In addition, the crystal structures of ([Cu(H2O(5-Cl-Sal(Neo] (1, [Cu(μ-Sal(Neo]2 (2, Cu2(μ-5-Cl-Sal(5-Cl-HSal2(Neo2]·EtOH (3 were determined. In order to compare structural and biological properties of the prepared complexes, spectroscopic and biological studies were performed. Results of X-ray diffraction show that prepared complexes form three types of crystal structures in a given system: monomeric, dimeric and dinuclear complex. The preliminary study on the DNA cleavage activity has shown that the complexes under study behave as the chemical nucleases in the presence of added hydrogen peroxide with slight differences in the activity (1 > 2 > 3. The complexes 1 and 2 exhibited nuclease activity itself indicating the interaction of complexes with the DNA. It has been proposed that the enhanced destructive effect of the complexes 1 and 2 on the DNA is a result of two possible mechanisms of action: (i the conversion of closed circular DNA (form I to the nicked DNA (form II caused by the copper complex itself and (ii damage of DNA by Reactive Oxygen Species (ROS—products of the interaction of copper with hydrogen peroxide by means of Fenton reaction (hydroxyl radicals. Thus the biological activity of the prepared Cu(II complexes containing derivatives of salicylic acid and phenanthroline molecules is substantiated by two independent mechanisms. While derivatives of salicylic acids in the coordination sphere of copper complexes are responsible for radical-scavenging activity (predominantly towards superoxide radical anion, the presence of chelating ligand 2,9-dimethyl-1,10-phenanthroline

  2. Using non-invasive molecular spectroscopic techniques to detect unique aspects of protein Amide functional groups and chemical properties of modeled forage from different sourced-origins.

    Science.gov (United States)

    Ji, Cuiying; Zhang, Xuewei; Yu, Peiqiang

    2016-03-05

    The non-invasive molecular spectroscopic technique-FT/IR is capable to detect the molecular structure spectral features that are associated with biological, nutritional and biodegradation functions. However, to date, few researches have been conducted to use these non-invasive molecular spectroscopic techniques to study forage internal protein structures associated with biodegradation and biological functions. The objectives of this study were to detect unique aspects and association of protein Amide functional groups in terms of protein Amide I and II spectral profiles and chemical properties in the alfalfa forage (Medicago sativa L.) from different sourced-origins. In this study, alfalfa hay with two different origins was used as modeled forage for molecular structure and chemical property study. In each forage origin, five to seven sources were analyzed. The molecular spectral profiles were determined using FT/IR non-invasive molecular spectroscopy. The parameters of protein spectral profiles included functional groups of Amide I, Amide II and Amide I to II ratio. The results show that the modeled forage Amide I and Amide II were centered at 1653 cm(-1) and 1545 cm(-1), respectively. The Amide I spectral height and area intensities were from 0.02 to 0.03 and 2.67 to 3.36 AI, respectively. The Amide II spectral height and area intensities were from 0.01 to 0.02 and 0.71 to 0.93 AI, respectively. The Amide I to II spectral peak height and area ratios were from 1.86 to 1.88 and 3.68 to 3.79, respectively. Our results show that the non-invasive molecular spectroscopic techniques are capable to detect forage internal protein structure features which are associated with forage chemical properties.

  3. Using non-invasive molecular spectroscopic techniques to detect unique aspects of protein Amide functional groups and chemical properties of modeled forage from different sourced-origins

    Science.gov (United States)

    Ji, Cuiying; Zhang, Xuewei; Yu, Peiqiang

    2016-03-01

    The non-invasive molecular spectroscopic technique-FT/IR is capable to detect the molecular structure spectral features that are associated with biological, nutritional and biodegradation functions. However, to date, few researches have been conducted to use these non-invasive molecular spectroscopic techniques to study forage internal protein structures associated with biodegradation and biological functions. The objectives of this study were to detect unique aspects and association of protein Amide functional groups in terms of protein Amide I and II spectral profiles and chemical properties in the alfalfa forage (Medicago sativa L.) from different sourced-origins. In this study, alfalfa hay with two different origins was used as modeled forage for molecular structure and chemical property study. In each forage origin, five to seven sources were analyzed. The molecular spectral profiles were determined using FT/IR non-invasive molecular spectroscopy. The parameters of protein spectral profiles included functional groups of Amide I, Amide II and Amide I to II ratio. The results show that the modeled forage Amide I and Amide II were centered at 1653 cm- 1 and 1545 cm- 1, respectively. The Amide I spectral height and area intensities were from 0.02 to 0.03 and 2.67 to 3.36 AI, respectively. The Amide II spectral height and area intensities were from 0.01 to 0.02 and 0.71 to 0.93 AI, respectively. The Amide I to II spectral peak height and area ratios were from 1.86 to 1.88 and 3.68 to 3.79, respectively. Our results show that the non-invasive molecular spectroscopic techniques are capable to detect forage internal protein structure features which are associated with forage chemical properties.

  4. UV-visible spectroscopic analysis of electrical properties in alkali metal-doped amorphous zinc tin oxide thin-film transistors.

    Science.gov (United States)

    Lim, Keon-Hee; Kim, Kyongjun; Kim, Seonjo; Park, Si Yun; Kim, Hyungjun; Kim, Youn Sang

    2013-06-04

    Solution-processed and alkali metals, such as Li and Na, are introduced in doped amorphous zinc tin oxide (ZTO) semiconductor TFTs, which show better electrical performance, such as improved field effect mobility, than intrinsic amorphous ZTO semiconductor TFTs. Furthermore, by using spectroscopic UV-visible analysis we propose a comprehensive technique for monitoring the improved electrical performance induced by alkali metal doping in terms of the change in optical properties. The change in the optical bandgap supported by the Burstein-Moss theory could successfully show a mobility increase that is related to interstitial doping of alkali metal in ZTO semiconductors.

  5. Spectroscopic properties and near-infrared broadband luminescence of Bi-doped SrB4O7 glasses and crystalline materials.

    Science.gov (United States)

    Su, Liangbi; Zhou, Peng; Yu, Jun; Li, Hongjun; Zheng, Lihe; Wu, Feng; Yang, Yan; Yang, Qiuhong; Xu, Jun

    2009-08-03

    Spectroscopic properties of Bi-doped SrB(4)O(7) glasses, sintered compounds, polycrystalline materials, and single crystals were investigated. Broadband near-infrared luminescence was realized in Bi-doped SrB(4)O(7) glasses with basicity and polycrystalline materials with non-bridging oxygens. In Bi:SrB(4)O(7) single crystals, only visible luminescence of Bi(3+) and Bi(2+) was observed, but no near-infrared. The rigid three-dimensional network of SrB(4)O(7) crystal is proved to be unfavorable for accommodation of Bi(+) ions.

  6. Compositional dependence of optical interband transition energies in GeSn and GeSiSn alloys

    Science.gov (United States)

    Xu, Chi; Senaratne, Charutha L.; Kouvetakis, John; Menéndez, José

    2015-08-01

    The dielectric functions of GeSn and GeSiSn alloys were measured in the 1-6 eV energy range using spectroscopic ellipsometry. The contributions from the E1, E1 + Δ1, E0‧, E2, and E1‧ critical points in the joint density of electronic states were enhanced by computing numerical second derivatives of the measured dielectric function, and the resulting lineshapes were fitted with model expressions from which the critical point energies, amplitudes, broadenings, and phases were determined. A detailed analysis of the compositional dependence of the different transition energies is presented. By describing this dependence in terms of quadratic polynomials, the bowing parameter (quadratic coefficient) for each transition is determined. It is shown that the bowing parameters in the ternary alloy follow a distinct chemical trend, in which the ternary is well described in terms of bowing parameters for the underlying binary alloys, and these bowing parameters increase as a function of the size and electronegativity mismatch of the alloy constituents.

  7. Compositional dependence of the band gap in Ga(NAsP) quantum well heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Jandieri, K., E-mail: kakhaber.jandieri@physik.uni-marburg.de; Ludewig, P.; Wegele, T.; Beyer, A.; Kunert, B.; Springer, P.; Baranovskii, S. D.; Koch, S. W.; Volz, K.; Stolz, W. [Materials Science Center and Faculty of Physics, Philipps-University Marburg, Marburg (Germany)

    2015-08-14

    We present experimental and theoretical studies of the composition dependence of the direct band gap energy in Ga(NAsP)/GaP quantum well heterostructures grown on either (001) GaP- or Si-substrates. The theoretical description takes into account the band anti-crossing model for the conduction band as well as the modification of the valence subband structure due to the strain resulting from the pseudomorphic epitaxial growth on the respective substrate. The composition dependence of the direct band gap of Ga(NAsP) is obtained for a wide range of nitrogen and phosphorus contents relevant for laser applications on Si-substrate.

  8. Structure and spectroscopic properties of neutral and cationic tetratomic [C,H,N,Zn] isomers: A theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Redondo, Pilar; Largo, Antonio; Vega-Vega, Álvaro; Barrientos, Carmen, E-mail: cbb@qf.uva.es [Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47011 Valladolid (Spain)

    2015-05-14

    The structure and spectroscopic parameters of the most relevant [C,H,N,Zn] isomers have been studied employing high-level quantum chemical methods. For each isomer, we provide predictions for their molecular structure, thermodynamic stabilities as well as vibrational and rotational spectroscopic parameters which could eventually help in their experimental detection. In addition, we have carried out a detailed study of the bonding situations by means of a topological analysis of the electron density in the framework of the Bader’s quantum theory of atoms in molecules. The analysis of the relative stabilities and spectroscopic parameters suggests two linear isomers of the neutral [C,H,N,Zn] composition, namely, cyanidehydridezinc HZnCN ({sup 1}Σ) and hydrideisocyanidezinc HZnNC ({sup 1}Σ), as possible candidates for experimental detections. For the cationic [C,H,N,Zn]{sup +} composition, the most stable isomers are the ion-molecule complexes arising from the direct interaction of the zinc cation with either the nitrogen or carbon atom of either hydrogen cyanide or hydrogen isocyanide, namely, HCNZn{sup +} ({sup 2}Σ) and HCNZn{sup +} ({sup 2}Σ)

  9. Structure and spectroscopic properties of neutral and cationic tetratomic [C,H,N,Zn] isomers: A theoretical study.

    Science.gov (United States)

    Redondo, Pilar; Largo, Antonio; Vega-Vega, Álvaro; Barrientos, Carmen

    2015-05-14

    The structure and spectroscopic parameters of the most relevant [C,H,N,Zn] isomers have been studied employing high-level quantum chemical methods. For each isomer, we provide predictions for their molecular structure, thermodynamic stabilities as well as vibrational and rotational spectroscopic parameters which could eventually help in their experimental detection. In addition, we have carried out a detailed study of the bonding situations by means of a topological analysis of the electron density in the framework of the Bader's quantum theory of atoms in molecules. The analysis of the relative stabilities and spectroscopic parameters suggests two linear isomers of the neutral [C,H,N,Zn] composition, namely, cyanidehydridezinc HZnCN ((1)Σ) and hydrideisocyanidezinc HZnNC ((1)Σ), as possible candidates for experimental detections. For the cationic [C,H,N,Zn](+) composition, the most stable isomers are the ion-molecule complexes arising from the direct interaction of the zinc cation with either the nitrogen or carbon atom of either hydrogen cyanide or hydrogen isocyanide, namely, HCNZn(+) ((2)Σ) and HCNZn(+) ((2)Σ).

  10. Optoelectronic and ferroelectric properties of cerium-doped (Na(0.5)Bi(0.5))(Ti(0.99)Fe(0.01))O3 nanocrystalline films on (111) Pt/TiO2/SiO2/Si: a composition-dependent study.

    Science.gov (United States)

    Zhang, Si; Han, Meijie; Zhang, Jinzhong; Li, Yawei; Hu, Zhigao; Chu, Junhao

    2013-04-24

    The optical and ferroelectric properties of (Na0.5Bi0.5)1-xCex(Ti0.99Fe0.01)O3 (NBCTFx; 0 ≤ x ≤ 0.10) nanocrystalline films deposited on platinized silicon (Pt/TiO2/SiO2/Si) substrates using a sol-gel method were investigated. The microstructure, surface, and cross-sectional morphology and compositions of the films were analyzed by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy, respectively. The X-ray diffraction patterns indicate that all films are polycrystalline and show the single perovskite structure. The dielectric functions of the NBCTFx films can be uniquely extracted by fitting the measured ellipsometric spectra with a four-phase-layered model (air/surface rough layer/NBCTFx/Pt) in the photon energy range of 0.6-6.4 eV. The Tauc-Lorentz model was successfully applied and reasonably describes the spectral response behavior of ferroelectric NBCTFx films in the light-frequency region. It was found that the optical band gap and grain size decrease with increasing cerium composition because of the introduction of disorder and defects. The electrical results show that the leakage current density of the films was decreased with increasing cerium composition by reducing the density of oxygen vacancies and forming the defect complexes. The optimal ferroelectric properties were obtained in the film doped with x = 0.10, whose remnant polarization and coercive field values are 14.9 μC/cm(2) and 217.3 kV/cm, respectively. The present results could be crucial for future applications of lead-free ferroelectric and optoelectronic devices.

  11. Compositional dependences of average positron lifetime in binary As-S/Se glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ingram, A. [Department of Physics of Opole University of Technology, 75 Ozimska str., Opole, PL-45370 (Poland); Golovchak, R., E-mail: roman_ya@yahoo.com [Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Kostrzewa, M.; Wacke, S. [Department of Physics of Opole University of Technology, 75 Ozimska str., Opole, PL-45370 (Poland); Shpotyuk, M. [Lviv Polytechnic National University, 12, Bandery str., Lviv, UA-79013 (Ukraine); Shpotyuk, O. [Institute of Physics of Jan Dlugosz University, 13/15al. Armii Krajowej, Czestochowa, PL-42201 (Poland)

    2012-02-15

    Compositional dependence of average positron lifetime is studied systematically in typical representatives of binary As-S and As-Se glasses. This dependence is shown to be in opposite with molar volume evolution. The origin of this anomaly is discussed in terms of bond free solid angle concept applied to different types of structurally-intrinsic nanovoids in a glass.

  12. C,C- and N,C-coupled dimers of 2-aminotetraphenylporphyrins: regiocontrolled synthesis, spectroscopic properties, and quantum-chemical calculations.

    Science.gov (United States)

    Bruhn, Torsten; Witterauf, Franziska; Götz, Daniel C G; Grimmer, Carina T; Würtemberger, Max; Radius, Udo; Bringmann, Gerhard

    2014-04-01

    β,β'-Bisporphyrins are intrinsically chiral porphyrin dimers with fascinating properties. The configurational stability at their axes can be directed by variation of the central metal atoms. Herein, we present a regioselective functionalization of the monomeric 2-amino-tetraphenyl-porphyrin as a versatile substrate for dimerization by oxidative coupling. By simple variation of the reaction conditions (solvent and oxidant), the oxidation selectively gave either the axially chiral C,C-coupled diaminobisporphyrin in high yields or, under Ullmann conditions, the twofold N,C-linked achiral dimer, also in good yields. A generalized mechanism for the coupling reaction is proposed based on DFT calculations. The axially chiral β,β'-coupled porphyrin dimers were isolated as racemic mixtures, but can be resolved by HPLC on a chiral phase. TDDFT and coupled-cluster calculations were used to explain the spectroscopic properties of the aminoporphyrins and their dimers and to elucidate the absolute configurations of the C,C-coupled bisporphyrins.

  13. Spectroscopic Properties and Laser Performance of Resonantly-Pumped Cryo-Cooled Er3+:GdVO4

    Science.gov (United States)

    2012-03-12

    conductivity in GdVO4, YVO4, and Y3Al5O12 measured by quasi- one-dimensional flash method ,” Opt. Express 14(22), 10528–10536 (2006). 10. J. Didierjean, E...Spectroscopy For spectroscopic characterization, we used an Er 3+ :GdVO4 crystal grown by the Czochralski technique with a doping concentration of 0.5% (NEr...σemi) of the 4 I13/2 → 4 I15/2 transitions in both polarizations, calculated using the standard Fuchtbauer-Landenburg method [14], are shown in Fig

  14. Composition Dependence of Dynamic Heterogeneity Time- and Length Scales in [Omim][BF4]/Water Binary Mixtures: Molecular Dynamics Simulation Study.

    Science.gov (United States)

    Pal, Tamisra; Biswas, Ranjit

    2015-12-24

    Composition dependence of four-point dynamic susceptibilities, overlap functions, and other dynamic heterogeneity (DH) parameters have been investigated by using all-atom molecular dynamics simulations for aqueous solutions of the ionic liquid (IL), 1-octyl-3-methyl imidazolium tetrafluoroborate ([Omim][BF4]) covering the pure-to-pure range. Upon addition of water in the IL, the DH time scales become faster and the four-point dynamic susceptibility time scale softens. Evidences for jump motions for both water and ions have been found from the simulated single particle displacements that show strong deviation from Gaussian distribution. Estimated dynamic correlation length for water reflects effects of IL, whereas those for ions remain largely insensitive to the mixture composition. Simulated structural aspects and DH time scales provide microscopic explanations to the existing experimental observations from time-resolved fluorescence and Kerr spectroscopic measurements.

  15. A new perspective on vanadyl tartrate dimers. Part II. Structure and spectroscopic properties of calcium vanadyl tartrate tetrahydrate

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Jaca, J.; Rojo, T.; Pizarro, J.L.; Goni, A.; Arriortua, M.I. [Universidad del Pais Vasco, Bilbao (Spain)

    1993-12-31

    The calcium vanadyl tartrate complex [Ca(VO)(d,l-C{sub 4}H{sub 2}O{sub 6})(H{sub 2}O){sub 4}] has been synthesized and characterized by spectroscopic methods. Its crystal structure was solved by X-ray metods. The compound is monoclinic, space group P2{sub 1/c}, with a = 8.0282(5), b = 17.1568(8), c = 7.6113(3) {angstrom}, {beta} = 94.269(4){degrees} and Z = 4. The structure consists of centrosymmetric vanadyl tartrate dimers, [(VO)(d,l-C{sub 4}H{sub 2}O{sub 6})]{sup 4{minus}}{sub 2}, and calcium cations placed between them. As a result, dimers form chains in the [101] direction. Neighbouring chains are linked by the coordination of the calcium ion to the oxygen atom of a vanadyl group of a different chain, thus forming a two-dimensional structure. Different layers are linked by hydrogen bonds. Spectroscopic studies show the existence of intra-dimeric interactions between vanadium atoms. 23 refs., 4 figs., 5 tabs.

  16. Synthesis, Spectroscopic, Anticancer, and Antimicrobial Properties of Some Metal(II Complexes of (Substituted Nitrophenol Schiff Base

    Directory of Open Access Journals (Sweden)

    Aderoju A. Osowole

    2012-01-01

    Full Text Available The Schiff base, 2-[(2,3-dihydro-1H-inden-4-yliminomethyl]-5-nitrophenol coordinates to Mn(II, Cu(II, Zn(II, and Pd(II ions through the phenolic O and imine N atoms. The complexes are characterized by physicochemical and spectroscopic methods. The metal complexes formed as [ML2]xH2O with exception of the Cu(II complex which is anhydrous. Spectroscopic data corroborate the adoption of a four-coordinate, tetrahedral geometry for the Mn(II, and Zn(II complexes, and a four-coordinate, square planar geometry for the Cu(II and Pd(II complexes. None is an electrolyte in DMSO. The in vitro anticancer activities of the metal free ligand, Cu(II, Zn(II, and Pd(II complexes against MCF-7 (human breast adenocarcinoma and HT-29 (colon carcinoma cells reveal that the Pd(II complex has the best cytotoxic activity against MCF-7 cells with an IC50 of 5.94 μM, which is within the same order of activity as cisplatin. Furthermore, the ligand and the Zn(II complex exhibit broad-spectrum activity against two gram-positive bacteria, three gram-negative bacteria, and a fungus with inhibitory zones range of 10.0–20.0 and 10.0–17.0 mm, respectively.

  17. Influence of different amino substituents in position 1 and 4 on spectroscopic and acid base properties of 9,10-anthraquinone moiety.

    Science.gov (United States)

    Wcisło, Anna; Niedziałkowski, Paweł; Wnuk, Elżbieta; Zarzeczańska, Dorota; Ossowski, Tadeusz

    2013-05-01

    A series of novel 1-amino and 1,4-diamino-9,10-anthraquinones, substituted with different alkyl groups, were synthesized as the result of alkylation with amino substituents. All the obtained aminoanthraquinone derivatives were characterized by NMR, IR spectroscopy and mass spectrometry. The spectroscopic properties of these compounds were determined by using UV-Vis spectroscopy in acetonitrile, and in the mixture of acetonitrile and methanol at different pH ranges. The effects of various substituents present in the newly developed anthraquinone derivatives and their ability to form hydrogen bonds between the carbonyl oxygen atom of anthraquinone moiety and nitrogen atom of N-H group in 1-aminoanthraquinone (1-AAQ) and 1,4-diaminoanthraquinone (1,4-DAAQ) were studied. Additionally, the effects of hydrogen bond formation between O-H group in hydroxyethylamino substituent and the carbonyl oxygen atom of anthraquinone were investigated. The spectroscopic behavior of the studied derivatives strongly depended on the solvent-solute interactions and the nature of solvent. The values of pKa for the new anthraquinones were determined by the combined potentiometric and spectrophotometric titration methods.

  18. A study on the spectroscopic, energy band, and optoelectronic properties of α,ω-dihexylsexithiophene/tris(8-hydroxyquinolinate) gallium blends; DH6T/Gaq3 composite system

    Science.gov (United States)

    Muhammad, Fahmi F.; Yahya, Mohd Yazid; Ketuly, Kamal Aziz; Muhammad, Abdulkader Jaleel; Sulaiman, Khaulah

    2016-12-01

    In this work the optical response, spectroscopic behaviour, and optoelectronic properties of solution and solid state composite systems based on α,ω-dihexylsexithiophene/tris(8-hydroxyquinolinate) gallium (DH6T/Gaq3) are studied upon the incorporation of different molar percentages of Gaq3. UV-vis, PL, FTIR spectrophotometers and SEM technique were utilized to perform the investigations. The results showed a reduced energy band (Eg) (from 2.33 eV to 1.83 eV) and a broadened absorption spectrum for the blend system when 29.8% molar of Gaq3 was incorporated. These were attributed to the enhanced intermolecular interactions that are brought about by the increased strength of π - π overlap between the molecular moieties. A mathematical formula was developed to interpret the non-monotonic change occurred in Eg, while numerical calculations have been made to assign the type and nature of the electronic transitions governing the spectroscopic behaviour of the system. The results were elaborated and comprehensively discussed in terms of the exciton generation, energy band theory, molecular interactions, and spatial geometry.

  19. Spectroscopic and quantum chemical investigations of substituent effects on the azo-hydrazone tautomerism and acid-base properties of arylazo pyridone dyes.

    Science.gov (United States)

    Dostanić, J; Mijin, D; Ušćumlić, G; Jovanović, D M; Zlatar, M; Lončarević, D

    2014-04-05

    A series of 5-(4-substituted arylazo)-6-hydroxy-4-methyl-3-cyano-2-pyridone dyes was synthesized and the structure of the dyes was confirmed by UV-Vis, FT-IR, (1)H NMR and (13)C NMR spectroscopic techniques. The azo-hydrazone tautomeric equilibrium was found to depend on the substituents as well as on the acidity and basicity of the media. Ionization constant, pKa, of the dyes was determined by UV-Vis spectroscopy and correlated with the Hammett substituent constants, σp and σI. The interpretation of the effect of different substituent in phenyl ring of arylazo pyridone dyes on their spectroscopic and structural properties was based on quantum chemical calculations performed by the density functional theory (DFT/M06-2X) method. The DFT calculations confirmed the existence of two forms in water solution: hydrazone form in acidic and neutral media and anionic form in basic media. The different contribution of azo and hydrazone canonical forms of anionic form is observed for dyes with electron-donating and dyes with electron-withdrawing groups. The dependence of absorption spectra and determined pKa values to the substituent type seems to be mostly due to azo/hydrazone canonical structure ratio in their anionic form. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Spectral classification and properties of the O Vz stars in the Galactic O-Star Spectroscopic Survey (GOSSS)

    CERN Document Server

    Arias, Julia I; Simon-Diaz, Sergio; Barba, Rodolfo H; Apellaniz, Jesus Maiz; Sabin-Sanjulian, Carolina; Gamen, Roberto C; Morrell, Nidia I; Sota, Alfredo; Marco, Amparo; Negueruela, Ignacio; Leao, Joao R S; Herrero, Artemio; Alfaro, Emilio J

    2016-01-01

    On the basis of the Galactic O-Star Spectroscopic Survey (GOSSS), a detailed systematic investigation of the O Vz stars is presented. The currently used spectral classification criteria are rediscussed, and the Vz phenomenon is recalibrated through the addition of a quantitative criterion based on the equivalent widths of the He I 4471, He II 4542, and He II 4686 spectral lines. The GOSSS O Vz and O V populations resulting from the newly adopted spectral classification criteria are comparatively analyzed. The locations of the O Vz stars are probed, showing a concentration of the most extreme cases toward the youngest star forming regions. The occurrence of the Vz spectral peculiarity in a solar-metallicity environment, as predicted by the fastwind code, is also investigated, confirming the importance of taking into account several processes for the correct interpretation of the phenomenon.

  1. Mechanical properties of NiO/Ni-YSZ composites depending on temperature, porosity and redox cycling

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Kaiser, Andreas; Mogensen, Mogens Bjerg

    2009-01-01

    with the Neel temperature, 250 degrees C, of NiO was observed. Above this temperature, a linear decrease occurred. Specific damping showed a peak at 170-180 degrees C and increased above ca. 1000 degrees C in NiO-YSZ. In the reduced state the elastic modulus decreased linearly with temperature; specific damping......The Impulse Excitation Technique (IET) was used to determine the elastic modulus and specific damping of different Ni/NiO-YSZ composites suitable for use in solid oxide fuel cells (SOFC). The porosity of the as-sintered samples varied from 9 to 38% and that of the reduced ones from 31 to 52...

  2. Compositional Dependence of Structural Properties of Prepared PbS1− Alloys and Films

    Directory of Open Access Journals (Sweden)

    M. F. A. Alias

    2011-01-01

    Full Text Available Results of a study of PbS1− alloys and films with various Pb content have been reported and discussed. Films of PbS1− of thickness 1.5 μm have been deposited on glass substrates by flash thermal evaporation method at room temperature, under vacuum at constant deposition rate. These films were annealed under vacuum around 10−6 Torr at different temperatures up to 523 K. The composition of the elements in PbS1− alloys was determined by standard surfaces techniques such as atomic absorption spectroscopy (AAS and X-ray fluorescence (XRF, and the results were found of high accuracy and in very good agreement with the theoretical values. The structure for alloys and films is determined by using X-ray diffraction. This measurement reveals that the structure is polycrystalline with cubic structure and there are strong peaks at the direction (200 and (111. The effect of heat treatment on the crystalline orientation, relative intensity, and grain size of PbS1− films is presented.

  3. Synthesis by coprecipitation technique and spectroscopic properties of some phosphates. [Yttrium or rare earth and potassium and alkaline earth metal phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Arbus, A.; Duranceau, C.; Zambon, D.; Cousseins, J.C. (Clermont-Ferrand-2 Univ., 63 - Aubiere (FR))

    1991-01-01

    The coprecipitation process has been used for the synthesis of some KBLn(PO{sub 4}){sub 2} compounds where B is an alkaline earth metal and Ln a lanthanide or yttrium. After the gel stage, an amorphous powder is obtained by drying, the thermal evolution of which is studied by X-ray diffraction. The temperature of calcination for the different powders is included in the 500-700{sup 0}C range, lower than that of the classical solid state synthesis, 800-1000{sup 0}C. The final phosphates crystallize with monoclinic or tetragonal symmetry. The spectroscopic properties of some Eu{sup 3+}-doped compounds prepared by coprecipitation technique are reported.

  4. Molecular structure and spectroscopic properties of 4-nitrocatechol at different pH: UV-visible, Raman, DFT and TD-DFT calculations

    Energy Technology Data Exchange (ETDEWEB)

    Cornard, Jean-Paul [Laboratoire de Spectrochimie Infrarouge and Raman LASIR, CNRS UMR 8516, Universite des Sciences et Technologies de Lille Bat C5, 59655 Villeneuve d' Ascq Cedex (France)]. E-mail: cornard@univ-lille1.fr; Rasmiwetti [Laboratoire de Spectrochimie Infrarouge and Raman LASIR, CNRS UMR 8516, Universite des Sciences et Technologies de Lille Bat C5, 59655 Villeneuve d' Ascq Cedex (France); Merlin, Jean-Claude [Laboratoire de Spectrochimie Infrarouge and Raman LASIR, CNRS UMR 8516, Universite des Sciences et Technologies de Lille Bat C5, 59655 Villeneuve d' Ascq Cedex (France)

    2005-03-14

    We investigated theoretically, by density functional theoretical calculations and by vibrational and electronic spectroscopies, the structure and the molecular spectroscopic properties of the 4-nitrocatechol molecule with varying pH. The lower energy stable structures of the neutral, monoanion and dianion forms were compared, and influence of water solvation was examined. The Raman and UV-visible spectra of 4-nitrocatechol and of its singly deprotonated form were recorded by varying the pH from 2 to 9. A calculation of the vibrational frequencies has allowed a complete assignment of the Raman spectra of the two forms of 4-nitrocatechol, and has permitted to investigate the evolution of vibrational normal modes upon deprotonation. Based on the molecular orbital analysis and the time dependent DFT (TD-DFT) calculations, we discussed the electronic structure and the assignment of the absorption bands in the electronic spectra of 4-nitrocatechol and mono-deprotonated 4-nitrocatechol.

  5. Molecular structure and spectroscopic properties of 4-nitrocatechol at different pH: UV visible, Raman, DFT and TD-DFT calculations

    Science.gov (United States)

    Cornard, Jean-Paul; Rasmiwetti; Merlin, Jean-Claude

    2005-03-01

    We investigated theoretically, by density functional theoretical calculations and by vibrational and electronic spectroscopies, the structure and the molecular spectroscopic properties of the 4-nitrocatechol molecule with varying pH. The lower energy stable structures of the neutral, monoanion and dianion forms were compared, and influence of water solvation was examined. The Raman and UV-visible spectra of 4-nitrocatechol and of its singly deprotonated form were recorded by varying the pH from 2 to 9. A calculation of the vibrational frequencies has allowed a complete assignment of the Raman spectra of the two forms of 4-nitrocatechol, and has permitted to investigate the evolution of vibrational normal modes upon deprotonation. Based on the molecular orbital analysis and the time dependent DFT (TD-DFT) calculations, we discussed the electronic structure and the assignment of the absorption bands in the electronic spectra of 4-nitrocatechol and mono-deprotonated 4-nitrocatechol.

  6. Synthesis,crystal structures,electrochemical and spectroscopic properties of ruthenium(Ⅱ) complexes containing diamino-1,3,5-triazine derivatives

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Three Ru(Ⅱ) complexes [Ru(bpy)2(1-IQTNH)](ClO4)2 (1), [Ru(bpy)2(2-QTNH)](ClO4)2 (2) and [Ru(bpy)2(3-IQTNH)](ClO4)2 (3) (bpy = 2,2′-bipyridine, 1-IQTNH = 6-(isoquinolin-1-yl)-1,3,5-triazine-2,4-diamine, 2-QTNH = 6-(quinolin-2-yl)-1,3,5-triazine-2,4-diamine, 3-IQTNH = 6-(isoquinolin-3-yl)-1,3,5-triazine-2,4-diamine) have been synthesized and characterized by elemental analysis, 1H NMR spectroscopy, electrospray ionization mass spectrometry and X-ray crystallography. The electrochemical and spectroscopic properties of the complexes differ from those of [Ru(bpy)3]2+ owing to the structural differences between the ligands and their complexes.

  7. Spectroscopic properties of Er3+-doped AlF3-La2O3-Al2O3-SiO2 glasses

    Institute of Scientific and Technical Information of China (English)

    Debao Zhang(张德宝); Baoyu Chen(陈宝玉); Zhuping Liu(柳祝平); Shunguang Li(李顺光); Lili Hu(胡丽丽)

    2004-01-01

    Er3+-doped fluoride lanthanum aluminosilicate glasses with compositions of (65- x/2)SiO2 · (25 -and their glass transition temperatures and spectroscopic properties were investigated. The Ω2, Ω4, and Ω6 intensity parameters of glasses were calculated by Judd-Ofelt theory from absorption curves. It was found that glasses transition temperature and melting temperature decreased with the increase of fluoride content in glass, Ω2 decreased gradually with the increase of AlF3 content, but both Ω4 and Ω6 did not increase until AlF3 content increased to 30 mol%. The quantum efficiency of 4I13/2 to 4I15/2 transition of Er3+ ions increases with the increase of AlF3 content in glass. Fluorescent lifetime is longer in glass containing more AlFa content.

  8. Synthesis, Characterization, Spectroscopic and Electrochemical Properties of New Mono-and Binuclear Copper(Ⅰ) Complexes with Substituted 2,2'-Bipyridine

    Institute of Scientific and Technical Information of China (English)

    CAO, Qian-Yong(曹迁永); GAN, Xin(甘欣); FU, Wen-Fu(傅文甫)

    2004-01-01

    The mono- and binuclear Cu(Ⅰ) complexes with substituted 2,2'-bipyridine and iodide ligands, [CuL2]BF4 (L=4-methoxycarbonyl-6-(4-methylphenyl)-2,2'-bipyridine (a), 6-(4-hydroxymethylphenyl)-2,2'-bipyridine (b) and 6-(4-methoxylphenyl)-2,2'-bipyridine (c)) and [Cu2(μ-I)2L2] were prepared, and the crystal structures of the complexes were obtained from signal-crystal X-ray diffractional analysis. The spectroscopic properties of the complexes in dichloromethane are dominated by low energy MLCT bands from 360 to 650 nm. The electrochemical studies of mononuclear complexes reveal that the complexes have stable copper(Ⅰ) state.

  9. On the spectroscopic and thermochemical properties of ClO, BrO, IO, and their anions.

    Science.gov (United States)

    Peterson, Kirk A; Shepler, Benjamin C; Figgen, Detlev; Stoll, Hermann

    2006-12-28

    A coupled cluster composite approach has been used to accurately determine the spectroscopic constants, bond dissociation energies, and heats of formation for the X1(2)II(3/2) states of the halogen oxides ClO, BrO, and IO, as well as their negative ions ClO-, BrO-, and IO-. After determining the frozen core, complete basis set (CBS) limit CCSD(T) values, corrections were added for core-valence correlation, relativistic effects (scalar and spin-orbit), the pseudopotential approximation (BrO and IO), iterative connected triple excitations (CCSDT), and iterative quadruples (CCSDTQ). The final ab initio equilibrium bond lengths and harmonic frequencies for ClO and BrO differ from their accurate experimental values by an average of just 0.0005 A and 0.8 cm-1, respectively. The bond length of IO is overestimated by 0.0047 A, presumably due to an underestimation of molecular spin-orbit coupling effects. Spectroscopic constants for the spin-orbit excited X2(2)III(1/2) states are also reported for each species. The predicted bond lengths and harmonic frequencies for the closed-shell anions are expected to be accurate to within about 0.001 A and 2 cm-1, respectively. The dissociation energies of the radicals have been determined by both direct calculation and through use of negative ion thermochemical cycles, which made use of a small amount of accurate experimental data. The resulting values of D0, 63.5, 55.8, and 54.2 kcal/mol for ClO, BrO, and IO, respectively, are the most accurate ab initio values to date, and those for ClO and BrO differ from their experimental values by just 0.1 kcal/mol. These dissociation energies lead to heats of formation, DeltaH(f) (298 K), of 24.2 +/- 0.3, 29.6 +/- 0.4, and 29.9 +/- 0.6 kcal/mol for ClO, BrO, and IO, respectively. Also, the final calculated electron affinities are all within 0.2 kcal/mol of their experimental values. Improved pseudopotential parameters for the iodine atom are also reported, together with revised correlation

  10. Spectroscopic data

    CERN Document Server

    Melzer, J

    1976-01-01

    During the preparation of this compilation, many people contributed; the compilers wish to thank all of them. In particular they appreciate the efforts of V. Gilbertson, the manuscript typist, and those of K. C. Bregand, J. A. Kiley, and W. H. McPherson, who gave editorial assistance. They would like to thank Dr. J. R. Schwartz for his cooperation and encouragement. In addition, they extend their grati­ tude to Dr. L. Wilson of the Air Force Weapons Laboratory, who gave the initial impetus to this project. v Contents I. I ntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . . . . . 11. Organization ofthe Spectroscopic Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Methods of Production and Experimental Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Band Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2...

  11. Emission spectroscopic properties of water soluble porphyrins in hydrogen peroxide chemiluminescence system with d- and f-electron metals

    Science.gov (United States)

    Staninski, Krzysztof; Kaczmarek, Małgorzata; Lis, Stefan; Elbanowski, Marian

    2003-02-01

    Two water-soluble porphyrins: 4,4',4'',4'''-(porphine-5,10,15,20-tetrayl)-tetrakis (benzoic acid) (TCPPH 2) and 4,4',4'',4'''-(porphine-5,10,15,20-tetrayl)-tetrakis (benzenesulfonic acid) (TSPPH 2) have been subjected to spectroscopic study in the presence of d-electron metals: Zn(II) and Cu(II) and f-electron metals: La(III), Eu(III), Gd (III) and Yb(III). Results of the spectrophotometric study have provided evidence proving the complexation of Cu(II) and Zn(II) cations by porphine in water solutions and the complexation of lanthanide ions exclusively by peripheral carboxyl and sulfonic groups. For the first time, chemiluminescence of the systems containing porphyrins has been measured without the use of strongly luminescent reagents such as TCPO or luminol. The emission spectra of the systems porphyrin/metal ion/H 2O 2 have been recorded and the quantum yield of their luminescence has been measured. The absorption spectra of the systems recorded before and after the reaction in the presence of hydrogen peroxide are identical, which means that the porphyrin ring does not undergo destruction. A significant similarity between the fluorescence and chemiluminescence spectra indicates a possibility of excitation of porphyrins and their complexes in the reaction with hydrogen peroxide.

  12. Structural and spectroscopic properties of pure and doped Ba6Ti2Nb8O30 tungsten bronze.

    Science.gov (United States)

    Massarotti, V; Capsoni, D; Bini, M; Azzoni, C B; Mozzati, M C; Galinetto, P; Chiodelli, G

    2006-09-14

    Pure and doped Ba(6)Ti(2)Nb(8)O(30) (BTN), obtained by substituting M = Cr, Mn, or Fe on the Ti site (Ba(6)Ti(2-x) M(x)Nb(8)O(30), x = 0.06 and 0.18) and Y and Fe on the Ba and Ti sites, respectively (Ba(6-x)Y(x)Ti(2-x)Fe(x)Nb(8)O(30), x= 0.18), are synthesized. The influence of cation doping on the local structure, the cation oxidation state, and the possible defect formation able to maintain the charge neutrality are investigated by spectroscopic (electron paramagnetic resonance (EPR) and micro-Raman), structural (X-ray powder diffraction) and transport (impedance spectroscopy, thermoelectric power) measurements, in the temperature range of 300-1200 K in air and N(2) flow. Starting from the valence state of the doping ions (Fe(3+), Cr(3+), and Mn(2+)), determined by EPR, and from thermoelectric power measurements, evidencing a negative charge transport, different charge-compensating defect equilibria, based on the creation of positive electron holes or oxygen vacancies and electrons, are discussed to interpret the conductivity results.

  13. THE LARGE SKY AREA MULTI-OBJECT FIBER SPECTROSCOPIC TELESCOPE QUASAR SURVEY: QUASAR PROPERTIES FROM THE FIRST DATA RELEASE

    Energy Technology Data Exchange (ETDEWEB)

    Ai, Y. L.; Wu, Xue-Bing; Yang, Jinyi; Yang, Qian; Wang, Feige; Guo, Rui; Dong, Xiaoyi [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Zuo, Wenwen; Shen, S.-Y. [Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China); Zhang, Y.-X.; Yuan, H.-L.; Song, Y.-H.; Yang, M.; Wu, H.; Shi, J.-R.; He, B.-L.; Lei, Y.-J.; Li, Y.-B. [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences 100012, Beijing (China); Wang, Jianguo; Dong, Xiaobo, E-mail: aiyl@pku.edu.cn [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); and others

    2016-02-15

    We present preliminary results of the quasar survey in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) first data release (DR1), which includes the pilot survey and the first year of the regular survey. There are 3921 quasars reliably identified, among which 1180 are new quasars discovered in the survey. These quasars are at low to median redshifts, with a highest z of 4.83. We compile emission line measurements around the Hα, Hβ, Mg ii, and C iv regions for the new quasars. The continuum luminosities are inferred from SDSS photometric data with model fitting, as the spectra in DR1 are non-flux-calibrated. We also compile the virial black hole mass estimates, with flags indicating the selection methods, and broad absorption line quasars. The catalog and spectra for these quasars are also available. Of the 3921 quasars, 28% are independently selected with optical–infrared colors, indicating that the method is quite promising for the completeness of the quasar survey. LAMOST DR1 and the ongoing quasar survey will provide valuable data for studies of quasars.

  14. An experimental and theoretical approach of spectroscopic and structural properties of a new chelidamate copper (II) complex.

    Science.gov (United States)

    Vural, Hatice; Uçar, İbrahim; Soylu, M Serkan

    2014-03-25

    The crystal structure of new chelidamate complex of copper (II) ion, [Cu(chel)H2O(pym)]·H2O [chel: chelidamate or 4-hydroxypyridine-2,6-dicarboxylate; pym: 2-Pyridylmethanol] has been determined by single crystal X-ray crystallographic method. The complex was characterized by IR and UV-Vis spectroscopic techniques. The magnetic environment of copper (II) ion has been defined by electron paramagnetic technique (EPR). The central copper (II) ion is six-coordinate with a distorted octahedral geometry, which exhibits Jahn-Teller distortions along one of the O-Cu-O axes with tetragonality of 0.81. Chelidamate behaved as a tridentate ligand was bonded to Cu(II) ion through carboxyl oxygens with nitrogen. The crystal structure is stabilized by O-H⋯O hydrogen bond and π-π interactions. Theoretical calculations have been carried out by using the DFT method. The modeling of copper (II) complex was made by geometric optimization. The geometry optimization and EPR study were carried out using the following unrestricted hybrid density functionals: LSDA, BPV86, B3LYP, B3PW91, MPW1PW91 and HCTH. Frontier molecular orbital energies, absorption wavelengths and excitation energy were computed by time dependent DFT (TD-DFT) method with polarizable continuum model. IR spectra were discussed and compared to other relevant complexes together with theoretical results. The natural charges on the atoms and second-order interaction energies were derived from natural bond orbital analysis (NBO).

  15. Absorption properties of type-II InAs/InAsSb superlattices measured by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Webster, P. T.; Riordan, N. A.; Liu, S.; Zhang, Y.-H.; Johnson, S. R., E-mail: shane.johnson@asu.edu [Center for Photonics Innovation and School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Steenbergen, E. H. [U.S. Air Force Research Laboratory, AFRL/RXAN, Wright Patterson, Ohio 45433 (United States); Synowicki, R. A. [J. A. Woollam Co., Inc., 645 M. Street, Suite 102, Lincoln, Nebraska 68508 (United States)

    2015-02-09

    Strain-balanced InAs/InAsSb superlattices offer access to the mid- to long-wavelength infrared region with what is essentially a ternary material system at the GaSb lattice constant. The absorption coefficients of InAs/InAsSb superlattices grown by molecular beam epitaxy on (100)-oriented GaSb substrates are measured at room temperature over the 30 to 800 meV photon energy range using spectroscopic ellipsometry, and the miniband structure of each superlattice is calculated using a Kronig-Penney model. The InAs/InAsSb conduction band offset is used as a fitting parameter to align the calculated superlattice ground state transition energy to the measured absorption onset at room temperature and to the photoluminescence peak energy at low temperature. It is observed that the ground state absorption coefficient and transition strength are proportional to the square of the wavefunction overlap and the ground state absorption coefficient approaches a maximum value of around 5780 cm{sup −1} as the wavefunction overlap approaches 100%. The absorption analysis of these samples indicates that the optical joint density of states is weakly dependent on the period thickness and Sb content of the superlattice, and that wavefunction overlap is the principal design parameter in terms of obtaining strong absorption in these structures.

  16. Structures, spectroscopic and thermodynamic properties of U₂On (n = 0 ∼ 2, 4) molecules: a density functional theory study.

    Science.gov (United States)

    Li, Peng; Niu, Wen-Xia; Gao, Tao; Wang, Fan; Jia, Ting-Ting; Meng, Da-Qiao; Li, Gan

    2013-12-01

    The equilibrium structures, spectroscopic and thermodynamic parameters [entropy (S), internal energy (E), heat capacity (C p)] of U₂, U₂O, U₂O₂ and U₂O₄ uranium oxide molecules were investigated systematically using density functional theory (DFT). Our computations indicated that the ground electronic state of U₂ is the septet state and the equilibrium bond length is 2.194 Å; the ground electronic state of U₂O and U₂O₂ were found to be X³Φ and X³Σ(g) with stable C(∞v) and D(∞h) linear structures, respectively. The bridge-bonded structure with D(2h) symmetry and X³B₁(g) state is the most stable configuration for the U₂O₄ molecule. Mulliken population analyses show that U atoms always lose electrons to become the donor and O atoms always obtain electrons as the acceptor. Molecular orbital analyses demonstrated that the frontier orbitals of the title molecules were contributed mostly by 5f atomic orbitals of U atoms. Vibrational frequencies analyses indicate that the maximum absorption peaks stem from the stretching mode of U-O bonds in U₂O, U₂O₂ and U₂O₄. In addition, thermodynamic data of U₂O(n) (n = 0 ∼ 4) molecules at elevated temperatures of 293.0 K to 393.0 K was predicted.

  17. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope Quasar Survey: Quasar Properties from First Data Release

    CERN Document Server

    Ai, Y L; Yang, Jinyi; Yang, Qian; Wang, Feige; Guo, Rui; Zuo, Wenwen; Dong, Xiaoyi; Zhang, Y -X; Yuan, H -L; Song, Y -H; Wang, Jianguo; Dong, Xiaobo; Yang, M; Wu, H; Shen, S -Y; Shi, J -R; He, B -L; Lei, Y -J; Li, Y -B; Luo, A -L; Zhao, Y -H; Zhang, Hao-Tong

    2015-01-01

    We present preliminary results of the quasar survey in Large Sky Area Multi- Object Fiber Spectroscopic Telescope (LAMOST) first data release (DR1), which includes pilot survey and the first year regular survey. There are 3921 quasars identified with reliability, among which 1180 are new quasars discovered in the survey. These quasars are at low to median redshifts, with highest z of 4.83. We compile emission line measurements around the H{\\alpha}, H{\\beta}, Mg II, and C IV regions for the new quasars. The continuum luminosities are inferred from SDSS photo- metric data with model fitting as the spectra in DR1 are non-flux-calibrated. We also compile the virial black hole mass estimates, and flags indicating the selec- tion methods, broad absorption line quasars. The catalog and spectra for these quasars are available online. 28% of the 3921 quasars are selected with optical- infrared colours independently, indicating that the method is quite promising in completeness of quasar survey. LAMOST DR1 and the on-g...

  18. Spectroscopic properties of the CaNb{sub 2}O{sub 6}:Pr{sup 3+} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Macalik, L.; Maczka, M. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Hanuza, J. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Department of Bioorganic Chemistry, Faculty of Engineering and Economics, Wroclaw University of Economics, 118/120 Komandorska str., 53-345 Wroclaw (Poland)], E-mail: j.hanuza@int.pan.wroc.pl; Godlewska, P. [Department of Bioorganic Chemistry, Faculty of Engineering and Economics, Wroclaw University of Economics, 118/120 Komandorska str., 53-345 Wroclaw (Poland); Solarz, P.; Ryba-Romanowski, W. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Kaminskii, A.A. [Joint Open Laboratory for Laser Crystals and Precise Laser Systems, Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation)

    2008-02-28

    The spectroscopic measurements of the calcium niobate CaNb{sub 2}O{sub 6} (columbite) single crystal doped with trivalent praseodymium ions have been performed. The polarised optical absorption and emission spectra as well as luminescence decay curves of this material have been recorded. The absorption spectra consist of well-resolved transitions from the {sup 3}H{sub 4} ground state to the {sup 3}P{sub J}, {sup 1}D{sub J}, {sup 1}G{sub J}, {sup 3}F{sub J} and {sup 3}H{sub J} levels. The strongest bands correspond to the {sup 3}H{sub 4} {yields} {sup 3}P{sub 0} and {sup 3}H{sub 4} {yields} {sup 3}F{sub 2} transitions. The former band is composed of three components of different intensity. This suggests the existence of three different centers in the CaNb{sub 2}O{sub 6} crystal for the Pr{sup 3+} ions that substitute for Ca{sup 2+}. The emission spectra of the crystal studied show clear temperature and polarisation dependence. The strongest band of the luminescence corresponds to the {sup 1}D{sub 2} {yields} {sup 3}H{sub 4} transition at 610 nm with small bandwidth and high intensity. The lifetime of the {sup 1}D{sub 2} level increases from 59 {mu}s to 78 {mu}s when temperature decreases from 300 K to 50 K.

  19. Exploring the Evolution of Star Formation and Dwarf Galaxy Properties with JWST/MIRI Serendipitous Spectroscopic Surveys

    Science.gov (United States)

    Bonato, Matteo; Sajina, Anna; De Zotti, Gianfranco; McKinney, Jed; Baronchelli, Ivano; Negrello, Mattia; Marchesini, Danilo; Roebuck, Eric; Shipley, Heath; Kurinsky, Noah; Pope, Alexandra; Noriega-Crespo, Alberto; Yan, Lin; Kirkpatrick, Allison

    2017-02-01

    The James Webb Space Telescope’s Medium Resolution Spectrometer (MRS), will offer nearly two orders of magnitude improvement in sensitivity and >3× improvement in spectral resolution over our previous space-based mid-IR spectrometer, the Spitzer IRS. In this paper, we make predictions for spectroscopic pointed observations and serendipitous detections with the MRS. Specifically, pointed observations of Herschel sources require only a few minutes on source integration for detections of several star-forming and active galactic nucleus lines, out to z = 3 and beyond. But the same data will also include tens of serendipitous 0 ≲ z ≲ 4 galaxies per field with infrared luminosities ranging ∼106–1013 L ⊙. In particular, for the first time and for free we will be able to explore the L IR star formation rate function. The above conclusions hold for a wide range in the potential low-L end of the IR luminosity function, and account for the PAH deficit in low-L, low-metallicity galaxies.

  20. The Rest-frame Optical Spectroscopic Properties of Lyalpha-emitters at Z~2.5: The Physical Origins of Strong Lyalpha Emission

    Science.gov (United States)

    Trainor, Ryan F.; Strom, Allison L.; Steidel, Charles C.; Rudie, Gwen C.

    2016-12-01

    We present the rest-frame optical spectroscopic properties of 60 faint (R AB ˜ 27; L ˜ 0.1 L *) Lyα-selected galaxies (LAEs) at z ≈ 2.56. These LAEs also have rest-UV spectra of their Lyα emission line morphologies, which trace the effects of interstellar and circumgalactic gas on the escape of Lyα photons. We find that the LAEs have diverse rest-optical spectra, but their average spectroscopic properties are broadly consistent with the extreme low-metallicity end of the populations of continuum-selected galaxies selected at z ≈ 2-3. In particular, the LAEs have extremely high [O iii] λ5008/Hβ ratios (log([O iii]/Hβ) ˜ 0.8) and low [N ii] λ6585/Hα ratios (log([N ii]/Hα) models of stellar evolution (including binary interactions) that have been shown to produce long-lived populations of hot, massive stars at low metallicities. We find that strong, hard ionizing continua are required to reproduce our observed line ratios, suggesting that faint galaxies are efficient producers of ionizing photons and important analogs of reionization-era galaxies. Furthermore, we investigate the physical trends accompanying Lyα emission across the largest current sample of combined Lyα and rest-optical galaxy spectroscopy, including both the 60 KBSS-Lyα LAEs and 368 more luminous galaxies at similar redshifts. We find that the net Lyα emissivity (parameterized by the Lyα equivalent width) is strongly correlated with nebular excitation and ionization properties and weakly correlated with dust attenuation, suggesting that metallicity plays a strong role in determining the observed properties of these galaxies by modulating their stellar spectra, nebular excitation, and dust content. Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W.M. Keck Foundation.

  1. CHARACTERIZATION OF A SAMPLE OF INTERMEDIATE-TYPE AGNs. I. SPECTROSCOPIC PROPERTIES AND SERENDIPITOUS DISCOVERY OF NEW DUAL AGNs

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, Erika; Cruz-Gonzalez, Irene; Martinez, Benoni; Jimenez-Bailon, Elena [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-264, Mexico D.F. 04510 (Mexico); Mendez-Abreu, Jairo; Lopez-Martin, Luis [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Fuentes-Carrera, Isaura [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional (ESFM-IPN), U.P. Adolfo Lopez Mateos, Mexico D.F. 07730 (Mexico); Leon-Tavares, Jonathan [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FI-02540, Kylmaelae (Finland); Chavushyan, Vahram H., E-mail: erika@astro.unam.mx [Instituto Nacional de Astrofisica, Optica y Electronica, Apdo. Postal 51-216, 72000 Puebla (Mexico)

    2013-01-20

    A sample of 10 nearby intermediate-type active galactic nuclei (AGNs) drawn from the Sloan Digital Sky Survey is presented. The aim of this work is to provide estimations of the black hole (BH) mass for the sample galaxies from the dynamics of the broad-line region. For this purpose, a detailed spectroscopic analysis of the objects was done. Using Baldwin-Phillips-Terlevich diagnostic diagrams, we have carefully classified the objects as true intermediate-type AGNs and found that 80%{sup +7.2%} {sub -17.3%} are composite AGNs. The BH mass estimated for the sample is within 6.54 {+-} 0.16 < log M {sub BH} < 7.81 {+-} 0.14. Profile analysis shows that five objects (J120655.63+501737.1, J121607.08+504930.0, J141238.14+391836.5, J143031.18+524225.8, and J162952.88+242638.3) have narrow double-peaked emission lines in both the red (H{alpha}, [N II] {lambda}{lambda}6548,6583 and [S II] {lambda}{lambda}6716, 6731) and the blue (H{beta} and [O III] {lambda}{lambda}4959, 5007) regions of the spectra, with velocity differences ({Delta}V) between the double peaks within 114 km s{sup -1} < {Delta}V < 256 km s{sup -1}. Two of them, J121607.08+504930.0 and J141238.14+391836.5, are candidates for dual AGNs since their double-peaked emission lines are dominated by AGN activity. In searches of dual AGNs, type 1, type II, and intermediate-type AGNs should be carefully separated, due to the high serendipitous number of narrow double-peaked sources (50% {+-} 14.4%) found in our sample.

  2. Spectroscopic properties and energy transfer parameters of Tm{sup 3+} ions in gallium lanthanum sulfide glass

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, A.S.S. de [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, CP 369, Sao Carlos, SP (Brazil)]. E-mail: andreasc@if.sc.usp.br; Oliveira, S.L. de; Sousa, D.F. de; Nunes, L.A.O. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, CP 369, Sao Carlos, SP (Brazil); Hewak, D.W. [Optoelectronics Research Center, University of Southampton, Southampton (United Kingdom)

    2002-10-21

    This work presents the spectroscopic characterization of Tm{sup 3+} doped gallium lanthanum sulfide (GaLaS) chalcogenide glass through absorption, fluorescence and lifetime measurements of excited{sup 3}H{sub 4} and{sup 3}F{sub 4} states, and a study of Tm{sup 3+}:Tm{sup 3+} energy transfer. The cross relaxation {sup 3}H{sub 4},{sup 3} H{sub 6}{yields} {sup 3} F{sub 4},{sup 3} F{sub 4} responsible for the pumping of level {sup 3}F{sub 4} and the laser transition at 1800 nm ({sup 3}F{sub 4}{yields}{sup 3}H{sub 6}), as well as the energy migration {sup 3}H{sub 4},{sup 3}H{sub 6}{yields}{sup 3}H{sub 4},{sup 3H}{sub 6} processes are studied in terms of the microscopic parameters of energy transfer C{sub da} and C{sub dd} obtained by the Kushida model of multipolar interactions and by a rate equation treatment of the dynamics of levels {sup 3}F{sub 4} and {sup 3}H{sub 4}. From this treatment it was possible to simulate level {sup 3}F{sub 4} temporal evolution curves for different Tm{sup 3+} concentrations, leading to results that are in excellent agreement with experimental ones. All the samples studied in the work present positive optical gain coefficients for excitation densities higher than 12 kW cm{sup -2} indicating the potentiality of GaLaS:Tm{sup 3+} glass as a mid-infrared laser active medium. (author)

  3. First Spectroscopic Confirmation of a Monster Galaxy at z=3.3 and Detailed Stellar Population and Structural Properties

    Science.gov (United States)

    Marsan, Zehra Cemile; Marchesini, Danilo

    2014-06-01

    We present the first spectroscopic confirmation of an ultra-massive galaxy at z,phot = 3.3 using data from Keck-NIRSPEC, VLT-Xshooter, and GTC-Osiris. We detect strong [OIII] and Lyα emission, and weak [OII], CIV, and HeII, confirming the redshift at z,spec = 3.3512. Modeling the emission-line corrected spectral energy distribution (from the Galex UV to IRAC 8 μm, as well as the binned spectra) results in a best-fit stellar mass of M,stellar = 3×10'11M,sun (Kroupa), SFR of a few solar masses per year, negligible dust extinction, an age of ˜ 300 Myr, and a very short burst of star formation, setting the formation redshift of this galaxy at z˜4. From the analysis of the line ratios and widths, and the observed flux at 24 μm we confirm the presence of a luminous AGN, with bolometric luminosity of ˜ 8 × 10'45erg/s. The non detection in the X-ray data implies a Compton-thick nature for the type-2 AGN. Potential contamination of the observed SED from the AGN continuum is constrained, placing a lower limit on the stellar mass of 2 × 10'11M,sun. HST/WFC3 H160 and ACS I814 images were modeled with GALFIT, resulting in a very compact galaxy (effective radius r,e ˜ 1 kpc) and a de Vaucouleurs’s profile with n˜4. This object represents the prototype galaxy of an ultra-massive galaxy that formed at z˜4 in a very intense burst, is about to transition to quiescent, and it hosts a very powerful super massive black hole potentially responsible for the quenching of the star formation activity.

  4. Spectroscopic and laser properties of BeLaAl 11O l9 crystals doped with Cr 3+ and Nd 3+ ions

    Science.gov (United States)

    Petrov, V. V.; Pestryakov, E. V.; Trunov, V. I.; Kirpichnikov, A. V.; Alimpiev, A. I.; Matrosov, V. N.

    2006-01-01

    In this work the opportunity of realization of laser action on vibronic transitions of Cr 3+ ions in new crystal - hexaaluminate of beryllium-lanthanum (BeLaAl 110 19:Cr) is investigated. The thermodynamic and physical parameters of host crystal were studied. The experimental spectroscopic and relaxation properties of Cr 3+ ions have been performed. Absorption and fluorescence spectra are characteristic for octahedral coordinated trivalent ions. The emission cross-section of broadband 4T II- 4A II transition is determined (~2•1O -20CM2). In configuration curves model the basic features of fluorescence and perspective of lasing in the 700-1000 nm range are considered. The new laser crystals BeLaAl 11O 19:Nd were grown by the Czochralski methods. This material has broad absorption bands at 580, 740 and 790 nm, the latest can be used for LD pumping. The broadest emission lines at 1050 and 1080 nm are perspective for ultrashort laser pulses generation. The intensity parameters, spontaneous emission probabilities, the inter-manifold branching ratios and fluorescent lifetime have been calculated by means of Judd-Ofelt theory and compared with the experiment. The CW generation was realized under Ar-laser pump and laser properties were investigated. The investigation shows that the BeLaAl 11O 19 is a promising host for a creature the new solid state laser media.

  5. Preparation, X-ray Structures, Spectroscopic, and Redox Properties of Di- and Trinuclear Iron-Zirconium and Iron-Hafnium Porphyrinoclathrochelates.

    Science.gov (United States)

    Dudkin, Semyon V; Erickson, Nathan R; Vologzhanina, Anna V; Novikov, Valentin V; Rhoda, Hannah M; Holstrom, Cole D; Zatsikha, Yuriy V; Yusubov, Mekhman S; Voloshin, Yan Z; Nemykin, Victor N

    2016-11-21

    The first hybrid di- and trinuclear iron(II)-zirconium(IV) and iron(II)-hafnium(IV) macrobicyclic complexes with one or two apical 5,10,15,20-tetraphenylporphyrin fragments were obtained using transmetalation reaction between n-butylboron-triethylantimony-capped or bis(triethylantimony)-capped iron(II) clathrochelate precursors and dichlorozirconium(IV)- or dichlorohafnium(IV)-5,10,15,20-tetraphenylporphyrins under mild conditions. New di- and trinuclear porphyrinoclathrochelates of general formula FeNx3((Bn-Bu)(MTPP)) and FeNx3(MTPP)2 [M = Zr, Hf; TPP = 5,10,15,20-tetraporphyrinato(2-); Nx = nioximo(2-)] were characterized by one-dimensional ((1)H and (13)C{(1)H}) and two-dimensional (COSY and HSQC) NMR, high-resolution electrospray ionization mass spectrometry, UV-visible, and magnetic circular dichroism spectra, single-crystal X-ray diffraction experiments, as well as elemental analyses. Redox properties of all complexes were probed using electrochemical and spectroelectrochemical approaches. Electrochemical and spectroelectrochemical data suggestive of a very weak, if any, long-range electronic coupling between two porphyrin π-systems in FeNx3(MTPP)2 complexes. Density functional theory and time-dependent density functional theory calculations were used to correlate spectroscopic signatures and redox properties of new compounds with their electronic structures.

  6. Synthesis of quinoline derivatives containing pyrazole group and investigation of their crystal structure and spectroscopic properties in relation to acidity and alkalinity of mediums

    Science.gov (United States)

    Ren, Tiegang; Wang, Jie; Li, Guihui; Cheng, Hongbin; Li, Yongzhe

    2014-08-01

    Two series of quinoline derivatives containing pyrazole group were synthesized and characterized by means of 1H NMR, FT-IR, MS, elemental analysis and X-ray single crystal diffraction, and their UV-vis absorption behavior and fluorescence properties were also measured. Moreover, the effects of acetic acid and triethylamine on the spectroscopic properties of synthesized products were examined with compounds 3a and 5a as examples. It has been found that all synthesized quinoline derivatives show maximum absorption peak at 303 nm and emission peaks around 445 nm. Besides, both acetic acid and triethylamine can change the acidity of the medium, thereby influencing the UV-vis absorption spectra and fluorescence spectra of synthesized products. Moreover, theoretical investigations indicate that the integration of H+ and N atom of quinoline ring favors the formation of a new product in the presence of acetic acid, and the product obtained in this case shows a new UV-vis absorption peak at 400 nm.

  7. Structures and spectroscopic properties of nonperipherally and peripherally substituted metal-free phthalocyanines: a substitution effect study based on density functional theory calculations.

    Science.gov (United States)

    Zhong, Aimin; Zhang, Yuexing; Bian, Yongzhong

    2010-11-01

    The molecular structures, molecular orbitals, atomic charges, electronic absorption spectra, and infrared (IR) and Raman spectra of a series of substituted metal-free phthalocyanine compounds with four (1, 3, 5, 7) or eight (2, 4, 6, 8) methoxyl (1, 2, 5, 6) or methylthio groups (3, 4, 7, 8) on the nonperipheral (1-4) or peripheral positions (5-8) of the phthalocyanine ring are studied by density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The calculated structural parameters and simulated electronic absorption and IR spectra are compared with the X-ray crystallography structures and the experimentally observed electronic absorption and IR spectra of the similar molecules, and good agreement between the calculated and experimental results is found. The substitution of the methoxyl or methylthio groups at the nonperipheral positions of the phthalocyanine ring has obvious effects on the molecular structure and spectroscopic properties of the metal-free phthalocyanine. Nonperipheral substitution has a more significant influence than peripheral substitution. The substitution effect increases with an increase in the number of substituents. The methylthio group shows more significant influence than the methoxyl group, despite the stronger electron-donating property of the methoxyl group than the methylthio group. The octa-methylthio-substituted metal-free phthalocyanine compounds have nonplanar structures whose low-lying occupied molecular orbitals and electronic absorption spectra are significantly changed by the substituents. The present systematical study will be helpful for understanding the relationship between structures and properties in phthalocyanine compounds and designing phthalocyanines with typical properties.

  8. Compositional Dependence Of Hardness Of Ge-Sb-Se Glass For Molded Lens Applications

    Directory of Open Access Journals (Sweden)

    Park J.K.

    2015-06-01

    Full Text Available Chalcogenide glass in the ternary Ge-Sb-Se system is inherently moldable, thus being considered as a strong candidate material for use in infrared-transmitting lens applications from the viewpoint of thermal and mechanical stability. In an effort to experimentally determine compositional region suitable for the molded lens applications, we evaluate its compositional dependence of hardness. Among the constituent atoms, Ge content turns out to exert a most conspicuous correlation with hardness. This phenomenological behavior is then explained in connection with the structural evolution that Ge brings about.

  9. Observational and laboratory studies of optical properties of black and brown carbon particles in the atmosphere using spectroscopic techniques

    Science.gov (United States)

    Nakayama, Tomoki; Matsumi, Yutaka

    2015-04-01

    Light absorption and scattering by aerosols are as an important contributor to radiation balance in the atmosphere. Black carbon (BC) is considered to be the most potent light absorbing material in the visible region of the spectrum, although light absorbing organic carbon (brown carbon or BrC) and mineral dust may also act as sources of significant absorption, especially in the ultraviolet (UV) and shorter visible wavelength regions. The optical properties of such particles depend on wavelength, particle size and shape, morphology, coating, and complex refractive index (or chemical composition), and therefore accurate in situ measurements of the wavelength dependence of the optical properties of particles are needed. Recently, cavity ring-down spectroscopy (CRDS) and photoacoustic spectroscopy (PAS) have been used for the direct measurements of extinction and absorption coefficients of particles suspended in air. We have applied these techniques to the observational studies of optical properties of BC and BrC in an urban site in Japan and to the laboratory studies of optical properties of secondary organic aerosols (SOAs) generated from a variety of biogenic and anthropogenic volatile organic compounds and those of diesel exhaust particles (DEPs). In the presentation, the basic principles of these techniques and the results obtained in our studies and in the recent literatures will be overviewed. References Guo, X. et al., Measurement of the light absorbing properties of diesel exhaust particles using a three-wavelength photoacoustic spectrometer, Atmos. Environ., 94, 428-437 (2014). Nakayama, T. et al., Measurements of aerosol optical properties in central Tokyo during summertime using cavity ring-down spectroscopy: Comparison with conventional techniques, Atmos. Environ., 44, 3034-3042 (2010). Nakayama, T. et al., Laboratory studies on optical properties of secondary organic aerosols generated during the photooxidation of toluene and the ozonolysis of alpha

  10. MRCI study of the spectroscopic parameters and transition properties of the 36 low-lying electronic states of the B2 molecule

    Science.gov (United States)

    Xing, Wei; Shi, Deheng; Sun, Jinfeng; Zhu, Zunlue

    2017-10-01

    This paper studied the spectroscopic and transition properties of 36 low-lying states, which came from the first two dissociation limits of B2 molecule. The potential energy curves were calculated with the complete active space self-consistent field (CASSCF) method, which was followed by the internally contracted multireference configuration interaction (icMRCI) plus Davidson modification (icMRCI + Q) approach. Of these 36 states, the 25Σu-, 15Σu+, 25Πu, and 15Δu states were repulsive; the B3Δu, E3Σu+, f1Σu-, g1Πg, 23Πu, 33Σg-, 33Πu, 15Πg, and 33Σu+ states had double wells; the B3Δu, E3Σu+, G3Σu+, f1Σu-, g1Πg, 33Σg-, 23Πu, 33Πu, 15Πg, 25Πg, 25Σg-, and 33Σu+ states had one barrier; the 25Σg- state and the second wells of B3Δu, E3Σu+, 15Πg, f1Σu-, g1Πg, and 23Πu states were weakly bound; and the 25Σg- state had no vibrational levels. The avoided crossings existed between the B3Δu and 23Δu states, the E3Σu+ and G3Σu+ states, the G3Σu+ and 33Σu+ states, the 33Σu+ and 43Σu+ states, the 23Πu and 33Πu states, the g1Πg and 21Πg states, the 23Σg- and 33Σg- states, the 15Πg and 25Πg states, the 25Πg and 35Πg states, the 25Σg- and 35Σg- states, as well as the F3Πg and 33Πg states. Core-valence correlation and scalar relativistic corrections were taken into account. The extrapolation to the complete basis set limit was done. The spectroscopic parameters and vibrational properties were obtained. The transition dipole moments were calculated. Franck-Condon factors of some transitions were evaluated. The spin-orbit coupling (SOC) effect on the spectroscopic parameters and vibrational properties is tiny and sometimes even can be negligible. The results determined in this paper can provide some powerful guidelines to observe these states, in particular the states which have not been studied in the experiment.

  11. Spectroscopic and time-dependent density functional theory investigation of the photophysical properties of zearalenone and its analogs

    Science.gov (United States)

    Structures of the mycotoxin zearalenone and its analogs were investigated using density functional theory methods to gain insight into the ground state and excited state properties related to detection. Zearalenone is an estrogenic mycotoxin that can occur in agricultural commodities, and ultraviole...

  12. Effects of thermal annealing on the optical, spectroscopic, and structural properties of tris (8-hydroxyquinolinate) gallium films grown on quartz substrates

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Fahmi Fariq, E-mail: fahmi982@gmail.com [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Physics, Faculty of Science and Engineering, University of Koya, Koya, Kurdistan Region (Iraq); Sulaiman, Khaulah [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2011-10-03

    Highlights: {yields} Achieving a broad absorption band for Gaq3 covering the whole UV and some parts of visible spectra. {yields} Increasing photoluminescence emission to five times stronger than that of pristine film. {yields} Conformational changes towards the formation of crystalline {alpha}-Gaq3 polymorph. {yields} Determination of glass transition temperature for Gaq3 (T{sub g} 182 deg. C) and Alq3 (T{sub g} = 173 deg. C). {yields} Improving and understanding the physical properties of Gaq3 film by means of thermal treatment. - Abstract: In this study we report the optical, spectroscopic, and structural properties of vacuum deposited tris (8-hydroxyquinolinate) gallium film upon thermal annealing in the temperature range from 85 deg. C to 255 deg. C under a flowing nitrogen gas for 10 min. The optical UV-vis-NIR and luminescence spectroscopy measurements were performed to estimate the absorption bands, optical energy gap (E{sub g}), and photoluminescence (PL) of the films. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques were used to probe the spectroscopic and structural nature of the films. We show that, by annealing the films from 85 deg. C to 235 deg. C, it is possible to achieve an enhanced absorption and increased photoluminescence to five times stronger than that of the pristine film. The PL quenching at 255 deg. C was attributed to the presence of plainer chains allow easy going for excitons to a long distance due to the crystalline region formation of {alpha}-Gaq3 polymorph. The reduction in E{sub g} and infrared absorption bands upon annealing were referred to the enhancement in {pi}-{pi} interchain interaction and conformational changes by re-arrangement of the Gaq3 quinolinate ligands, respectively. Stokes shift for the films were observed and calculated. From the differential scanning calorimetry, DSC measurements, higher glass transition temperature was observed for Gaq3 (T{sub g} = 182 deg. C) compared to

  13. Synthesis and study of spectroscopic properties of CdF{sub 2} crystals codoped with luminescent rare earth ions (Ho{sup 3+}/Yb{sup 3+})

    Energy Technology Data Exchange (ETDEWEB)

    Fartas, R. [Laboratory of Laser Physics, Optical Spectroscopy and Optoelectronics (LAPLASO), Badji Mokhtar Annaba University, POB 12, 23000 Annaba (Algeria); Diaf, M., E-mail: diafma@yahoo.fr [Laboratory of Laser Physics, Optical Spectroscopy and Optoelectronics (LAPLASO), Badji Mokhtar Annaba University, POB 12, 23000 Annaba (Algeria); Boubekri, H. [Laboratory of Laser Physics, Optical Spectroscopy and Optoelectronics (LAPLASO), Badji Mokhtar Annaba University, POB 12, 23000 Annaba (Algeria); Guerbous, L. [Laser Department, Nuclear Technique Division, Nuclear Research Center of Algiers, 02 Bd Frantz Fanon, 16000 Algiers (Algeria); Jouart, J.P. [ECATHERM/GRESPI, Reims Champagne-Ardenne University (France)

    2014-09-01

    Highlights: • Holmium doped CdF{sub 2} single crystals grown by Bridgman technique. • Absorption, excitation, emission spectra and fluorescence decay recorded at room temperature. • Spectroscopic properties investigated by use of the Judd–Ofelt theory. • Radiative lifetimes and branching ratios of the main emitting levels are calculated. • Laser parameters such as emission cross-section, radiative quantum efficiency and optical gain are then deduced. - Abstract: In this paper, we report the optical analysis of Ho{sup 3+} ions doped CdF{sub 2} single crystals. The pulled crystals were prepared by use of the Bridgman technique from a vacuum furnace in fluoride atmosphere after purification of the starting materials. Absorption, excitation, emission and fluorescence decay spectra were recorded at room temperature. The Judd–Ofelt (JO) analysis was applied to obtain the three phenomenological intensity parameters (Ω{sub t}, t = 2, 4, 6) and the transition strengths. The JO intensity parameters Ω{sub 2}, Ω{sub 4} and Ω{sub 6} for 4f–4f transitions of Ho{sup 3+} ions were computed from the optical absorption spectra using UV, visible and near infrared transitions. These parameters were then used to calculate the radiative transition probabilities (A{sub JJ′}), branching ratios (β{sub JJ′}) and radiative lifetimes (τ{sub rad}) of the main laser emitting levels of Ho{sup 3+} ions. The obtained spectroscopic properties are compared to those of Ho{sup 3+} transitions in other fluoride and oxide hosts. The excitation spectrum in the UV–Visible spectral range is very close to the absorption spectrum indicating that all observed absorption levels can excite the holmium green emission corresponding to {sup 5}F{sub 4}({sup 5}S{sub 2}) → {sup 5}I{sub 8} transition. The emission spectrum is mainly dominated by the green emission alongside the blue and red emissions. For the main transitions, there is a good agreement between the emission spectrum and

  14. DFT evaluation of the electronic structures and spectroscopic properties of the self-assembled [Pt_2M_4(C=CH)_8](M=Cu,Ag) clusters

    Institute of Scientific and Technical Information of China (English)

    BAI FuQuan; XIA BaoHui; ZHANG HongXing; YANG BaoZhu; WANG Jian; SUN Lei

    2009-01-01

    Electronic structures and spectroscopic properties of self-assembled[Pt_2M_4(C≡CH)_8](M=Cu,Ag) clusters have been studied by the TD-DFT (time-dependent density functional theory) calculations with the polarizable continuum model (PCM).The ground-and excited-state structures were optimized by the DFT (density functional theory) methods.The calculated structures and spectroscopic properties are in agreement with the corresponding experimental results.The[Pt_2M_4(C≡CH)_8]clusters have two stable ground state geometries (D_4 and D_(4h) symmetry).The calculated Pt-M distances suggest only very weak interactions.The Cu-Cu distances are larger than the van der Waals radii of two Cu atoms and the Ag-Ag distances are analogous with the sum of van der Waals radii of two Ag atoms.Upon excitation,the interaction of Pt…M,Ag…Ag is strengthened,while the Cu…Cu distances are shortened but they are still larger than the sum of van der Waals radii of two Cu atoms.The lowest-energy absorptions are at 450,365 and 375 nm and the emissions are at 611,431 and 435 nm for[Pt_2M_4(C≡CH)_8],[Pt_2M_4(C≡CH)_8](A) and (B),respectively.The transitions are all perturbed by the Cu or Ag composition through the UV-Vis spectra region;therefore,there are not pure ILCT or M_(pt)LCT characteristics (ILCT:intraligand charge transfer;MLCT:metal-to-ligand charge transfer) in absorptions of heteropolynuclear [Pt_2M_4(C≡CH)_8]clusters.Since the emissions and the lowest-absorptions have different transition characteristics for each complex,the emissions should not come from the lowest-energy absorptions.Because the M…M interactions in the excited state of[Pt_2Ag_4(C≡CH)_8]are augmented,the emissions of [Pt_2Ag_4(C≡CH)_8]clusters bear prominent ILCT character,which is the reason why the emission wavelengths of[Pt_2Ag_4(C≡CH)_8]have a small hypsochromic shift relative to the emission wavelength of homoleptic[Pt(C≡CH)_4]~(2-)precursor.

  15. Composition dependent non-ideality in aqueous binary mixtures as a signature of avoided spinodal decomposition

    Indian Academy of Sciences (India)

    Sarmistha Sarkar; Saikat Banerjee; Susmita Roy; Rikhia Ghosh; Partha Pratim Ray; Biman Bagchi

    2015-01-01

    We explore the potential energy landscape of structure breaking binary mixtures (SBBM) where two constituents dislike each other, yet remain macroscopically homogeneous at intermediate to high temperatures. Interestingly, we find that the origin of strong composition dependent non-ideal behaviour lies in its phase separated inherent structure. The inherent structure (IS) of SBBM exhibits bi-continuous phase as is usually formed during spinodal decomposition.We draw analogy of this correlation between non-ideality and phase separation in IS to explain observation of non-ideality in real aqueous mixtures of small amphiphilic solutes, containing both hydrophilic and hydrophobic groups. Although we have not been able to obtain IS of these liquids, we find that even at room temperature these liquids sustain formation of fluctuating, transient bicontinuous phase, with limited lifetime ( ≲ 20 ps). While in the model (A, B) binary mixture, the non-ideal composition dependence can be considered as a fluctuation from a phase separated state, a similar scenario is expected to be responsible for the unusually strong non-ideality in these aqueous binary mixtures.

  16. First-Principles Study on Structural, Electronic, and Spectroscopic Properties of γ-Ca2SiO4:Ce(3+) Phosphors.

    Science.gov (United States)

    Wen, Jun; Ning, Lixin; Duan, Chang-Kui; Zhan, Shengbao; Huang, Yucheng; Zhang, Jie; Yin, Min

    2015-07-23

    In the present work, geometric structures, electronic properties, and 4f → 5d transitions of γ-Ca2SiO4:Ce(3+) phosphors have been investigated by using first-principles calculations. Four categories of typical substitutions (i.e., the doping of the Ce(3+) without the neighboring dopants/defects and with the neighboring VO(••), AlSi', and VCa″) are taken into account to simulate local environments of the Ce(3+) located at two crystallographically different calcium sites in the γ-Ca2SiO4. Density functional theory (DFT) geometry optimization calculations are first performed on the constructed supercells to obtain the information about the local structures and preferred sites for the Ce(3+). On the basis of the optimized crystal structures, the electronic properties of γ-Ca2SiO4:Ce(3+) phosphors are calculated with the Heyd-Scuseria-Ernzerhof screened hybrid functional, and the energies and relative oscillator strengths of the 4f → 5d transitions of the Ce(3+) are derived from the ab initio embedded cluster calculations at the CASSCF/CASPT2/RASSI-SO level. A satisfactory agreement with the available experimental results is thus achieved. Moreover, the relationships between the dopants/defects and the electronic as well as spectroscopic properties of γ-Ca2SiO4:Ce(3+) phosphors have been explored. Such information is vital, not least for the design of Ce(3+)-based phosphors for the white light-emitting diodes (w-LEDs) with excellent performance.

  17. A unified description of the electrochemical, charge distribution, and spectroscopic properties of the special-pair radical cation in bacterial photosynthesis.

    Science.gov (United States)

    Reimers, Jeffrey R; Hush, Noel S

    2004-04-01

    We apply our four-state 70-vibration vibronic-coupling model for the properties of the photosynthetic special-pair radical cation to: (1) interpret the observed correlations between the midpoint potential and the distribution of spin density between the two bacteriochlorophylls for 30 mutants of Rhodobacter sphaeroides, (2) interpret the observed average intervalence hole-transfer absorption energies as a function of spin density for six mutants, and (3) simulate the recently obtained intervalence electroabsorption Stark spectrum of the wild-type reaction center. While three new parameters describing the location of the sites of mutation with respect to the special pair are required to describe the midpoint-potential data, a priori predictions are made for the transition energies and the Stark spectrum. In general, excellent predictions are made of the observed quantities, with deviations being typically of the order of twice the experimental uncertainties. A unified description of many chemical and spectroscopic properties of the bacterial reaction center is thus provided. Central to the analysis is the assumption that the perturbations made to the reaction center, either via mutations of protein residues or by application of an external electric field, act only to independently modify the oxidation potentials of the two halves of the special pair and hence the redox asymmetry E0. While this appears to be a good approximation, clear evidence is presented that effects of mutation can be more extensive than what is allowed for. A thorough set of analytical equations describing the observed properties is obtained using the Born-Oppenheimer adiabatic approximation. These equations are generally appropriate for intervalence charge-transfer problems and include, for the first time, full treatment of both symmetric and antisymmetric vibrational motions. The limits of validity of the adiabatic approach to the full nonadiabatic problem are obtained.

  18. Synthesis, structure and spectroscopic properties of rare earth complexes with a new aryl amide 2,2'-bipydine derivative

    Science.gov (United States)

    Song, Xue-Qin; Zheng, Jiang-Rong; Liu, Wei-Sheng; Ju, Zheng-Hua

    2008-01-01

    Solid complexes of rare earth nitrates and picrates with a new aryl amide ligand 3.3'-bis(benzylamido)-2,2'-bipyridine ( L) were synthesized and characterized by elemental analysis, IR and molar conductivity measurements. The molecular structures of the complex [TbL 2(NO 3) 3H 2O]·2H 2O have been determined by single-crystal X-ray diffraction. The fluorescent properties of the Eu(III) and Tb(III) nitrates and picrates complexes in solid state were also investigated in detail. Under the excitation, these complexes exhibited characteristic emissions of europium and terbium ions. It is worth noting that the nature of the anion has a great effect upon the composition of the complexes as well as emission properties of them.

  19. Autofluorescence-Free Targeted Tumor Imaging Based on Luminous Nanoparticles with Composition-Dependent Size and Persistent Luminescence.

    Science.gov (United States)

    Wang, Jie; Ma, Qinqin; Hu, Xiao-Xiao; Liu, Haoyang; Zheng, Wei; Chen, Xueyuan; Yuan, Quan; Tan, Weihong

    2017-08-22

    Optical bioimaging is an indispensable tool in modern biology and medicine, but the technique is susceptible to autofluorescence interference. Persistent nanophosphors provide an easy-to-perform and highly efficient means to eliminate tissue autofluorescence. However, direct synthesis of persistent nanophosphors with tunable properties to meet different bioimaging requirements remains largely unexplored. In this work, zinc gallogermanate (Zn1+xGa2-2xGexO4:Cr, 0 ≤ x ≤ 0.5, ZGGO:Cr) persistent luminescence nanoparticles with composition-dependent size and persistent luminescence are reported. The size of the ZGGO:Cr nanoparticles gradually increases with the increase of x in the chemical formula. Moreover, the intensity and decay time of persistent luminescence in ZGGO:Cr nanoparticles can also be fine-tuned by simply changing x in the formula. In vivo bioimaging tests demonstrate that ZGGO:Cr nanoparticles can efficiently eliminate tissue autofluorescence, and the nanoparticles also show good promise in long-term bioimaging as they can be easily reactivated in vivo. Furthermore, an aptamer-guided ZGGO:Cr bioprobe is constructed, and it displays excellent tumor-specific accumulation. The ZGGO:Cr nanoparticles are ideal for autofluorescence-free targeted bioimaging, indicating their great potential in monitoring cellular networks and construction of guiding systems for surgery.

  20. Spectroscopic properties of 2.7 μm emission in Er{sup 3+} doped telluride glasses and fibers

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xiaokang [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Li, Kefeng, E-mail: kfli@siom.ac.cn [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Xia; Kuan, Peiwen; Wang, Xin [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Hu, Lili [Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2014-12-05

    Highlights: • Telluride glasses with high Er{sup 3+} doping concentration and good thermal property are prepared. • Energy transfer processes for 1.5 μm, 2.7 μm and visible emission are fully discussed. • Enhanced 2.7 μm emission is achieved from the bulk glasses. • An Er{sup 3+} doped fiber is successfully drawn and strong upconversion emission is observed in the fiber. - Abstract: Emissions at 2.7 μm from telluride glasses with various Er{sub 2}O{sub 3} doping concentrations are investigated. The prepared glasses have excellent thermostability and high rare-earth solubility. Judd–Ofelt parameters are calculated based on the absorption spectra. A large emission cross section (1.12 × 10{sup −20} cm{sup 2}) and a high spontaneous radiative coefficient (57.8 s{sup −1}) are obtained at 2.7 μm. The fluorescence properties of glasses with different concentrations are analyzed and presented. An Er{sup 3+}-doped fiber is fabricated via a rod-in-tube technique, and the loss at 1310 nm is ∼2.1 dB/m measured by using the cut-back method. Strong upconversion emission caused by intense pump absorption is observed from the Er{sup 3+}doped fiber under excitation by a 980 nm laser diode (LD). Telluride glasses with high Er{sup 3+} doping concentration and good thermal property are prepared. Energy transfer processes for 1.5 μm, and 2.7 μm, as well as visible emission are fully discussed. Enhanced 2.7 μm emission is achieved from the bulk glass. An Er{sup 3+} doped fiber is successfully drawn, and strong upconversion emission is observed in the fiber.

  1. Molecular structure, experimental and theoretical spectroscopic characterization and non-linear optical properties studies of a new non-centrosymmetric hybrid material

    Science.gov (United States)

    Chihaoui, Nejla; Hamdi, Besma; Dammak, Thameur; Zouari, Ridha

    2016-11-01

    This paper gathers the synthesis and study of a novel nonlinear organic-inorganic (1,2-diammoniumcyclohexane tetrabromozincate (II) monohydrate; [C6H10(NH3)2]ZnBr4·H2O) hybrid. The newly developed hybrid was characterized by XRD and spectroscopic (FT-IR, Raman, UV-Visible and CP/MAS-NMR) studies. All theoretical calculations and structural optimization parameters were conducted by using DFT approach with B3LYP/6-31G(d) basis set and the vibrational wavenumbers were evaluated for the affectation of [C6H10(NH3)2]ZnBr4·H2O compound by using transferable scale factor. The inspection of intermolecular links in the studied framework has been executed by the Hirshfeld surface analysis. The nonlinear optical characteristics of this compound were theoretically explored also the molecular orbitals (HOMO) and (LUMO) properties are performed to describe the charge transfer within the crystal.

  2. Understanding Thermodynamic and Spectroscopic Properties of Tetragonal Mn12 Single-Molecule Magnets from Combined Density Functional Theory/Spin-Hamiltonian Calculations.

    Science.gov (United States)

    Ghassemi Tabrizi, Shadan; Arbuznikov, Alexei V; Kaupp, Martin

    2016-09-01

    We apply broken-symmetry density functional theory to determine isotropic exchange-coupling constants and local zero-field splitting (ZFS) tensors for the tetragonal Mn12(t)BuAc single-molecule magnet. The obtained parametrization of the many-spin Hamiltonian (MSH), taking into account all 12 spin centers, is assessed by comparing theoretical predictions for thermodynamic and spectroscopic properties with available experimental data. The magnetic susceptibility (calculated by the finite-temperature Lanczos method) is well approximated, and the intermultiplet excitation spectrum from inelastic neutron scattering (INS) experiments is correctly reproduced. In these respects, the present parametrization of the 12-spin model represents a significant improvement over previous theoretical estimates of exchange-coupling constants in Mn12, and additionally offers a refined interpretation of INS spectra. Treating anisotropic interactions at the third order of perturbation theory, the MSH is mapped onto the giant-spin Hamiltonian describing the S = 10 ground multiplet. Although the agreement with high-field EPR experiments is not perfect, the results clearly point in the right direction and for the first time rationalize the angular dependence of the transverse-field spectra from a fully microscopic viewpoint. Importantly, transverse anisotropy of the effective S = 10 manifold is explicitly shown to arise largely from the ZFS-induced mixing of exchange multiplets. This effect is given a thorough analysis in the approximate D2d spin-permutational symmetry group of the exchange Hamiltonian.

  3. Effect of concentration quenching on the spectroscopic properties of Er3+/Yb3+ co-doped AlF3-based glasses

    Institute of Scientific and Technical Information of China (English)

    Junjie Zhang(张军杰); Shixun Dai(戴世勋); Shiqing Xu(徐时清); Guonian Wang(汪国年); Liyan Zhang(张丽艳); Lili Hu(胡丽丽)

    2004-01-01

    A series of highly Er3+/Yb3+ co-doped fluoroaluminate glasses have been investigated in order to develop a microchip laser at 1.54 μm under 980 nm excitation. Measurements of absorption, emission and upconversion spectra have been performed to examine the effect of Er3+/Yb3+ concentration quenching on spectroscopic properties. In the glasses with Er3+ concentrations below 10 mol%, concentration quenching is very low and the Er3+/Yb3+ co-doped fluoroaluminate glasses have stronger fluorescence of 1.54 μm due to the 4I13/2 → 4I15/2 transition than that of Er3+ singly-doped glasses. As Er3+ concentrations above 10 mol% in the Er3+/Yb3+ co-doped samples, concentration quenching of 1.54 μm does obviously occur as a result of the back energy transfer from Er3+ to Yb3+. To obtain the highest emission efficiency at 1.54 μm, the optimum doping-concentration ratio of Er3+/Yb3+ was found to be approximately 1:1 in mol fraction when the Er3+ concentration is less than 10 mol%.

  4. The spectroscopic properties of anticancer drug Apigenin investigated by using DFT calculations, FT-IR, FT-Raman and NMR analysis

    Science.gov (United States)

    Mariappan, G.; Sundaraganesan, N.; Manoharan, S.

    2012-09-01

    The FT-Raman and FT-Infrared spectra of solid Apigenin sample were measured in order to elucidate the spectroscopic properties of title molecule in the spectral range of 3500-50 cm-1 and 4000-400 cm-1, respectively. The recorded FT-IR and FT-Raman spectral measurements favor the calculated (by B3LYP/6-31G(d,p) method) structural parameters which are further supported by spectral simulation. Additional support is given by the collected 1H and 13C NMR spectra recorded with the sample dissolved in DMSO. The predicted chemical shifts at the B3LYP/6-31G(d) level obtained using the Gauge-Invariant Atomic Orbitals (GIAO) method with and without inclusion of solvent using the Polarizable Continuum Model (PCM). By using TD-DFT method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFT method and the experimental one is determined. The UV-visible absorption spectra of the compound that dissolved in Ethanol, Methanol and DMSO were recorded in the range of 800-200 nm. The formation of hydrogen bond and the most possible interaction are explained using natural bond orbital (NBO) analysis. In addition, the molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis and atomic charges of the title compound were investigated using theoretical calculations. The results are discussed herein and compared with similar molecules whenever appropriate.

  5. Redox properties of structural Fe in clay minerals. 2. Electrochemical and spectroscopic characterization of electron transfer irreversibility in ferruginous smectite, SWa-1.

    Science.gov (United States)

    Gorski, Christopher A; Klüpfel, Laura; Voegelin, Andreas; Sander, Michael; Hofstetter, Thomas B

    2012-09-04

    Structural Fe in clay minerals is an important, albeit poorly characterized, redox-active phase found in many natural and engineered environments. This work develops an experimental approach to directly assess the redox properties of a natural Fe-bearing smectite (ferruginous smectite, SWa-1, 12.6 wt % Fe) with mediated electrochemical reduction (MER) and oxidation (MEO). By utilizing a suite of one-electron-transfer mediating compounds to facilitate electron transfer between structural Fe in SWa-1 and a working electrode, we show that the Fe2+/Fe3+ couple in SWa-1 is redox-active over a large range of potentials (from E(H) = -0.63 V to +0.61 V vs SHE). Electrochemical and spectroscopic analyses of SWa-1 samples that were subject to reduction and re-oxidation cycling revealed both reversible and irreversible structural Fe rearrangements that altered the observed apparent standard reduction potential (E(H)(ø)) of structural Fe. E(H)(ø)-values vary by as much as 0.56 V between SWa-1 samples with different redox histories. The wide range of E(H)-values over which SWa-1 is redox-active and redox history-dependent E(H)(ø)-values underscore the importance of Fe-bearing clay minerals as redox-active phases in a wide range of redox regimes.

  6. Luminescence Spectroscopical Properties of Plagioclase Particles from the Hayabusa Sample Return Mission: An Implication for Study of Space Weathering Processes in the Asteroid Itokawa.

    Science.gov (United States)

    Gucsik, Arnold; Nakamura, Tomoki; Jäger, Cornelia; Ninagawa, Kiyotaka; Nishido, Hirotsugu; Kayama, Masahiro; Tsuchiyama, Akira; Ott, Ulrich; Kereszturi, Ákos

    2017-02-01

    We report a systematic spectroscopical investigation of three plagioclase particles (RB-QD04-0022, RA-QD02-0025-01, and RA-QD02-0025-02) returned by the Hayabusa spacecraft from the asteroid Itokawa, by means of scanning electron microscopy, cathodoluminescence microscopy/spectroscopy, and micro-Raman spectroscopy. The cathodoluminescence properties are used to evaluate the crystallization effects and the degree of space weathering processes, especially the shock-wave history of Itokawa. They provide new insights regarding spectral changes of asteroidal bodies due to space weathering processes. The cathodoluminescence spectra of the plagioclase particles from Itokawa show a defect-related broad band centered at around 450 nm, with a shoulder peak at 425 nm in the blue region, but there are no Mn- or Fe-related emission peaks. The absence of these crystal field-related activators indicates that the plagioclase was formed during thermal metamorphism at subsolidus temperature and extreme low oxygen fugacity. Luminescence characteristics of the selected samples do not show any signatures of the shock-induced microstructures or amorphization, indicating that these plagioclase samples suffered no (or low-shock pressure regime) shock metamorphism. Cathodoluminescence can play a key role as a powerful tool to determine mineralogy of fine-grained astromaterials.

  7. Process analytical technology: chemometric analysis of Raman and near infra-red spectroscopic data for predicting physical properties of extended release matrix tablets.

    Science.gov (United States)

    Shah, Rakhi B; Tawakkul, Mobin A; Khan, Mansoor A

    2007-05-01

    The purpose of this work was to develop a correlation between pharmaceutical properties such as hardness, porosity, and content with prediction models employed using Raman and near infra-red (NIR) spectroscopic methods. Metoprolol tartrate tablets were prepared by direct compression and wet granulation methods. NIR spectroscopy and chemical imaging, and Raman spectra were collected, and hardness, porosity, and dissolution were measured. The NIR PLS model showed a validated correlation coefficient of >0.90 for the predicted versus measured porosity, hardness, and amount of drug with raw and second derivative NIR spectra. Raman spectra correlated porosity of the tablets using raw data for directly compressed tablets and wet granulated tablets (r(2) > 0.90). A very close root-mean square error of calibration (RMSEC) and root-mean square error of prediction (RMSEP) values were found in all the cases indicating validity of the calibration models. Raman spectroscopy was used for the first time to predict physical quality attribute such as porosity successfully. Chemical imaging utilizing NIR detector also demonstrated to show physical changes due to compression differences. In conclusion, sensor technologies can be potentially used to predict physical parameters of the matrix tablets.

  8. Physicochemical and spectroscopic properties of natural organic matter (NOM) from various sources and implications for ameliorative effects on metal toxicity to aquatic biota.

    Science.gov (United States)

    Al-Reasi, Hassan A; Wood, Chris M; Smith, D Scott

    2011-06-01

    Natural organic matter (NOM), expressed as dissolved organic carbon (DOC in mgCL(-1)), is an ubiquitous complexing agent in natural waters, and is now recognized as an important factor mitigating waterborne metal toxicity. However, the magnitude of the protective effect, judged by toxicity measures (e.g. LC50), varies substantially among different NOM sources even for similar DOC concentrations, implying a potential role of NOM physicochemical properties or quality of NOM. This review summarizes some key quality parameters for NOM samples, obtained by reverse osmosis, and by using correlation analyses, investigates their contribution to ameliorating metal toxicity towards aquatic biota. At comparable and environmentally realistic DOC levels, molecular spectroscopic characteristics (specific absorbance coefficient, SAC, and fluorescence index, FI) as well as concentrations of fluorescent fractions obtained from mathematical mixture resolution techniques (PARAFAC), explain considerable variability in the protective effects. NOM quality clearly influences the toxicity of copper (Cu) and lead (Pb). NOM quality may also influence the toxicity of silver (Ag), cadmium (Cd) and inorganic mercury (Hg), but as yet insufficient data are available to unequivocally support the latter correlations between toxicity reduction and NOM quality predictors. Cu binding capacities, protein-to-carbohydrate ratio, and lipophilicity, show insignificant correlation to the amelioration offered by NOMs, but these conclusions are based on data for Norwegian NOMs with very narrow ranges for the latter two parameters. Certainly, various NOMs alleviate metal toxicity differentially and therefore their quality measures should be considered in addition to their quantity.

  9. Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of manganese (II) complex of picolinate: A combined experimental and computational study

    Science.gov (United States)

    Tamer, Ömer; Avcı, Davut; Atalay, Yusuf; Çoşut, Bünyemin; Zorlu, Yunus; Erkovan, Mustafa; Yerli, Yusuf

    2016-02-01

    A novel manganese (II) complex with picolinic acid (pyridine 2-carboxylic acid, Hpic), namely, [Mn(pic)2(H2O)2] was prepared and its crystal structure was fully characterized by using single crystal X-ray diffraction. Picolinate (pic) ligands were coordinated to the central manganese(II) ion as bidentate N,O-donors through the nitrogen atoms of pyridine rings and the oxygen atoms of carboxylate groups forming five-membered chelate rings. The spectroscopic characterization of Mn(II) complex was performed by the applications of FT-IR, Raman, UV-vis and EPR techniques. In order to support these studies, density functional theory (DFT) calculations were carried out by using B3LYP level. IR and Raman spectra were simulated at B3LYP level, and obtained results indicated that DFT calculations generally give compatible results to the experimental ones. The electronic structure of the Mn(II) complex was predicted using time dependent DFT (TD-DFT) method with polarizable continuum model (PCM). Molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength were investigated by applying natural bond orbital (NBO) analysis. Nonlinear optical properties of Mn(II) complex were investigated by the determining of molecular polarizability (α) and hyperpolarizability (β) parameters.

  10. A microwave molecular solution based approach towards high-κ-tantalum(V)oxide nanoparticles: synthesis, dielectric properties and electron paramagnetic resonance spectroscopic studies of their defect chemistry.

    Science.gov (United States)

    Hoffmann, R C; Kaloumenos, M; Spiehl, D; Erdem, E; Repp, S; Weber, S; Schneider, J J

    2015-12-21

    Stable dispersions of tantalum oxide nanoparticles are accessible from solutions of tantalum(V) complexes with a mixed malonato and alkanolato ligand sphere in ethoxyethanol by microwave processing. The malonato ligand is cleaved during decomposition and acetic acid or acetic acid esters are formed as derived from in situ spectroscopic studies. The solubility of the tantalum precursor and the obtained particle size therefrom depend strongly on the type of alkanolato ligand moiety. Dispersions of the molecular complexes possess good film forming properties. Films with low surface roughness can be obtained by spincoating. These exhibited a dielectric constant of about 15 and disruptive strengths above 1.5 MV cm(-1). The electrical measurements indicate that the presence of moisture is detrimental with respect to the dielectric performance of the films. After removal of the solvent from the suspensions of the nanoparticles, the residue can be redispersed in aprotic solvents. The particles can be isolated therefrom by precipitation with pentane. XRD and HRTEM indicate that the material remains amorphous up to temperatures of 750 °C. XPS proved that only Ta2O5 is formed as lower oxidation states of Ta cannot be detected. A detailed EPR study allows us to gain insight into the surface defect chemistry. Multiple types of oxygen vacancies exist at the surface of the Ta2O5 particles which are influenced by additional calcination and annealing in a vacuum.

  11. Thermal and plasma enhanced atomic layer deposition of TiO{sub 2}: Comparison of spectroscopic and electric properties

    Energy Technology Data Exchange (ETDEWEB)

    Das, Chittaranjan, E-mail: chittaiit@yahoo.com; Henkel, Karsten; Tallarida, Massimo; Schmeißer, Dieter [Brandenburg University of Technology Cottbus-Senftenberg, Applied Physics and Sensors, K.-Wachsmann-Allee 17, D-03046 Cottbus (Germany); Gargouri, Hassan; Kärkkänen, Irina; Schneidewind, Jessica; Gruska, Bernd; Arens, Michael [SENTECH Instruments GmbH, Schwarzschildstraße 2, 12489 Berlin (Germany)

    2015-01-15

    Titanium oxide (TiO{sub 2}) deposited by atomic layer deposition (ALD) is used as a protective layer in photocatalytic water splitting system as well as a dielectric in resistive memory switching. The way ALD is performed (thermally or plasma-assisted) may change the growth rate as well as the electronic properties of the deposited films. In the present work, the authors verify the influence of the ALD mode on functional parameters, by comparing the growth rate and electronic properties of TiO{sub 2} films deposited by thermal (T-) and plasma-enhanced (PE-) ALD. The authors complete the study with the electrical characterization of selected samples by means of capacitance–voltage and current–voltage measurements. In all samples, the authors found a significant presence of Ti{sup 3+} states, with the lowest content in the PE-ALD grown TiO{sub 2} films. The observation of Ti{sup 3+} states was accompanied by the presence of in-gap states above the valence band maximum. For films thinner than 10 nm, the authors found also a strong leakage current. Also in this case, the PE-ALD films showed the weakest leakage currents, showing a correlation between the presence of Ti{sup 3+} states and leakage current density.

  12. Differences between Zn-porphyrin-coupled titanate nanotubes with various anchoring modes: Thermostability, spectroscopic, photocatalytic and photoelectronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiangqing [Department of Chemical Engineering, Laboratory of New Energy Materials, Shanghai Institute of Technology, 120 Caobao Road, Shanghai 200235 (China); Liu Lifang [School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Kang Shizhao, E-mail: kangsz@sit.edu.cn [Department of Chemical Engineering, Laboratory of New Energy Materials, Shanghai Institute of Technology, 120 Caobao Road, Shanghai 200235 (China); Mu Jin [School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Li Guodong [State Key Laboratory of Inorganic Synthesis Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China)

    2011-05-01

    In order to study the effects of anchoring modes on the properties of porphyrin zinc (ZnP) coupled titanate nanotubes (TNTs), the TNTs coupled with 5,10,15,20-tetraphenylporphyrin zinc (ZnTPP) and 5-(4-hydroxyphenyl)10,15,20-triphenylporphyrin zinc (ZnMOHPP), which were denoted as TNTs-ZnTPP and TNTs-ZnMOHPP, were prepared using a simple refluxing method, respectively. Based on the different experimental phenomena observed during the synthesis process as well as the results of the spectral characterization, thermogravimetric analysis, photocatalysis test and photoelectrochemistry measurement, it was demonstrated that the ZnMOHPP molecules were bonded mainly on the outer surfaces of the TNTs through hydrogen bonds, while the ZnTPP molecules were physically adsorbed into the pore channels of the TNTs via a capillary process. The different anchoring modes of ZnP on the TNTs as well as the special morphology of TNTs resulted in the remarkable distinctions in the thermal stability, photocatalytic and photoelectrochemical properties.

  13. Spectroscopic Properties of Star-Forming Host Galaxies and Type Ia Supernova Hubble Residuals in a Nearly Unbiased Sample

    Energy Technology Data Exchange (ETDEWEB)

    D' Andrea, Chris B. [Univ. of Pennsylvania, Philadelphia, PA (United States); et al.

    2011-12-20

    We examine the correlation between supernova host galaxy properties and their residuals on the Hubble diagram. We use supernovae discovered during the Sloan Digital Sky Survey II - Supernova Survey, and focus on objects at a redshift of z < 0.15, where the selection effects of the survey are known to yield a complete Type Ia supernova sample. To minimize the bias in our analysis with respect to measured host-galaxy properties, spectra were obtained for nearly all hosts, spanning a range in magnitude of -23 < M_r < -17. In contrast to previous works that use photometric estimates of host mass as a proxy for global metallicity, we analyze host-galaxy spectra to obtain gas-phase metallicities and star-formation rates from host galaxies with active star formation. From a final sample of ~ 40 emission-line galaxies, we find that light-curve corrected Type Ia supernovae are ~ 0.1 magnitudes brighter in high-metallicity hosts than in low-metallicity hosts. We also find a significant (> 3{\\sigma}) correlation between the Hubble residuals of Type Ia supernovae and the specific star-formation rate of the host galaxy. We comment on the importance of supernova/host-galaxy correlations as a source of systematic bias in future deep supernova surveys.

  14. Judd–Ofelt analysis of spectroscopic properties of Eu{sup 3+} doped KLa(PO{sub 3}){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Ferhi, M., E-mail: ferhi.mounir@gmail.com [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, Technopole de Borj Cedria, BP 73, 8027 Soliman (Tunisia); Bouzidi, C.; Horchani-Naifer, K. [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, Technopole de Borj Cedria, BP 73, 8027 Soliman (Tunisia); Elhouichet, H. [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, Technopole de Borj Cedria, BP 73, 8027 Soliman (Tunisia); Département de Physique, Faculté des Sciences de Tunis, Campus ElManar, 2092 Tunis (Tunisia); Ferid, M. [Laboratoire de Physico-chimie des Matériaux Minéraux et leurs Applications, Centre National des Recherches en Sciences des Matériaux, Technopole de Borj Cedria, BP 73, 8027 Soliman (Tunisia)

    2015-01-15

    Based on Judd–Ofelt (J–O) theory, the intensity parameters (Ω{sub 2} and Ω{sub 4}) have been evaluated from the emission spectra of KLa{sub (1−x)}Eu{sub x}(PO{sub 3}){sub 4} (where x=2, 5, 10, 15, 20 and 30 mol%) polycrystalline powders as a function of Eu{sup 3+} ion concentration. The registered trend (Ω{sub 2}<Ω{sub 4}) reveals the ionic character of the La(Eu)–O bonds as well as a relatively high symmetry environment around the rare earth ion (RE) site in KLa(PO{sub 3}){sub 4} as compared to other host matrix. From these intensity parameters various radiative properties like spontaneous emission probability (A), branching ratio (β{sub R}), stimulated emission cross-section (σ) and the radiative lifetime (τ{sub R}) have been calculated. The decay profiles for the {sup 5}D{sub 0} excited level of Eu{sup 3+} in KLa(PO{sub 3}){sub 4} have been found to be single exponential and independent of Eu{sup 3+} ion concentration even at 30 mol%. In comparison with other Eu{sup 3+}-doped materials, KLa(PO{sub 3}){sub 4}:Eu{sup 3+} has a long lifetime, low multiphonon relaxation rates (W{sub NR}), high quantum efficiency (η) and better optical gain parameter (σxτ{sub exp}). The determined radiative properties reveal the usefulness of KLa{sub (1−x)}Eu{sub x}(PO{sub 3}){sub 4} in developing visible red lasers as well as optical display devices at around 613 nm. Our results were discussed as a function of Eu{sup 3+} concentration, crystal structure of KLa(PO{sub 3}){sub 4} and particle-size distributions. - Highlights: • Judd–Ofelt theory has been applied to KLa{sub (1−x)}Eu{sub x}(PO{sub 3}){sub 4}. • Radiative properties of KLa{sub (1−x)}Eu{sub x}(PO{sub 3}){sub 4} have been determined. • The obtained results were discussed and compared to other hosts matrix. • KLa{sub (1−x)}Eu{sub x}(PO{sub 3}){sub 4} can be used in red lasers and optical display devices.

  15. Spectroscopic properties and radiation damage investigation of a diamond based Schottky diode for ion-beam therapy microdosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Verona, C.; Marinelli, Marco; Verona-Rinati, G. [INFN - Dipartimento di Ingegneria Industriale, Università di Roma “Tor Vergata,” Roma (Italy); Magrin, G.; Solevi, P.; Mayer, R. [EBG MedAustron Marie Curie-St. 5, 2700 Wiener Neustadt (Austria); Grilj, V.; Jakšić, M. [Ruder Boškovic Institute, Bijenicka cesta 54, P.O. Box 180, 10002 Zagreb (Croatia)

    2015-11-14

    In this work, a detailed analysis of the properties of a novel microdosimeter based on a synthetic single crystal diamond is reported. Focused ion microbeams were used to investigate the device spectropscopic properties as well as the induced radiation damage effects. A diamond based Schottky diode was fabricated by chemical vapor deposition with a very thin detecting region, about 400 nm thick (approximately 1.4 μm water equivalent thickness), corresponding to the typical size in microdosimetric measurements. A 200 × 200 μm{sup 2} square metallic contact was patterned on the diamond surface by standard photolithography to define the sensitive area. Experimental measurements were carried out at the Ruder Boškovic′ Institute microbeam facility using 4 MeV carbon and 5 MeV silicon ions. Ion beam induced charge maps were employed to characterize the microdosimeter response in terms of its charge collection properties. A stable response with no evidence of polarization or memory effects was observed up to the maximum investigated ion beam flux of about 1.7 × 10{sup 9} ions·cm{sup −2}·s{sup −1}. A homogeneity of the response about 6% was found over the sensitive region with a well-defined confinement of the response within the active area. Tests of the radiation damage effect were performed by selectively irradiating small areas of the device with different ion fluences, up to about 10{sup 12} ions/cm{sup 2}. An exponential decrease of the charge collection efficiency was observed with a characteristic decay constant of about 4.8 MGy and 1 MGy for C and Si ions, respectively. The experimental data were analyzed by means of GEANT4 Monte Carlo simulations. A direct correlation between the diamond damaging effect and the Non Ionizing Energy Loss (NIEL) fraction was found. In particular, an exponential decay of the charge collection efficiency with an exponential decay as a function of NIEL is observed, with a characteristic constant of about

  16. Electrical modulation of static and dynamic spectroscopic properties of coupled nanoscale GaSe quantum dot assemblies

    Science.gov (United States)

    Verma, Y. K.; Inman, R. H.; Ferri, C. G. L.; Mirafzal, H.; Ghosh, S. N.; Kelley, D. F.; Hirst, L. S.; Ghosh, S.; Chin, W. C.

    2010-10-01

    We demonstrate the formation and spatial modulation of strongly coupled gallium selenide quantum dot (QD) nanoassemblies suspended in a nematic liquid-crystal (NLC) matrix at room temperature. Using static and dynamic optical techniques we show that the coupled QDs aggregate with a well-defined directionality commensurate with the NLC director axis. This results in highly anisotropic spectral properties of the QD assembly. The spatial orientation of the aggregates is selectively controlled in situ by the application of in-plane electric fields. The strong interdot coupling further increases the excitonic recombination rate which is both direction and electric field dependent. This electrical modulation, a noninvasive process, could potentially be an important functionality for the design and creation of building blocks for novel optoelectronic devices.

  17. Conformational, spectroscopic and nonlinear optical properties of biologically active N,N-dimethyltryptamine molecule: A theoretical study

    Science.gov (United States)

    Öner, Nazmiye; Tamer, Ömer; Avcı, Davut; Atalay, Yusuf

    2014-12-01

    The effective psychoactive properties of N,N-dimethyltryptamine (DMT) known as the near-death molecule have encouraged the imagination of many research disciplines for several decades. Although there is no theoretical study, a number of paper composed by experimental techniques have been reported for DMT molecule. In this study, the molecular modeling of DMT was carried out using B3LYP and HSEh1PBE levels of density functional theory (DFT). Our calculations showed that the energy gap between HOMO and LUMO is low, demonstrating that DMT is a biologically active molecule. Large hyperconjugation interaction energies imply that molecular charge transfer occurs in DMT. Moreover, NLO analysis indicates that DMT can be used an effective NLO material.

  18. Luminescence properties of ZnO/TiO$_2$ nanocomposite activated by Eu$^{3+}$ and their spectroscopic analysis

    Indian Academy of Sciences (India)

    PANKAJ KUMAR BAITHA; J MANAM

    2016-09-01

    A new type of novel orange-red emitting Eu-doped ZnO/TiO$_2$ nanocomposite phosphors have been synthesized by simple low temperature co-precipitation route. Structure and morphology of the prepared sample havebeen investigated using X-ray diffraction and field emission scanning electron microscopy (FESEM) techniques. XRD pattern confirmed the presence of both phases of ZnO and TiO$_2$ simultaneously. The luminescence properties, such as photoluminescence (PL) excitation and emission spectra, Judd–Ofelt parameters, CIE colour coordinates and the dependence of luminescence intensity on the doping level were investigated. The luminescence spectrumcharacteristics of Eu$^{3+}$ ions have a strong dependence on Eu$^{3+}$ doping levels as well as ZnO/TiO$_2$ ratio variations. The photoluminescence results indicate that these phosphors could be efficiently excited by near-ultraviolet radiation, which causes emissions in orange–red regions.

  19. Spectroscopic Properties and Judd-Ofelt Theory Analysis of Er3+-Doped Heavy Metal Oxyfluoride Silicate Glass

    Institute of Scientific and Technical Information of China (English)

    徐时清; 杨中民; 戴世勋; 张军杰; 胡丽丽; 姜中宏

    2004-01-01

    Er3+-doped heavy metal oxyfluoride silicate glass was fabricated and characterized, and the absorption spectrum and fluorescence spectrum of the glass were studied. The Judd-Ofelt intensity parameters Ωt (t=2, 4, 6), spontaneous transition probability, fluorescence branching ratio and radiative lifetime of each energy levels for Er3+ were calculated by Judd-Ofelt theory, and stimulated emission cross-section of 4I13/2→4I15/2 transition was calculated by McCumber theory. The results show that fluorescence full width at half maximum and stimulated emission cross-section of Er3+-doped heavy metal oxyfluoride silicate glass are broad and large, respectively. Compared with other host glasses, the gain bandwidth property of Er3+-doped heavy metal oxyfluoride silicate glass is close to those of tellurite and bismuth glasses, and has advantage over those of silicate, phosphate and germante glasses.

  20. Spectroscopic analysis and mechanical properties of electron beam irradiated polypropylene/epoxidized natural rubber (PP/ENR) polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Senna, Magdy M.H. [National Center for Radiation Research and Technology, P.O.Box 29, Nasr City, Cairo (Egypt)], E-mail: magdysenna@yahoo.com; Abdel-Fattah, Atef A. [National Center for Radiation Research and Technology, P.O.Box 29, Nasr City, Cairo (Egypt); Abdel-Monem, Y.K. [Faculty of Science, Chemistry Department, Menoufia University (Egypt)

    2008-06-15

    Polymer blends based on different ratios of polypropylene (PP) and epoxidized natural rubber (ENR) were prepared by melt extrusion into sheets. The PP/ENR blends were exposed to various dose of accelerated electrons. The formation of free radicals during and after electron beam irradiation was illustrated by electron spin resonance (ESR). Also, the effect of electron beam irradiation on the mechanical and structural morphology was investigated by stress-strain behavior and scanning electron microscope (SEM). The ESR spectra indicated the formation of alkyl and allyl radicals during electron beam irradiation and peroxyl radicals during the post effect. The rate of radical decay was found to be second-order kinetics. The improvement in mechanical properties and structural morphology was confirmed to be due to the effect of electron beam irradiation.

  1. SPECTROSCOPIC STUDY OF EFFECTS OF TETRAALKYLAMMONIUM CATIONS ON F--SENSING PROPERTIES OF CALIX[4]PYRROLE BORADIAZAINDACENE DYE

    Directory of Open Access Journals (Sweden)

    Yongjun Lv

    Full Text Available A novel meso-tetracyclohexylcalix[4]pyrrole-based boradiazaindacene dye 3 was synthesized and characterized. F--binding properties of the dye in the presence of tetrabutylammonium (TBA+, tetraethylammonium (TEA+, and tetramethylammonium (TMA+ counter ions were investigated by UV-Vis, fluorescence, and NMR spectroscopies. Dye 3 displayed various degrees of absorption red shift, fluorescence quenching, and downfield shifts of NH signals for the three fluoride salts. The association constants of these salts mainly depend on cation size effects and ion-pairing effects and were in the order KTMA+ > KTEA+ > KTBA+. Thus, we speculate that both F- and tetraalkylammonium cations are concomitantly located above and below a bowl-shaped calix[4]pyrrole cup in an ion-paired complex, respectively.

  2. Spectroscopic properties of the UO{sub 2}(ACAC){sub 2}.(H{sub 2}O)n:Eu{sup 3+}(ACAC=Acetylacetonate Ion)

    Energy Technology Data Exchange (ETDEWEB)

    Felinto, Maria Claudia F.C.; Luiz, Jose Eduardo M. Sa; Nakagawa, Fabio T. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Brito, Hermi F. [Universidade de Sao Paulo (USP/IQ), SP (Brazil). Inst. de Quimica], E-mail: hefbrito@iq.usp.br; Teotonio, Ercules E.S. [Universidade Federal de Goias (UFG), Catalao, GO (Brazil)], E-mail: ercteot@gmail.com

    2007-07-01

    The uranyl ion possesses some properties, which makes it a potential component for a solar energy conversion system or biological application. It absorbs light in the shorter wavelength range of the solar spectrum, producing a relatively long-lived excited state. The excited state of uranyl ion has fluorescence peak at 520 nm, a property that makes it relatively convenient to investigate its reaction. The redox potential of the excited uranyl ion makes a powerful oxidizing agent. This may be of potential use in the photo generation of oxygen, which is of great importance for the photo cleavage of water. In this work, it is described the synthesis, characterization and spectroscopic study of the matrix UO{sub 2}(ACAC){sub 2}.(H{sub 2}O)n.(x% mol) Eu{sup 3+} (where x= 1, 3, 5 and 10). The compounds obtained were characterized by elementary analyses for determine the U{sup 6+} and Eu{sup 3+} concentrations, infrared spectra, thermal analyses, absorption in the UV-VIS range and luminescence spectra. The mainly bands in infrared spectra of the b-diketone observed in this work are {nu}{sub s} C=O in 1540 cm{sup -1}, {nu}{sub ass} C=O in 1540 cm{sup -1} and ns C=C in 1577 cm{sup -1}. In the emission spectra, transitions of the triplet 3{sup {pi}}{sub u} {yields} {sup 1}{sigma}{sub g} + was observed. The spectra of the uranyl matrix present behavior superimposed to doped 5% and 10% ones. The emission spectra of matrix doped with 1 and 3% showed a band shift to red region of spectrum light. (author)

  3. Compositional dependence of absorption and fluorescence of Yb{sup 3+} in oxide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Takebe, Hiromichi; Murata, Takahiro; Morinaga, Kenji [Kyushu Univ., Kasuga, Fukuoka (Japan)

    1996-03-01

    The integrated absorption cross section, the spontaneous emission probability, and the stimulated emission cross section of Yb{sup 3+} were determined in silicate, phosphate, borate, germanate, aluminate, gallate, and ZBLAN host glasses. The compositional dependence of the stimulated emission cross section of the {sup 2}F{sub 5/2} {yields} {sup 2}F{sub 7/2} transition is determined mainly by the integrated absorption cross section in the glasses. A peak stimulated emission cross section above 1 pm{sup 2}, which is the highest value in glasses, was obtained in a gallate glass with a composition of 40K{sub 2}O{center_dot}20Ta{sub 2}O{sub 5}{center_dot}40Ga{sub 2}O{sub 3}. The factors affecting the integrated absorption cross section are discussed using the Judd-Ofelt parameters of Er{sup 3+} calculated in previous studies.

  4. Rhenium complexes of chromophore-appended dipicolylamine ligands: syntheses, spectroscopic properties, DNA binding and X-ray crystal structure

    Energy Technology Data Exchange (ETDEWEB)

    Mullice, L.A.; Buurma, N.J.; Pope, S.J.A. [Cardiff Univ., School of Chemistry (United Kingdom); Laye, R.H. [Sheffield Univ., Dept. of Chemistry (United Kingdom); Harding, L.P. [Huddersfield Univ., School of Biological and Chemical Sciences (United Kingdom)

    2008-12-15

    The syntheses of two chromophore-appended dipicolylamine-derived ligands and their reactivity with penta-carbonyl-chloro-rhenium have been studied. The resultant complexes each possess the fac-Re(CO){sub 3} core. The ligands L{sup 1} 1-[bis(pyridine-2-yl-methyl)amino]methyl-pyrene and L{sup 2} 2-[bis(pyridine-2-yl-methyl)amino]methyl-quinoxaline were isolated via a one-pot reductive amination in moderate yield. The corresponding rhenium complexes were isolated in good yields and characterised by {sup 1}H NMR, MS, IR and UV-Vis studies. X-Ray crystallographic data were obtained for fac-{l_brace}Re(CO){sub 3}(L{sup 1}){r_brace}(BF{sub 4}), C{sub 34}H{sub 26}BF{sub 4}N{sub 4}O{sub 3}Re: monoclinic, P2(1)/c, a 18.327(2) Angstroms, {alpha} = 90.00 degrees, b 14.1537(14) Angstroms, {beta}96.263(6) degrees, c = 23.511(3) Angstroms, {gamma} 90.00 Angstroms, 6062.4(11) (Angstroms){sup 3}, Z=8. The luminescence properties of the ligands and complexes were also investigated, with the emission attributed to the appended chromophore in each case. Isothermal titration calorimetry suggests that fac-{l_brace}Re(CO){sub 3}(L{sup 1}){r_brace}(BF{sub 4}) self-aggregates cooperatively in aqueous solution, probably forming micelle-like aggregates with a cmc of 0.18 mM. Investigations into the DNA-binding properties of fac-{l_brace}Re(CO){sub 3}(L{sup 1}){r_brace}(BF{sub 4}) were undertaken and revealed that fac-{l_brace}Re(CO){sub 3}(L{sup 1}){r_brace}(BF{sub 4}) binding to fish sperm DNA (binding constant 1.5 {+-} 0.2 * 10{sup 5} M{sup -1}, binding site size 3.2 {+-} 0.3 base pairs) is accompanied by changes in the UV-Vis spectrum as typically observed for pyrene-based intercalators while the calorimetrically determined binding enthalpy (-14 {+-} 2 kcal mol{sup -1}) also agrees favourably with values as typically found for intercalators. (authors)

  5. An efficient approach for treating composition-dependent diffusion within organic particles

    Energy Technology Data Exchange (ETDEWEB)

    O' Meara, Simon; Topping, David; Zaveri, Rahul A.; McFiggans, Gordon

    2017-09-07

    Mounting evidence demonstrates that under certain conditions the rate of component partitioning between the gas- and particle-phase in atmospheric organic aerosol is limited by particle-phase diffusion. To date, however, particle-phase diffusion has not been incorporated to regional atmospheric models. An analytical rather than numerical solution to diffusion through organic particulate matter is desirable because of its comparatively small computational expense in regional models. Current analytical models assume diffusion to be independent of composition, and therefore use a constant diffusion coefficient. To realistically model diffusion, however, it should be composition-dependent (e.g. due to the partitioning of components that plasticise, vitrify or solidify). This study assesses the modelling capability of an analytical solution to diffusion corrected to account for composition dependence against a numerical solution. Results show reasonable agreement when the gas-phase saturation ratio of a partitioning component is constant and particle-phase diffusion limits partitioning rate (< 10% discrepancy in estimated radius change). How-ever, when the saturation ratio of the partitioning component varies a generally applicable correction could not be found, indicating that existing methodologies are incapable of de-riving a general solution. Until such time as a general solution is found, caution should be given to sensitivity studies that assume constant diffusivity. The correction was implemented in the polydisperse multi-process Model for Simulating Aerosol Interactions and Chemistry (MOSAIC), and is used to illustrate how the evolution of number size distribution may be accelerated by condensation of a plasticising component onto viscous organic particles.

  6. Spectroscopic properties of Er3+-doped phosphate based glasses for broadband 1.54 μm emission

    Science.gov (United States)

    Rasool, Sk. Nayab; Jamalaiah, B. C.; Suresh, K.; Moorthy, L. Rama; Jayasankar, C. K.

    2017-02-01

    Er3+-doped phosphate based glasses were prepared by the conventional melt-quenching technique with the chemical composition of 44 P2O5 - 17 K2O - 9 Al2O3 - (30-x) CaF2 - x Er2O3, (where x = 0.1, 0.5, 1.0, 2.0and 3.0 mol %) and their spectral properties have been investigated from absorption, emission and decay measurements. The phenomenological Judd - Ofelt intensity parameters Ωλ(λ = 2, 4, 6) were determined from the intensities of absorption bands in order to calculate the radiative transition probability (AR), radiative lifetime (τR), branching ratios (βR) of various excited states. The McCumber's theory has been adopted to predict, the emission cross-section (σeM) of 4I13/2 → 4I15/2 transition from the absorption cross-section (σa) of the 4I15/2 ? 4I13/2 transition of Er3+ ions. From near infrared emission spectra, full width at half maxima (FWHM), stimulated emission cross-section (σe) and gain bandwidth (ΔG) for the 4I13/2 → 4I15/2 emission transition at 1.536 μm were evaluated and discussed their utility for optical communication networks.

  7. An electrochemical impedance spectroscopic study of the electronic and ionic transport properties of LiCoO2 cathode

    Institute of Scientific and Technical Information of China (English)

    ZHUANG QuanChao; XU JinMei; FAN XiaoYong; DONG QuanFeng; JIANG YanXia; HUANG Ling; SUN ShiGang

    2007-01-01

    The storage behavior and process of the first delithiation-lithiation of LiCoO2 cathode were investigated by electrochemical impedance spectroscopy (EIS). The electronic and ionic transport properties of LiCoO2 cathode along with variation of electrode potential were obtained in 1 mol.L-1 LiPF6-EC: DMC:DEC electrolyte solution. It was found that after 9 h storage of the LiCoO2 cathode in electrolyte solutions, a new arc appears in the medium frequency range in Nyquist plots of ElS, which increases with increasing the storage time. In the charge/discharge processes, the diameter of the new arc is reversibly changed with electrode potential. Such variation coincides well with the electrode potential dependence of electronic conductivity of the LiCoO2. Thus this new ElS feature is attributed to the change of electronic conductivity of LixCoO2 during storage of the LiCoO2 cathode in electrolyte solutions, as well as in processes of intercalation-deintercalationtion of lithium ions. It has been revealed that the reversible increase and decrease of the resistance of SEI film in charge-discharge processes can be also ascribed to the variation of electronic conductance of active materials of the LiCoO2 cathode.

  8. Vanillin and isovanillin: Comparative vibrational spectroscopic studies, conformational stability and NLO properties by density functional theory calculations

    Science.gov (United States)

    Balachandran, V.; Parimala, K.

    This study is a comparative analysis of FT-IR and FT-Raman spectra of vanillin (3-methoxy-4-hydroxybenzaldehyde) and isovanillin (3-hydroxy-4-methoxybenzaldehyde). The molecular structure, vibrational wavenumbers, infrared intensities, Raman scattering activities were calculated for both molecules using the B3LYP density functional theory (DFT) with the standard 6-311++G∗∗ basis set. The computed values of frequencies are scaled using multiple scaling factors to yield good coherence with the observed values. The calculated harmonic vibrational frequencies are compared with experimental FT-IR and FT-Raman spectra. The geometrical parameters and total energies of vanillin and isovanillin were obtained for all the eight conformers (a-h) from DFT/B3LYP method with 6-311++G∗∗ basis set. The computational results identified the most stable conformer of vanillin and isovanillin as in the "a" form. Non-linear properties such as electric dipole moment (μ), polarizability (α), and hyperpolarizability (β) values of the investigated molecules have been computed using B3LYP quantum chemical calculation. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecules.

  9. Density, viscosity, surface tension, and spectroscopic properties for binary system of 1,2-ethanediamine + diethylene glycol

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lihua; Zhang, Jianbin, E-mail: tadzhang@pku.edu.cn; Li, Qiang; Guo, Bo; Zhao, Tianxiang; Sha, Feng

    2014-08-20

    Graphical abstract: Excess property of the binary system 1,2-ethanediamine (EDA) + diethylene glycol (DEG). - Highlights: • Densities and viscosities of EDA + DEG at 298.15–318.150 K were listed. • Thermodynamics data of EDA + DEG at 298.15–318.15 K were calculated. • Surface tension of EDA + DEG at 298.15 K was measured. • Intermolecular interaction of EDA with DEG was discussed. - Abstract: This paper reports density and viscosity data at T = 298.15, 303.15, 308.15, 313.15, and 318.15 K and surface tension data at 298.15 K for the binary system 1,2-ethanediamine (EDA) + diethylene glycol (DEG) as a function of composition under atmospheric pressure. From the experimental density and viscosity data, the excess molar volume and viscosity deviation were calculated, and the results were fitted to a Redlich–Kister equation to obtain the coefficients and to estimate the standard deviations between the experimental and calculated quantities. Based on the kinematic viscosity data, enthalpy of activation for viscous flow, entropy of activation for the viscous flow, and Gibbs energies of activation of viscous flow were calculated. In addition, based on Fourier transform infrared spectra, UV–vis spectra, and electrical conductivity for the system EDA + DEG with various concentrations, intermolecular interaction of EDA with DEG was discussed.

  10. Theoretical Studies on Structural and Spectroscopic Properties of Photoelectrochemical Cell Ruthenium Sensitizers——the Derivatives of N3

    Institute of Scientific and Technical Information of China (English)

    CHEN Jie; WANG Jian; BAI Fu-quan; ZHENG Qing-chuan; ZHANG Hong-xing

    2012-01-01

    A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru(dcbpyH2)2(NCS)2](N3,dcbpy=4,4'-dicarboxy2,2'-bipyridine; NCS=thiocyanato).Density functional theory(DFT) based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT(TD-DFT) results indicate that the ancillary ligand dominates the molecular orbital(MO) energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO(HOMO) to the lowest unoccupied MO(LUMO) and LUMO to LUMO+ 1 orbital.If the gap between LUMO-LUMO+1 is small enough,the higher efficiency of dye-sensitized solar cell(DSSC) should be expected.

  11. Structures and spectroscopic properties of fluoroboron-subtriazaporphyrin derivatives: density functional theory approach on the benzo-fusing effect.

    Science.gov (United States)

    Qi, Dongdong; Zhang, Yuexing; Zhang, Lijuan; Jiang, Jianzhuang

    2010-02-04

    Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations were carried out to comparatively study the molecular structures, atomic charges, molecular orbitals, and electronic absorption spectra of fluoroboron-subtriazaporphyrin (SubTAP) and fluoroboron-subphthalocyanine (SubPc) as well as their benzo-fused low-symmetrical derivatives A(a)B(b)C(c) (3 > or = a, b, c > or = 0). The peripherally fused benzene rings are revealed to have a significant effect on the structure and charge density distribution of the inner nitrogen atoms of subtriazaporphyrin core, while the charge of the central fluoroboron group changes very little. The effect of peripherally fused benzene rings on the frontier molecular orbitals of different compounds is comparatively discussed. The nature of the electron excitation between the frontier molecular orbitals of the 20 compounds is assigned according to the calculation results. The benzene rings fused directly onto pyrrole rings have been revealed to show more effect on the inner nitrogen atom than the outer benzene rings fused onto the periphery of isoindole rings. The present work will be helpful toward systematically understanding the effect of ring enlargement through asymmetrically fusing benzene ring(s) onto the subtriazaporphyrin skeleton on the structures and properties of fluoroboron-subtriazaporphyrin and fluoroboron-subphthalocyanine analogues.

  12. Fabrication and spectroscopic properties of Co:MgAl2O4 transparent ceramics by the HIP post-treatment

    Science.gov (United States)

    Luo, Wei; Ma, Peng; Xie, Tengfei; Dai, Jiawei; Pan, Yubai; Kou, Huamin; Li, Jiang

    2017-07-01

    Cobalt-doped magnesium aluminate spinel (Co:MgAl2O4) is one of the most important saturable absorbers for the passive Q-switching of solid-state lasers operating at eye-safe wavelength of 1.5 μm. In this work, highly transparent Co:MgAl2O4 ceramics were fabricated by vacuum sintering combined with hot isostatic pressing (HIP) post-treatment, using the mixture of the commercial spinel and the lab-made Co:MgAl2O4 powder as the raw materials. The densification mechanism of Co:MgAl2O4 transparent ceramics was discussed. The microstructure and optical properties of the samples were investigated. The ground state absorption cross section (σGSA) was calculated from the fitted curve of the absorption coefficient spectrum. The results show that Co:MgAl2O4 ceramics fabricated by vacuum sintering at 1500 °C for 5 h and then HIP post-treatment at 1650 °C for 3 h perform good transparency, whose in-line transmittance exceeds 80% at 2500 nm. Moreover, the ground state absorption cross section of 0.02 at.% Co:MgAl2O4 ceramics is calculated to be 3.35 × 10-19 cm2 at the wavelength of 1540 nm, which is promising for the application to the passive Q-switching of solid-state laser operating in the near infrared region (NIR).

  13. Microstructural, spectroscopic, and antibacterial properties of silver-based hybrid nanostructures biosynthesized using extracts of coriander leaves and seeds

    Science.gov (United States)

    Luna, Carlos; Barriga-Castro, Enrique Díaz; Gómez-Treviño, Alberto; Núñez, Nuria O; Mendoza-Reséndez, Raquel

    2016-01-01

    Coriander leaves and seeds have been highly appreciated since ancient times, not only due to their pleasant flavors but also due to their inhibitory activity on food degradation and their beneficial properties for health, both ascribed to their strong antioxidant activity. Recently, it has been shown that coriander leaf extracts can mediate the synthesis of metallic nanoparticles through oxidation/reduction reactions. In the present study, extracts of coriander leaves and seeds have been used as reaction media for the wet chemical synthesis of ultrafine silver nanoparticles and nanoparticle clusters, with urchin- and tree-like shapes, coated by biomolecules (mainly, proteins and polyphenols). In this greener route of nanostructure preparation, the active biocompounds of coriander simultaneously play the roles of reducing and stabilizing agents. The morphological and microstructural studies of the resulting biosynthesized silver nanostructures revealed that the nanostructures prepared with a small concentration of the precursor Ag salt (AgNO3 =5 mM) exhibit an ultrafine size and a narrow size distribution, whereas particles synthesized with high concentrations of the precursor Ag salt (AgNO3 =0.5 M) are polydisperse and formation of supramolecular structures occurs. Fourier transform infrared and Raman spectroscopy studies indicated that the bioreduction of the Ag− ions takes place through their interactions with free amines, carboxylate ions, and hydroxyl groups. As a consequence of such interactions, residues of proteins and polyphenols cap the biosynthesized Ag nanoparticles providing them a hybrid core/shell structure. In addition, these biosynthesized Ag nanomaterials exhibited size-dependent plasmon extinction bands and enhanced bactericidal activities against both Gram-positive and Gram-negative bacteria, displaying minimal inhibitory Ag concentrations lower than typical values reported in the literature for Ag nanoparticles, probably due to the synergy of

  14. An insight into the metal coordination and spectroscopic properties of artistic Fe and Fe/Cu logwood inks

    Science.gov (United States)

    Bronzato, Maddalena; Zoleo, Alfonso; Biondi, Barbara; Centeno, Silvia A.

    2016-01-01

    Fe- and Fe/Cu-based logwood inks were synthesized following recipes in nineteenth and early twentieth century manuals and were characterized by EPR, ESI-MS, FTIR, and Raman spectroscopies. This multi-technique approach allowed us to shed light on the structures of the complexes responsible for the inks' colors and to obtain vibrational signatures that can be used to identify the different inks in works of art and in historic documents. Information on the nature and chemical properties of the complexes formed between a dye and a mordant is important as these determine, at least in part, their lightfastness. EPR permitted to determine the coordination environment of the metallic ions. The results of the ESI-MS analysis demonstrated, for the first time, the breakdown of the hematein molecule during the ink preparation, and that the colorants are formed by the complexation of the metallic ions by hematein breakdown products, mainly catechol and/or bicyclic compounds. The FTIR spectra obtained were found to be dominated by bands due to the binding medium and sulfates used as reagents. The Raman analysis showed that the characteristic features for the different inks studied depend on the historic recipe used, attesting to the challenges that their identification and characterization in works of art present. In the Raman spectra of the inks applied on paper, broadening of bands in the 750-400 cm- 1 range are observed when compared to the spectra of the inks' powders, possibly due to the interaction of the compounds with the cellulose in the substrate.

  15. An insight into the metal coordination and spectroscopic properties of artistic Fe and Fe/Cu logwood inks.

    Science.gov (United States)

    Bronzato, Maddalena; Zoleo, Alfonso; Biondi, Barbara; Centeno, Silvia A

    2016-01-15

    Fe- and Fe/Cu-based logwood inks were synthesized following recipes in nineteenth and early twentieth century manuals and were characterized by EPR, ESI-MS, FTIR, and Raman spectroscopies. This multi-technique approach allowed us to shed light on the structures of the complexes responsible for the inks' colors and to obtain vibrational signatures that can be used to identify the different inks in works of art and in historic documents. Information on the nature and chemical properties of the complexes formed between a dye and a mordant is important as these determine, at least in part, their lightfastness. EPR permitted to determine the coordination environment of the metallic ions. The results of the ESI-MS analysis demonstrated, for the first time, the breakdown of the hematein molecule during the ink preparation, and that the colorants are formed by the complexation of the metallic ions by hematein breakdown products, mainly catechol and/or bicyclic compounds. The FTIR spectra obtained were found to be dominated by bands due to the binding medium and sulfates used as reagents. The Raman analysis showed that the characteristic features for the different inks studied depend on the historic recipe used, attesting to the challenges that their identification and characterization in works of art present. In the Raman spectra of the inks applied on paper, broadening of bands in the 750-400 cm(-1) range are observed when compared to the spectra of the inks' powders, possibly due to the interaction of the compounds with the cellulose in the substrate. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Microstructural, spectroscopic, and antibacterial properties of silver-based hybrid nanostructures biosynthesized using extracts of coriander leaves and seeds

    Directory of Open Access Journals (Sweden)

    Luna C

    2016-09-01

    Full Text Available Carlos Luna,1 Enrique Díaz Barriga-Castro,2 Alberto Gómez-Treviño,3 Nuria O Núñez,4 Raquel Mendoza-Reséndez1 1Research Center of Mathematics and Physics, Faculty of Mathematics and Physics, Autonomous University of Nuevo León, Nuevo León, Mexico; 2Central Laboratory of Analytical Instrumentation, Research Center for Applied Chemistry, Coahuila, Mexico; 3Laboratory of Molecular Biology, Faculty of Chemistry, Autonomous University of Nuevo León, Nuevo León, Mexico; 4Colloidal Materials Research Group, Institute of Materials Science of Seville, Spanish National Research Council, University of Seville, Seville, Spain Abstract: Coriander leaves and seeds have been highly appreciated since ancient times, not only due to their pleasant flavors but also due to their inhibitory activity on food degradation and their beneficial properties for health, both ascribed to their strong antioxidant activity. Recently, it has been shown that coriander leaf extracts can mediate the synthesis of metallic nanoparticles through oxidation/reduction reactions. In the present study, extracts of coriander leaves and seeds have been used as reaction media for the wet chemical synthesis of ultrafine silver nanoparticles and nanoparticle clusters, with urchin- and tree-like shapes, coated by biomolecules (mainly, proteins and polyphenols. In this greener route of nanostructure preparation, the active biocompounds of coriander simultaneously play the roles of reducing and stabilizing agents. The morphological and microstructural studies of the resulting biosynthesized silver nanostructures revealed that the nanostructures prepared with a small concentration of the precursor Ag salt (AgNO3 =5 mM exhibit an ultrafine size and a narrow size distribution, whereas particles synthesized with high concentrations of the precursor Ag salt (AgNO3 =0.5 M are polydisperse and formation of supramolecular structures occurs. Fourier transform infrared and Raman spectroscopy

  17. Spectroscopic investigation of the chemical and electronic properties of chalcogenide materials for thin-film optoelectronic devices

    Science.gov (United States)

    Horsley, Kimberly Anne

    optoelectronic properties of these films. Through publication and/or discussion with collaborators, each project presented in this dissertation contributed to the understanding of the chemical and electronic properties of the material surface, near-surface bulk, and/or interfaces formed. The information gained on these unique chalcogenide materials will assist in designing more efficient and successful optoelectronic devices for the next generation of solar cells and LEDs.

  18. Visible and near-infrared luminescent Eu{sup 3+} or Er{sup 3+} doped laponite-derived xerogels and thick films: Structural and spectroscopic properties

    Energy Technology Data Exchange (ETDEWEB)

    Tronto, Jairo [Universidade Federal de Vicosa, Campus de Rio Paranaiba, Rodovia BR 354-km 310, Rio Paranaiba, CEP 38810-000, MG (Brazil); Ribeiro, Sidney Jose Lima [Departamento de Quimica Geral e Inorganica, Instituto de Quimica de Araraquara - Universidade Estadual Paulista, R. Francisco Degni, s/n, CEP 14.800-090, Araraquara, SP (Brazil); Valim, Joao Barros [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. dos Bandeirantes 3900, CEP 14.040-901, Ribeirao Preto, SP (Brazil); Goncalves, Rogeria Rocha [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. dos Bandeirantes 3900, CEP 14.040-901, Ribeirao Preto, SP (Brazil)], E-mail: rrgoncalves@ffclrp.usp.br

    2009-01-15

    Laponite-derived materials represent promising materials for optical applications. In this work, Eu{sup 3+}- or Er{sup 3+}-doped laponite xerogels and films were prepared from colloidal dispersion. Homogeneous, crack-free and transparent single layers were deposited on soda-lime substrates with a thickness of 10 {mu}m. Structural and spectroscopic properties were analyzed by thermal analyses, X-ray diffractometry, transmission electron microscopy, infrared spectroscopy, and luminescence spectroscopy. The addition of a rare earth ion to the laponite does not promote any changes in thermal stability or phase transition. Laponite clay was identified after annealing up to 500 deg. C, with a decrease in basal spacing when the annealing temperature is changed from 100 deg. C to 500 deg. C. Enstatite polymorphs and amorphous silicate phases were observed after heat treatment at 700 deg. C and 900 deg. C. Stationary and time-dependent luminescence spectra in the visible region for Eu{sup 3+}, and {sup 5}D{sub 0} lifetime are discussed in terms of thermal treatment and structural evolution. In the layered host, the Eu{sup 3+} ions are distributed in many different local environments. However, Eu{sup 3+} ions were found to occupy at least two symmetry sites, and the ions are preferentially incorporated into the crystalline enstatite for the materials annealed at 700 deg. C and 900 deg. C. A {sup 5}D{sub 0} lifetime of 1.3 ms and 3.1 ms was obtained for Eu{sup 3+} ions in an amorphous silicate and crystalline MgSiO{sub 3} local environment, respectively. Strong Er{sup 3+} emission at the 1550 nm region was observed for the materials annealed at 900 deg. C, with a bandwidth of 44 nm.

  19. Structural characterization, spectroscopic signatures, nonlinear optical response, and antioxidant property of 4-benzyloxybenzaldehyde and its binding activity with microtubule-associated tau protein

    Science.gov (United States)

    Anbu, V.; Vijayalakshmi, K. A.; Karthick, T.; Tandon, Poonam; Narayana, B.

    2017-09-01

    In the proposed work, the non-linear optical response, spectroscopic signature and binding activity of 4-Benzyloxybenzaldehyde (4BB) has been investigated. In order to find the vibrational contribution of functional groups in mixed or coupled modes in the experimental FT-IR and FT-Raman spectra, the potential energy distribution (PED) based on the internal coordinates have been computed. Since the molecule exists in the form of dimer in solid state, the electronic structure of dimer has been proposed in order to explain the intermolecular hydrogen bonding interactions via aldehyde group. The experimental and simulated powder X-ray diffraction data was compared and the miller indices which define the crystallographic planes in the crystal lattices were identified. Optical transmittance and absorbance measurement were taken at ambient temperature in order to investigate the transparency and optical band gap. For screening the material for nonlinear applications, theoretical second order hyperpolarizability studies were performed and compared with the standard reference urea. To validate the theoretical results, powder second harmonic generation (SHG) studies were carried out using Kurtz and Perry technique. The results show that the molecule studied in this work exhibit considerable non-linear optical (NLO) response. In addition to the characterization and NLO studies, we also claimed based on the experimental and theoretical data that the molecule shows antioxidant property and inhibition capability. Since the title molecule shows significant binding with Tau protein that helps to stabilize microtubules in the nervous system, the molecular docking investigation was performed to find the inhibition constant, binding affinity and active binding residues.

  20. Synthetic Tuning of Redox, Spectroscopic, and Photophysical Properties of {Mo6I8}(4+) Core Cluster Complexes by Terminal Carboxylate Ligands.

    Science.gov (United States)

    Mikhailov, Maxim A; Brylev, Konstantin A; Abramov, Pavel A; Sakuda, Eri; Akagi, Soichiro; Ito, Akitaka; Kitamura, Noboru; Sokolov, Maxim N

    2016-09-06

    The reactions between the tetra-n-butylammonium salt of [{Mo6I8}I6](2-) and silver carboxylates RCOOAg (R = CH3 (1), C(CH3)3 (2), α-C4H3O (3), C6H5 (4), α-C10H7 (5), or C2F5 (6)) in CH2Cl2 afforded new carboxylate complexes [{Mo6I8}(RCOO)6](2-). The complexes were characterized by X-ray single-crystal diffraction and elemental analysis, cyclic/differential pulse voltammetry, and IR, NMR, and UV-visible spectroscopies. The emission properties of the complexes 1-6, and those of the earlier reported complexes with R = CF3 (7) and n-C3F7 (8), were studied both in acetonitrile solution and in the solid state. In deaerated CH3CN at 298 K, all of the complexes 1-8 exhibit intense and long-lived emission with the quantum yield and lifetime being 0.48-0.73 and 283-359 μs, respectively. The oxidation (Eox)/reduction (Ered) potentials of the complexes correlate linearly with the pKa value of the terminal carboxylate ligands L = RCOO (pKa(L)). Reflecting the pKa(L) dependences of Eox/Ered, the emission energy (νem) of the complexes was also shown to correlate with pKa(L). The present study successfully demonstrates synthetic tuning of the redox, spectroscopic, and photophysical characteristics of a {Mo6I8}(4+)-based cluster complex with pKa(L).

  1. Electronic Structures and Spectroscopic Properties of a Novel Iridium (III) Complex with an Ancillary Ligand 2-(4-Trifluoromethyl -2-Hydroxylphenyl) Benzothiazole

    Science.gov (United States)

    Lei, Li-Ping; Hao, Yu-Ying; Fan, Wen-Hao; Xu, Bing-She

    2011-06-01

    Iridium (III) complexes with 2-phenylpyridine (ppy) have been demonstrated as a type of promising phosphorescence dopant in emitting layers of organic light emitting diodes (OLEDs). In most iridium (III) complexes, there exist the strong spin-orbit coupling between π-orbitals of cyclometalated ligands and 5d orbitals of the centric iridium. We study a novel iridium (III) complex (ppy)2Ir(4-TfmBTZ) with ppy as cyclometalated ligands and 2-(4-trifluoromethyl-2-hydroxylphenyl)benzothiazole (4-TfmBTZ) as an ancillary ligand using the Gaussian 03 program. The geometries, electronic structures and spectroscopic properties of this iridium (III) complex are investigated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The results show that the spin-orbit coupling occurs not only between ppy and iridium atom but also between 4-TfmBTZ and iridium atom in this complex. The highest occupied molecular orbital is dominantly localized on the Ir atom and 4-TfmBTZ ligand, while the lowest unoccupied molecular orbital on 4-TfmBTZ ligand. The triplet lowest-lying transition is attributed to the Ir-to-4-TfmBTZ charge-transfer (3MLCT) transition while the sub-low-lying transitions are assigned to the 3MLCT transitions of Ir(ppy)2. The nature of the lowest unoccupied orbital changes from ppy-localized to 4-TfmBTZ-localized and reveals that phosphorescent color of Ir(III) complex can be controlled by the ancillary ligand and substituent.

  2. Facile growth and composition-dependent photocatalytic activity of flowerlike BiOCl1-xBrx hierarchical microspheres

    Science.gov (United States)

    Qin, Qin; Guo, Yingna; Zhou, Dandan; Yang, Yuxin; Guo, Yihang

    2016-12-01

    A group of nanosheet-assembled three-dimensional BiOCl1-xBrx hierarchical microspheres (x = 0, 0.3, 0.4, 0.5, 0.7, 0.8 and 1.0) with layered tetragonal crystal phase were prepared by 2-methoxyethanol-assisted solvothermal route and using ionic liquids as both halogen sources and structure-directing agent. By the combination of the results including XRD, XPS and UV-vis/DR spectra, lattice substitution of halogen atoms each other and then formation of BiOCl1-xBrx solid solution was evidenced. Additionally, the BiOCl1-xBrx microspheres exhibited interesting composition-dependent band gaps. The simulated sunlight and visible-light photocatalytic properties including degradation, mineralization and reusability of the BiOCl1-xBrx microspheres were evaluated by selecting p-nitrophenol (PNP) and tetrabromobisphenol-A (TBBPA) as the target pollutant compounds, finding that the balance between the suitable band gap and adequate potential of the valence band in BiOCl1-xBrx crystals dominated their photocatalytic activity. Additionally, the BiOCl1-xBrx microspheres with advantages such as enhanced photon utilization efficiency, larger BET surface area and favorable (110) exposed reactive surface gave the positive influence on their photocatalytic activity. Based on the results of photoelectrochemistry experiment and indirect chemical probe testing, direct •O2- and hVB+ photooxidation for the decomposition of PNP or TBBPA was revealed.

  3. Spectroscopic and DFT-based computational studies on the molecular electronic structural characteristics and the third-order nonlinear property of an organic NLO crystal: (E)-N‧-(4-chlorobenzylidene)-4-methylbenzenesulfonohydrazide

    Science.gov (United States)

    Sasikala, V.; Sajan, D.; Joseph, Lynnette; Balaji, J.; Prabu, S.; Srinivasan, P.

    2017-04-01

    Single crystals of (E)-N‧-(4-chlorobenzylidene)-4-methylbenzenesulfonohydrazide (CBMBSH) have been grown by slow evaporation crystal growth method. The structure stabilizing intramolecular donor-acceptor interactions and the presence of the Nsbnd H⋯O, Csbnd H⋯O and Csbnd H⋯C(π) hydrogen bonds in the crystal were confirmed by vibrational spectroscopic and DFT methods. The linear optical absorption characteristics of the solvent phase of CBMBSH were investigated using UV-Vis-NIR spectroscopic and TD-DFT approaches. The 2PA assisted RSA nonlinear absorption and the optical limiting properties of CBMBSH were studied using the open-aperture Z-scan method. The topological characteristics of the electron density have been determined using the quantum theory of atoms in molecules method.

  4. New composition dependent cooling and heating curves for galaxy evolution simulations

    CERN Document Server

    De Rijcke, Sven; Vandenbroucke, Bert; Jachowicz, Natalie; Decroos, Jeroen; Cloet-Osselaer, Annelies; Koleva, Mina

    2013-01-01

    In this paper, we present a new calculation of composition-dependent radiative cooling and heating curves of low-density gas, intended primarily for use in numerical simulations of galaxy formation and evolution. These curves depend on only five parameters: temperature, density, redshift, [Fe/H], and [Mg/Fe]. They are easily tabulated and can be efficiently interpolated during a simulation. The ionization equilibrium of 14 key elements is determined for temperatures between 10K and 10^9K and densities up to 100 amu/cm^3 taking into account collisional and radiative ionization, by the cosmic UV background and an interstellar radiation field, and by charge-transfer reactions. These elements, ranging from H to Ni, are the ones most abundantly produced and/or released by SNIa, SNII, and intermediate-mass stars. Self-shielding of the gas at high densities by neutral Hydrogen is taken into account in an approximate way by exponentially suppressing the H-ionizing part of the cosmic UV background for HI densities abo...

  5. Composition dependent band offsets of ZnO and its ternary alloys.

    Science.gov (United States)

    Yin, Haitao; Chen, Junli; Wang, Yin; Wang, Jian; Guo, Hong

    2017-01-30

    We report the calculated fundamental band gaps of wurtzite ternary alloys Zn1-xMxO (M = Mg, Cd) and the band offsets of the ZnO/Zn1-xMxO heterojunctions, these II-VI materials are important for electronics and optoelectronics. Our calculation is based on density functional theory within the linear muffin-tin orbital (LMTO) approach where the modified Becke-Johnson (MBJ) semi-local exchange is used to accurately produce the band gaps, and the coherent potential approximation (CPA) is applied to deal with configurational average for the ternary alloys. The combined LMTO-MBJ-CPA approach allows one to simultaneously determine both the conduction band and valence band offsets of the heterojunctions. The calculated band gap data of the ZnO alloys scale as Eg = 3.35 + 2.33x and Eg = 3.36 - 2.33x + 1.77x(2) for Zn1-xMgxO and Zn1-xCdxO, respectively, where x being the impurity concentration. These scaling as well as the composition dependent band offsets are quantitatively compared to the available experimental data. The capability of predicting the band parameters and band alignments of ZnO and its ternary alloys with the LMTO-CPA-MBJ approach indicate the promising application of this method in the design of emerging electronics and optoelectronics.

  6. Composition-dependent structural changes and antitumor activity of ASC-DP/DSPE-PEG nanoparticles.

    Science.gov (United States)

    Higashi, Kenjirou; Mibu, Fusako; Saito, Kengo; Limwikrant, Waree; Yamamoto, Keiji; Moribe, Kunikazu

    2017-03-01

    Ascorbyl 2,6-dipalmitate (ASC-DP) and distearoyl phosphatidylethanolamine polyethylene glycol 2000 (DSPE-PEG) formed stable nanoparticles at a molar ratio of less than or equal to 2:1 after dispersing the solvent-evaporated film in water. The mean particle sizes measured by dynamic light scattering were within the range of ca. 100-160nm. Composition-dependent changes of the ASC-DP and DSPE-PEG molecular states within the film were analyzed by wide-angle X-ray diffraction and infrared (IR) and solid-state nuclear magnetic resonance (NMR) spectroscopy. Transmission electron microscopy (TEM) of nanoparticles revealed that ASC-DP/DSPE-PEG changed from a micelle to a disk and tubular structure as the molar ratio increased. Quantitative solution-state (1)H NMR measurements elucidated the structure of nanoparticle in water; the core could be composed of ASC-DP and hydrophobic acyl chains of DSPE, whereas the hydrophilic PEG chains of DSPE-PEG on the surface form the hydration shell to stabilize the nanoparticle dispersion in water. Cytotoxicity of ASC-DP against cancer cell lines was observed by using ASC-DP/DSPE-PEG nanoparticles, and no cytotoxicity against normal cells was found. Thus, the ASC-DP/DSPE-PEG formulation, with tumor cell specific cytotoxicity, can be applicable for cancer monotherapy or in combination with other anticancer drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Spectroscopic properties of a series of Co(II) coordination polymers and the influence of Co(II) coordination environment on photoelectric property

    Science.gov (United States)

    Jin, Jing; Gong, Yuanyuan; Li, Lei; Han, Xiao; Meng, Qin; Liu, Yonghua; Niu, Shuyun

    2015-02-01

    Four Co(II) coordination polymers, [Co(suc)]n1, [Co(pdc)]n2, {[Co7(suc)4(OH)6(H2O)3] · 8H2O}n3, {[Co(bdc)(phen)(H2O)] · H2O}n4 (H2suc = succinic acid, H2pdc = pyridine-3,4-dicarboxylic acid, H2bdc = 1,2-benzenedicarboxylic acid, phen = 1,10-phenanthroline) were hydrothermally synthesized and characterized by X-ray single-crystal diffraction, surface photovoltage spectroscopy (SPS), electrical conductivity, thermogravimetric analysis (TG), ultraviolet visible and near-infrared absorption spectrum (UV-Vis-NIR), infrared spectrum (IR), and elemental analysis. The structural analyses indicate that the coordination numbers of the Co(II) ions are 4, 5, 6 and 6 for the polymers 1-4, respectively. And polymers 1 and 2 exhibit 3D structure formed by suc2- and pdc2- anions bridging Co(II) ions, respectively. Polymer 3 exhibits a 2D structure with suc2- anions bridging seven-nuclear [Co7(OH)6(H2O)3]3- unit and polymer 4 is a 1D structure bridged by bdc2- anions. The surface photoelectric properties of the cobalt polymers were mainly studied by SPS. The results of SPS reveal that all polymers possess certain photoelectric conversion property in the range of 300-800 nm. The influences of the structure, coordination micro-environment of central metal ion and structural dimensionality on response bands of SPS were discussed.

  8. Structure and Optical Properties of Polycrystalline InxSb30 – xSe70 (0 ≤ x ≤ 25 Chalcogenide Alloys

    Directory of Open Access Journals (Sweden)

    Shaveta Sharma

    2016-06-01

    Full Text Available The spectroscopic studies of various physical properties of glassy and polycrystalline chalcogenide alloys are important due to their importance as active materials in various solid state devices. The composition dependence of these properties are explained on the basis of coordination number, but the splitting of this effect from the nature of additive is imperative for furthering the understanding of these systems. In the present work, the structural and spectroscopic investigations of melt quenched bulk In-Sb-Se chalcogenide alloys have been studied by XRD, RAMAN and optical spectroscopic techniques. The XRD study reveals the polycrystalline nature of the samples. The composition was analysed using the energy dispersive X-ray spectroscopy technique. The XRD study reveals the crystallization of Sb2Se3 and β-In2Se3 phases while the increase in the intensity for β-In2Se3 phase has been observed with the increase in indium content. The RAMAN spectra also reveal the formation of chalcogenide based Sb and In structural units. The diffused reflectance spectrum was used to calculate the optical absorption in 800-1500 nm spectral region and used to study the composition dependence of the optical gap in these samples. The results have been discussed in conjunction with the heterogeneous phases; density of defect states; electronegativity and average mean bond energy for these polycrystalline alloys.

  9. Modeling the acid-base properties of bacterial surfaces: A combined spectroscopic and potentiometric study of the gram-positive bacterium Bacillus subtilis.

    Science.gov (United States)

    Leone, Laura; Ferri, Diego; Manfredi, Carla; Persson, Per; Shchukarev, Andrei; Sjöberg, Staffan; Loring, John

    2007-09-15

    In this study, macroscopic and spectroscopic data were combined to develop a surface complexation model that describes the acid-base properties of Bacillus subtilis. The bacteria were freeze-dried and then resuspended in 0.1 M NaCl ionic medium. Macroscopic measurements included potentiometric acid-base titrations and electrophoretic mobility measurements. In addition, ATR-FTIR spectra of wet pastes from suspensions of Bacillus subtilis at different pH values were collected. The least-squares program MAGPIE was used to generate a surface complexation model that takes into account the presence of three acid-base sites on the surface: tripple bond COOH, tripple bond NH+, and tripple bond PO-, which were identified previously by XPS measurements. Both potentiometric titration data and ATR-FTIR spectra were used quantitatively, and electrostatic effects at the charged bacterial surface were accounted for using the constant capacitance model. The model was calculated using two different approaches: in the first one XPS data were used to constrain the ratio of the total concentrations of all three surface sites. The capacitance of the double layer, the total buffer capacity, and the deprotonation constants of the tripple bond NH+, tripple bond POH, and tripple bond COOH species were determined in the fit. A second approach is presented in which the ratio determined by XPS of the total concentrations of tripple bond NH+ to tripple bond PO- sites is relaxed. The total concentration of tripple bond PO- sites was determined in the fit, while the deprotonation constant for tripple bond POH was manually varied until the minimization led to a model which predicted an isoelectric point that resulted in consistency with electrophoretic mobility data. The model explains well the buffering capacity of Bacillus subtilis suspensions in a wide pH range (between pH=3 and pH=9) which is of considerable environmental interest. In particular, a similar quantitative use of the IR data

  10. The 1.53 μm spectroscopic properties of Er3+/Ce3+/Yb3+ tri-doped tellurite glasses containing silver nanoparticles

    Science.gov (United States)

    Huang, Bo; Zhou, Yaxun; Yang, Fengjing; Wu, Libo; Qi, Yawei; Li, Jun

    2016-01-01

    The metallic silver nanoparticles (NPs) was introduced into the Er3+/Ce3+/Yb3+ tri-doped tellurite glasses with composition TeO2-ZnO-La2O3 to improve the 1.53 μm band fluorescence. The UV/Vis/NIR absorption spectra, 1.53 μm band fluorescence spectra, fluorescence lifetimes, X-ray diffraction (XRD) curves, differential scanning calorimeter (DSC) curves and transmission electron microscopy (TEM) image of tri-doped tellurite glasses were measured, together with the Judd-Ofelt intensity parameters, emission cross-sections, absorption cross-sections and radiative quantum efficiencies were calculated to investigate the effects of silver NPs on the 1.53 μm band spectroscopic properties of Er3+ ions, structural nature and thermal stability of glass hosts. It is shown that Er3+/Ce3+/Yb3+ tri-doped tellurite glasses can emit intense 1.53 μm band fluorescence through the combined energy transfer (ET) processes from Yb3+ to Er3+ ions and Er3+ to Ce3+ ions under the 980 nm excitation. At the same time, the introduction of an appropriate amount of silver NPs can further improve the 1.53 μm band fluorescence owing to the enhanced local electric field effect induced by localized surface Plasmon resonance (LSPR) of silver NPs and the possible energy transfer from silver NPs to Er3+ ions, and an improvement by about 120% of fluorescence intensity is found in the studied Er3+/Ce3+/Yb3+ tri-doped tellurite glass containing 0.5 mol% amount of silver NPs with average diameter of ∼15 nm. The energy transfer mechanisms from Yb3+ to Er3+ ions and Er3+ to Ce3+ ions were also quantitatively investigated by calculating energy transfer microparameters and phonon contribution ratios. Furthermore, the thermal stability of glass host increases slightly with the introduction of silver NPs while the glass structure maintains the amorphous nature. The results indicate that the prepared Er3+/Ce3+/Yb3+ tri-doped tellurite glass with an appropriate amount of silver NPs is an excellent gain

  11. Effect of cryogenic temperature on spectroscopic and laser properties of Er,La:SrF2-CaF2 crystal

    Science.gov (United States)

    Švejkar, Richard; Šulc, Jan; Němec, Michal; Jelínková, Helena; Doroshenko, Maxim E.; Nakladov, Andrei N.; Osiko, Vjatcheslav V.

    2016-03-01

    The laser and spectroscopic properties of crystal Er,La:SrF2-CaF2 at temperature range 80 - 300 K, which is appropriate for generation of radiation around 2.7 um is presented. The sample of Er,La:SrF2-CaF2 (concentration Er(0.04), La(0.12):Ca(0.77)Sr(0.07)) had plan-parallel face-polished faces without anti-reflection coatings (thickness 8.2 mm). During spectroscopy and laser experiments the Er,La:SrF2-CaF2 was attached to temperature controlled copper holder and it was placed in vacuum chamber. The transmission and emission spectra of Er,La:SrF2-CaF2 together with the fluorescence decay time were measured in dependence on temperature. The excitation of Er,La:SrF2-CaF2 was carried out by a laser diode radiation (pulse duration 5 ms, repetition rate 20 Hz, pump wavelength 973 nm). Laser resonator was hemispherical, 140 mm in length with at pumping mirror (HR @ 2.7 µm) and spherical output coupler (r = 150 mm, R = 95 % @ 2.5 - 2.8 µm). Tunability of laser at 80 K in range 2690 - 2765 nm was obtained using MgF2 birefringent filter. With decreasing temperature of sample the fluorescence lifetime of manifold 4I11/2 (upper laser level) became shorter and intensity of up-conversion radiation was increasing. The highest slope efficiency with respect to absorbed power was 2.3 % at 80 K. The maximum output of peak amplitude power was 0.3 W at 80 K, i.e. 1.5 times higher than measured this value at 300 K. The wavelength generated by Er,La:SrF2-CaF2 laser (2.7 µm) is relatively close to absorption peak of water (3 µm) and so, one of the possible usage should be in medicine and spectroscopy.

  12. Electronic Structures and Spectroscopic Properties of a Novel Iridium (Ⅲ) Complex with an Ancillary Ligand 2- (4-Trifluoromethyl -2-Hydroxylphenyl)Benzothiazole

    Institute of Scientific and Technical Information of China (English)

    LEI Li-Ping; HAO Yu-Ying; FAN Wen-Hao; XU Sing-She

    2011-01-01

    Iridium (W) complexes with 2-phenylpyridine (ppy) have been demonstrated as a type of promising phosphorescence dopant in emitting layers of organic light emitting diodes (OLKDs). In most iridium (M) complexes, there exist the strong spin-orbit coupling between it-orbiteds of cyclometalated ligands and 5d orbitals of the centric iridium. We study a novel iridium (M) complex (ppy)2lr(4-TfmBTZ) with ppy as cyclometalated ligands and 2-(4-trifluoromcthyl-2-hydroxyIphenyl)benzothiazole (4-TfmBTZ) as an ancillary ligand using the Gaussian 03 program. The geometries, electronic structures and spectroscopic properties of this iridium (M) complex are investigated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The results show that the spin-orbit coupling occurs not only between ppy and iridium atom but also between 4-TfmBTZ and iridium atom in this complex. The highest occupied molecular orbital is dominantly localized on the Ir atom and 4-TfmBTZ ligand, while the lowest unoccupied molecular orbital on 4-TfmBTZ ligand. The triplet lowest-lying transition is attributed to the Ir-to-4-TfmBTZ charge-transfer ^MLCT) transition while the sub-low-lying transitions are assigned to the AMLCT transitions oflr(ppy)I. The nature of the lowest unoccupied orbital changes from ppy-localizcd to 4-TfmBTZ-locaIized and reveals that phosphorescent color oflr(M) complex can be controlled by the ancillary ligand and substitucnt.%@@ Iridium (Ⅲ) complexes with 2-phenylpyridine (ppy) have been demonstrated as a type of promising phospho- rescence dopant in emitting layers of organic light emitting diodes (OLEI)s).In most iridium (Ⅲ) complexes, there exist the strong spin-orbit coupling between π-orbitals of cyclometalated ligands anti 5d orbitals of the ccntric iridium.We study a novel iridium (Ⅲ) complex (ppy)2Ir(4-TfmBTZ) with ppy as cyclometalated ligands and 2-(4-trifluoromethyl-2-hydroxylphenyl)benzothiazole (4-TfmBTZ) as an ancillary ligand

  13. Composition dependent band offsets of ZnO and its ternary alloys

    Science.gov (United States)

    Yin, Haitao; Chen, Junli; Wang, Yin; Wang, Jian; Guo, Hong

    2017-01-01

    We report the calculated fundamental band gaps of wurtzite ternary alloys Zn1−xMxO (M = Mg, Cd) and the band offsets of the ZnO/Zn1−xMxO heterojunctions, these II-VI materials are important for electronics and optoelectronics. Our calculation is based on density functional theory within the linear muffin-tin orbital (LMTO) approach where the modified Becke-Johnson (MBJ) semi-local exchange is used to accurately produce the band gaps, and the coherent potential approximation (CPA) is applied to deal with configurational average for the ternary alloys. The combined LMTO-MBJ-CPA approach allows one to simultaneously determine both the conduction band and valence band offsets of the heterojunctions. The calculated band gap data of the ZnO alloys scale as Eg = 3.35 + 2.33x and Eg = 3.36 − 2.33x + 1.77x2 for Zn1−xMgxO and Zn1−xCdxO, respectively, where x being the impurity concentration. These scaling as well as the composition dependent band offsets are quantitatively compared to the available experimental data. The capability of predicting the band parameters and band alignments of ZnO and its ternary alloys with the LMTO-CPA-MBJ approach indicate the promising application of this method in the design of emerging electronics and optoelectronics. PMID:28134298

  14. Structural, spectroscopic and redox properties of a mononuclear Co(II) thiolate complex--the reactivity toward S-alkylation: an experimental and theoretical study.

    Science.gov (United States)

    Gennari, Marcello; Gerey, Bertrand; Hall, Nikita; Pécaut, Jacques; Vezin, Hervé; Collomb, Marie-Noëlle; Orio, Maylis; Duboc, Carole

    2012-10-28

    The structural, spectroscopic, redox properties and also the reactivity toward S-alkylation of a new mononuclear N2S2 dithiolate Co(II) complex [CoL] (1), with H(2)L = 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(1,1-diphenylethanethiol), have been investigated. The X-ray structure of 1 has revealed an unusual distorted square planar geometry for a Co(II) ion within a thiolate environment. The X-band EPR spectrum of displays a rhombic S = 1/2 signal consistent with a low spin configuration for the d(7) Co(II) ion with a large g-anisotropy (g(x) = 2.94, g(y) = 2.32 and g(z) = 2.01). By pulsed EPR experiments (HYSCORE), two weak hyperfine couplings (hfc) of 3.2 and 2.2 MHz have been measured and attributed respectively to protons and nitrogen nuclei of the bipyridine unit. In addition, another hyperfine coupling (hfc) of 7.5 MHz has been attributed to the cobalt ion. DFT calculations have successfully reproduced the (59)Co and (14)N hfc parameters. However, multiconfigurational ab initio calculations were required to predict the g-tensor of 1. The cyclic voltammogram (CV) displays two one-electron metal based processes: a quasi-reversible Co(III)/Co(II) oxidation wave at E(1/2) = -0.5 V vs. Fc(+)/Fc and a quasi-reversible Co(II)/Co(I) reduction wave at E(1/2) = -1.7 V. 1 reacts with CH(3)I, generating the mono S-methylated complex, [CoL(Me)I] (1(Me)). The X-band EPR spectrum of 1(Me) displays a typical signal of a high spin (S = 3/2) Co(II) species. An optimized structure of 1(Me), calculated by DFT, is consistent with its EPR and UV-visible spectra. Time dependent density functional theory (TD-DFT) calculations attribute the most prominent features observed in the electronic absorption spectra of 1 and 1(Me). The singly occupied MO (SOMO) of 1 shows a notable delocalization of the unpaired electron over the metal (85%) and the ligand, especially over the sulphur atoms (10.5%), indicating a certain degree of covalency for the Co-S bonds. In 1(Me), for two of the three SOMOs

  15. Synthesis and Spectroscopic Investigation of Azoporphyrins

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The synthesis of a series of new covalently-connected azoporphyrin derivatives is described and the photochemical properties of the new compounds are discussed. The two chromophores of these derivatives exhibit their absorption spectroscopic properties respectively.In the fluorescence emission spectra, intermolecular fluorescence quenching is detected.

  16. Spectroscopic Properties of Metaldehyde and Copper Nitrate-ammonia Mixture%四聚乙醛和硝酸铜氨体系谱学特性

    Institute of Scientific and Technical Information of China (English)

    霸书红; 周龙; 孙振兴; 王桂萍; 程秀莲; 杜雪峰

    2014-01-01

    In order to study the burning spectrum of metaldehyde and copper nitrate-ammoniamixture,spectroscopic properties of the mixture were tested by thermogravimetry-differential scanning calorimetry( TG-DDSC)TG/DSC method)and photoelectric detection technology. Based on thermal analysis of the mixture,its thermal decomposition process and possible combustion lumi-nous mechanism were studied,and compared with those tested by the burning spectrum. Results show that the burning flame of metaldehyde is yellow and there is a peak at 591. 35 nm which is formed by burning of carbon. When mixed the metaldehyde, thermal decomposition process of copper nitrate-ammonia is changed,with the exothermic peak decreasing from 272. 88 ℃ to 254. 78 ℃. The green and yellow flame gives off when metaldehyde and copper nitrate-ammonia mixture burns and the spectrum peaks appear separatly at 545. 8 nm and 589. 33 nm,which is related to carbon burning and forming of copper free radical. The results of theoretical prediction are in agreement with the experimental.%为研究四聚乙醛和硝酸铜氨烟火药的燃烧光谱,利用热重-差示扫描量热法和光电探测技术表征了该体系的谱学特性。基于热重-差示扫描量热分析,得到了四聚乙醛与硝酸铜氨体系的热分解历程,提出了可能的燃烧发光机理,并与燃烧光谱的测试结果进行了对比分析。结果表明:四聚乙醛燃烧时发出黄色火焰,在591.35 nm 处出现峰值,这是由于碳燃烧产生。当硝酸铜氨与四聚乙醛均匀混合后,硝酸铜氨的热分解历程改变,其放热峰从272.88℃提前到254.78℃。四聚乙醛与硝酸铜氨体系燃烧时呈黄绿色火焰,分别在545.8,589.33 nm处产生谱峰,这与碳的燃烧和铜自由基的形成有关,燃烧火焰的理论预测与光谱测试结果一致。

  17. Structural, spectroscopic, and electrochemical properties of tri- and tetradentate N3 and N3S copper complexes with mixed benzimidazole/thioether donors.

    Science.gov (United States)

    Castillo, Ivan; Ugalde-Saldívar, Víctor M; Rodríguez Solano, Laura A; Sánchez Eguía, Brenda N; Zeglio, Erica; Nordlander, Ebbe

    2012-08-21

    Cupric and cuprous complexes of bis(2-methylbenzimidazolyl)(2-methylthiophene)amine (L(1)), bis(2-methylbenzimidazolyl)benzylamine (L(2)), bis(2-methylbenzimidazolyl)(2,4-dimethylphenylthioethyl)amine (L(3)), bis(1-methyl-2-methylbenzimidazolyl)benzylamine (Me(2)L(2)), and bis(1-methyl-2-methylbenzimidazolyl)(2,4-dimethylphenylthioethyl)amine (Me(2)L(3)) have been spectroscopically, structurally, and electrochemically characterised. The thioether-containing ligands L(3) and Me(2)L(3) give rise to complexes with Cu-S bonds in solution and in the solid state, as evidenced by UV-vis spectroscopy and X-ray crystallography. The Cu(2+) complexes [L(1)CuCl(2)] (1), [L(2)CuCl(2)] (2) and [Me(2)L(3)CuCl]ClO(4) (3(Me,ClO4)) are monomeric in solution according to ESI mass spectrometry data, as well as in the solid state. Their Cu(+) analogues [L(1)Cu]ClO(4), [L(2)Cu]ClO(4), [L(3)Cu]ClO(4) (4-6), [BOC(2)L(1)Cu(NCCH(3))]ClO(4) (4(BOC)), [Me(2)L(2)Cu(NCCH(3))(2)]PF(6) (5(Me)) and [Me(2)L(3)Cu](2)(ClO(4))(2) (6(Me)) are also monomeric in acetonitrile solution, as confirmed crystallographically for 4(BOC) and 5(Me). In contrast, 6(Me) is dimeric in the solid state, with the thioether group of one of the ligands bound to a symmetry-related Cu(+) ion. Cyclic voltammetry studies revealed that the bis(2-methylbenzimidazolyl)amine-Cu(2+)/Cu(+) systems possess half-wave potentials in the range -0.16 to -0.08 V (referenced to the ferrocenium-ferrocene couple); these values are nearly 0.23 V less negative than those reported for related bis(picolyl)amine-derived ligands. Based on these observations, the N(3) or N(3)S donor set of the benzimidazole-derived ligands is analogous to previously reported chelating systems, but the electronic environment they provide is unique, and may have relevance to histidine and methionine-containing metalloenzymes. This is also reflected in the reactivity of [Me(2)L(2)Cu(NCCH(3))(2)](+) (5(Me)) and [Me(2)L(3)Cu](+) (6(Me)) towards dioxygen, which results

  18. Size-confined fixed-composition and composition-dependent engineered band gap alloying induces different internal structures in L-cysteine-capped alloyed quaternary CdZnTeS quantum dots

    Science.gov (United States)

    Adegoke, Oluwasesan; Park, Enoch Y.

    2016-06-01

    The development of alloyed quantum dot (QD) nanocrystals with attractive optical properties for a wide array of chemical and biological applications is a growing research field. In this work, size-tunable engineered band gap composition-dependent alloying and fixed-composition alloying were employed to fabricate new L-cysteine-capped alloyed quaternary CdZnTeS QDs exhibiting different internal structures. Lattice parameters simulated based on powder X-ray diffraction (PXRD) revealed the internal structure of the composition-dependent alloyed CdxZnyTeS QDs to have a gradient nature, whereas the fixed-composition alloyed QDs exhibited a homogenous internal structure. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis confirmed the size-confined nature and monodispersity of the alloyed nanocrystals. The zeta potential values were within the accepted range of colloidal stability. Circular dichroism (CD) analysis showed that the surface-capped L-cysteine ligand induced electronic and conformational chiroptical changes in the alloyed nanocrystals. The photoluminescence (PL) quantum yield (QY) values of the gradient alloyed QDs were 27–61%, whereas for the homogenous alloyed QDs, the PL QY values were spectacularly high (72–93%). Our work demonstrates that engineered fixed alloying produces homogenous QD nanocrystals with higher PL QY than composition-dependent alloying.

  19. Spectroscopic analysis and control

    Science.gov (United States)

    Tate; , James D.; Reed, Christopher J.; Domke, Christopher H.; Le, Linh; Seasholtz, Mary Beth; Weber, Andy; Lipp, Charles

    2017-04-18

    Apparatus for spectroscopic analysis which includes a tunable diode laser spectrometer having a digital output signal and a digital computer for receiving the digital output signal from the spectrometer, the digital computer programmed to process the digital output signal using a multivariate regression algorithm. In addition, a spectroscopic method of analysis using such apparatus. Finally, a method for controlling an ethylene cracker hydrogenator.

  20. Structures and spectroscopic properties of sulfur-nitrogen-pnictogen chains: R2P-Ndbnd Sdbnd N-PR2 and R2P-Ndbnd Sdbnd N-AsR2

    Science.gov (United States)

    Bal, Kristof M.; Cautereels, Julie; Blockhuys, Frank

    2017-03-01

    The conformational and configurational preferences of Me2P-Ndbnd Sdbnd N-PMe2 (3) and Me2P-Ndbnd Sdbnd N-AsMe2 (4) have been identified using quantum chemical calculations at the DFT/B3LYP/6-311+G* level of theory. An approach in which energetic, structural (geometries and bond orders), electronic (analysis of the electron density) and spectroscopic properties are combined leads to the conclusion that these sulfur-nitrogen-pnictogen chains share many of the properties of their chalcogen-nitrogen analogues but that the through-space intramolecular interactions favouring the Z,Z configuration are even weaker than in these latter compounds. The results of this analysis also lead to an unambiguous assignment of the variable-temperature 31P and 15N NMR spectra of these compounds and their structures both in solution and in the solid state.

  1. Non-linear composition dependence of the conductivity parameters in alkali halides mixed crystals

    Energy Technology Data Exchange (ETDEWEB)

    Zardas, Georgios E., E-mail: gzardas@phys.uoa.g [Department of Solid State Physics, Faculty of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos (Greece)

    2009-06-01

    Since mixed alkali halides were found to have applications in optical, optoelectronic and electronic devices, a strong interest has recently expressed for the study of their physical properties. Here, we discuss the experimental finding that a maximum conductivity enhancement with respect to pure constituents is obtained at a certain composition. We show that this composition can be predicted from the bulk properties of the end members.

  2. The Subaru-XMM-Newton Deep Survey (SXDS) VIII.: Multi-wavelength Identification, Optical/NIR Spectroscopic Properties, and Photometric Redshifts of X-ray Sources

    CERN Document Server

    Akiyama, Masayuki; Watson, Mike G; Furusawa, Hisanori; Takata, Tadafumi; Simpson, Chris; Morokuma, Tomoki; Yamada, Toru; Ohta, Kouji; Iwamuro, Fumihide; Yabe, Kiyoto; Tamura, Naoyuki; Moritani, Yuuki; Takato, Naruhisa; Kimura, Masahiko; Maihara, Toshinori; Dalton, Gavin; Lewis, Ian; Lee, Hanshin; Lake, Emma Curtis; Macaulay, Edward; Clarke, Frazer; Silverman, John D; Croom, Scott; Ouchi, Masami; Hanami, Hitoshi; Tello, J Diaz; Yoshikawa, Tomohiro; Fujishiro, Naofumi; Sekiguchi, Kazuhiro

    2015-01-01

    We report the multi-wavelength identification of the X-ray sources found in the Subaru-XMM-Newton Deep Survey (SXDS) using deep imaging data covering the wavelength range between the far-UV to the mid-IR. We select a primary counterpart of each X-ray source by applying the likelihood ratio method to R-band, 3.6micron, near-UV, and 24micron source catalogs as well as matching catalogs of AGN candidates selected in 1.4GHz radio and i'-band variability surveys. Once candidates of Galactic stars, ultra-luminous X-ray sources in a nearby galaxy, and clusters of galaxies are removed there are 896 AGN candidates in the sample. We conduct spectroscopic observations of the primary counterparts with multi-object spectrographs in the optical and NIR; 65\\% of the X-ray AGN candidates are spectroscopically-identified. For the remaining X-ray AGN candidates, we evaluate their photometric redshift with photometric data in 15 bands. Utilising the multi-wavelength photometric data of the large sample of X-ray selected AGNs, w...

  3. Spectroscopic properties of MgH2, MgD2, and MgHD calculated from a new ab initio potential energy surface.

    Science.gov (United States)

    Li, Hui; Le Roy, Robert J

    2007-07-19

    A three-dimensional potential energy surface for the ground electronic state of MgH2 has been constructed from 9030 symmetry-unique ab initio points calculated using the icMRCI+Q method with aug-cc-pVnZ basis sets for n=3, 4, and 5, with core-electron correlation calculated at the MR-ACPF level of theory using cc-pCVnZ basis sets, with both calculations being extrapolated to the complete basis set limit. Calculated spectroscopic constants of MgH2 and MgD2 are in excellent agreement with recent experimental results: for four bands of MgH2 and one band of MgD2 the root-mean-square (rms) band origin discrepancies were only 0.44 and 0.06 cm(-1), respectively, and the rms relative discrepancies in the inertial rotational constants (B[v]) were only 0.0196% and 0.0058%, respectively. Spectroscopic constants for MgHD were predicted using the same potential surface.

  4. The Pigment Color Wheat Spectroscopic and Antioxidant Properties%彩色小麦色素的光谱及抗氧化特性

    Institute of Scientific and Technical Information of China (English)

    周桂娟; 王坤; 刘佳明; 孙慧君; 李集临; 张杰

    2011-01-01

    In color pigment made of wheat, but the research and development of wheat ErBenJi clear color -2 - bitter hydrazine base of free radicals are rarely studied.Studies of the pigment color grain spectroscopic and antioxidant properties in common wheat, through and ascorbic acid and determination by DPPH black wheat, blue, violet wheat grain of wheat, red, white, wheat grain of wheat pigment antioxidant, scavenging free radicals, the ability of the wheat with the increase of the concentration of the pigment, its antioxidant ability of free radicals, correspondingly improved.All sorts of color pigment crude extractings wheat with concentration-response relationship of antioxidant activity, and its free radicalsability than common wheat,but less than ascorbic acid, including black wheat pigment scavenging free radicals, the strongest blue and purple wheat grain of wheat scavenging free radicals, white wheat ability and red wheat clear ability weak but most common wheat than.This explains the darker skins of wheat, the stronger ability of free radicals.Common wheat, black, blue wheat grain of wheat, red, purple wheat grain of wheat, white wheat and Vc DPPH 50% clear of free radicals EC50 concentration (effective) respectively188.27, 54.26, 76.22, 94.05, 126.24, 110.04,0.139.Its free radical scavenging capacity AE respectively by 0.53× 10-2, 1.84× 10-2, 1.31 × 10-2, 1.06× 10-2,0.79× 10-2, 0.91 ×10-2, 719× 10-2.Such as wheat color skin of a crude extractings pigment its ability of free radicals, which are better for further research, development and utilization of wheat color pigment theoretical basis.%国内外对彩色小麦色素作了一定的开发研究,但彩色小麦清除二苯基-2-苦肼基自由基的研究还很少.此文研究彩色籽粒色素的光谱及抗氧化特性,通过以普通小麦(中国春)和抗坏血酸为对照,用DPPH法测定黑粒小麦,蓝粒小麦,紫粒小麦,红粒小麦,白粒小麦色素的抗氧化、清除自由基的能

  5. Composition dependence of electrical properties of ZnF2–MO–TeO2 glasses

    Indian Academy of Sciences (India)

    D K Durga; N Veeraiah

    2001-08-01

    Dielectric constant ('), loss (tan ), a.c. conductivity () of ZnF2–MO–TeO2 glasses with varying concentrations of MO (P2O5, As2O3 and Bi2O3) were measured as a function of frequency and temperature over moderately wide ranges. From the analysis of these studies along with IR spectra and DTA results of these glasses, the structural changes in the systems with the concentration of metal oxides are discussed.

  6. Toward feasible and comprehensive computational protocol for simulation of the spectroscopic properties of large molecular systems: the anharmonic infrared spectrum of uracil in the solid state by the reduced dimensionality/hybrid VPT2 approach.

    Science.gov (United States)

    Fornaro, Teresa; Carnimeo, Ivan; Biczysko, Malgorzata

    2015-05-28

    Feasible and comprehensive computational protocols for simulating the spectroscopic properties of large and complex molecular systems are very sought after. Indeed, due to the great variety of intra- and intermolecular interactions that may take place, the interpretation of experimental data becomes more and more difficult as the system under study increases in size or is placed in a complex environment, such as condensed phases. In this framework, we are actively developing a comprehensive and robust computational protocol aimed at quantitative reproduction of the spectra of nucleic acid base complexes, with increasing complexity toward condensed phases and monolayers of biomolecules on solid supports. We have resorted to fully anharmonic quantum mechanical computations within the generalized second-order vibrational perturbation theory (GVPT2) approach, combined with the cost-effective B3LYP-D3 method, in conjunction with basis sets of double-ζ plus polarization quality. Such an approach has been validated in a previous work ( Phys. Chem. Chem. Phys. 2014 , 16 , 10112 - 10128 ) for simulating the IR spectra of the monomers of nucleobases and some of their dimers. In the present contribution we have extended such computational protocol to simulate spectroscopic properties of a molecular solid, namely polycrystalline uracil. First we have selected a realistic molecular model for representing the spectroscopic properties of uracil in the solid state, the uracil heptamer, and then we have computed the relative anharmonic frequencies combining less demanding approaches such as the hybrid B3LYP-D3/DFTBA one, in which the harmonic frequencies are computed at a higher level of theory (B3LYP-D3/N07D) whereas the anharmonic shifts are evaluated at a lower level of theory (DFTBA), and the reduced dimensionality VPT2 (RD-VPT2) approach, where only selected vibrational modes are computed anharmonically along with the couplings with other modes. The good agreement between the

  7. Predicting Composition Dependence of Glass Forming Ability in Ternary Al-Cu-Y System by Thermodynamic Calculation

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2014-11-01

    Full Text Available The composition dependence of glass forming ability in the ternary Al-Cu-Y system is predicted by thermodynamic calculations based on the Miedema’s model and Alonso’s method. By comparing the relative energetic status of the amorphous phase versus the solid solution phase, a hexagonal composition region that energetically favoring the metallic glass formation is predicted. The glass formation driving force and crystallization resistance are further calculated and the composition of Al72Cu10Y18 is pinpointed with the largest glass forming ability in the Al-Cu-Y system. The calculation results are well supported by the experimental observations reported in the literature.

  8. K[AsW2O9], the first member of the arsenate-tungsten bronze family: Synthesis, structure, spectroscopic and non-linear optical properties

    Science.gov (United States)

    Alekseev, Evgeny V.; Felbinger, Olivier; Wu, Shijun; Malcherek, Thomas; Depmeier, Wulf; Modolo, Giuseppe; Gesing, Thorsten M.; Krivovichev, Sergey V.; Suleimanov, Evgeny V.; Gavrilova, Tatiana A.; Pokrovsky, Lev D.; Pugachev, Alexey M.; Surovtsev, Nikolay V.; Atuchin, Victor V.

    2013-08-01

    K[AsW2O9], prepared by high-temperature solid-state reaction, is the first member of the arsenate-tungsten bronze family. The structure of K[AsW2O9] is based on a 3-dimensional (3D) oxotungstate-arsenate framework with the non-centrosymmetric P212121 space group, a=4.9747(3) Å, b=9.1780(8) Å, c=16.681(2) Å. The material was characterized using X-ray diffraction, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Raman and infrared (IR) spectroscopic techniques. The results of DSC demonstrate that this phase is stable up to 1076 K. Second harmonic generation (SHG) measurements performed on a powder sample demonstrate noticeable (0.1 of LiIO3) non-linear optical (NLO) activity.

  9. Synthesis, spectroscopic, fluorescence properties and biological evaluation of novel Pd(II) and Cd(II) complexes of NOON tetradentate Schiff bases.

    Science.gov (United States)

    Ali, Omyma A M

    2014-01-01

    The solid complexes of Pd(II) and Cd(II) with N,N/bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H2L(1)), and N,N/bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2L(2)) have been synthesized and characterized by several techniques using elemental analysis (CHN), FT-IR, (1)H NMR, UV-Vis spectra and thermal analysis. Elemental analysis data proved 1:1 stoichiometry for the reported complexes while spectroscopic data indicated square planar and octahedral geometries for Pd(II) and Cd(II) complexes, respectively. The prepared ligands, Pd(II) and Cd(II) complexes exhibited intraligand (π-π(∗)) fluorescence and can potentially serve as photoactive materials. Thermal behavior of the complexes was studied and kinetic parameters were determined by Coats-Redfern method. Both the ligands and their complexes have been screened for antimicrobial activities.

  10. Spectroscopic properties of UV active medium Ce3+:LiSr0.8Ca0.2AlF6

    Science.gov (United States)

    Nizamutdinov, A. S.; Shavelev, A. A.; Marisov, M. A.; Semashko, V. V.

    2016-02-01

    The aim of this work is phase composition and near UV spectroscopic studies of UV active media in fluoride crystals with colquiriite structure, such as Ce3+:LiSr0.8Ca0.2AlF6. Colquiriite structure mixed crystals show higher segregation coefficient of Ce3+ activator ions than common LiCaAlF6 hosts. An important result is based on the fact that this enhancement was achieved for two types of Ce3+ centers in a multisite Ce:LiSr0.8Ca0.2AlF6 system. Thus, it provides a higher gain coefficient for the 5d-4f transitions of Ce3+ ions and it spans a wider continuous wavelength tuning range between 280 and 320 nm for tunable Ce:LiSr0.8Ca0.2AlF6 laser systems.

  11. Spectroscopic Dosimeter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Analysis of Phase I test data demonstrates that the Photogenics Spectroscopic Dosimeter will detect neutron energies from 0.8 up to 600 MeV. The detector...

  12. Spectroscopic properties of long-lifetime Tm3+ optical centers in Ca-Sr-Ba fluorides in the form of single crystals and ceramics at the 1G4-3H5 magnetic dipole allowed transition

    Science.gov (United States)

    Doroshenko, M. E.; Papashvili, A. G.; Martynova, K. A.; Konyushkin, V. A.; Nakladov, A. N.; Osiko, V. V.

    2017-02-01

    The spectroscopic properties of new long-lifetime Tm3+ tetragonal optical centers at low (77 K) temperature were investigated using a site-selective time-resolved technique. The absorption and excitation spectra at the 3H6-1G4 transition and the fluorescence spectra at the 1G4-3H5 transition were measured in CaF2, SrF2, and BaF2 single crystals. The appearance of additional weak lines in the excitation and fluorescence spectra in hot-formed ceramics produced from the same crystals was observed. These lines were attributed to the recently observed long-lifetime tetragonal optical centers with a modified local environment formed in fluoride ceramics.

  13. A DFT/TD DFT study of the structure and spectroscopic properties of 5-methyl-2-(8-quinolinyl)benzoxazole and its complexes with Zn(II) ion.

    Science.gov (United States)

    Guzow, Katarzyna; Milewska, Magda; Czaplewski, Cezary; Wiczk, Wiesław

    2010-02-01

    The structure and spectroscopic properties of 5-methyl-2-(8-quinolinyl)benzoxazole and its complexes with Zn(II) ion were studied using a DFT and TD DFT methods with def2-TZVP basis set. It was shown that the type of functional used (B3-LYP or pbe0) implemented in TURBOMOLE package does not have essential influence on the geometry (small differences in bond length, valence and dihedral angles) of studied compounds in both ground and excited states. However, significant differences were obtained for the position of vertical absorption and emission transition but not for the oscillator strength of transition. Application of pbe0 functional seems to reproduce better the experimental spectrum.

  14. Study on molecular structure, spectroscopic properties (FTIR and UV-Vis), NBO, QTAIM, HOMO-LUMO energies and docking studies of 5-fluorouracil, a substance used to treat cancer

    Science.gov (United States)

    Almeida, Michell O.; Barros, Daiane A. S.; Araujo, Sheila C.; Faria, Sergio H. D. M.; Maltarollo, Vinicius G.; Honorio, Kathia M.

    2017-09-01

    Cancer cells can expand to other parts of body through blood system and nodes from a mechanism known as metastasis. Due to the large annual growth of cancer cases, various biological targets have been studied and related to this disorder. A very interesting target related to cancer is human epidermal growth factor receptor 2 (HER2). In this study, we analyzed the main intermolecular interactions between a drug used in the cancer treatment (5-fluorouracil) and HER2. Molecular modeling methods were also employed to assess the molecular structure, spectroscopic properties (FTIR and UV-Vis), NBO, QTAIM and HOMO-LUMO energies of 5-FU. From the docking simulations it was possible to analyze the interactions that occur between some residues in the binding site of HER2 and 5-FU. To validate the choice of basis set that was used in the NBO and QTAIM analyses, theoretical calculations were performed to obtain FT-IR and UV/Vis spectra, and the theoretical results are consistent with the experimental data, showing that the basis set chosen is suitable. For the maximum λ from the theoretical calculation (254.89 nm) of UV/Vis, the electronic transition from HOMO to LUMO occurs at 4.89 eV. From NBO analyses, we observed interactions between Asp863 and 5-FU, i.e. the orbitals with high transfer of electrons are LP O15 (donor NBO) and BD* (π) N1-H10 (acceptor NBO), being that the value of this interaction is 7.72 kcal/mol. Results from QTAIM indicate one main intermolecular H bond, which is necessary to stabilize the complex formed between the ligands and the biological target. Therefore, this study allowed a careful evaluation on the main structural, spectroscopic and electronic properties involved in the interaction between 5-FU and HER2, an important biological complex related to the cancer treatment.

  15. Fretting wear damage of HexTOOL{sup TM} composite depending on the different fibre orientations

    Energy Technology Data Exchange (ETDEWEB)

    Terekhina, S; Salvia, M; Fouvry, S [Laboratoire de Tribologie et Dynamique des Systemes, UMR CNRS ECL ENISE ENSMSE 5513, Ecole Centrale de Lyon, 69134 Ecully cedex (France); Malysheva, G; Tarasova, T, E-mail: svetlana.terekhina@ec-lyon.fr, E-mail: svetlanaterekhina@yandex.ru [Bauman Moscow State Technical University, 105005 Moscow, 5, 2nd Baumanskaya str (Russian Federation)

    2009-09-15

    The composites have drawn considerable interest in the mould processes. The vibrations and fatigue stresses induced in the moulds made evident to characterize the composite HexTOOL{sup TM} under fretting conditions. Fretting is a small-amplitude oscillatory motion between contacting surfaces. The running conditions fretting maps (RCFM) of composite at ambient conditions were established. The influence of different fiber orientations of HexTOOL{sup TM} composite on the wear kinetics was shown. An energy wear approach was developed. According to results of dynamic mechanical analysis (DMA), the viscoelastic properties of composite material were obtained.

  16. On the necessity of composition-dependent low-temperature opacity in metal-poor AGB stars

    CERN Document Server

    Constantino, Thomas; Gil-Pons, Pilar; Lattanzio, John

    2014-01-01

    The vital importance of composition-dependent low-temperature opacity in low-mass (M 0.001 has recently been demonstrated (e.g. Marigo 2002; Ventura & Marigo 2010). Its significance to more metal-poor, intermediate mass (M > 2.5Msun) models has yet to be investigated. We show that its inclusion in lower-metallicity models ([Fe/H] < -2) is essential, and that there exists no threshold metallicity below which composition-dependent molecular opacity may be neglected. We find it to be crucial in all intermediate-mass models investigated ([Fe/H] < -2 and 2.5 < M/Msun < 5), because of the evolution of the surface chemistry, including the orders of magnitude increase in the abundance of molecule-forming species. Its effect on these models mirrors that previously reported for higher-metallicity models - increase in radius, decrease in Teff, faster mass loss, shorter thermally pulsing AGB lifetime, reduced enrichment in third dredge-up products (by a factor of three to ten), and an increase in the mas...

  17. Composition dependent behavior in the ternary mixed magnetic insulator Co1-xMnyNix-yCl2·2H2O

    Science.gov (United States)

    DeFotis, G. C.; Hampton, A. S.; Wallin, T. J.; Trowell, K. T.; Pothen, J. M.; Welshhans, E. A.; Havas, K. C.

    2016-05-01

    The properties of ternary mixed magnetic Co1-xMnyNix-yCl2·2H2O are examined by dc magnetization and susceptibility measurements, from 1.8 to 300 K as a function of composition. This is only the second ternary magnetic insulator so studied. The three transition metal chloride dihydrate components are known to differ in the degree of spin anisotropy and in the distribution of ferromagnetic and antiferromagnetic exchange interactions within and between strongly coupled chemical and structural chains. The Curie and Weiss constants, in χM=C/(T-θ) fits to high temperature susceptibilities, are compared with weighted averages of pure component values. The observed Weiss constant is almost uniformly less negative than calculated. Maxima in low temperature susceptibilities vary widely in presence and location with composition. Some compositions exhibit no susceptibility maximum, many exhibit one maximum, and three exhibit two maxima. A T(x,y) diagram is constructed. Magnetization vs field isotherms exhibit different shapes as a function of composition, with hysteresis markedly composition dependent. For three mixtures hysteresis loops are studied as a function of temperature. An activation process model does not describe the temperature dependence well.

  18. SPECTROSCOPIC GRADIENTS IN EARLY-TYPE GALAXIES

    Directory of Open Access Journals (Sweden)

    A. Buzzoni

    2009-01-01

    Full Text Available We review some relevant properties of the observed changes of H , Mg2, and Fei Lick indices across the surface of 25 bright elliptical galaxies. The impact of these spectroscopic gradients is brie y discussed, in the framework of the leading physical mechanisms that led to galaxy formation. In particular, three relevant evolutionary scenarios are sketched, each one able, in principle, to consistently match galaxy spectral properties and e ectively constrain the composing stellar populations in these systems.

  19. Spectroscopic Gradients in Early-type Galaxies

    Science.gov (United States)

    Buzzoni, A.; Battistini, C.; Carrasco, L.; Recillas, E.

    2009-11-01

    We review some relevant properties of the observed changes of Hβ, Mg_2, and FeI Lick indices across the surface of 25 bright elliptical galaxies. The impact of these spectroscopic gradients is briefly discussed, in the framework of the leading physical mechanisms that led to galaxy formation. In particular, three relevant evolutionary scenarios are sketched, each one able, in principle, to consistently match galaxy spectral properties and effectively constrain the composing stellar populations in these systems.

  20. Structural, spectroscopic aspects, and electronic properties of (TiO2)n clusters: a study based on the use of natural algorithms in association with quantum chemical methods.

    Science.gov (United States)

    Ganguly Neogi, Soumya; Chaudhury, Pinaki

    2014-01-05

    In this article, we propose a stochastic search-based method, namely genetic algorithm (GA) and simulated annealing (SA) in conjunction with density functional theory (DFT) to evaluate global and local minimum structures of (TiO2)n clusters with n = 1-12. Once the structures are established, we evaluate the infrared spectroscopic modes, cluster formation energy, vertical excitation energy, vertical ionization potential, vertical electron affinity, highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps, and so forth. We show that an initial determination of structure using stochastic techniques (GA/SA), also popularly known as natural algorithms as their working principle mimics certain natural processes, and following it up with density functional calculations lead to high-quality structures for these systems. We have shown that the clusters tend to form three-dimensional networks. We compare our results with the available experimental and theoretical results. The results obtained from SA/GA-DFT technique agree well with available theoretical and experimental data of literature.

  1. ALMA spectroscopic survey in the Hubble Ultra Deep Field: Continuum number counts, resolved 1.2-mm extragalactic background, and properties of the faintest dusty star forming galaxies

    CERN Document Server

    Aravena, Manuel; Walter, Fabian; Da Cunha, Elisabete; Bauer, Franz E; Carilli, Christopher; Daddi, Emanuele; Elbaz, David; Ivison, R J; Riechers, Dominik; Smail, Ian R; Swinbank, Mark; Weiss, Axel; Anguita, Timo; Assef, Roberto J; Bell, Eric; Bertoldi, Frank; Bacon, Roland; Bouwens, Rychard; Cortes, Paulo; Cox, Pierre; Gónzalez-López, Jorge; Hodge, Jacqueline; Ibar, Eduardo; Inami, Hanae; Infante, Leopoldo; Karim, Alexander; Fèvre, Olivier Le; Magnelli, Benjamin; Ota, Kauzuaki; Popping, Gergö; Sheth, Kartik; van der Werf, Paul; Wagg, Jeffrey

    2016-01-01

    We present an analysis of a deep (1$\\sigma$=13 $\\mu$Jy) cosmological 1.2-mm continuum map based on ASPECS, the ALMA Spectroscopic Survey in the Hubble Ultra Deep Field. In the 1 arcmin$^2$ covered by ASPECS we detect nine sources at $>3.5\\sigma$ significance at 1.2-mm. Our ALMA--selected sample has a median redshift of $z=1.6\\pm0.4$, with only one galaxy detected at z$>$2 within the survey area. This value is significantly lower than that found in millimeter samples selected at a higher flux density cut-off and similar frequencies. Most galaxies have specific star formation rates similar to that of main sequence galaxies at the same epoch, and we find median values of stellar mass and star formation rates of $4.0\\times10^{10}\\ M_\\odot$ and $\\sim40~M_\\odot$ yr$^{-1}$, respectively. Using the dust emission as a tracer for the ISM mass, we derive depletion times that are typically longer than 300 Myr, and we find molecular gas fractions ranging from $\\sim$0.1 to 1.0. As noted by previous studies, these values ar...

  2. Determination of thermo-optic properties of atomic layer deposited thin TiO2 films for athermal resonant waveguide gratings by spectroscopic ellipsometry

    Science.gov (United States)

    Saleem, Muhammad Rizwan; Ali, Rizwan; Honkanen, Seppo; Turunen, Jari

    2014-05-01

    We report on variation in the refractive index of amorphous and isotropic TiO2 thin films grown by Atomic Layer Deposition (ALD) in nano optical devices. ALD-TiO2 films of thicknesses negative thermo-optic coefficient (TOC) due to decrease in refractive index with temperature, owing to inherent hydrophilic nature. While ALD-TiO2 films with thicknesses > 200 nm show positive TOC due to the predominance of TiO2 thickness over the very thin surface porosity region. The negative TOC of thin TiO2 films was controlled by depositing thin ALD-Al2O3 diffusion barrier films that showed impermeable behavior to block the evaporation of adsorbed water molecules on TiO2 surfaces in thermal environments. This approach turns negative sign of TOC of TiO2 thin films to positive one which is necessary to stabilize the central resonance peak of a guided mode resonance filter (GMRF). The ALD-TiO2 and ALDAl2O3 bi-layer stack was modeled by VASE analysis of spectroscopic ellipsometry using Cauchy Model to extract refractive indices at various temperatures, measured at two different angle of incidence (65° and 75°), covering a wide spectral range 380 <= λ <= 1800. The temperature dependent index and density of TiO2 films were calculated from ellipsometric measured data using Lorentz-Lorenz relation.

  3. Fe2+-doped CdSe single crystal: growth, spectroscopic and laser properties, potential use as a 6 µm broadband amplifier

    Science.gov (United States)

    Frolov, M. P.; Gordienko, V. M.; Korostelin, Yu V.; Kozlovsky, V. I.; Podmar'kov, Yu P.; Potemkin, F. V.; Skasyrsky, Ya K.

    2017-02-01

    We report on the successful growth of single crystals of Fe2+:CdSe by seeded physical vapor transport (SPVT) technique with doping within the growing process and subsequent annealing in Se vapor. Luminescence lifetime measurements, spectroscopic studies of 5E-5T2 transition of Fe2+ in CdSe, and laser experiments were performed. The lifetime of the 5T2 energy level was measured to be 20  ±  5 ns at a room temperature (RT) of 290 K. At liquid nitrogen (LN) temperature, luminescence kinetics displayed a non-exponential decay, which can be fitted to a bi-exponential function with time constants τ 1  =  6 µs and τ 2  =  29 µs. As much as 3.2 mJ of output energy at 5.2 µm with 27% absorbed pump energy slope efficiency of an Fe2+:CdSe laser was achieved at RT under 2.94 µm nanosecond Er:YAG laser pumping. The Fe2+:CdSe laser was tuned from 4.63 to 6.10 µm. Obtained characteristics of Fe2+:CdSe indicate that the crystal can be considered a promising medium for amplification of femtosecond pulses in the middle infrared range up to 6 µm.

  4. Optical properties and surface characterization of pulsed laser-deposited Cu{sub 2}ZnSnS{sub 4} by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Crovetto, Andrea, E-mail: ancro@nanotech.dtu.dk [DTU Nanotech, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Cazzaniga, Andrea; Ettlinger, Rebecca B.; Schou, Jørgen [DTU Fotonik, Technical University of Denmark, DK-4000 Roskilde (Denmark); Hansen, Ole [DTU Nanotech, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); CINF, Center for Individual Nanoparticle Functionality, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2015-05-01

    Cu{sub 2}ZnSnS{sub 4} films prepared by pulsed laser deposition at different temperatures are characterized by spectroscopic ellipsometry. The focus is on confirming results from direct measurement techniques, by finding appropriate models of the surface overlayer for data fitting, and extracting the dielectric function of the films. It is found that the surface overlayer changes with film thickness and deposition temperature. Adopting different ellipsometry measurements and modeling strategies for each film, dielectric functions are extracted and compared. As the deposition temperature is increased, the dielectric functions exhibit additional critical points related to optical transitions in the material other than absorption across the fundamental band gap. In the case of a thin film < 200 nm thick, surface features observed by scanning electron microscopy and atomic force microscopy are accurately reproduced by ellipsometry data fitting. - Highlights: • Inhomogeneous Cu{sub 2}ZnSnS{sub 4} films are prepared by pulsed laser deposition. • The film surface includes secondary phases and topographic structures. • We model a film surface layer that fits ellipsometry data. • Ellipsometry data fits confirm results from direct measurement techniques. • We obtain the dielectric function of inhomogeneous Cu{sub 2}ZnSnS{sub 4} films.

  5. MRCI study of spectroscopic and molecular properties of X1∑g+and A1 Πu electronic states of the C2 radical

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiao-Niu; Shi De-Heng; Sun Jin-Feng; Zhu Zun-Lue

    2011-01-01

    The potential energy curves(PECs)of X1∑g+and A1 IIu- electronic states of the C2 radical have been studied using the full valence complete active space self-consistent field(CASSCF)method followed by the highly accurate valence internally contracted multireference configuration interaction(MRCI)approach in conjunction with the aug-cc-pV6Z basis set for internuclear separations from 0.08 nm to 1.66 run. With these PECs of the C2 radical, the spectroscopic parameters of three isotopologues(12 C2, 12C13C and 13 C2)have been determined. Compared in detail with previous studies reported in the literature, excellent agreement has been found. The complete vibrational levels G(v), inertial rotation constants B- and centrifugal distortion constants D- for the 12 C2, 12C13C and 13 C2 isotopologues have been calculated for the first time for the X1∑g+and A1Πu electronic states when the rotational quantum number J equals zero. The results are in excellent agreement with previous experimental data in the literature, which shows that the presented molecular constants in this paper are reliable and accurate.

  6. Synthesis, spectroscopic, photoluminescence properties and biological evaluation of novel Zn(II) and Al(III) complexes of NOON tetradentate Schiff bases

    Science.gov (United States)

    Abdel Aziz, Ayman A.; Badr, Ibrahim H. A.; El-Sayed, Ibrahim S. A.

    2012-11-01

    Novel mononuclear Zn(II) and Al(III) complexes were synthesized from the reactions of Zn(OAc)2·2H2O and anhydrous AlCl3 with neutral N2O2 donor tetradentate Schiff bases; N,N'bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H2L1) and N,N'bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2L2). The new complexes were fully characterized by using micro analyses (CHN), FT-IR, 1H NMR, UV-Vis spectra and thermal analysis. The analytical data have been showed that, the stoichiometry of the complexes is 1:1. Spectroscopic data suggested tetrahedral and square pyramidal geometries for Zn(II) and Al(III) complexes, respectively. The synthesized Zn(II), and Al(III) complexes exhibited intense fluorescence emission in the visible region upon UV-excitation in methylene chloride solution at ambient temperature. This high fluorescence emission was assigned to the strong coordination of the ligands to the small and the highly charged Zn(II) and Al(III) ions. Such strong coordination seems to extend the π-conjugation of the complexes. Thermal analysis measurements indicated that the complexes have good thermal stability. As a potential application the biological activity (e.g., antimicrobial action) of the prepared ligands and complexes was assessed by in-vitro testing of their effect on the growth of various strains of bacteria and fungi.

  7. Synthesis, spectroscopic, photoluminescence properties and biological evaluation of novel Zn(II) and Al(III) complexes of NOON tetradentate Schiff bases.

    Science.gov (United States)

    Abdel Aziz, Ayman A; Badr, Ibrahim H A; El-Sayed, Ibrahim S A

    2012-11-01

    Novel mononuclear Zn(II) and Al(III) complexes were synthesized from the reactions of Zn(OAc)(2).2H(2)O and anhydrous AlCl(3) with neutral N2O2 donor tetradentate Schiff bases; N,N'bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H(2)L(1)) and N,N'bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H(2)L(2)). The new complexes were fully characterized by using micro analyses (CHN), FT-IR, (1)H NMR, UV-Vis spectra and thermal analysis. The analytical data have been showed that, the stoichiometry of the complexes is 1:1. Spectroscopic data suggested tetrahedral and square pyramidal geometries for Zn(II) and Al(III) complexes, respectively. The synthesized Zn(II), and Al(III) complexes exhibited intense fluorescence emission in the visible region upon UV-excitation in methylene chloride solution at ambient temperature. This high fluorescence emission was assigned to the strong coordination of the ligands to the small and the highly charged Zn(II) and Al(III) ions. Such strong coordination seems to extend the π-conjugation of the complexes. Thermal analysis measurements indicated that the complexes have good thermal stability. As a potential application the biological activity (e.g., antimicrobial action) of the prepared ligands and complexes was assessed by in-vitro testing of their effect on the growth of various strains of bacteria and fungi.

  8. The KMOS Redshift One Spectroscopic Survey (KROSS): Dynamical properties, gas and dark matter fractions of typical z~1 star-forming galaxies

    CERN Document Server

    Stott, John P; Johnson, Helen L; Tiley, Alfie; Magdis, Georgios; Bower, Richard; Bunker, Andrew J; Bureau, Martin; Harrison, Chris M; Jarvis, Matt J; Sharples, Ray; Smail, Ian; Sobral, David; Best, Philip; Cirasuolo, Michele

    2016-01-01

    The KMOS Redshift One Spectroscopic Survey (KROSS) is an ESO guaranteed time survey of 795 typical star-forming galaxies in the redshift range z=0.8-1.0 with the KMOS instrument on the VLT. In this paper we present resolved kinematics and star formation rates for 584 z~1 galaxies. This constitutes the largest near-infrared Integral Field Unit survey of galaxies at z~1 to date. We demonstrate the success of our selection criteria with 90% of our targets found to be Halpha emitters, of which 81% are spatially resolved. The fraction of the resolved KROSS sample with dynamics dominated by ordered rotation is found to be 83$\\pm$5%. However, when compared with local samples these are turbulent discs with high gas to baryonic mass fractions, ~35%, and the majority are consistent with being marginally unstable (Toomre Q~1). There is no strong correlation between galaxy averaged velocity dispersion and the total star formation rate, suggesting that feedback from star formation is not the origin of the elevated turbule...

  9. Physical Properties of Spectroscopically-Confirmed Galaxies at $z\\ge6$. III. Stellar Populations from SED Modeling with Secure Ly$\\alpha$ Emission and Redshifts

    CERN Document Server

    Jiang, Linhua; Cohen, Seth H; Egami, Eiichi; Windhorst, Rogier A; Fan, Xiaohui; Dave, Romeel; Kashikawa, Nobunari; Mechtley, Matthew; Ouchi, Masami; Shimasaku, Kazuhiro; Clement, Benjamin

    2015-01-01

    We present a study of stellar populations in a sample of spectroscopically-confirmed Lyman-break galaxies (LBGs) and Ly$\\alpha$ emitters (LAEs) at $5.7

  10. Analysis of bound-free fluorescence and improved characterization of the electronic and spectroscopic properties of the 11Σ{/u +} state of Cl2

    Science.gov (United States)

    Wörmer, J.; Möller, T.; Stapelfeldt, J.; Zimmerer, G.; Haaks, D.; Kampf, S.; Le Calvé, J.; Castex, M. C.

    1988-12-01

    Synchrotron radiation is used to selectively excite the chlorine molecule in the VUV spectral range. Stationary fluorescence spectra of the 11Σ{/u +} state are observed following primary excitation of 11Σ{/u +} and 21Σ{/u +}. The bound-free part of the spectra is analysed with the aid of quantum mechanical computer simulations. A potential energy curve is constructed which is an approximation of the adiabatic double well potential energy curve of the 11Σ{/u +} state. The inner well is characterized by T e =(73428±50) cm-1, r e =(1.85 ± 0.05) Å; for the outer well hold T e =(64631±50) cm-1, r e =(2.57±0.05) Å, ω e =(261±5) cm-1, ω e x e =(0.668±0.01) cm-1 (35Cl2; v'<30). The potential energy curve is successfully checked with fluorescence excitation spectra. Within the error limits, the results of a former synchrotron radiation study are verified. It is ruled out, that the Cl2 “γ-state” recently observed with laser spectroscopic methods, can be attributed to the outer well of 11Σ{/u +}.

  11. Alloy and composition dependence of hydrogen embrittlement susceptibility in high-strength steel fasteners

    Science.gov (United States)

    Brahimi, S. V.; Yue, S.; Sriraman, K. R.

    2017-06-01

    High-strength steel fasteners characterized by tensile strengths above 1100 MPa are often used in critical applications where a failure can have catastrophic consequences. Preventing hydrogen embrittlement (HE) failure is a fundamental concern implicating the entire fastener supply chain. Research is typically conducted under idealized conditions that cannot be translated into know-how prescribed in fastener industry standards and practices. Additionally, inconsistencies and even contradictions in fastener industry standards have led to much confusion and many preventable or misdiagnosed fastener failures. HE susceptibility is a function of the material condition, which is comprehensively described by the metallurgical and mechanical properties. Material strength has a first-order effect on HE susceptibility, which increases significantly above 1200 MPa and is characterized by a ductile-brittle transition. For a given concentration of hydrogen and at equal strength, the critical strength above which the ductile-brittle transition begins can vary due to second-order effects of chemistry, tempering temperature and sub-microstructure. Additionally, non-homogeneity of the metallurgical structure resulting from poorly controlled heat treatment, impurities and non-metallic inclusions can increase HE susceptibility of steel in ways that are measurable but unpredictable. Below 1200 MPa, non-conforming quality is often the root cause of real-life failures. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  12. Composition dependence of luminescence of Eu and Eu/Tb doped silicate glasses for LED applications

    DEFF Research Database (Denmark)

    Zhu, C.F.; Chaussedent, S.; Liu, S.

    2013-01-01

    The Eu and Eu/Tb doped silicate glasses are good candidates for light emitting diode (LED) applications. But the optical performance of these glasses is sensitive to variations in chemical composition. In this paper we report our recent findings about the effect of addition of minor components....... The results show that the asymmetry factor and luminescence lifetimes of as-prepared materials are dependent on composition. White fluorescence is achieved in Eu/Tb co-doped glasses, which can be attributed to the simultaneous generation of red, green and blue wavelengths from Eu3+ and Tb3+ ions...... such as B2O3, Al2O3 and CaF2 on the luminescent properties of the above-mentioned glasses. We explore the role of Eu3+ ions as a structural probe of the glasses by determining the asymmetry factor, i.e., the ratio of the emission intensity of the 5D0→7F2 transition to that of the 5D0 →7F1 transition...

  13. Composition dependent mechanical behaviour of S53P4 bioactive glass putty for bone defect grafting.

    Science.gov (United States)

    van Gestel, N A P; Hulsen, D J W; Geurts, J; Hofmann, S; Ito, K; Arts, J J; van Rietbergen, B

    2017-05-01

    To improve the handling properties of S53P4 bioactive glass granules for clinical applications, bioactive glass putty formulations were developed. These formulations contain both granules and a synthetic binder to form an injectable material that is easy to shape. To explore its applicability in load-bearing bone defect grafting, the relation between the putty composition and its mechanical behaviour was assessed in this study. Five putty formulations with variations in synthetic binder and granule content were mechanically tested in confined compression. The results showed that the impaction strains significantly decreased and the residual strains significantly increased with an increasing binder content. The stiffness of all tested formulations was found to be in the same range as the reported stiffness of cancellous bone. The measured creep strains were low and no significant differences between formulations were observed. The stiffness significantly increased when the samples were subjected to a second loading stage. The residual strains calculated from this second loading stage were also significantly different from the first loading stage, showing an increasing difference with an increasing binder content. Since residual strains are detrimental for graft layer stability in load-bearing defects, putty compositions with a low binder content would be most beneficial for confined, load-bearing bone defect grafting.

  14. Composition dependence of luminescence of Eu and Eu/Tb doped silicate glasses for LED applications

    DEFF Research Database (Denmark)

    Zhu, C.F.; Chaussedent, S.; Liu, S.

    2013-01-01

    such as B2O3, Al2O3 and CaF2 on the luminescent properties of the above-mentioned glasses. We explore the role of Eu3+ ions as a structural probe of the glasses by determining the asymmetry factor, i.e., the ratio of the emission intensity of the 5D0→7F2 transition to that of the 5D0 →7F1 transition......The Eu and Eu/Tb doped silicate glasses are good candidates for light emitting diode (LED) applications. But the optical performance of these glasses is sensitive to variations in chemical composition. In this paper we report our recent findings about the effect of addition of minor components....... The results show that the asymmetry factor and luminescence lifetimes of as-prepared materials are dependent on composition. White fluorescence is achieved in Eu/Tb co-doped glasses, which can be attributed to the simultaneous generation of red, green and blue wavelengths from Eu3+ and Tb3+ ions...

  15. Composition dependence on the martensitic structures of the Mn-rich NiMnGa alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Chengbao; Muhammad, Yousaf; Deng Lifeng; Wu Wei; Xu Huibin

    2004-05-17

    The Mn-rich Ni{sub 50}Mn{sub 25+x}Ga{sub 25-x} (x=0-5) alloys were developed to investigate the structural transitions and magnetic properties. Structural transitions from austenite to 5M, 7M, and non-modulated martensite were observed with the increase of Mn content. The lattice parameter a elongates, as where b and c contract, and the unit cell volume reduces with increasing Mn content. The martensitic transformation start temperatures M{sub s} increase monotonically from 10.7 deg. C for x=2 to 102.7 deg. C for x=5. The saturation magnetization was measured at 5 K, where all the samples exhibit a martensitic structure. The average magnetic moments per Mn atom vary from 4.38 {mu}{sub B} to 2.93 {mu}{sub B} for x=0 to x=5. The negative effect of excess Mn atoms changes from -3.00 {mu}{sub B} for x=2 to -7.25 {mu}{sub B} for x=5. The excess Mn atoms modify the electronic structures of the unsubstituted Mn atoms, resulting in the sharp decrease of the magnetic moments of the unsubstituted Mn atoms with increasing Mn content. Structural incommensurability was observed with 7M for powder and non-modulated for bulk samper in a specific range of compositions and proved to be reversible when performing martensitic transformation. The 7M and non-modulated martensites Ni{sub 50}Mn{sub 30}Ga{sub 20} possess similar saturation magnetizations and Curie temperatures. The non-modulated martensite was estimated to have a lower free energy than 7M, and should be more stable for a reverse martensitic transformation, leading to a higher austenite start temperature A{sub s}, which is consistent with the experimental result.

  16. Near-bandgap optical properties of pseudomorphic GeSn alloys grown by molecular beam epitaxy

    Science.gov (United States)

    D'Costa, Vijay Richard; Wang, Wei; Yeo, Yee-Chia

    2016-08-01

    We investigated the compositional dependence of the near-bandgap dielectric function and the E0 critical point in pseudomorphic Ge1-xSnx alloys grown on Ge (100) substrate by molecular beam epitaxy. The complex dielectric functions were obtained using spectroscopic ellipsometry from 0.5 to 4.5 eV at room temperature. Analogous to the E1 and E1+Δ1 transitions, a model consisting of the compositional dependence of relaxed alloys along with the strain contribution predicted by the deformation potential theory fully accounts for the observed compositional dependence in pseudomorphic alloys.

  17. Evaluation of spectroscopic properties of Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal for use in mid-infrared lasers

    Science.gov (United States)

    Xia, Houping; Feng, Jianghe; Wang, Yan; Li, Jianfu; Jia, Zhitai; Tu, Chaoyang

    2015-01-01

    Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal was firstly grown by Czochralski method. Detailed spectroscopic analyses of Er3+/Yb3+/Pr3+: SrGdGa3O7 were carried out. Besides better absorption characteristic, the spectra of Er3+/Yb3+/Pr3+: SrGdGa3O7 show weaker up-conversion and near-infrared emissions as well as superior mid-infrared emission in comparison to Er3+: SrGdGa3O7 and Er3+/Yb3+: SrGdGa3O7 crystals. Furthermore, the self-termination effect for Er3+ 2.7 μm laser is suppressed successfully because the fluorescence lifetime of the 4I13/2 lower level of Er3+ decreases markedly while that of the upper 4I11/2 level changes slightly in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal. The sensitization effect of Yb3+ and deactivation effect of Pr3+ ions as well as the energy transfer mechanism in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal were also studied in this work. The introduction of Yb3+ and Pr3+ is favorable for achieving an enhanced 2.7 μm emission in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal which can act as a promising candidate for mid-infrared lasers. PMID:26369289

  18. Evaluation of spectroscopic properties of Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal for use in mid-infrared lasers.

    Science.gov (United States)

    Xia, Houping; Feng, Jianghe; Wang, Yan; Li, Jianfu; Jia, Zhitai; Tu, Chaoyang

    2015-09-15

    Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal was firstly grown by Czochralski method. Detailed spectroscopic analyses of Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 were carried out. Besides better absorption characteristic, the spectra of Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 show weaker up-conversion and near-infrared emissions as well as superior mid-infrared emission in comparison to Er(3+): SrGdGa3O7 and Er(3+)/Yb(3+): SrGdGa3O7 crystals. Furthermore, the self-termination effect for Er(3+) 2.7 μm laser is suppressed successfully because the fluorescence lifetime of the (4)I(13/2) lower level of Er(3+) decreases markedly while that of the upper (4)I(11/2) level changes slightly in Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal. The sensitization effect of Yb(3+) and deactivation effect of Pr(3+) ions as well as the energy transfer mechanism in Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal were also studied in this work. The introduction of Yb(3+) and Pr(3+) is favorable for achieving an enhanced 2.7 μm emission in Er(3+)/Yb(3+)/Pr(3+): SrGdGa3O7 crystal which can act as a promising candidate for mid-infrared lasers.

  19. Structure and spectroscopic properties of ruthenium(II) bipyridyl N-benzoyl-N'-(1,10-phenanthrolin-5-Yl)-thiourea

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Siew San [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Kassim, Mohammad B. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Ruthenium bipyridyl incorporating phenanthroline with thiourea molecules, [Ru(bpy){sub 2}(Phen-BT)](PF{sub 6}){sub 2}], has been synthesized and characterized by spectroscopic and electrochemical techniques. The infrared spectra of the complex shows the characteristics stretching frequencies for N-H at 3646 and 3585 cm{sup −1}, ν(C-N){sub phen} 1426 cm{sup −1}, ν(C=O) 1675 cm{sup −1}, ν(C=S) 1246 cm{sup −1}, ν(C-H){sub aromatic} 3353-3086 cm{sup −1}, ν(C-N){sub aliphatic} 1169-1026 cm{sup −1}, ν(C-H){sub bend} 764 cm{sup −1} and ν(PF{sub 6}{sup −}){sub free} 842 cm{sup −1}. The complex reveals two π→π* absorption bands at 237 (ε=26,302) and 286 nm (ε=36,848), which were assigned to the phenanthroline and bipyridyl moieties, respectively. A slightly broad and low energy band in the UV-vis spectrum at 450 nm (ε=7,209) of the complex was assigned to a MLCT transition. Besides, the complex also exhibits an emission band at 615 nm that arises from an excitation with a 440 nm light energy. The cyclic voltammetry of the complex shows an oxidation potential at +1.305 V vs. SCE that corresponds to the formal oxidation of Ru(II) to Ru(III)

  20. Equiatomic AEAuX (AE=Ca-Ba, X=Al-In) Intermetallics: A Systematic Study of their Electronic Structure and Spectroscopic Properties.

    Science.gov (United States)

    Benndorf, Christopher; Stegemann, Frank; Seidel, Stefan; Schubert, Lea; Bartsch, Manfred; Zacharias, Helmut; Mausolf, Bernhard; Haarmann, Frank; Eckert, Hellmut; Pöttgen, Rainer; Janka, Oliver

    2017-01-31

    The three intermetallic compounds SrAuGa, BaAuAl and BaAuGa were synthesised from the elements in niobium ampoules. The Sr compound crystallises in the orthorhombic KHg2 -type structure (Imma, a=465.6(1), b=771.8(2), c=792.6(2) pm, wR2 =0.0740, 324 F(2) values, 13 variables), whereas the Ba compounds were both found to crystallise in the cubic non-centrosymmetric LaIrSi-type structure (P21 3, BaAuAl: a=696.5(1) pm; wR2 =0.0427, 446 F(2) values, 12 variables; BaAuGa: a=693.49(4) pm, wR2 =0.0717, 447 F(2) values, 12 variables). The samples were investigated by powder X-ray diffraction and their structures refined on the basis of single-crystal X-ray diffraction data. The title compounds, along with references from the literature (CaAuAl, CaAuGa, CaAuIn, and SrAuIn), were characterised further by susceptibility measurements and (27) Al and (71) Ga solid-state NMR spectroscopy. Theoretical calculations of the density of states (DOS) and the NMR parameters were used for the interpretation of the spectroscopic data. The electron transfer from the alkaline-earth metals and the group 13 elements onto the gold atoms was investigated through X-ray photoelectron spectroscopy (XPS), classifying these intermetallics as aurides.

  1. The KMOS Redshift One Spectroscopic Survey (KROSS): dynamical properties, gas and dark matter fractions of typical z ˜ 1 star-forming galaxies

    Science.gov (United States)

    Stott, John P.; Swinbank, A. M.; Johnson, Helen L.; Tiley, Alfie; Magdis, Georgios; Bower, Richard; Bunker, Andrew J.; Bureau, Martin; Harrison, Chris M.; Jarvis, Matt J.; Sharples, Ray; Smail, Ian; Sobral, David; Best, Philip; Cirasuolo, Michele

    2016-04-01

    The KMOS Redshift One Spectroscopic Survey (KROSS) is an ESO-guaranteed time survey of 795 typical star-forming galaxies in the redshift range z = 0.8-1.0 with the KMOS instrument on the Very Large Telescope. In this paper, we present resolved kinematics and star formation rates for 584 z ˜ 1 galaxies. This constitutes the largest near-infrared Integral Field Unit survey of galaxies at z ˜ 1 to date. We demonstrate the success of our selection criteria with 90 per cent of our targets found to be H α emitters, of which 81 per cent are spatially resolved. The fraction of the resolved KROSS sample with dynamics dominated by ordered rotation is found to be 83 ± 5 per cent. However, when compared with local samples these are turbulent discs with high gas to baryonic mass fractions, ˜35 per cent, and the majority are consistent with being marginally unstable (Toomre Q ˜ 1). There is no strong correlation between galaxy averaged velocity dispersion and the total star formation rate, suggesting that feedback from star formation is not the origin of the elevated turbulence. We postulate that it is the ubiquity of high (likely molecular) gas fractions and the associated gravitational instabilities that drive the elevated star formation rates in these typical z ˜ 1 galaxies, leading to the 10-fold enhanced star formation rate density. Finally, by comparing the gas masses obtained from inverting the star formation law with the dynamical and stellar masses, we infer an average dark matter to total mass fraction within 2.2re (9.5 kpc) of 65 ± 12 per cent, in agreement with the results from hydrodynamic simulations of galaxy formation.

  2. In rich In{sub 1-x}Ga{sub x}N: Composition dependence of longitudinal optical phonon energy

    Energy Technology Data Exchange (ETDEWEB)

    Tiras, E. [School of Computer Science and Electronic Engineering, University of Essex, Wivenhoe Park, CO4 3SQ Colchester (United Kingdom); Faculty of Science, Department of Physics, Anadolu University, Yunus Emre Campus, 26470 Eskisehir (Turkey); Gunes, M.; Balkan, N. [School of Computer Science and Electronic Engineering, University of Essex, Wivenhoe Park, CO4 3SQ Colchester (United Kingdom); Schaff, W.J. [Department of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853 (United States)

    2010-01-15

    The composition dependence of longitudinal optical (LO) phonon energies in undoped and Mg-doped In{sub 1-x}Ga{sub x}N samples are determined using Raman spectroscopy in the range of Ga fraction from x = 0 to x = 56%. The LO phonon energy varies from 73 meV for InN to 83 meV for In{sub 1-x}Ga{sub x}N with 56% Ga. Independent measurements of temperature dependent mobility at high temperatures where LO phonon scattering dominates the transport were also used to obtain the LO phonon energy for x = 0 and x = 20%. The results obtained from the two independent techniques compare extremely well. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  3. Compositional dependence of Raman scattering and photoluminescence emission in Cu-Ga-Se films grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Grossberg, M., E-mail: mgross@staff.ttu.e [Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Krustok, J. [Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Siebentritt, S. [Universite du Luxembourg, 162a avenue de la Faiencerie, L-1511 Luxembourg (Luxembourg); Albert, J. [Helmholtz Centre Berlin, Glienicker Strasse 100, 14109 Berlin (Germany)

    2009-07-01

    This paper presents Raman scattering and photoluminescence (PL) analysis of polycrystalline Cu-Ga-Se films grown epitaxially on the GaAs substrate. In the compositional dependence of the Raman spectra of the CuGaSe{sub 2} films, the appearance of the ordered vacancy compounds (OVCs) CuGa{sub 3}Se{sub 5} and CuGa{sub 5}Se{sub 8} was observed. The dominating A{sub 1} Raman modes were detected at 185, 166 and 159 cm{sup -1}, respectively. The PL bands of CuGaSe{sub 2}, CuGa{sub 3}Se{sub 5} and CuGa{sub 5}Se{sub 8} at T=10 K were detected at 1.615, 1.72 and 1.76 eV, respectively. The dominating PL emission channel is the band-to-tail (BT) type recombination.

  4. Hydrothermal synthesis, structural elucidation, spectroscopic studies, thermal behavior and luminescence properties of a new 3-d compound: FeAlF2(C10H8N2)(HPO4)2(H2O)

    Science.gov (United States)

    Bouzidia, Nabaa; Salah, Najet; Hamdi, Besma; Ben Salah, Abdelhamid

    2017-04-01

    The study of metal phosphate has been a proactive field of research thanks to its applied and scientific importance, especially in terms of the development of optical devices such as solid state lasers as well as optical fibers. The present paper seeks to investigate the synthesis, crystal structure, elemental analysis and properties of FeAlF2(C10H8N2)(HPO4)2(H2O) compound investigated by spectroscopic studies (FT-IR and FT-Raman), thermal behavior and luminescence. The Hirshfeld surface analysis and 2-D fingerprint plot have been performed to explore the behavior of these weak interactions and crystal cohesion. This investigation shows that the molecules are connected by hydrogen bonds of the type Osbnd H⋯O and Osbnd H⋯F. In addition, the 2,2'‒bipyridine ligand plays a significant role in the construction of 3-D supramolecular framework via π‒π stacking. FT‒IR and FT‒Raman spectra were used so as to ease the responsibilities of the vibration modes of the title compound. The thermal analysis (TGA) study shows a mass loss evolution as a temperature function. Finally, the optical properties were evaluated by photoluminescence spectroscopy.

  5. K[AsW{sub 2}O{sub 9}], the first member of the arsenate–tungsten bronze family: Synthesis, structure, spectroscopic and non-linear optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, Evgeny V., E-mail: e.alekseev@fz-juelich.de [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, D-52428 Jülich (Germany); Institut für Kristallographie, RWTH Aachen, Jägerstraße 17–19 D-52066 Aachen (Germany); Felbinger, Olivier [Institut für Geowissenschaften, Universität Kiel, Ludewig-Meyn-Str. 10, D-24118 Kiel (Germany); Wu, Shijun [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, D-52428 Jülich (Germany); Institut für Geowissenschaften, Universität Kiel, Ludewig-Meyn-Str. 10, D-24118 Kiel (Germany); Malcherek, Thomas [Mineralogisch-Petrographisches Institut, Universität Hamburg, Grindelallee 48, 20146 Hamburg (Germany); Depmeier, Wulf [Institut für Geowissenschaften, Universität Kiel, Ludewig-Meyn-Str. 10, D-24118 Kiel (Germany); Modolo, Giuseppe [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, D-52428 Jülich (Germany); Gesing, Thorsten M. [Solid State Chemical Crystallography, Institute for Inorganic Chemistry, University Bremen, Leobener Straße/NW2, D-28359 Bremen (Germany); Krivovichev, Sergey V. [Department of Crystallography, Saint Petersburg State University, per. Dekabristov 16, Saint Petersburg (Russian Federation); Suleimanov, Evgeny V. [Faculty of Chemistry, Lobachevsky State University of Nizhny Novgorod, Gagarin Av. 23b, 603950 Nizhny Novgorod (Russian Federation); and others

    2013-08-15

    K[AsW{sub 2}O{sub 9}], prepared by high-temperature solid-state reaction, is the first member of the arsenate–tungsten bronze family. The structure of K[AsW{sub 2}O{sub 9}] is based on a 3-dimensional (3D) oxotungstate–arsenate framework with the non-centrosymmetric P2{sub 1}2{sub 1}2{sub 1} space group, a=4.9747(3) Å, b=9.1780(8) Å, c=16.681(2) Å. The material was characterized using X-ray diffraction, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Raman and infrared (IR) spectroscopic techniques. The results of DSC demonstrate that this phase is stable up to 1076 K. Second harmonic generation (SHG) measurements performed on a powder sample demonstrate noticeable (0.1 of LiIO{sub 3}) non-linear optical (NLO) activity. - Graphical abstract: K[AsW{sub 2}O{sub 9}], the first member of arsenate–tungsten bronze family exhibit new three dimensional structure type, significant thermal stability and NLO properties. Highlights: • K[AsW{sub 2}O{sub 9}], the first member of the arsenate–tungsten bronze family was synthesized with solid state reaction technique. • Structure of this phase was investigated with X-ray diffraction, IR and Raman spectroscopy and electron microscopy. • Thermal stability of the phase was determinate with DSC techniques. • NLO properties were investigated.

  6. Spectroscopic ellipsometry thin film and first-principles calculations of electronic and linear optical properties of [(C9H19NH3)2PbI2Br2] 2D perovskite

    Science.gov (United States)

    Abid, H.; Hlil, E. K.; Abid, Y.

    2017-03-01

    In this study we report results of first-principles density functional calculations using the full-potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2K code. We employed the generalized gradient approximation (GGA) for the exchange-correlation energy to calculate electronic and linear optical properties of the (C9H19NH3)2PbI2Br2 compound. The linear optical properties, namely, the real ε1 (ω) and imaginary ε2 (ω) parts of dielectric function, the refractive index n (ω) and the extinction coefficient k (ω) are calculated and compared with experimental spectroscopic ellipsometry spectra. The reflectivity R (ω) and electron energy loss function L (ω) are calculated too. Our calculations performed for band structure and density of states show that the valence band maximum and conduction band minimum are located at Γ point resulting in a direct band gap of about (Γv -Γc) of 2.42 eV in good agreement with the experimental data. The investigated compound has a large uniaxial anisotropy of the dielectric function of about 0.0739 and a negative birefringence at zero energy Δn (0) =-0.11.

  7. Electronic structure, Fermi surface topology and spectroscopic optical properties of LaBaCo{sub 2}O{sub 5.5} compound

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, A.H. [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, Pilsen 306 14 (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Al-Douri, Y. [Institute of Nano Electronic Engineering, University Malaysia Perlis, 01000 Kangar, Perlis (Malaysia); Khenata, R. [Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, Mascara 29000 (Algeria); Khan, Wilayat; Khan, Saleem Ayaz [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, Pilsen 306 14 (Czech Republic); Azam, Sikander, E-mail: sikander.physicst@gmail.com [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, Pilsen 306 14 (Czech Republic)

    2014-08-01

    We have investigated the electronic band structure, Fermi surface topology, chemical bonding and optical properties of LaBaCo{sub 2}O{sub 5.5} compound. The first-principle calculations based on density functional theory (DFT) by means of the full-potential linearized augmented plane-wave method were employed. The atomic positions of LaBaCo{sub 2}O{sub 5.5} compound were optimized by minimizing the forces acting on atoms. We employed the local density approximation (LDA), generalized gradient approximation (GGA) and Engel–Vosko GGA (EVGGA) to treat the exchange correlation potential by solving Kohn–Sham equations. Electronic structure and bonding properties are studied throughout the calculation of densities of states, Fermi surfaces and charge densities. Furthermore, the optical properties are investigated via the calculation of the dielectric tensor component in order to characterize the linear optical properties. Optical spectra are analyzed by means of the electronic structure, which provides theoretical understanding of the conduction mechanism of the investigated compound. - Highlights: • DFT-FPLAPW method used for calculating the properties of LaBaCo{sub 2}O{sub 5.5} compound. • This study shows that nature of the compound is metallic. • Crystallographic plane which shows covalent character of O–Co bond. • The optical properties were also calculated and analyzed. • The Fermi surface of LaBaCo{sub 2}O{sub 5.5} is composed of five bands crossing along Γ–Z direction.

  8. Synthesis, spectroscopic characterization, photochemical and photophysical properties and biological activities of ruthenium complexes with mono- and bi-dentate histamine ligand.

    Science.gov (United States)

    Cardoso, Carolina R; de Aguiar, Inara; Camilo, Mariana R; Lima, Márcia V S; Ito, Amando S; Baptista, Maurício S; Pavani, Christiane; Venâncio, Tiago; Carlos, Rose M

    2012-06-14

    The monodentate cis-[Ru(phen)(2)(hist)(2)](2+)1R and the bidentate cis-[Ru(phen)(2)(hist)](2+)2A complexes were prepared and characterized using spectroscopic ((1)H, ((1)H-(1)H)COSY and ((1)H-(13)C)HSQC NMR, UV-vis, luminescence) techniques. The complexes presented absorption and emission in the visible region, as well as a tri-exponential emission decay. The complexes are soluble in aqueous and non-aqueous solution with solubility in a buffer solution of pH 7.4 of 1.14 × 10(-3) mol L(-1) for (1R + 2A) and 6.43 × 10(-4) mol L(-1) for 2A and lipophilicity measured in an aqueous-octanol solution of -1.14 and -0.96, respectively. Photolysis in the visible region in CH(3)CN converted the starting complexes into cis-[Ru(phen)(2)(CH(3)CN)(2)](2+). Histamine photorelease was also observed in pure water and in the presence of BSA (1.0 × 10(-6) mol L(-1)). The bidentate coordination of the histamine to the ruthenium center in relation to the monodentate coordination increased the photosubstitution quantum yield by a factor of 3. Pharmacological studies showed that the complexes present a moderate inhibition of AChE with an IC(50) of 21 μmol L(-1) (referred to risvagtini, IC(50) 181 μmol L(-1) and galantamine IC(50) 0.006 μmol L(-1)) with no appreciable cytotoxicity toward to the HeLa cells (50% cell viability at 925 μmol L(-1)). Cell uptake of the complexes into HeLa cells was detected by fluorescence confocal microscopy. Overall, the observation of a luminescent complex that penetrates the cell wall and has low cytotoxicity, but is reactive photochemically, releasing histamine when irradiated with visible light, are interesting features for application of these complexes as phototherapeutic agents.

  9. Spectroscopic analysis of the impact of oxidative stress on the structure of human serum albumin (HSA) in terms of its binding properties

    Science.gov (United States)

    Maciążek-Jurczyk, M.; Sułkowska, A.

    2015-02-01

    Oxygen metabolism has an important role in the pathogenesis of rheumatoid arthritis (RA). Reactive oxygen species (ROS) are produced in the course of cellular oxidative phosphorylation and by activated phagocytic cells during oxidative bursts, exceed the physiological buffering capacity and result in oxidative stress. ROS result in oxidation of serum albumin, which causes a number of structural changes in the spatial structure, may influence the binding and cause significant drug interactions, particularly in polytherapy. During the oxidation modification of amino acid residues, particularly cysteine and methionine may occur. The aim of the study was to investigate the influence of oxidative stress on human serum albumin (HSA) structure and evaluate of possible alterations in the binding of the drug to oxidized human serum albumin (oHSA). HSA was oxidized by a chloramine-T (CT). CT reacts rapidly with sulfhydryl groups and at pH 7.4 the reaction was monitored by spectroscopic techniques. Modification of free thiol group in the Cys residue in HSA was quantitatively determined by the use of Ellman's reagent. Changes of albumin conformation were examined by comparison of modified (oHSA) and nonmodified human serum albumin (HSA) absorption spectra, emission spectra, red-edge shift (REES) and synchronous spectroscopy. Studies of absorption spectra indicated that changes in the value of absorbance associated with spectral changes in the region of 200-250 nm involve structural alterations in peptide backbone conformation. Synchronous fluorescence spectroscopy technique confirmed changes of position of tryptophanyl and tyrosyl residues fluorescent band caused by CT. Moreover analysis of REES effect allowed to observe structural changes caused by CT in the region of the hydrophobic pocket containing the tryptophanyl residue. Effect of oxidative stress on binding of anti-rheumatic drugs, sulfasalazine (SSZ) and sulindac (SLD) in the high and low affinity binding sites was

  10. Manganese binding properties of human calprotectin under conditions of high and low calcium: X-ray crystallographic and advanced electron paramagnetic resonance spectroscopic analysis.

    Science.gov (United States)

    Gagnon, Derek M; Brophy, Megan Brunjes; Bowman, Sarah E J; Stich, Troy A; Drennan, Catherine L; Britt, R David; Nolan, Elizabeth M

    2015-03-04

    The antimicrobial protein calprotectin (CP), a hetero-oligomer of the S100 family members S100A8 and S100A9, is the only identified mammalian Mn(II)-sequestering protein. Human CP uses Ca(II) ions to tune its Mn(II) affinity at a biologically unprecedented hexahistidine site that forms at the S100A8/S100A9 interface, and the molecular basis for this phenomenon requires elucidation. Herein, we investigate the remarkable Mn(II) coordination chemistry of human CP using X-ray crystallography as well as continuous-wave (CW) and pulse electron paramagnetic resonance (EPR) spectroscopies. An X-ray crystallographic structure of Mn(II)-CP containing one Mn(II), two Ca(II), and two Na(I) ions per CP heterodimer is reported. The CW EPR spectrum of Ca(II)- and Mn(II)-bound CP prepared with a 10:0.9:1 Ca(II):Mn(II):CP ratio is characterized by an unusually low zero-field splitting of 485 MHz (E/D = 0.30) for the S = 5/2 Mn(II) ion, consistent with the high symmetry of the His6 binding site observed crystallographically. Results from electron spin-echo envelope modulation and electron-nuclear double resonance experiments reveal that the six Mn(II)-coordinating histidine residues of Ca(II)- and Mn(II)-bound CP are spectroscopically equivalent. The observed (15)N (I = 1/2) hyperfine couplings (A) arise from two distinct classes of nitrogen atoms: the coordinating ε-nitrogen of the imidazole ring of each histidine ligand (A = [3.45, 3.71, 5.91] MHz) and the distal δ-nitrogen (A = [0.11, 0.18, 0.42] MHz). In the absence of Ca(II), the binding affinity of CP for Mn(II) drops by two to three orders of magnitude and coincides with Mn(II) binding at the His6 site as well as other sites. This study demonstrates the role of Ca(II) in enabling high-affinity and specific binding of Mn(II) to the His6 site of human calprotectin.

  11. Shell model and spectroscopic factors

    Energy Technology Data Exchange (ETDEWEB)

    Poves, P. [Madrid Univ. Autonoma and IFT, UAM/CSIC, E-28049 (Spain)

    2007-07-01

    In these lectures, I introduce the notion of spectroscopic factor in the shell model context. A brief review is given of the present status of the large scale applications of the Interacting Shell Model. The spectroscopic factors and the spectroscopic strength are discussed for nuclei in the vicinity of magic closures and for deformed nuclei. (author)

  12. Electronic structure of Ge-2 and Ge-2 and thermodynamic properties of Ge-2 from all electron ab initio investigations and Knudsen effusion mass spectroscopic measurements

    DEFF Research Database (Denmark)

    Shim, Irene; Baba, M. Sai; Gingerich, K.A.

    2002-01-01

    excited states are presented. Thermal functions based on the theoretically determined molecular parameters were used to derive the thermodynamic properties of the Ge-2 molecule from new mass spectrometric equilibrium data. The literature value for the dissociation energy of Ge-2 has been re...

  13. SO2-binding properties of cationic η6,η1-NCN-pincer arene ruthenium platinum complexes: spectroscopic and theoretical studies

    NARCIS (Netherlands)

    Bonnet, S.A.; van Lenthe, J.H.; van Dam, H.J.J.; van Koten, G.; Klein Gebbink, R.J.M.

    2011-01-01

    The SO2-binding properties of a series of h6,h1-NCN-pincer ruthenium platinum complexes (NCN = 2,6-bis[(dimethylamino)methyl]phenyl anion) have been studied by both UV-visible spectroscopy and theoretical calculations. When an electron-withdrawing [Ru(C5R5)]+ fragment (R = H or Me) is h6-coordinated

  14. SO2-binding properties of cationic η6,η1-NCN-pincer arene ruthenium platinum complexes: spectroscopic and theoretical studies

    NARCIS (Netherlands)

    Bonnet, S.A.; van Lenthe, J.H.; van Dam, H.J.J.; van Koten, G.; Klein Gebbink, R.J.M.

    2011-01-01

    The SO2-binding properties of a series of h6,h1-NCN-pincer ruthenium platinum complexes (NCN = 2,6-bis[(dimethylamino)methyl]phenyl anion) have been studied by both UV-visible spectroscopy and theoretical calculations. When an electron-withdrawing [Ru(C5R5)]+ fragment (R = H or Me) is h6-coordinated

  15. A new series of bis(ene-1,2-dithiolato)tungsten(IV), -(V), -(VI) complexes as reaction centre models of tungsten enzymes: preparation, crystal structures and spectroscopic properties.

    Science.gov (United States)

    Sugimoto, Hideki; Hatakeda, Kohei; Toyota, Kazuo; Tatemoto, Susumu; Kubo, Minoru; Ogura, Takashi; Itoh, Shinobu

    2013-03-07

    The carbomethoxy substituted dithiolene ligand (L(COOMe)) enabled us to develop a series of new bis(ene-1,2-dithiolato)tungsten complexes including W(IV)O, W(IV)(OSiBuPh(2)), W(VI)O(2), W(VI)O(OSiBuPh(2)) and W(VI)O(S) core structures. By using these tungsten complexes, a systematic study of the terminal monodentate ligand effects has been performed on the structural, spectroscopic properties and reactivity. The structure and spectroscopic properties of the tungsten complexes have also been compared to those of the molybdenum complexes coordinated by the same ligand to investigate the effects of the metal ion (W vs. Mo). X-ray crystallographic analyses of the tungsten(IV) complexes have revealed that the tungsten centres adopt a distorted square pyramidal geometry with a dithiolene ligand having an ene-1,2-dithiolate form. On the other hand, the dioxotungsten(VI) complex exhibits an octahedral structure consisting of the bidentate L(COOMe) and two oxo groups, in which π-delocalization was observed between the W(VI)O(2) and ene-1,2-dithiolate units. The tungsten(IV) and dioxotungsten(VI) complexes are isostructural with the molybdenum counter parts. DFT calculation study of the W(VI)O(S) complex has indicated that the W=S bond of 2.2 Å is close to the bond length between the tungsten centre and ambiguously assigned terminal monodentate atom in aldehyde oxidoreductase of the tungsten enzyme. Resonance Raman (rR) spectrum of the W(VI)O(S) complex has shown the two inequivalent L(COOMe) ligands with respect to their bonding interactions with the tungsten centre, reproducing the appearance of two ν(C=C) stretches in the rR spectrum of aldehyde oxidoreductase. Sulfur atom transfer reaction from the W(VI)O(S) complex to triphenylphosphines has also been studied kinetically to demonstrate that the tungsten complex has a lower reactivity by about one-order of magnitude, when compared with its molybdenum counterpart.

  16. Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te studied by variable angle spectroscopic ellipsometry between 0.75 and 6.24 eV

    Energy Technology Data Exchange (ETDEWEB)

    Yao, H.W.; Erickson, J.C. [Univ. of Nebraska, Lincoln, NE (United States)]|[Sandia National Labs., Livermore, CA (United States); Barber, H.B. [Univ. of Arizona, Tucson, AZ (United States); James, R.B.; Hermon, H. [Sandia National Labs., Livermore, CA (United States)

    1999-06-01

    Cadmium zinc telluride (CZT) is a leading technological material for room-temperature gamma-ray and x-ray detectors. Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te (CZT) were studied by variable angle spectroscopic ellipsometry (VASE). Measurements made by VASE were performed on CZT and CdTe samples in air at room temperature at multiple angles of incidence. A parametric function model was employed in the VASE analysis to determine the dielectric functions {epsilon} = {epsilon}{sub 1} + i{epsilon}{sub 2} in the range of 0.75 to 6.24 eV. A two-oscillator analytical model was used to describe the dielectric response of native oxides on CZT. Surface oxide optical properties and thickness on CZT were also determined in conjunction with the VASE measurement and analysis of a CdTe sample. Two samples of CZT of different oxide thicknesses were measured and their optical constants were coupled together in a multiple-sample, multiple-model VASE analysis to resolve correlations between fitting parameters. Effective medium approximation was used to describe the optical properties of the CZT oxide with roughness. A Kramers-Kronig self-consistency check of the real and imaginary parts of the Cd{sub 0.9}Zn{sub 0.1}Te dielectric functions was performed over the energy range 0.75 to 6.24 eV. A five-Lorentz-oscillator model was employed to describe the dielectric response of CZT in the range of 1.6 to 6.24 eV. Intensity transmission measurements were made on the Cd{sub 0.9}Zn{sub 0.1}Te and CdTe, showing the absorption energy band edges of {approximately}1.58 and 1.46 eV, respectively.

  17. Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te studied by variable angle spectroscopic ellipsometry between 0.75 and 6.24 eV

    Energy Technology Data Exchange (ETDEWEB)

    Ralph B. James

    2000-01-07

    Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te (CZT) were studied by variable angle spectroscopic ellipsometry (VASE). Measurements made by VASE were performed on CZT and CdTe samples in air at room temperature at multiple angles of incidence. A parametric function model was employed in the VASE analysis to determine the dielectric functions {var_epsilon}={var_epsilon}{sub 1} + i{var_epsilon}{sub 2} in the range of 0.75 to 6.24 eV. A two-oscillator analytical model was used to describe the dielectric response of native oxides on CZT. Surface oxide optical properties and thickness on CZT were also determined in conjunction with the VASE measurement and analysis of a CdTe sample. Two samples of CZT of different oxide thicknesses were measured and their optical constants were coupled together in a multiple-sample, multiple-model VASE analysis to resolve correlations between fitting parameters. Effective medium approximation (EMA) was used to describe the optical properties of the CZT oxide with roughness. A Kramers-Kronig self-consistency check of the real and imaginary parts of the Cd{sub 0.9}Zn{sub 0.1} dielectric functions was performed over the energy range 0.75 to 6.24 eV. A five-Lorentz-oscillator model was employed to describe the dielectric response of CZT in the range of 1.6 to 6.24 eV. Intensity transmission measurements were made on the Cd{sub 0.9}Zn{sub 0.1}Te and CdTe, showing the absorption energy band edges of {approximately} 1.58 and 1.46 eV, respectively.

  18. State-of-the-art ab initio potential energy curve for the xenon atom pair and related spectroscopic and thermophysical properties

    Science.gov (United States)

    Hellmann, Robert; Jäger, Benjamin; Bich, Eckard

    2017-07-01

    A new ab initio interatomic potential energy curve for two ground-state xenon atoms is presented. It is based on supermolecular calculations at the coupled-cluster level with single, double, and perturbative triple excitations [CCSD(T)] employing basis sets up to sextuple-zeta quality, which were developed as part of this work. In addition, corrections were determined for higher coupled-cluster levels up to CCSDTQ as well as for scalar and spin-orbit relativistic effects at the CCSD(T) level. A physically motivated analytical function was fitted to the calculated interaction energies and used to compute the vibrational spectrum of the dimer, the second virial coefficient, and the dilute gas transport properties. The agreement with the best available experimental data for the investigated properties is excellent; the new potential function is superior not only to previous ab initio potentials but also to the most popular empirical ones.

  19. Spectroscopic properties and cyclic voltammetry on a series of meso-tetra( p-alkylamidophenyl)porphyrin liquid crystals and their Mn complexes

    Science.gov (United States)

    Sun, Erjun; Shi, Yuhua; Zhang, Ping; Zhou, Mi; Zhang, Yihua; Tang, Xuexin; Shi, Tongshun

    2008-10-01

    A series of meso-tetra( p-alkylamidophenyl)porphyrin ligands and their manganese(III) complexes are reported in this paper. The mesomorphism was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM) and the results show that only the porphyrin ligands with long side chains show liquid crystalline behavior, and they exhibit a high phase transition temperature and a broad mesophase temperature span. Furthermore, we investigated the properties of the compounds by means of UV-vis spectra, infrared spectra, Resonance Raman spectra, fluorescence spectra, thermal analysis and cyclic voltammetry. These studies indicate that the length of side chains has little effect on the properties of porphyrin compounds. According to thermal studies, the decomposition of porphyrin ligand and Mn complex is a continuous process.

  20. Evaluation of the structural, electronic, topological and vibrational properties of N-(3,4-dimethoxybenzyl)-hexadecanamide isolated from Maca (Lepidium meyenii) using different spectroscopic techniques

    Science.gov (United States)

    Chain, Fernando; Iramain, Maximiliano Alberto; Grau, Alfredo; Catalán, César A. N.; Brandán, Silvia Antonia

    2017-01-01

    N-(3,4-dimethoxybenzyl)-hexadecanamide (DMH) was characterized by using Fourier Transform infrared (FT-IR) and Raman (FT-Raman), Ultraviolet- Visible (UV-Visible) and Hydrogen and Carbon Nuclear Magnetic Resonance (1H and 13C NMR) spectroscopies. The structural, electronic, topological and vibrational properties were evaluated in gas phase and in n-hexane employing ONIOM and self-consistent force field (SCRF) calculations. The atomic charges, molecular electrostatic potentials, stabilization energies and topological properties of DMH were analyzed and compared with those calculated for N-(3,4-dimethoxybenzyl)-acetamide (DMA) in order to evaluate the effect of the side chain on the properties of DMH. The reactivity and behavior of this alkamide were predicted by using the gap energies and some descriptors. Force fields and the corresponding force constants were reported for DMA only in gas phase and n-hexane due to the high number of vibration normal modes showed by DMH, while the complete vibrational assignments are presented for DMA and both forms of DMH. The comparisons between the experimental FTIR, FT-Raman, UV-Visible and 1H and 13C NMR spectra with the corresponding theoretical ones showed a reasonable concordance.

  1. Interactions fulvate-metal (Zn²⁺, Cu²⁺ and Fe²⁺): theoretical investigation of thermodynamic, structural and spectroscopic properties.

    Science.gov (United States)

    Bertoli, Alexandre C; Garcia, Jerusa S; Trevisan, Marcello G; Ramalho, Teodorico C; Freitas, Matheus P

    2016-04-01

    The use of theoretical calculation to determine structural properties of fulvate-metal complex (zinc, copper and iron) is here related. The species were proposed in the ratio 1:1 and 2:1 for which the molecular structure was obtained through the semi-empirical method PM6. The calculation of thermodynamic stability ([Formula: see text]) predicted that the iron complex were more exo-energetic. Metallic ions were coordinated to the phtalate groups of the model-structure of fulvic acid Suwannee River and the calculations of vibrational frequencies suggested that hydrogen bonds may help on the stability of the complex formation.

  2. Effect of heat treatment on structural and Mössbauer spectroscopic properties of coprecipitated Mn0.5Ni0.5Fe2O4 ferrite nanoparticles

    Science.gov (United States)

    Srinivas, Ch.; Tirupanyam, B. V.; Meena, S. S.; Babu, Ch. Seshu; Sastry, D. L.

    2015-06-01

    Results obtained in a systamatic study by X-ray diffraction and Mösssbauer spectroscopy on the structural and magnetic properties on Mn0.5Ni0.5Fe2O4 ferrite nanoparticles heat treated at 200 °C, 500 °C and 800 °C are reported. Average crystallite sizes are estimated to be in the range (2.6nm - 12.8nm). It is observed that crystallite sizes increase with increase in sintering temperature and random variation in lattice parameter was observed. At relatively low sintering temperatures the samples exhibit superparamagnetism and complete ferrite phase was observed at higher heat treatment.

  3. Vibrational spectroscopic and thermo dynamical property studies, Fukui functions, HOMO-LUMO, NLO, NBO and crystal structure analysis of a new Schiff base bearing phenoxy-imine group

    Science.gov (United States)

    Ceylan, Ümit; Çapan, Ali; Yalçın, Şerife Pınar; Sönmez, Mehmet; Aygün, Muhittin

    2017-05-01

    This study covers the synthesis, structural characterization by experimental FT-IR, 1H NMR and 13C NMR, UV-Vis and single crystal XRD and comparison with theoretical calculations of a Schiff base compound bearing phenoxy group, C34H28N2O4 by using the DFT method 6-311G(d,p) basis set. The molecular geometry, the dipole moments, electrostatic potential, vibrational frequencies, HOMO-LUMO energy were calculated. NBO, NLO, thermodynamic properties and Fukui function were studied. In this work, theoretical values show good agreement with experimental values.

  4. Composition Dependence of Surface Phonon Polariton Mode in Wurtzite InxGa1-xN (0 ≤ x ≤ 1) Ternary Alloy

    Institute of Scientific and Technical Information of China (English)

    S. S. Ng; Z. Hassan; H. Abu Hassan

    2008-01-01

    @@ We present a theoretical study on the composition dependence of the surface phonon polariton (SPP) mode in wurtzite structure α-Inx Ga1-xN ternary alloy over the whole composition range. The SPP modes are obtained by the theoretical simulations by means of an anisotropy model. The results reveal that the SPP mode of α-InxGa1-Xn semiconductors exhibits one-mode behaviour. From these data, composition dependence of the SPP mode with bowing parameter of -28.9 cm-1 is theoretically obtained.

  5. Synthesis, spectroscopic, physicochemical properties and binding site analysis of 4-(1H-phenanthro[9,10-d]-imidazol-2-yl)-benzaldehyde fluorescent probe for imaging in cell biology: Experimental and theoretical study.

    Science.gov (United States)

    Krawczyk, Przemysław; Jędrzejewska, Beata; Pietrzak, Marek; Janek, Tomasz

    2016-11-01

    In this study, the 4-(1H-phenanthro[9,10-d]-imidazol-2-yl)-benzaldehyde (PB1) was investigated as a fluorescent dye. For this reason, the spectroscopic properties in different solvents were thoroughly studied. The experimental data were supported by quantum-chemical calculations using density functional theory. Measurements and theoretical calculations showed that PB1 dye is characterized by the non-monotonic solvatochromism, strongly polar charge transfer excited state, large Stokes' shift, high fluorescence quantum yield and high fluorescence lifetime. Simulations using AutoDock presented in this study, showed that after conjugation with Concanavalin A in the active site with LYS116, the PB1 possesses the highest probability of binding affinity. The interaction between the PB1 dye and the Concanavalin A lectin has been investigated by circular dichroism spectroscopy. Conventional fluorescence microscopy imaging of Candida albicans and Yarrowia lipolytica cells, incubated with the PB1-Concanavalin A, was demonstrated. Results show that the PB1 dye is a photostable low molecular weight fluorescent probe, which emits a blue fluorescence. The results of this study have implications for designing PB1-protein conjugate as a valuable alternative to commercial probes designed for cellular labeling in biological and biomedical research. Calculated LogP value together with LogBCF show that PB1-protein conjugate is a valuable alternative to commercial probes designed for cellular labeling in biological and biomedical research. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. The influence of nickel ions on spectroscopic and magnetic properties of PbO-Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3} glass system

    Energy Technology Data Exchange (ETDEWEB)

    Satyanarayana, T; Rao, P Venkateswara; Rao, N Narasimha; Rambabu, M; Kumar, V Ravi, E-mail: vrksurya@rediffmail.com [Department of Physics, Acharya Nagarjuna University Nuzvid Campus - 521 201, A.P. (India)

    2009-07-15

    PbO-Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3} glasses mixed with different concentrations of NiO (ranging from 0 to 2.0 mol %) have been prepared by melt quenching technique and their spectroscopic properties viz., optical absorption and infrared transmission have been investigated. The optical absorption spectra of these glasses indicated that Ni{sup 2+} ions exist both in octahedral and tetrahedral sites. The IR spectral studies have revealed that the glasses containing NiO beyond 1.0 mol %, nickel ions mostly occupy octahedral positions, act as modifiers and induce higher degree of disorder in the glass network. The magnetic susceptibility studies indicated that a gradual decrease of the effective magnetic moment from 4.21 {mu}{sub B} (for sample N{sub 10}) to 2.91 {mu}{sub B} (for sample N{sub 20}); from this result, it is concluded that there is a gradual transformation of Ni{sup 2+} ions from the tetrahedral sites to the octahedral sites as the concentration of NiO is increased beyond 1.0 mol %.

  7. Spectroscopic studies of ion implanted PPV films

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, C. (Cavendish Lab., Univ. of Cambridge (United Kingdom)); Friend, R.H. (Cavendish Lab., Univ. of Cambridge (United Kingdom)); Sarnecki, G.J. (Cavendish Lab., Univ. of Cambridge (United Kingdom)); Lucas, B. (LEPOFI, Faculte des Sciences, 87 - Limoges (France)); Moliton, A. (LEPOFI, Faculte des Sciences, 87 - Limoges (France)); Ratier, B. (LEPOFI, Faculte des Sciences, 87 - Limoges (France)); Belorgeot, C. (Lab. de Physique Moleculaire, Faculte des Sciences, 87 - Limoges (France))

    1993-03-15

    The main results of the spectroscopic analyses (infrared and ultraviolet - visible - near infrared) carried out on PPV films before and after ion implantation with halogen and alkali ions are presented in this paper. The influence of both ions nature and implantation parameters on optical properties of this polymer have been pointed out and the appearance of a weak band due to doping has been observed by infrared spectroscopy. (orig.)

  8. In situ FTIR spectroscopic assessment of methylbutynol catalytic conversion products in relation to the surface acid-base properties of systematically modified aluminas

    Science.gov (United States)

    Mekhemer, Gamal A. H.; Zaki, Mohamed I.

    2016-10-01

    The present investigation was designed to assess the credibility of methylbutynol (MBOH) as an infrared (IR) reactive probe molecule for surface acid-base properties of metal oxides. Accordingly, pure alumina was systematically modified with varied amounts (0.5-10 wt.%) of K+ or SO42 - additives. Then, the influence of nature and amount of the additive on the following alumina properties were examined: (i) bulk composition and structure by X-ray powder diffractometry and ex-situ IR spectroscopy, (ii) surface area and net charge by N2 sorptiometry and pH-metry, respectively, and (iii) nature and strength of exposed surface acid sites by in-situ IR spectroscopy of adsorbed pyridine at ambient and higher temperatures. Results obtained were correlated with IR-identified product distribution of MBOH catalytic decomposition/conversion at 200 °C. It is thereby concluded that MBOH is superior to conventional IR inactive probe molecules in gauging sensitively the prevailing acid or base character, availability of base sites, relative population of Bronsted to Lewis acid sites, and strength and reactivity of the sites exposed on metal oxide surfaces. Hence, all that is needed to get this information is to handle IR spectra taken from the gas phase, a task that is experimentally much more accessible than taking spectra from adsorbed species of irreactive probe molecules.

  9. Spectroscopic and laser properties of BeLaAl11O19 single crystals doped with Cr3+, Ti3+, and Nd3+ ions

    Science.gov (United States)

    Pestryakov, Efim V.; Petrov, V. V.; Trunov, V. I.; Kirpichnikov, A. V.; Alimpiev, A. I.

    2001-03-01

    The new laser crystals BeLaAl11O19 doped with Cr3+, Ti3+ and Nd3+ ions were grown by the Czochralski technique. The absorption and fluorescence spectra of impurity ions are reported and the temperature dependence of the fluorescence lifetime are described. The laser properties of these ions were investigated. The laser action has been achieved on 4F3/2-4I11/2 (1052 nm) transition of Nd3+ -ions under selective laser pumping. The physical properties of BeLaAl11O19 crystal were studied: the values of all independent component of elastic constant tensor were determined. On the base of a number of dynamic parameters of crystals, such as Young's modulus, the shear modulus, the volume elasticity modulus and Poisson's factor, Debye temperature and specific heat capacity were calculated. The investigation show that the BeLaAl11O19 is a promising host for a creature the new solid state laser media.

  10. FT-IR, FT-Raman and UV spectroscopic investigation, electronic properties, electric moments, and NBO analysis of anethole using quantum chemical calculations.

    Science.gov (United States)

    Sinha, L; Prasad, O; Chand, S; Sachan, A K; Pathak, S K; Shukla, V K; Karabacak, M; Asiri, A M

    2014-12-10

    FT-IR and FT-Raman spectra of anethole (1-Methoxy-4-(1-propenyl)benzene), a flavoring agent of commercial value, have been recorded in the regions 4000-400 and 4000-100cm(-1) respectively. The structure of the title molecule has been optimized and the structural parameters have been calculated by DFT/B3LYP method with 6-311++G(d,p) basis set. The fundamental vibrational wavenumbers as well as their intensities were calculated and a good agreement between observed and scaled calculated wavenumbers has been achieved. UV-Vis spectrum of the title compound was recorded in the region 200-500nm and the electronic properties such as HOMO and LUMO energies and associated energy gap were calculated by Time dependent-density functional theory (TD-DFT) approach. Nonlinear optical (NLO) study divulges the nonlinear properties of the molecule. Stability of the title molecule arising from hyper-conjugative interactions and charge delocalization has been investigated using natural bond orbital (NBO) analysis. The theoretical results were found to be in coherence with the measured experimental data. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Spectroscopic studies of copper enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, D.M.; Moog, R.; Zumft, W.; Koenig, S.H.; Scott, R.A.; Cote, C.E.; McGuirl, M.

    1986-05-01

    Several spectroscopic methods, including absorption, circular dichroism (CD), magnetic CD (MCD), X-ray absorption, resonance Raman, EPR, NMR, and quasi-elastic light-scattering spectroscopy, have been used to probe the structures of copper-containing amine oxidases, nitrite reductase, and nitrous oxide reductase. The basic goals are to determine the copper site structure, electronic properties, and to generate structure-reactivity correlations. Collectively, the results on the amine oxidases permit a detailed model for the Cu(II) sites in these enzymes to be constructed that, in turn, rationalizes the ligand-binding chemistry. Resonance Raman spectra of the phenylhydrazine and 2,4-dinitrophenyl-hydrazine derivatives of bovine plasma amine oxidase and models for its organic cofactor, e.g. pyridoxal, methoxatin, are most consistent with methoxatin being the intrinsic cofactor. The structure of the Cu(I) forms of the amine oxidases have been investigated by X-ray absorption spectroscopy (XAS); the copper coordination geometry is significantly different in the oxidized and reduced forms. Some anomalous properties of the amine oxidases in solution are explicable in terms of their reversible aggregation, which the authors have characterized via light scattering. Nitrite and nitrous oxide reductases display several novel spectral properties. The data suggest that new types of copper sites are present.

  12. Unraveling the composition dependence of the martensitic transformation temperature: A first-principles study of Ti-Ta alloys

    Science.gov (United States)

    Chakraborty, Tanmoy; Rogal, Jutta; Drautz, Ralf

    2016-12-01

    The martensitic start temperature Ms is one of the key characteristics of shape memory materials. High-temperature shape memory alloys are a special class of materials where transformation temperatures between the martensite and austenite phase above 373 K are desirable. For the design of new high-temperature shape memory alloys it is therefore important to understand and predict the dependence of Ms on the composition of the material. Using density functional theory in combination with the quasiharmonic Debye model, we evaluate the different contributions to the free energy to determine the transition temperature T0 over a wide range of compositions in Ti-Ta alloys. Our approach provides physical insight into the various contributions that explain the strong composition dependence of Ms that is observed experimentally. Based on our calculations, we identify the relative phase stability at T =0 K and the vibrational entropy difference between the involved phases as critical parameters to predict changes in T0. We propose a simple, one-dimensional descriptor to estimate the transition temperature that can be used in the identification of new alloys suitable for high-temperature shape memory applications.

  13. Composition dependent multiple structural transformations of myoglobin in aqueous ethanol solution: A combined experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, R.; Samajdar, R. N.; Bhattacharyya, Aninda Jiban; Bagchi, B., E-mail: bbagchi@sscu.iisc.ernet.in [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012 (India)

    2015-07-07

    Experimental studies (circular dichroism and ultra-violet (UV) absorption spectra) and large scale atomistic molecular dynamics simulations (accompanied by order parameter analyses) are combined to establish a number of remarkable (and unforeseen) structural transformations of protein myoglobin in aqueous ethanol mixture at various ethanol concentrations. The following results are particularly striking. (1) Two well-defined structural regimes, one at x{sub EtOH} ∼ 0.05 and the other at x{sub EtOH} ∼ 0.25, characterized by formation of distinct partially folded conformations and separated by a unique partially unfolded intermediate state at x{sub EtOH} ∼ 0.15, are identified. (2) Existence of non-monotonic composition dependence of (i) radius of gyration, (ii) long range contact order, (iii) residue specific solvent accessible surface area of tryptophan, and (iv) circular dichroism spectra and UV-absorption peaks are observed. Interestingly at x{sub EtOH} ∼ 0.15, time averaged value of the contact order parameter of the protein reaches a minimum, implying that this conformational state can be identified as a molten globule state. Multiple structural transformations well known in water-ethanol binary mixture appear to have considerably stronger effects on conformation and dynamics of the protein. We compare the present results with studies in water-dimethyl sulfoxide mixture where also distinct structural transformations are observed along with variation of co-solvent composition.

  14. Photoacoustic Spectroscopic Study of Optical Properties of hbox {Cu}2hbox {GeTe}3 in Temperature Range from 80 K to 300 K

    Science.gov (United States)

    Deviprasadh, P. S.; Madhuri, W.; Verma, A. S.; Sarkar, B. K.

    2016-05-01

    We used photoacoustic spectroscopy to investigate the optical properties of hbox {Cu}2hbox {GeTe}3. The temperature dependence of the bandgap energy was evaluated from optical absorption spectra obtained in the photon energy range of 0.76 eV to 0.81 eV between 80 K and 300 K. We used the empirical and semi-empirical models of Varshni, Viña, and Pässler to describe the observed bandgap shrinkage in this compound. The Debye temperature and effective phonon temperature of the compound were estimated to be approximately 227.4 K and 151.6 K, respectively. Thus, the temperature dependence of the bandgap is mediated by acoustic phonons.

  15. DFT/TD-DFT study on spectroscopic properties of zinc(II, nickel(II, and palladium(II metal complexes with a thiourea derivative

    Directory of Open Access Journals (Sweden)

    Wang Xin

    2016-01-01

    Full Text Available The geometries, electronic structures, and spectral properties of three metal complexes Zn(C10H12N3OS2 (1, Ni(C10H12N3OS2 (2, and Pd(C10H12N3OS2 (3 with N-(2-pyridinylmorpholine-4-carbothioamide as a ligand are investigated by means of DFT (density functional theory and TD-DFT (time-dependent density functional theory methods. Complex 1 is a distorted tetrahedral geometry, while complexes 2 and 3 present a distorted square-planar coordination environment. In the simulated range, the spectrum of complex 1 has five obvious absorption peaks and one of them has the strongest intensity. The latter two complexes have one more absorption peak and shoulder peak with the similar intensity. Moreover, the strongest peaks of complexes 2.

  16. Spectroscopic and Physical Properties of Mn2+ spin probe in ROP2O5-ZnO-Pb3O4 (R=Li, Na and K Glasses

    Directory of Open Access Journals (Sweden)

    S. Sreehari Sastry

    2015-04-01

    Full Text Available RO-P2O5-ZnO-Pb3O4 (R=Li, Na and K glasses containing 0.1concentrations of MnO have been prepared. The structural, optical and physical properties of prepared glasses are studied by XRD, UV-Visible, EPR and FTIR techniques. The nature of local symmetry and structural information of the neighboring atoms of dopant ions (Mn2+ in the host matrix have been understood by evaluating the crystal field strength (Dq and Racah (B & C parameters. The combined analysis of optical absorption and EPR spectroscopy has indicated that the manganese ions exist in Mn2+ (in octahedral local coordination sites. FTIR results showed that PO4 are the main structural unit of the glass system and the manganese ions are located in the glass matrix network.

  17. Synthesis, structural and spectroscopic properties of acentric triple molybdate Cs{sub 2}NaBi(MoO{sub 4}){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Savina, A.A. [Laboratory of Oxide Systems, Baikal Institute of Nature Management, SB RAS, Ulan-Ude 670047 (Russian Federation); Department of Chemistry, Buryat State University, Ulan-Ude 670000 (Russian Federation); Atuchin, V.V., E-mail: atuchin@isp.nsc.ru [Laboratory of Optical Materials and Structures, Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090 (Russian Federation); Functional Electronics Laboratory, Tomsk State University, Tomsk 634050 (Russian Federation); Laboratory of Semiconductor and Dielectric Materials, Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Solodovnikov, S.F. [Laboratory of Crystal Chemistry, Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Solodovnikova, Z.A. [Laboratory of Crystal Chemistry, Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Krylov, A.S. [Laboratory of Molecular Spectroscopy, Kirensky Institute of Physics, SB RAS, Krasnoyarsk 660036 (Russian Federation); Maximovskiy, E.A. [Laboratory of Epitaxial Layers, Nikolaev Institute of Inorganic Chemistry, SB RAS, Novosibirsk 630090 (Russian Federation); Laboratory of Research Methods of Composition and Structure of Functional Materials, Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Molokeev, M.S. [Laboratory of Crystal Structure, Kirensky Institute of Physics, SB RAS, Krasnoyarsk 660036 (Russian Federation); Oreshonkov, A.S [Laboratory of Molecular Spectroscopy, Kirensky Institute of Physics, SB RAS, Krasnoyarsk 660036 (Russian Federation); Department of Photonics and Laser Technology, Siberian Federal University, Krasnoyarsk 660079 (Russian Federation); Pugachev, A.M. [Laboratory of Condenced Matter Spectroscopy, Institute of Automation and Electrometry, SB RAS, Novosibirsk 90, 630090 (Russian Federation); and others

    2015-05-15

    New ternary molybdate Cs{sub 2}NaBi(MoO{sub 4}){sub 3} is synthesized in the system Na{sub 2}MoO{sub 4}–Cs{sub 2}MoO{sub 4}–Bi{sub 2}(MoO{sub 4}){sub 3}. The structure of Cs{sub 2}NaBi(MoO{sub 4}){sub 3} of a new type is determined in noncentrosymmetric space group R3c, a=10.6435(2), c=40.9524(7) Å, V=4017.71(13) Å{sup 3}, Z=12 in anisotropic approximation for all atoms taking into account racemic twinning. The structure is completely ordered, Mo atoms are tetrahedrally coordinated, Bi(1) and Bi(2) atoms are in octahedra, and Na(1) and Na(2) atoms have a distorted trigonal prismatic coordination. The Cs(1) and Cs(2) atoms are in the framework cavities with coordination numbers 12 and 10, respectively. No phase transitions were found in Cs{sub 2}NaBi(MoO{sub 4}){sub 3} up to the melting point at 826 K. The compound shows an SHG signal, I{sub 2w}/I{sub 2w}(SiO{sub 2})=5 estimated by the powder method. The vibrational properties are evaluated by Raman spectroscopy, and 26 narrow lines are measured. - Graphical abstract: - Highlights: • The crystal structure of Cs{sub 2}NaBi(MoO{sub 4}){sub 3} is defined. • The molybdate Cs{sub 2}NaBi(MoO{sub 4}){sub 3} is stable up to melting point at 826 K. • Vibrational properties of Cs{sub 2}NaBi(MoO{sub 4}){sub 3} are evaluated by Raman spectroscopy.

  18. Spectroscopic and dielectric properties of crystallized PbO-Sb{sub 2}O{sub 3}-As{sub 2}O{sub 3}:NiO glass system

    Energy Technology Data Exchange (ETDEWEB)

    Padmanabham, A.; Gandhi, Y.; Satyanarayana, T. [Department of Physics, Acharya Nagarjuna University-Nuzvid Campus, Nuzvid 521201, A.P. (India); Veeraiah, N., E-mail: nvr8@rediffmail.co [Department of Physics, Acharya Nagarjuna University-Nuzvid Campus, Nuzvid 521201, A.P. (India)

    2009-11-20

    Glasses of the composition 40PbO-(20 - x)Sb{sub 2}O{sub 3}-40As{sub 2}O{sub 3} were crystallized with different concentrations of NiO (x) ranging from 0 to 1.5 mol%. The samples were characterized by X-ray diffraction, scanning electron microscopy and differential thermal analysis techniques. The X-ray diffraction and the scanning electron microscopic studies have revealed the presence of NiSb{sub 2}O{sub 6}, NiAs{sub 2}O{sub 4}, Ni{sub 2}As{sub 2}O{sub 7}, Pb{sub 5}Sb{sub 2}O{sub 8}, PbSb{sub 2}O{sub 6}, Pb{sub 5}Sb{sub 4}O{sub 11} crystalline phases in these samples. Spectroscopic (IR and optical absorption), magnetic and dielectric studies have been investigated. The IR spectral studies have pointed out the glass ceramic network is composed of conventional AsO{sub 3} and SbO{sub 3} structural units; these studies have further indicated that the concentration of symmetrical vibrations of above structural groups decrease with increase in the concentration of NiO beyond 0.8 mol%. The analysis of the results of optical absorption, magnetic properties and dielectric properties has indicated that there is a gradual transformation of Ni{sup 2+} ions from octahedral to tetrahedral positions when the concentration of the crystallizing agent NiO is increased beyond 0.8 mol%. From these results it is also assessed that the glass crystallized with about 0.8 mol% of NiO is more suitable for getting maximum luminescence efficiency in the NIR region.

  19. Vibrational spectroscopic analysis of cyanopyrazine-2-carboxamide derivatives and investigation of their reactive properties by DFT calculations and molecular dynamics simulations

    Science.gov (United States)

    Beegum, Shargina; Mary, Y. Sheena; Varghese, Hema Tresa; Panicker, C. Yohannan; Armaković, Stevan; Armaković, Sanja J.; Zitko, Jan; Dolezal, Martin; Van Alsenoy, C.

    2017-03-01

    Using density functional theory technique in the B3LYP approximation and cc-pVDZ (5D, 7F) basis set, the molecular structural parameters and vibrational wave numbers of two cyanopyrazine-2-carboxamide derivatives have been investigated. On the basis of potential energy distribution detailed vibrational assignments of observed FT-IR and FT-Raman bands have been proposed. Using molecular electrostatic potential map relative reactivities towards electrophilic and nucleophilic attack are predicted. The first and second hyperpolarizabilities are calculated and the first hyperpolarizability of the title compounds are greater than that of the standard NLO material urea. Molecular studies reveal that the predicted binding affinities of the best poses were -8.7 kcal/mol for BACPC, -9.0 kcal/mol for CBACPC, and -8.8 kcal/mol for the original inhibitor. Efforts were made in order to investigate local reactivity properties of title compounds as well. In order to do so we have calculated average local ionization energy (ALIE) surfaces, Fukui functions, bond dissociation energies (BDE) (within the framework of DFT calculations) and radial distribution functions (RDF) (within the molecular dynamics simulations). ALIE surfaces and Fukui functions gave us initial information on the site reactivity towards electrophilic and nucleophilic attacks. BDE indicated locations that might be prone to autoxidation mechanism, while RDF indicated which atoms of title molecules are having pronounced interactions with water.

  20. Synthesis, aggregation and spectroscopic studies of novel water soluble metal free, zinc, copper and magnesium phthalocyanines and investigation of their anti-bacterial properties

    Science.gov (United States)

    Bayrak, Rıza; Akçay, Hakkı Türker; Beriş, Fatih Şaban; Şahin, Ertan; Bayrak, Hacer; Demirbaş, Ümit

    2014-12-01

    In this study, novel phthalonitrile derivative (3) was synthesized by the reaction between 4-nitrophthalonitrile (2) and a triazole derivative (1) containing pyridine moiety. Crystal structure of compound (3) was characterized by X-ray diffraction. New metal free and metallo-phthalocyanine complexes (Zn, Cu, and Mg) were synthesized using the phthalonitrile derivative (3). Cationic derivatives of these phthalocyanines (5, 7, 9, and 11) were prepared from the non-ionic phthalocyanines (4, 6, 8, and 10). All proposed structures were supported by instrumental methods. The aggregation behaviors of the phthalocyanines (4-11) were investigated in different solvents such as dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), chloroform and water. Water soluble cationic Pcs (5, 7, 9, and 11) aggregated in water and sodium dodecyl sulfate was used to prevent the aggregation. The second derivatives of the UV-Vis spectra of aggregated Pcs were used for analyzing the Q and B bands of aggregated species. Thermal behaviors of the phthalocyanines were also studied. In addition, anti-bacterial properties of the phthalocyanines were investigated. We used four gram negative and two gram positive bacteria to determine antibacterial activity of these compounds. Compound 7 has the best activity against the all bacteria with 125 μg/mL of MIC value. Compounds 4, 6, and 10 have the similar effect on the bacteria with 250 μg/mL of MIC value.

  1. DFT studies on antioxidant mechanisms, electronic properties, spectroscopic (FT-IR and UV) and NBO analysis of C-glycosyl flavone, an isoorientin

    Science.gov (United States)

    Deepha, V.; Praveena, R.; Sadasivam, K.

    2015-02-01

    The relationship between structure and electronic properties of isoorientin, a C-glycoside flavone is investigated to relate its radical scavenging activity using molecular descriptors. To elucidate the antioxidant activity of polyphenolics, three mechanisms namely hydrogen atom transfer (HAT), single electron transfer-proton transfer (SET-PT) and sequential proton-loss electron-transfer (SPLET) are employed. In gas-phase, Osbnd H bond dissociation enthalpies (BDE), ionization potential (IP), proton dissociation enthalpies (PDE), proton affinity (PA) and electron transfer enthalpy (ETE) are computed and correlated relevant to antioxidant potency of the title compound employing DFT/6-311G(d,p) protocol. The theoretically simulated FT-IR and the UV-visible absorption spectra have been compared with the experimental data. Based on the absorbed UV spectra and TD-DFT calculations, assignment of the absorption bands are carried out. In addition, formation of intramolecular hydrogen bond and most possible interaction sites are explained by using natural bond orbital (NBO) analysis.

  2. Synthesis, structure, spectroscopic and transport properties of (Ba{sub 1{minus}x}Sr{sub x})NbO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Jaca, J.; Santos, J.; Insausti, M.; Arriortua, M.I.; Rojo, T. [Univ. del Pais Vasco, Bilbao (Spain)

    1996-12-01

    Oxides of the (Ba{sub 1{minus}x}Sr{sub x})NbO{sub 3} system (x = 0, 0.1, 0.4, 0.5, 0.7, and 1.0) have been synthesized by a solid-state reaction technique with zirconium metal. The oxides with x = 0, 0.1, 0.5, 0.7, and 1.0 present a simple cubic perovskite structure while a distorted perovskite is observed in the oxide with x = 0.4. Infrared spectra showed the presence of two absorption maxima in the case of the cubic perovskites and only one for the distorted perovskite. The observed vibration modes have been associated with stretching vibration modes of a [NbO{sub 6}] octahedral entity. The substitution of barium by strontium influences the transport properties specially in the case of the (Ba{sub 0.6}Sr{sub 0.4})NbO{sub 3} oxide.

  3. Effects of salt concentration and pH on structural and functional properties of Lactobacillus acidophilus: FT-IR spectroscopic analysis.

    Science.gov (United States)

    Gandhi, Akanksha; Shah, Nagendra P

    2014-03-03

    The effects of sodium chloride concentration and varying pH levels on the structural and functional properties of Lactobacillus acidophilus were investigated. Reconstituted skim milk was inoculated with Lb. acidophilus at varying salt concentrations (0, 1, 2, 5 and 10% NaCl) and pH levels (4.0, 5.0 and 6.0) and ACE-inhibitory activity and proteolytic activity were determined and the viable cell count was enumerated after 24h of fermentation at 37 °C. The degree of proteolysis exhibited an increase with higher salt concentration at pH 5.0 and 6.0. ACE-inhibitory activity was found to be the highest at pH 5.0 at all salt concentrations. Fourier transform infrared spectroscopy results demonstrated significant changes occurring beyond 2% NaCl particularly at low pH (4.0). The findings revealed that significant changes occurred in amide I and amide III regions when Lb. acidophilus was subjected to varying salt concentrations.

  4. Vibrational spectroscopic study, structural analysis, photophysical properties and theoretical calculations of cis-(±)-2,4,5-tris(pyridin-2-yl)imidazoline

    Science.gov (United States)

    Baldenebro-López, Jesús; Báez-Castro, Alberto; Glossman-Mitnik, Daniel; Höpfl, Herbert; Cruz-Enríquez, Adriana; Miranda-Soto, Valentín; Parra-Hake, Miguel; Campos-Gaxiola, José J.

    2017-02-01

    cis-(±)-2,4,5-tris(pyridin-2-yl)imidazoline has been fully characterized by FT-IR, FT-Raman, UV-Vis and fluorescence spectroscopy, one- and two-dimensional NMR spectroscopy (1H, 1H-1H gCOSY, 1H-1H gNOESY,13C{1H} ATP, 1H-13C and 1H-15N gHSQC and 1H-13C gHMBC), high-resolution mass spectrometry (HR-FAB+), TG-DSC analysis and low-temperature single-crystal X-ray diffraction analysis. Additionally, the molecular geometry and the vibrational infrared and Raman frequencies were calculated by density functional theory using the M06/6-31G(d) level of theory, showing good agreement with the experimental results. The title compound showed interesting photophysical properties, which were studied experimentally in solution and in the solid state by UV-Vis and fluorescence spectroscopy and compared to the theoretically obtained parameters using TD-DFT calculations. Natural and Mulliken atomic charges and the molecular electrostatic potential (MEP) have been mapped.

  5. Spectroscopic investigation (FTIR spectrum), NBO, HOMO-LUMO energies, NLO and thermodynamic properties of 8-Methyl-N-vanillyl-6-nonenamideby DFT methods

    Science.gov (United States)

    Sherin Percy Prema Leela, J.; Hemamalini, R.; Muthu, S.; Al-Saadi, Abdulaziz A.

    2015-07-01

    Capsicum a hill grown vegetable is also known as red pepper or chili pepper. Capsaicin(8-Methyl-N-vanillyl-6-nonenamide) is the active component in chili peppers, which is currently used in the treatment of osteoarthritis, psoriasis and cancer. Fourier transform infrared (FT-IR) spectrum of Capsaicin in the solid phase were recorded in the region 4000-400 cm-1 and analyzed. The vibrational frequencies of the title compound were obtained theoretically by DFT/B3LYP calculations employing the standard 6-311++G(d,p) basis set and were compared with Fourier transform infrared spectrum. Complete vibrational assignment analysis and correlation of the fundamental modes for the title compound were carried out. The vibrational harmonic frequencies were scaled using scale factor, yielding a good agreement between the experimentally recorded and the theoretically calculated values. Stability of the molecule arising from hyper conjugative interactions, charge delocalization and intra molecular hydrogen bond-like weak interaction has been analyzed using Natural bond orbital (NBO) analysis by using B3LYP/6-311++G(d,p) method. The results show that electron density (ED) in the σ∗ and π∗ antibonding orbitals and second-order delocalization energies E (2) confirm the occurrence of intra molecular charge transfer (ICT) within the molecule. The dipole moment (μ), polarizability (α) and the hyperpolarizability (β) values of the molecule has been computed. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated.

  6. A theoretical and experimental investigation of the spectroscopic properties of a DNA-intercalator salphen-type Zn(II) complex.

    Science.gov (United States)

    Biancardi, Alessandro; Burgalassi, Azzurra; Terenzi, Alessio; Spinello, Angelo; Barone, Giampaolo; Biver, Tarita; Mennucci, Benedetta

    2014-06-10

    The photophysical and DNA-binding properties of the cationic zinc(II) complex of 5-triethylammonium methyl salicylidene ortho-phenylenediiminato (ZnL(2+)) were investigated by a combination of experimental and theoretical methods. DFT calculations were performed on both the ground and the first excited states of ZnL(2+) and on its possible mono- and dioxidation products, both in vacuo and in selected solvents mimicked by the polarizable continuum model. Comparison of the calculated absorption and fluorescence transitions with the corresponding experimental data led to the conclusion that visible light induces a two-electron photooxidation process located on the phenylenediiminato ligand. Kinetic measurements, performed by monitoring absorbance changes over time in several solvents, are in agreement with a slow unimolecular photooxidation process, which is faster in water and slower in less polar solvents. Moreover, structural details of ZnL-DNA binding were obtained by DFT calculations on the intercalation complexes between ZnL and the d(ApT)2 and d(GpC)2 dinucleoside monophosphate duplexes. Two main complementary binding interactions are proposed: 1) intercalation of the central phenyl ring of the ligand between the stacked DNA base pairs; 2) external electrostatic attraction between the negatively charged phosphate groups and the two cationic triethylammonium groups of the Schiff-base ligand. Such suggestions are supported by fluorescence titrations performed on the ZnL/DNA system at different ionic strengths and temperatures. In particular, the values of the DNA-binding constants obtained at different temperatures provided the enthalpic and entropic contributions to the binding and confirmed that two competitive mechanisms, namely, intercalation and external interaction, are involved. The two mechanisms are coexistent at room temperature under physiological conditions.

  7. Comparitive study on structural, magnetic and spectroscopic properties of four new copper(II) coordination polymers with 4‧-substituted terpyridine ligands

    Science.gov (United States)

    Toledo, Dominique; Vega, Andrés; Pizarro, Nancy; Baggio, Ricardo; Peña, Octavio; Roisnel, Thierry; Pivan, Jean-Yves; Moreno, Yanko

    2017-09-01

    The synthesis and characterization of four copper(II) complexes with different terpyridyl ligands have been carried out, their crystal and molecular structures determined and their magnetic and luminescent properties analyzed. The ligands used in the coordination reactions were 4‧-(3-methyl-2-thienyl)-4,2‧:6‧,4''-terpyridine (4-stpy), -4‧-(4-quinolinyl)-4,2‧:6‧,4''-terpyridine (4-qtpy), 4‧-(4-quinolinyl)-3,2‧:6‧,3''-terpyridine (3-qtpy, unreported so far) and 4‧-(4-cyanophenyl)-4,2‧:6‧,4''-terpyridine (4-cntpy); the reaction of these ligands with Cu(II)-hexafluoroacetylacetone (Cu(hfacac)2) gives rise to coordination polymers Cu(4-stpy)(hfacac)2 (I), Cu(4-qtpy)(hfacac)2 (II), Cu(3-qtpy)(hfacac)2 (III) and Cu(4-cntpy)(hfacac)2 (IV). The different location of the nitrogen atom of the outer ring is responsible for the different coordination modes. The emission spectra of dichloromethane solutions are consistent with dissociation of the complexes; the emission maxima simulate those of the free ligands. The emission of I, III and IV in the solid state is essentially quenched upon complexation with Cu(II), whereas for compound II an emission at 420 nm is observed. The interaction between copper centers has been related with the coplanarity of terpyridine rings. Complexes I-III exhibit a paramagnetic behavior, while compound IV, with the smallest torsion angle between pyridine moieties, shows an antiferromagnetic behavior described by a dimeric model, with J=-4.38 cm-1, g =2.06 and ρ=0.07.

  8. Structural, optical, spectroscopic and electrical properties of Mo-doped ZnO thin films grown by radio frequency magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Soumahoro, I. [Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Loess, B.P. 43, 67034 Strasbourg Cedex 2 (France); Colis, S., E-mail: colis@ipcms.u-strasbg.fr [Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Loess, B.P. 43, 67034 Strasbourg Cedex 2 (France); Schmerber, G.; Leuvrey, C.; Barre, S.; Ulhaq-Bouillet, C. [Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Loess, B.P. 43, 67034 Strasbourg Cedex 2 (France); Muller, D. [Laboratoire ICube, Université de Strasbourg, CNRS UMR 7357, 23 rue du Loess, B.P. 20, 67037 Strasbourg Cedex 2 (France); Abd-lefdil, M.; Hassanain, N. [Université Mohammed V- Agdal, Laboratoire de Physique des Matériaux, Faculté des Sciences, B.P. 1014, Rabat (Morocco); Petersen, J. [Department of Advanced Materials and Structure, Centre de Recherche Public Henri Tudor, 66 rue du Luxembourg, Esch/Alzette 4002 (Luxembourg); Berrada, A. [Université Mohammed V- Agdal, Laboratoire de Physique des Matériaux, Faculté des Sciences, B.P. 1014, Rabat (Morocco); Slaoui, A. [Laboratoire ICube, Université de Strasbourg, CNRS UMR 7357, 23 rue du Loess, B.P. 20, 67037 Strasbourg Cedex 2 (France); Dinia, A., E-mail: aziz.dinia@ipcms.u-strasbg.fr [Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Loess, B.P. 43, 67034 Strasbourg Cedex 2 (France)

    2014-09-01

    Undoped and Mo-doped ZnO (2% Mo) films about 1 μm thick were deposited by radio-frequency magnetron sputtering on Si(100) and glass substrates at 30 and 300 °C. X-ray diffraction patterns show that all films exhibit the hexagonal wurtzite crystal structure with a preferred orientation of the crystallites along the [002] direction. Plane view and cross-section transmission electron microscopy observations showed that the films present a columnar growth. Rutherford backscattering spectrometry indicates that Mo is homogeneously distributed inside the films. Scanning electron microscopy and atomic force microscopy show that Mo doping leads to a reduction of the grain size and surface roughness. According to X-ray photoelectron spectroscopy measurements, the valence of the Mo ions in the ZnO matrix is + 5 and + 6. Optical measurements in the UV–Visible range show a transmittance increasing from about 60 to 80% when increasing the wavelength from 400 to 800 nm. A sharp absorption onset is observed at about 375 nm corresponding to the fundamental absorption edge of ZnO at 3.26 eV. This gap value remains unchanged upon Mo doping. The Hall effect measurements carried out at room temperature show that both undoped and Mo-doped ZnO films present an n-type conduction. The 2% Mo doping increases the carrier concentration and decreases the resistivity measured in pure ZnO by about three orders of magnitude. A comparison with 2% Al-doped ZnO films grown in the same conditions underlines the important role of the preparation conditions on the transport properties of ZnO based transparent conductive oxides. - Highlights: • ZnO and Zn{sub 0.98}Mo{sub 0.02}O films were grown by sputtering on glass and Si(100). • The concentration of defects increases upon doping. • Mo ions with 5 + and 6 + valences are uniformly distributed inside the layers. • Transmittance varies between 60 and 80% in the visible range. • The conductivity increases by about three orders of magnitude

  9. Spectroscopic and photoluminescence properties of Sm{sup 3+} ions in Pb–K–Al–Na phosphate glasses for efficient visible lasers

    Energy Technology Data Exchange (ETDEWEB)

    Basavapoornima, Ch.; Jayasankar, C.K., E-mail: ckjaya@yahoo.com

    2014-09-15

    The Sm{sup 3+}-doped lead phosphate glasses (PKAPbNSm:44P{sub 2}O{sub 5}–17K{sub 2}O–9Al{sub 2}O{sub 3}–(24−x) PbO–6Na{sub 2}O–xSm{sub 2}O{sub 3}, where x=0.1, 0.5, 1.0 and 2.0 mol%) have been prepared by conventional melt quenching technique and are characterized through absorption and emission spectra and decay rate analysis. The partial energy level structure of Sm{sup 3+} ions in these glasses have been evaluated from the measured absorption and emission spectra using free-ion Hamiltonian model. The emission spectra of Sm{sup 3+} ions in these glasses have been measured using 488 nm line of Ar{sup +} laser as an excitation source. The decay rates for {sup 4}G{sub 5/2} level of Sm{sup 3+} ions have been measured and are found to exhibit single exponential nature at lower concentration (0.1 and 0.5 mol% Sm{sub 2}O{sub 3}-doped glass) and turns into non-exponential at higher concentrations (≥1.0 mol% Sm{sub 2}O{sub 3}-doped glasses). The experimental lifetimes for {sup 4}G{sub 5/2} level of Sm{sup 3+} ions are found to decrease from 2.34 to 1.24 ms when the concentration is increased from 0.1 to 2.0 mol% Sm{sub 2}O{sub 3} due to cross-relaxation energy transfer. The non-exponential decay rates are well-fitted to Inokuti-Hirayama model for S=6, indicates that the energy transfer is of dipole–dipole type. - Highlights: • Lead phosphate glasses have been investigated to develop visible optical devices and tunable lasers. • PbO mixed glasses found to be of fussy interest for non-linear optical effects, when doped with RE ions. • Lead phosphate glasses exhibit good optical properties while having an improved chemical durability. • The calculated colour coordinates fall well within the reddish–orange region. • The CCT values obtained for the present glasses are below the warm CCT (i.e. CCT<4000 K)

  10. First principal studies of spectroscopic (IR and Raman, UV-visible), molecular structure, linear and nonlinear optical properties of L-arginine p-nitrobenzoate monohydrate (LANB): A new non-centrosymmetric material.

    Science.gov (United States)

    Shkir, Mohd; AlFaify, S; Abbas, Haider; Muhammad, Shabbir

    2015-08-05

    In current work, the authors have been applied the density functional theory (DFT) using B3LYP and CAM-B3LYP exchange-correlation functional with 6-31G(∗) basis set on l-arginine p-nitrobenzoate monohydrate (LANB) molecule for the first time to optimize its geometry and study the spectroscopic, electronic structure, nonlinear optical properties. Vibrational modes were found in good agreement with experimental reports. The calculated UV spectra by B3LYP/6-31G(∗) and CAM-B3LYP/6-31G(∗) level of theory shows an electronic transition at ∼268 nm (4.63 eV) and 264 nm (4.70 eV) respectively. To explain the charge interaction taking place within the molecule highest occupied molecular orbital and lowest unoccupied molecular orbital were analyzed and their calculated energy gap was found to be 4.3eV with an oscillatory strength 0.3796 at B3LYP/6-31G(∗) level of theory. The dipole moment (μtot), average and anisotropy of polarizability (αtot, Δα) and static and total first hyperpolarizability (β0, βtot) values were calculated. The value of μtot and βtot are found to be 4.124D and 1.630 × 10(-30) esu and 4.127D and 1.133 × 10(-30) esu using B3LYP/6-31G(∗) and CAM-B3LYP/6-31G(∗) functional respectively. The value of βtot is >4 and >3 times higher than prototype urea molecule calculated at both level of theory, respectively. The molecular electrostatic potential (MEP), frontier molecular orbital's (FMOs), global reactivity descriptors and thermodynamic properties are also calculated and discussed. The properties of LANB calculated at B3LYP are in good correlation with experimental than the CAM-B3LYP level of theory. The obtained results show that LANB molecule can be treated as a good candidate for nonlinear optical devices. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Electronic structures and spectroscopic properties for a new type of Iridium( Ⅲ )phenylpyrazole complexes%一类新型苯基吡唑銥(Ⅲ)配合物的电子结构及光谱性质

    Institute of Scientific and Technical Information of China (English)

    雷利平; 张叶; 解晓东; 郝玉英; 王华; 许并社

    2011-01-01

    为了探索新型苯基吡唑銥(Ⅲ)配合物的电子结构与光谱性质之间的关系,采用密度泛函理论(DFT)优化了銥金属配合物(ppz)2Ir (BTZ) (1)和(ppz)2Ir(4-TfmBTZ) (2)的基态与激发态的几何结构.通过含时密度泛函理论(TD-DRT)方法计算了配合物的吸收和发射谱,指认了它们的跃迁性质.和Ir(ppz)3相比,通过引入新的辅助配体并对其修饰实现了发光颜色的调节.配合物1和2的最低能磷光发射可指认为3 MLCT/3MLCT/3ILCT[π*(R-BTZ)→d(Ir)+π(ppz)+π(R-BTZ)]的电荷混合跃迁.此外,它们的磷光发射和吸收有相似的跃迁性质.MLCT主要发生在Ir(R-BTZ)片段而不是Ir(ppz)2片段.第二配体在此配合物的发光过程中起了主要作用.%The geometries of ground state and excited state were optimized on the basis of the density functional theory (DFT) to investigate the relationship between the electronic structures and spectroscopic properties for Indium ( IE ) phenylpyrazole complexes(ppz)2Ir(LX)(LX = BTZ and 4-TfrnBTZ) .Time-dependent density functional theory (TD-DFT) was employed to obtain their absorption and phosphorescent emission spectra and to assign the transition properties. The result revealed that the emission wavelength was adjusted compared with Ir(ppz)3 by introducing new ancillary ligand BTZ/4-TfmBTZ.The lowest-lying emission was assigned to 3 MLCT/3LLCT/3ILCT [ n * (R-BTZ)→ d(Ir) + 7r(ppz) + π(R-BTZ)] mixed transition.The phosphorescence emissions of the two complexes have similar transition properties to their absorptions. MLCT occurred mainly on the fragment of Ir( R-BTZ) other than the Ir(ppz)2.It revealed that the ancillary ligand played an important role in the luminescence process.

  12. Spectroscopic Imaging of Strongly Correlated Electronic States

    Science.gov (United States)

    Yazdani, Ali; da Silva Neto, Eduardo H.; Aynajian, Pegor

    2016-03-01

    The study of correlated electronic systems from high-Tc cuprates to heavy-fermion systems continues to motivate the development of experimental tools to probe electronic phenomena in new ways and with increasing precision. In the past two decades, spectroscopic imaging with scanning tunneling microscopy has emerged as a powerful experimental technique. The combination of high energy and spatial resolutions provided by this technique reveals unprecedented detail of the electronic properties of strongly correlated metals and superconductors. This review examines specific experiments, theoretical concepts, and measurement methods that have established the application of these techniques to correlated materials. A wide range of applications, such as the study of collective responses to single atomic impurities, the characterization of quasiparticle-like excitations through their interference, and the identification of competing electronic phases using spectroscopic imaging, are discussed.

  13. Electronic Structure and Optical Properties of Cu2ZnGeSe4. First-Principles Calculations and Vacuum-Ultraviolet Spectroscopic Ellipsometric Studies

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sukgeun [National Renewable Energy Lab. (NREL), Golden, CO (United States); Park, Ji-Sang [National Renewable Energy Lab. (NREL), Golden, CO (United States); Donohue, Andrea [J. A. Woollam Co. Inc., Lincoln, NE (United States); Christensen, Steven T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); To, Bobby [National Renewable Energy Lab. (NREL), Golden, CO (United States); Beall, Carolyn [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wei, Su-Huai [National Renewable Energy Lab. (NREL), Golden, CO (United States); Repins, Ingid L. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-11-19

    Cu2ZnGeSe4 is of interest for the development of next-generation thin-film photovoltaic technologies. To understand its electronic structure and related fundamental optical properties, we perform first-principles calculations for three structural variations: kesterite, stannite, and primitive-mixed CuAu phases. The calculated data are compared with the room-temperature dielectric functionϵ=ϵ1+iϵ2 spectrum of polycrystalline Cu2ZnGeSe4 determined by vacuum-ultraviolet spectroscopic ellipsometry in the photon-energy range of 0.7 to 9.0 eV. Ellipsometric data are modeled with the sum of eight Tauc-Lorentz oscillators, and the best-fit model yields the band-gap and Tauc-gap energies of 1.25 and 1.19 eV, respectively. A comparison of overall peak shapes and relative intensities between experimental spectra and the calculated ϵ data for three structural variations suggests that the sample may not have a pure (ordered) kesterite phase. We found that the complex refractive index N=n+ik, normal-incidence reflectivity R, and absorption coefficients α are calculated from the modeled ϵ spectrum, which are also compared with those of Cu2ZnSnSe4 . The spectral features for Cu2ZnGeSe4 appear to be weaker and broader than those for Cu2ZnSnSe4 , which is possibly due to more structural imperfections presented in Cu2ZnGeSe4 than Cu2ZnSnSe4 .

  14. A Comparison of Galaxy Counting Techniques in Spectroscopically Undersampled Regions

    Science.gov (United States)

    Specian, Mike A.; Szalay, Alex S.

    2016-11-01

    Accurate measures of galactic overdensities are invaluable for precision cosmology. Obtaining these measurements is complicated when members of one’s galaxy sample lack radial depths, most commonly derived via spectroscopic redshifts. In this paper, we utilize the Sloan Digital Sky Survey’s Main Galaxy Sample to compare seven methods of counting galaxies in cells when many of those galaxies lack redshifts. These methods fall into three categories: assigning galaxies discrete redshifts, scaling the numbers counted using regions’ spectroscopic completeness properties, and employing probabilistic techniques. We split spectroscopically undersampled regions into three types—those inside the spectroscopic footprint, those outside but adjacent to it, and those distant from it. Through Monte Carlo simulations, we demonstrate that the preferred counting techniques are a function of region type, cell size, and redshift. We conclude by reporting optimal counting strategies under a variety of conditions.

  15. Measurement of InAsSb bandgap energy and InAs/InAsSb band edge positions using spectroscopic ellipsometry and photoluminescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Webster, P. T.; Riordan, N. A.; Liu, S.; Zhang, Y.-H.; Johnson, S. R., E-mail: shane.johnson@asu.edu [Center for Photonics Innovation and School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Steenbergen, E. H. [U. S. Air Force Research Laboratory, AFRL/RXAN, Wright Patterson, Ohio 45433 (United States); Synowicki, R. A. [J. A. Woollam Co., Inc., 645 M. Street, Suite 102, Lincoln, Nebraska 68508 (United States)

    2015-12-28

    The structural and optical properties of lattice-matched InAs{sub 0.911}Sb{sub 0.089} bulk layers and strain-balanced InAs/InAs{sub 1−x}Sb{sub x} (x ∼ 0.1–0.4) superlattices grown on (100)-oriented GaSb substrates by molecular beam epitaxy are examined using X-ray diffraction, spectroscopic ellipsometry, and temperature dependent photoluminescence spectroscopy. The photoluminescence and ellipsometry measurements determine the ground state bandgap energy and the X-ray diffraction measurements determine the layer thickness and mole fraction of the structures studied. Detailed modeling of the X-ray diffraction data is employed to quantify unintentional incorporation of approximately 1% Sb into the InAs layers of the superlattices. A Kronig-Penney model of the superlattice miniband structure is used to analyze the valence band offset between InAs and InAsSb, and hence the InAsSb band edge positions at each mole fraction. The resulting composition dependence of the bandgap energy and band edge positions of InAsSb are described using the bandgap bowing model; the respective low and room temperature bowing parameters for bulk InAsSb are 938 and 750 meV for the bandgap, 558 and 383 meV for the conduction band, and −380 and −367 meV for the valence band.

  16. Measurement of InAsSb bandgap energy and InAs/InAsSb band edge positions using spectroscopic ellipsometry and photoluminescence spectroscopy

    Science.gov (United States)

    Webster, P. T.; Riordan, N. A.; Liu, S.; Steenbergen, E. H.; Synowicki, R. A.; Zhang, Y.-H.; Johnson, S. R.

    2015-12-01

    The structural and optical properties of lattice-matched InAs0.911Sb0.089 bulk layers and strain-balanced InAs/InAs1-xSbx (x ˜ 0.1-0.4) superlattices grown on (100)-oriented GaSb substrates by molecular beam epitaxy are examined using X-ray diffraction, spectroscopic ellipsometry, and temperature dependent photoluminescence spectroscopy. The photoluminescence and ellipsometry measurements determine the ground state bandgap energy and the X-ray diffraction measurements determine the layer thickness and mole fraction of the structures studied. Detailed modeling of the X-ray diffraction data is employed to quantify unintentional incorporation of approximately 1% Sb into the InAs layers of the superlattices. A Kronig-Penney model of the superlattice miniband structure is used to analyze the valence band offset between InAs and InAsSb, and hence the InAsSb band edge positions at each mole fraction. The resulting composition dependence of the bandgap energy and band edge positions of InAsSb are described using the bandgap bowing model; the respective low and room temperature bowing parameters for bulk InAsSb are 938 and 750 meV for the bandgap, 558 and 383 meV for the conduction band, and -380 and -367 meV for the valence band.

  17. Influence of different water-ethanol solvent systems on the spectroscopic and physico-chemical properties of the macrocyclic compounds pheophytin and chlorophyll a; Influencia de diferentes sistemas de solvente agua-etanol sobre as propriedades fisico-quimicas e espectroscopicas dos compostos macrociclicos feofitina e clorofila a

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Leonardo M.; Rodrigues, Maira R.; Oliveira, Hueder P. M. de [Universidade Camilo Castelo Branco, Sao Jose dos Campos, SP (Brazil); Lima, Adriana [Universidade do Vale do Paraiba, Sao Jose dos Campos, SP (Brazil); Soares, Rafael R. S.; Batistela, Vagner R.; Gerola, Adriana P.; Hioka, Noboru [Universidade Estadual de Maringa (UEM), PR (Brazil). Dept. de Quimica; Severino, Divinomar; Baptista, Mauricio S. [Universidade de Sao Paulo, (USP), SP (Brazil). Inst. de Quimica; Machado, Antonio Eduardo da Hora [Universidade Federal de Uberlandia (UFU), MG (Brazil). Inst. de Quimica

    2010-07-01

    This work focus on the influence of solvent on the photophysical properties of chlorophyll a and pheophytin. Both compounds are related to the photosynthesis process and are considered prototypes of photosensitizers in Photodynamic Therapy. Fluorescence measurements were developed using water/ethanol mixtures at different compositions, since both solvents could be employed in biological applications. The spectroscopic properties of these compounds undergo profound changes depending on water content in the ethanol due to auto-aggregation processes. The major hydrophobicity and the lower dielectric constant of ethanol when compared with water precluded significantly the auto-aggregation process of these compounds. (author)

  18. Spectroscopic Detection of Caries Lesions

    Directory of Open Access Journals (Sweden)

    Mika Ruohonen

    2013-01-01

    Full Text Available Background. A caries lesion causes changes in the optical properties of the affected tissue. Currently a caries lesion can be detected only at a relatively late stage of development. Caries diagnosis also suffers from high interobserver variance. Methods. This is a pilot study to test the suitability of an optical diffuse reflectance spectroscopy for caries diagnosis. Reflectance visible/near-infrared spectroscopy (VIS/NIRS was used to measure caries lesions and healthy enamel on extracted human teeth. The results were analysed with a computational algorithm in order to find a rule-based classification method to detect caries lesions. Results. The classification indicated that the measured points of enamel could be assigned to one of three classes: healthy enamel, a caries lesion, and stained healthy enamel. The features that enabled this were consistent with theory. Conclusions. It seems that spectroscopic measurements can help to reduce false positives at in vitro setting. However, further research is required to evaluate the strength of the evidence for the method’s performance.

  19. The Spectroscopic Diversity of Type Ia Supernovae

    CERN Document Server

    Blondin, S; Kirshner, R P; Mandel, K S; Berlind, P; Calkins, M; Challis, P; Garnavich, P M; Jha, S W; Modjaz, M; Riess, A G; Schmidt, B P

    2012-01-01

    We present 2603 spectra of 462 nearby Type Ia supernovae (SN Ia) obtained during 1993-2008 through the Center for Astrophysics Supernova Program. Most of the spectra were obtained with the FAST spectrograph at the FLWO 1.5m telescope and reduced in a consistent manner, making data set well suited for studies of SN Ia spectroscopic diversity. We study the spectroscopic and photometric properties of SN Ia as a function of spectroscopic class using the classification schemes of Branch et al. and Wang et al. The width-luminosity relation appears to be steeper for SN Ia with broader lines. Based on the evolution of the characteristic Si II 6355 line, we propose improved methods for measuring velocity gradients, revealing a larger range than previously suspected, from ~0 to ~400 km/s/day considering the instantaneous velocity decline rate at maximum light. We find a weaker and less significant correlation between Si II velocity and intrinsic B-V color at maximum light than reported by Foley et al., owing to a more ...

  20. Particle in a Disk: A Spectroscopic and Computational Laboratory Exercise Studying the Polycyclic Aromatic Hydrocarbon Corannulene

    Science.gov (United States)

    Frey, E. Ramsey; Sygula, Andrzej; Hammer, Nathan I.

    2014-01-01

    This laboratory exercise introduces undergraduate chemistry majors to the spectroscopic and theoretical study of the polycyclic aromatic hydrocarbon (PAH), corannulene. Students explore the spectroscopic properties of corannulene using UV-vis and Raman vibrational spectroscopies. They compare their experimental results to simulated vibrational…

  1. Particle in a Disk: A Spectroscopic and Computational Laboratory Exercise Studying the Polycyclic Aromatic Hydrocarbon Corannulene

    Science.gov (United States)

    Frey, E. Ramsey; Sygula, Andrzej; Hammer, Nathan I.

    2014-01-01

    This laboratory exercise introduces undergraduate chemistry majors to the spectroscopic and theoretical study of the polycyclic aromatic hydrocarbon (PAH), corannulene. Students explore the spectroscopic properties of corannulene using UV-vis and Raman vibrational spectroscopies. They compare their experimental results to simulated vibrational…

  2. Influence of titanium ions on spectroscopic properties of TeO{sub 2}-Sb{sub 2}O{sub 3}-B{sub 2}O{sub 3}: TiO{sub 2} glass ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Satyanarayana, T.; Valente, M.A. [Department of Physics, University of Aveiro (Portugal); LBR College of Engineering, Mylavaram (India); Gandhi, Y.; Veeraiah, N. [Acharya Nagarjuna University, Nuzvid (India); Kityk, I.V. [Electrical Engineering Department, Technical University of Czestochowa, Czestochowa (Poland)

    2011-11-15

    A family of antimony tellurite glasses of the composition (55-x)TeO{sub 2}-10Sb{sub 2}O{sub 3}-35B{sub 2}O{sub 3} mixed with different concentrations of TiO{sub 2} (0 to 2 mol%) were prepared and crystallized. The samples were characterized by XRD and SEM techniques; spectroscopic (optical absorption and Raman) and PIB properties have been investigated. Randomly distributed crystals were identified by SEM. The XRD studies have revealed the presence of Sb{sub 2}Te{sub 2}O{sub 7}, Sb{sub 2}Te{sub 2}O{sub 9}, TiTe{sub 3}O{sub 8,}TiBO{sub 3} crystalline phases in these samples. The diffraction data also indicated that, the antimony ions coexist in Sb{sup 5+} state with Sb{sup 3+} state in these samples; however, the concentration of Sb{sup 3+} ions seems to be dominant over Sb{sup 5+} ions in the samples containing lower concentrations of TiO{sub 2}. Optical absorption spectral studies have indicated that a considerable proportion of Ti ions do exist in Ti{sup 3+} state in addition to Ti{sup 4+} state and the redox ratio seems to be increasing with increase in the concentration of TiO{sub 2}. The Raman spectral studies have revealed the presence of several conventional structural groups viz., TeO{sub 4}, SbO{sub 3}, BO{sub 3}, BO{sub 4}, TiO{sub 4,}TiO{sub 6} in the glass ceramic network; these studies have also indicated a growing degree of disorder in the glass ceramic with increase in the concentration of TiO{sub 2}. The experiments on PIB with 7 ns 1064 nm Nd:YAG laser beam indicated the maximum intensity of birefringence for the sample crystallized with 2.0 mol% of TiO{sub 2}. This result combined with the optical absorption studies allowed us to conclusion that Ti ion surrounding ligands play principal role in the observed PIB effects (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Mutation of His465 Alters the pH-dependent Spectroscopic Properties of Escherichia coli Glutamate Decarboxylase and Broadens the Range of Its Activity toward More Alkaline pH

    NARCIS (Netherlands)

    Pennacchietti, E.; Lammens, T.M.; Capitani, G.; Franssen, M.C.R.; John, R.A.; Bossa, F.; Biase, De D.

    2009-01-01

    Glutamate decarboxylase (GadB) from Escherichia coli is a hexameric, pyridoxal 5'-phosphate-dependent enzyme catalyzing CO2 release from the a-carboxyl group of l-glutamate to yield ¿-aminobutyrate. GadB exhibits an acidic pH optimum and undergoes a spectroscopically detectable and strongly cooperat

  4. Theoretical Mid-UV Spectroscopic Indices for Evolved Stellar Populations

    Science.gov (United States)

    Bertone, E.; Buzzoni, A.; Chavez, M.; Rodriguez-Merino, L. H.

    2007-12-01

    Aiming at picking up suitable theoretical tools to break the age-metallicity degeneracy in simple stellar populations (SSPs), we explore here the properties of a set of 17 synthetic mid-UV spectroscopic indices relying on the Uvblue synthetic stellar library and the Buzzoni population synthesis code.

  5. Spectroscopic Studies of Nearby Cool Stars: The DUNES Sample

    Science.gov (United States)

    Maldonado, J.; Martinez-Arnáiz, R. M.; Eiroa, C.; Montes, D.

    At the universities of Madrid we are carrying out a systematic analysis of the spectroscopic properties of the nearby (dDUNES, a Herschel OTKP aiming at detecting and studying cold, faint dust disks around nearby stars. In this contribution we present some preliminary results on the kinematics of the DUNES sample.

  6. Conformações distorcida e planar do anel porfirínico em complexos e hemoproteínas: propriedades físico-químicas e implicações espectroscópicas Ruffled and planar conformations of the porphyrin ring in complexes and heme proteins: physical-chemistry properties and spectroscopic implications

    Directory of Open Access Journals (Sweden)

    Leonardo M. Moreira

    2004-12-01

    Full Text Available The different conformations of porphyrin rings are strongly related with the electronic configurations of the metallic center in the ferriheme coordination compounds and heme proteins. The usual electronic configuration, (d xy²(d xz,d yz ³ presents a planar conformation of the porphyrin ring and the less common electronic configuration (d xz,d yz4(d xy ¹ occurs in the case of a strongly ruffled ring. These states are responsible for distinct chemical and spectroscopic properties of the porphyrin systems. The importance of the ring conformations, their characteristics, implications and applications are discussed.

  7. Compositional dependence of charge carrier transport in kesterite Cu2ZnSnS4 solar cells

    Science.gov (United States)

    Just, Justus; Nichterwitz, Melanie; Lützenkirchen-Hecht, Dirk; Frahm, Ronald; Unold, Thomas

    2016-12-01

    Cu2ZnSnS4 solar cells deposited by thermal co-evaporation have been characterized structurally and electronically to determine the dependence of the electronic properties on the elemental composition of the kesterite phase, which can significantly deviate from the total sample composition. To this end, the kesterite phase content and composition were determined by a combination of X-ray fluorescence and X-ray absorption measurements. The electronic properties, such as carrier density and minority carrier diffusion length, were determined by electron beam induced current measurements and capacitance-voltage profiling. The charge-carrier transport properties are found to strongly depend on the Cu/(Sn+Zn) ratio of the kesterite phase. For the Cu-poor sample, a minority carrier diffusion length of 270 nm and a total collection length of approx. 500 nm are deduced, indicating that current collection should not be an issue in thin devices.

  8. On the necessity of composition-dependent low-temperature opacity in models of metal-poor asymptotic giant branch stars

    Energy Technology Data Exchange (ETDEWEB)

    Constantino, Thomas; Campbell, Simon; Lattanzio, John [Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Victoria 3800 (Australia); Gil-Pons, Pilar, E-mail: thomas.constantino@monash.edu [Department of Applied Physics, Polytechnic University of Catalonia, 08860 Barcelona (Spain)

    2014-03-20

    The vital importance of composition-dependent low-temperature opacity in low-mass (M ≤ 3 M {sub ☉}) asymptotic giant branch (AGB) stellar models of metallicity Z ≥ 0.001 has recently been demonstrated. Its significance to more metal-poor, intermediate-mass (M ≥ 2.5 M {sub ☉}) models has yet to be investigated. We show that its inclusion in lower-metallicity models ([Fe/H] ≤–2) is essential and that there exists no threshold metallicity below which composition-dependent molecular opacity may be neglected. We find it to be crucial in all intermediate-mass models investigated ([Fe/H] ≤–2 and 2.5 ≤ M/M {sub ☉} ≤ 5), because of the evolution of the surface chemistry, including the orders of magnitude increase in the abundance of molecule-forming species. Its effect on these models mirrors that previously reported for higher-metallicity models—increase in radius, decrease in T {sub eff}, faster mass loss, shorter thermally pulsing AGB lifetime, reduced enrichment in third dredge-up products (by a factor of 3-10), and an increase in the mass limit for hot bottom burning. We show that the evolution of low-metallicity models with composition-dependent low-temperature opacity is relatively independent of initial metal abundance because its contribution to the opacity is far outweighed by changes resulting from dredge-up. Our results imply a significant reduction in the expected number of nitrogen-enhanced metal-poor stars, which may help explain their observed paucity. We note that these findings are partially a product of the macrophysics adopted in our models, in particular, the Vassiliadis and Wood mass loss rate which is strongly dependent on radius.

  9. Spectroscopic analysis of LYSO:Ce crystals

    Science.gov (United States)

    Martins, A. F.; Carreira, J. F. C.; Rodrigues, J.; Sedrine, N. Ben; Castro, I. F. C.; Correia, P. M. M.; Veloso, J. F. C. A.; Rino, L.; Monteiro, T.

    2017-02-01

    Rare earth orthosilicates are among the most widely used scintillator materials in the last decades. Particularly, lutetium-yttrium oxyorthosilicate (LYSO) is known to exhibit great potentialities in the field of radiation detectors for medical imaging. Consequently, an in-depth knowledge of the material properties is of utmost interest for the mentioned applications. In this work the spectroscopic properties of commercial cerium doped lutetium-yttrium oxyorthosilicate crystals (LYSO:Ce) were investigated by Raman spectroscopy, steady state photoluminescence, photoluminescence excitation and time resolved photoluminescence. Site selective excitation was used under steady state (325 nm) and pulsed (266 nm) conditions to separately investigate the temperature dependence of the 5d → 4f Ce1 and Ce2 luminescence, allowing to establish the thermal quenching dependence of the Ce2 optical center. In the case of the Ce1 optical center, a luminescence quantum efficiency of 78% was obtained from 14 K to room temperature with 266 nm photon excitation.

  10. Scanning Tunneling Spectroscope Use in Electrocatalysis Testing

    Science.gov (United States)

    Knutsen, Turid

    2010-01-01

    The relationship between the electrocatalytic properties of an electrode and its ability to transfer electrons between the electrode and a metallic tip in a scanning tunneling microscope (STM) is investigated. The alkaline oxygen evolution reaction (OER) was used as a test reaction with four different metallic glasses, Ni78Si8B14, Ni70Mo20Si5B5, Ni58Co20Si10B12, and Ni25Co50Si15B10, as electrodes. The electrocatalytic properties of the electrodes were determined. The electrode surfaces were then investigated with an STM. A clear relationship between the catalytic activity of an electrode toward the OER and its tunneling characteristics was found. The use of a scanning tunneling spectroscope (STS) in electrocatalytic testing may increase the efficiency of the optimization of electrochemical processes.

  11. Scanning Tunneling Spectroscope Use in Electrocatalysis Testing

    Directory of Open Access Journals (Sweden)

    Turid Knutsen

    2010-06-01

    Full Text Available The relationship between the electrocatalytic properties of an electrode and its ability to transfer electrons between the electrode and a metallic tip in a scanning tunneling microscope (STM is investigated. The alkaline oxygen evolution reaction (OER was used as a test reaction with four different metallic glasses, Ni78Si8B14, Ni70Mo20Si5B5, Ni58Co20Si10B12, and Ni25Co50Si15B10, as electrodes. The electrocatalytic properties of the electrodes were determined. The electrode surfaces were then investigated with an STM. A clear relationship between the catalytic activity of an electrode toward the OER and its tunneling characteristics was found. The use of a scanning tunneling spectroscope (STS in electrocatalytic testing may increase the efficiency of the optimization of electrochemical processes.

  12. An Extragalactic Spectroscopic Survey of the SSA22 Field

    CERN Document Server

    Saez, C; Bauer, F E; Stern, D; Gonzales, A; Rreza, I; Alexander, D M; Matsuda, Y; Geach, J E; Harrison, F A; Havashino, T

    2015-01-01

    We present VLT VIMOS, Keck DEIMOS and Keck LRIS multi-object spectra of 367 sources in the field of the z ~ 3.09 protocluster SSA22. Sources are spectroscopically classified via template matching, allowing new identifications for 206 extragalactic sources, including 36 z > 2 Lyman-break galaxies (LBGs) and Lyman-a emitters (LAEs), 8 protocluster members, and 94 X-ray sources from the ~ 400 ks Chandra deep survey of SSA22. Additionally, in the area covered by our study, we have increased by ~ 4, 13, and 6 times the number of reliable redshifts of sources at 1.0 3.4, and with X-Ray emission, respectively. We compare our results with past spectroscopic surveys of SSA22 to investigate the completeness of the LBGs and the X-Ray properties of the new spectroscopically-classified sources in the SSA22 field.

  13. Characterising galaxy groups: spectroscopic observations of the Shakhbazyan sample

    CERN Document Server

    Capozzi, Diego; Barbati, Silvio; Paolillo, Maurizio; De Filippis, Elisabetta; Longo, Giuseppe

    2012-01-01

    Groups of galaxies are the most common cosmic structures. However, due to the poor statistics, projection effects and the lack of accurate distances, our understanding of their dynamical and evolutionary status is still limited. This is particularly true for the so called Shakhbazyan groups (SHK) which are still largely unexplored due to the lack of systematic spectroscopic studies of both their member galaxies and the surrounding environment. In our previous paper, we investigated the statistical properties of a large sample of SHK groups using SDSS data and photometric redshifts. Here we present the follow-up of 5 SHK groups (SHK 10, 71, 75, 80, 259) observed within our spectroscopic campaign with the Telescopio Nazionale Galileo, aimed at confirming their physical reality and strengthening our photometric results. For each of the selected groups we were able to identify between 6 and 13 spectroscopic members, thus confirming the robustness of the photometric redshift approach in identifying real galaxy ove...

  14. Spectroscopic analysis of optoelectronic semiconductors

    CERN Document Server

    Jimenez, Juan

    2016-01-01

    This book deals with standard spectroscopic techniques which can be used to analyze semiconductor samples or devices, in both, bulk, micrometer and submicrometer scale. The book aims helping experimental physicists and engineers to choose the right analytical spectroscopic technique in order to get specific information about their specific demands. For this purpose, the techniques including technical details such as apparatus and probed sample region are described. More important, also the expected outcome from experiments is provided. This involves also the link to theory, that is not subject of this book, and the link to current experimental results in the literature which are presented in a review-like style. Many special spectroscopic techniques are introduced and their relationship to the standard techniques is revealed. Thus the book works also as a type of guide or reference book for people researching in optical spectroscopy of semiconductors.

  15. Composition dependence of the rate of bainitic transformation in Cu-Zn-Al alloys; Cu-Zn-Al gokin ni okeru bainite hentai sokudo no gokin sosei izonsei

    Energy Technology Data Exchange (ETDEWEB)

    Tabuchi, M.; Marukawa, K. [Hokkaido University, Sapporo (Japan). Faculty of Engineering

    1998-04-20

    The bainitic transformation is known to have an intermediate nature between the martensitic transformation and the diffusional transformation, while its transformation mechanism has not yet been clarified precisely. If this transformation involves lattice shearing like the martensitic transformation, it should take place more easily in those alloys which have a higher tendency to transform martensitically. On this expectation, the composition dependence of bainitic transformation kinetics has been studied in Cu-Zn-Al alloys. Especially, the relation between the martensitic transformation temperature (Ms) and the bainitic transformation rate was examined. The transformation process was traced by measuring the electrical resistivity of specimens during aging. It was found that the transformation rate is higher in those alloys having a higher Ms temperature. The activation energy for the process, obtained from its temperature dependence, is independent of the alloy composition and roughly equal to that for solute diffusion in the parent alloy. This indicates that the transformation is controlled by diffusion of solute atoms. The composition dependence of the bainitic transformation rate is discussed in terms of a diffusion controlled growth theory. 15 refs., 7 figs., 3 tabs.

  16. Compositional dependence of Pb(Mg1/3,Nb2/3)O3-PbTiO3 piezoelectric thin films by combinatorial sputtering

    Science.gov (United States)

    Kurokawa, Fumiya; Tsujiura, Yuichi; Hida, Hirotaka; Kanno, Isaku

    2014-09-01

    We evaluated the compositional dependence of Pb(Mg1/3,Nb2/3)O3-PbTiO3 (PMN-PT) polycrystalline thin films by combinatorial sputtering. We prepared compositional gradient (1 - x)PMN-xPT polycrystalline thin films with preferential orientation along the direction in the composition range of x = 0-0.62. We determined that the morphotropic phase boundary (MPB) composition of PMN-PT polycrystalline thin film existed at around x = 0.35, from the X-ray diffraction (XRD) measurements. The maximum value of relative dielectric constants (ɛr = 1498) was obtained at approximately x = 0.23. On the other hand, the piezoelectric coefficients (|e31,f| = 14.1 C/m2) peaked at the determined MPB composition of x = 0.35. From the results of the compositional dependence of dielectric and piezoelectric characteristics, the FOM (e_{31,\\text{f}}^{2}/\\varepsilon _{0}\\varepsilon _{\\text{r}}) of the PMN-PT (x = 0.35) thin film reached 21 GPa, which is much higher than that of the other polycrystalline piezoelectric thin films. These results suggest that PMN-PT (x = 0.35) thin film is a promising material for high-efficiency piezoelectric MEMS energy harvesters.

  17. Composition dependence of the synergistic effect of nucleating agent and plasticizer in poly(lactic acid: A Mixture Design study

    Directory of Open Access Journals (Sweden)

    M. K. Fehri

    2016-04-01

    Full Text Available Blends consisting of commercial poly(lactic acid (PLA, poly(lactic acid oligomer (OLA8 as plasticizer and a sulfonic salt of a phthalic ester and poly(D-lactic acid as nucleating agents were prepared by melt extrusion, following a Mixture Design approach, in order to systematically study mechanical and thermal properties as a function of composition. The full investigation was carried out by differential scanning calorimetry (DSC, dynamic mechanical thermal analysis (DMTA and tensile tests. The crystallization half-time was also studied at 105 °C as a function of the blends composition. A range of compositions in which the plasticizer and the nucleation agent minimized the crystallization half-time in a synergistic way was clearly identified thanks to the application of the Mixture Design approach. The results allowed also the identification of a composition range to maximize the crystallinity developed during the rapid cooling below glass transition temperature in injection moulding, thus allowing an easier processing of PLA based materials. Moreover the mechanical properties were discussed by correlating them to the chemical structural features and thermal behaviour of blends.

  18. A DVD Spectroscope: A Simple, High-Resolution Classroom Spectroscope

    Science.gov (United States)

    Wakabayashi, Fumitaka; Hamada, Kiyohito

    2006-01-01

    Digital versatile disks (DVDs) have successfully made up an inexpensive but high-resolution spectroscope suitable for classroom experiments that can easily be made with common material and gives clear and fine spectra of various light sources and colored material. The observed spectra can be photographed with a digital camera, and such images can…

  19. Composition dependent behavior in the ternary mixed magnetic insulator Co{sub 1−x}Mn{sub y}Ni{sub x−y}Cl{sub 2}·2H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    DeFotis, G.C., E-mail: gxdefo@wm.edu; Hampton, A.S.; Wallin, T.J.; Trowell, K.T.; Pothen, J.M.; Welshhans, E.A.; Havas, K.C.

    2016-05-01

    The properties of ternary mixed magnetic Co{sub 1−x}Mn{sub y}Ni{sub x−y}Cl{sub 2}·2H{sub 2}O are examined by dc magnetization and susceptibility measurements, from 1.8 to 300 K as a function of composition. This is only the second ternary magnetic insulator so studied. The three transition metal chloride dihydrate components are known to differ in the degree of spin anisotropy and in the distribution of ferromagnetic and antiferromagnetic exchange interactions within and between strongly coupled chemical and structural chains. The Curie and Weiss constants, in χ{sub M}=C/(T−θ) fits to high temperature susceptibilities, are compared with weighted averages of pure component values. The observed Weiss constant is almost uniformly less negative than calculated. Maxima in low temperature susceptibilities vary widely in presence and location with composition. Some compositions exhibit no susceptibility maximum, many exhibit one maximum, and three exhibit two maxima. A T(x,y) diagram is constructed. Magnetization vs field isotherms exhibit different shapes as a function of composition, with hysteresis markedly composition dependent. For three mixtures hysteresis loops are studied as a function of temperature. An activation process model does not describe the temperature dependence well.

  20. The HITRAN 2004 molecular spectroscopic database

    Energy Technology Data Exchange (ETDEWEB)

    Rothman, L.S. [Harvard-Smithsonian Center for Astrophysics, Atomic and Molecular Physics Division, Cambridge, MA 02138 (United States)]. E-mail: lrothman@cfa.harvard.edu; Jacquemart, D. [Harvard-Smithsonian Center for Astrophysics, Atomic and Molecular Physics Division, Cambridge, MA 02138 (United States); Barbe, A. [Universite de Reims-Champagne-Ardenne, Groupe de Spectrometrie Moleculaire et Atmospherique, 51062 Reims (France)] (and others)

    2005-12-01

    This paper describes the status of the 2004 edition of the HITRAN molecular spectroscopic database. The HITRAN compilation consists of several components that serve as input for radiative transfer calculation codes: individual line parameters for the microwave through visible spectra of molecules in the gas phase; absorption cross-sections for molecules having dense spectral features, i.e., spectra in which the individual lines are unresolvable; individual line parameters and absorption cross-sections for bands in the ultra-violet; refractive indices of aerosols; tables and files of general properties associated with the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for 39 molecules including many of their isotopologues. The format of the section of the database on individual line parameters of HITRAN has undergone the most extensive enhancement in almost two decades. It now lists the Einstein A-coefficients, statistical weights of the upper and lower levels of the transitions, a better system for the representation of quantum identifications, and enhanced referencing and uncertainty codes. In addition, there is a provision for making corrections to the broadening of line transitions due to line mixing.

  1. The Maunakea Spectroscopic Explorer: Science and Status

    Science.gov (United States)

    Hopkins, A.; McConnachie, A.; MSE Team

    2016-10-01

    MSE is a project to replace the current 3.6 m CFHT with a 10 m class, segmented, wide-field telescope that will feed a dedicated suite of multi-object spectrographs, operating at resolutions from R˜2000 to R>20000, and obtaining >3000 spectra per pointing (>> 5 million spectra/yr). It will use much of the existing infrastructure of the current CFHT, including the pier, and will closely approximate the envelope of the existing facility. MSE will be the only fully dedicated, 10 m class, wide-field spectroscopic telescope at first light in ˜ 2025. It will fill arguably the single biggest "missing link" in the international network of astronomical facilities. At optical wavelengths, LSST, WFIRST, Euclid, and Gaia will identify many millions of astrophysically interesting targets that otherwise lack the dedicated, large aperture, spectroscopic followup facilities required to probe their chemodynamical properties. Elsewhere, SKA, eRosita and others will provide a revolution in our understanding of the multiwavelength Universe. Among this capability, MSE will be an essential tool by providing the optical data that will otherwise be chronically absent.

  2. Composition dependence of the ferroelectric properties of lanthanum-modified bismuth titanate thin films grown by using pulsed-laser deposition

    CERN Document Server

    Bu, S D; Park, B H; Noh, T W

    2000-01-01

    Lanthanum-modified bismuth titanate, Bi sub 4 sub - sub x La sub x Ti sub 3 O sub 1 sub 2 (BLT), thin films with a La concentration of 0.25<=x<=1.00 were grown on Pt/Ti/SiO sub 2 /Si substrates by using pulsed-laser deposition. The BLT films showed well-saturated polarization-electric field curves whose remnant polarizations were 16.1 mu C/cm sup 2 , 27.8 mu C/cm sup 2 , 19.6 mu C/cm sup 2 , and 2.7 mu C/cm sup 2 , respectively, for x=0.25, 0.05, 0.75, and 1.00. The fatigue characteristics became better with increasing x up to 0.75. The Au/BLT/Pt capacitor with a La concentration of 0.50 showed an interesting dependence of the remanent polarization on the number of repetitive read/write cycles. On the other hand, the capacitor with a La concentration of 0.75 showed fatigue-free characteristics.

  3. Compositional Dependence of the Optical Properties of Amorphous Semiconducting Glass Se80Ge20- x Cd x (0 ≤ x ≤ 12 at.%) Thin Films

    Science.gov (United States)

    Hegab, N. A.; Farid, A. S.; Shakra, A. M.; Afifi, M. A.; Alrebati, A. M.

    2016-07-01

    Se80Ge20- x Cd x (0 ≤ x ≤ 12 at.%) compositions were prepared by a quenching technique. Thin films of the obtained compositions were deposited on dry clean glass substrates by a thermal evaporation technique. The chemical composition of the film samples have been determined by energy dispersive x-ray spectroscopy (EDX). X-ray diffraction measurements showed the amorphous nature of the studied films. The optical constants ( n, k) were determined for the studied films using spectrophotometric measurements of transmittance T( λ) in the wavelength range (350 nm to 2500 nm), and using Swanepoel's method. The values of the dispersion energy E d, oscillator energy E o, the lattice dielectric constant ɛ ∞L and the high-frequency dielectric constant ɛ s were determined. The optical band gap Eg^{{opt}} is estimated for all compositions from the absorption coefficient α. The analysis of the optical absorption data revealed the existence of allowed indirect transitions for all compositions. The effect of adding Cd content on the obtained optical parameters was also discussed.

  4. Nonlinearities in composition dependence of structure parameters and magnetic properties of nanocrystalline fcc/bcc-mixed Co-Ni-Fe thin films

    NARCIS (Netherlands)

    Chechenin, N. G.; Khomenko, E. V.; Vainchtein, D. I.; De Hosson, J. Th. M.

    2008-01-01

    In this report, the nonlinearities are analyzed in fcc-to-bcc (fcc/bcc) population ratio, lattice parameters (a(exp)(fcc)/a(ideal)(fcc) and a(exp)(bcc)/a(ideal)(bcc)) and saturation magnetization (I(S)(obs)/I(S)(a)) of the electrodeposited thin Co-Fe-Ni films as a function of average number of elect

  5. Composition-dependent trap distributions in CdSe and InP quantum dots probed using photoluminescence blinking dynamics

    Science.gov (United States)

    Chung, Heejae; Cho, Kyung-Sang; Koh, Weon-Kyu; Kim, Dongho; Kim, Jiwon

    2016-07-01

    Although Group II-VI quantum dots (QDs) have attracted much attention due to their wide range of applications in QD-based devices, the presence of toxic ions in II-VI QDs raises environmental concerns. To fulfill the demands of nontoxic QDs, synthetic routes for III-V QDs have been developed. However, only a few comparative analyses on optical properties of III-V QDs have been performed. In this study, the composition-related energetic trap distributions have been explored by using three different types of core/multishell QDs: CdSe-CdS (CdSe/CdS/ZnS), InP-ZnSe (InP/ZnSe/ZnS), and InP-GaP (InP/GaP/ZnS). It was shown that CdSe-CdS QDs have much larger trap densities than InP-shell QDs at higher energy states (at least 1Eg (band gap energy) above the lowest conduction band edge) based on probability density plots and Auger ionization efficiencies which are determined by analyses of photoluminescence blinking dynamics. This result suggests that the composition of encapsulated QDs is closely associated with the charge trapping processes, and also provides an insight into the development of more environmentally friendly QD-based devices.Although Group II-VI quantum dots (QDs) have attracted much attention due to their wide range of applications in QD-based devices, the presence of toxic ions in II-VI QDs raises environmental concerns. To fulfill the demands of nontoxic QDs, synthetic routes for III-V QDs have been developed. However, only a few comparative analyses on optical properties of III-V QDs have been performed. In this study, the composition-related energetic trap distributions have been explored by using three different types of core/multishell QDs: CdSe-CdS (CdSe/CdS/ZnS), InP-ZnSe (InP/ZnSe/ZnS), and InP-GaP (InP/GaP/ZnS). It was shown that CdSe-CdS QDs have much larger trap densities than InP-shell QDs at higher energy states (at least 1Eg (band gap energy) above the lowest conduction band edge) based on probability density plots and Auger ionization

  6. How spectroscopic ellipsometry can aid graphene technology?

    Energy Technology Data Exchange (ETDEWEB)

    Losurdo, Maria, E-mail: maria.losurdo@cnr.it; Giangregorio, Maria M.; Bianco, Giuseppe V.; Capezzuto, Pio; Bruno, Giovanni

    2014-11-28

    We explore the effects of substrate, grain size, oxidation and cleaning on the optical properties of chemical vapor deposited polycrystalline monolayer graphene exploiting spectroscopic ellipsometry in the NIR-Vis–UV range. Both Drude–Lorentz oscillators' and point-by-point fit approaches are used to analyze the ellipsometric spectra. For monolayer graphene, since anisotropy cannot be resolved, an isotropic model is used. A prominent absorption peak at approximately 4.8 eV, which is a mixture of π–π* interband transitions at the M-point of the Brillouin zone and of the π-plasmonic excitation, is observed. We discuss the sensitivity of this peak to the structural and cleaning quality of graphene. The comparison with previous published dielectric function spectra of graphene is discussed giving a rationale for the observed differences. - Highlights: • Optical properties of graphene are determined by ellipsometry on copper and on glass. • Optical spectra reveal the cleaning quality of transferred graphene. • Sensitivity of absorption peak to graphene structural quality is proven. • Optical properties are proven to be sensitive to oxidation of graphene. • Electronic interaction with substrate affects graphene optical properties.

  7. Spectroscopic and chemometric exploration of food quality

    DEFF Research Database (Denmark)

    Pedersen, Dorthe Kjær

    2002-01-01

    The desire to develop non-invasive rapid measurements of essential quality parameters in foods is the motivation of this thesis. Due to the speed and noninvasive properties of spectroscopic techniques, they have potential as on-line or atline methods and can be employed in the food industry...... in order to control the quality of the end product and to continuously monitor the production. In this thesis, the possibilities and limitations of the application of spectroscopy and chemometrics in rapid control of food quality are discussed and demonstrated by the examples in the eight included...... publications. Different aspects of food quality are covered, but the focus is mainly on the development of multivariate calibrations for predictions of rather complex attributes such as the water-holding capacity of meat, ethical quality of the slaughtering procedure, protein content of single wheat kernels...

  8. Selective spectroscopic methods for water analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vaidya, Bikas [Iowa State Univ., Ames, IA (United States)

    1997-06-24

    This dissertation explores in large part the development of a few types of spectroscopic methods in the analysis of water. Methods for the determination of some of the most important properties of water like pH, metal ion content, and chemical oxygen demand are investigated in detail. This report contains a general introduction to the subject and the conclusions. Four chapters and an appendix have been processed separately. They are: chromogenic and fluorogenic crown ether compounds for the selective extraction and determination of Hg(II); selective determination of cadmium in water using a chromogenic crown ether in a mixed micellar solution; reduction of chloride interference in chemical oxygen demand determination without using mercury salts; structural orientation patterns for a series of anthraquinone sulfonates adsorbed at an aminophenol thiolate monolayer chemisorbed at gold; and the role of chemically modified surfaces in the construction of miniaturized analytical instrumentation.

  9. Spectroscopic sensitive polarimeter for biomedical applications.

    Science.gov (United States)

    Ramella-Roman, Jessica C; Nayak, Amritha; Prahl, Scott A

    2011-04-01

    We present the design and calibration of a spectroscopic sensitive polarimeter. The polarimeter can measure the full Stokes vector in the wavelength range 550 to 750 nm with 1-nm resolution and consists of a fiber-based spectrophotometer, a white light emitting diode light source, two liquid crystal retarders, and one polarizer. Calibration of the system is achieved with a scheme that does not require knowledge of the polarizing elements' orientation or retardation. Six intensity spectra are required to calculate the full spectrum Stokes vector. Error in the polarimeter is less than 5%. We report the Stokes vectors for light transmitted through nonscattering polarizing elements as well as a measurement of the depolarizing properties of chicken muscle at several wavelengths.

  10. Property.

    Science.gov (United States)

    Piele, Philip K.

    Chapter 7 of a book on school law, this chapter deals with 1979 cases involving disputes over property. Cases involving taxpayer attempts to prevent the construction of school buildings dominate this year's property chapter, as they did last year's. Yet, paradoxically, there is also a significant increase in cases in which taxpayers tried to…

  11. Synthesis, structural and spectroscopic evaluations and nonlinear optical properties of 3,5-bis(4-methoxyphenyl)-4,5-dihydro-1H-pyrazole-1-carbothioic O-acid

    Science.gov (United States)

    Tamer, Ömer; Dege, Necmi; Avcı, Davut; Atalay, Yusuf; Özer İlhan, İlhan; Çadır, Mehmet

    2015-02-01

    In this study, we report a combined experimental and theoretical study on 3,5-bis(4-methoxyphenyl)-4,5-dihydro-1H-pyrazole-1-carbothioic O-acid (C18H18N2O3S) molecule. The compound crystallizes in the trigonal space group R-3 with a = b = 27.7151(12) Å, c = 12.4866(6) Å, α = β = 90.0°, γ = 120.0° and Z = 18. The crystal packing is stabilized by Osbnd H⋯O and Osbnd H⋯S intermolecular hydrogen bonds. These hydrogen bond interactions are also proved by NBO analysis. A detailed spectroscopic investigation is performed by the application of FT-IR and FT-NMR in addition to the theoretical approaches. Small energy gap between the frontier molecular orbitals is responsible for the nonlinear optical activity of the title molecule.

  12. The APOKASC Catalog: An Asteroseismic and Spectroscopic Joint Survey of Targets in the Kepler Fields

    CERN Document Server

    Pinsonneault, Marc H; Epstein, Courtney; Hekker, Saskia; Mészáros, Sz; Chaplin, William J; Johnson, Jennifer A; García, Rafael A; Holtzman, Jon; Mathur, Savita; Pérez, Ana García; Aguirre, Victor Silva; Girardi, Léo; Basu, Sarbani; Shetrone, Matthew; Stello, Dennis; Prieto, Carlos Allende; An, Deokkeun; Beck, Paul; Beers, Timothy C; Bizyaev, Dmitry; Bloemen, Steven; Bovy, Jo; Cunha, Katia; De Ridder, Joris; Frinchaboy, Peter M; Garcia-Hernández, D A; Gilliland, Ronald; Harding, Paul; Hearty, Fred R; Huber, Daniel; Ivans, Inese; Kallinger, Thomas; Majewski, Steven R; Metcalfe, Travis S; Miglio, Andrea; Mosser, Benoit; Muna, Demitri; Nidever, David L; Schneider, Donald P; Serenelli, Aldo; Smith, Verne V; Tayar, Jamie; Zamora, Olga; Zasowski, Gail

    2014-01-01

    We present the first APOKASC catalog of spectroscopic and asteroseismic properties of 1916 red giants observed in the Kepler fields. The spectroscopic parameters provided from the Apache Point Observatory Galactic Evolution Experiment project are complemented with asteroseismic surface gravities, masses, radii, and mean densities determined by members of the Kepler Asteroseismology Science Consortium. We assess both random and systematic sources of error and include a discussion of sample selection for giants in the Kepler fields. Total uncertainties in the main catalog properties are of order 80 K in Teff , 0.06 dex in [M/H], 0.014 dex in log g, and 12% and 5% in mass and radius, respectively; these reflect a combination of systematic and random errors. Asteroseismic surface gravities are substantially more precise and accurate than spectroscopic ones, and we find good agreement between their mean values and the calibrated spectroscopic surface gravities. There are, however, systematic underlying trends with...

  13. The 1997 spectroscopic GEISA databank.

    Science.gov (United States)

    Jacquinet-Husson, N.; Arie, E.; Ballard, J.; Barbe, A.; Bjoraker, G.; Bonnet, B.; Brown, L. R.; Camy-Peyret, C.; Champion, J. P.; Chedin, A.; Chursin, A.; Clerbaux, C.; Duxbury, G.; Flaud, J.-M.; Fourrie, N.; Fayt, A.; Graner, G.; Gamache, R.; Goldman, A.; Golovko, V.; Guelachvili, G.; Hartmann, J. M.; Hilico, J. C.; Hillman, J.; Lefevre, G.; Lellouch, E.; Mikhailenko, S. N.; Naumenko, O. V.; Nemtchinov, V.; Newnham, D. A.; Nikitin, A.; Orphal, J.; Perrin, A.; Reuter, D. C.; Rinsland, C. P.; Rosenmann, L.; Rothman, L. S.; Scott, N. A.; Selby, J.; Sinitsa, L. N.; Sirota, J. M.; Smith, A. M.; Smith, K. M.; Tyuterev, V. G.; Tipping, R. H.; Urban, S.; Varanasi, P.; Weber, M.

    1999-05-01

    The current version GEISA-97 of the computer-accessible database system GEISA (Gestion et Etude des Informations Spectroscopiques Atmospheriques: Management and Study of Atmospheric Spectroscopic Information) is described. This catalogue contains 1,346,266 entries. These are the spectroscopic parameters required to describe adequately the individual spectral lines belonging to 42 molecules (96 isotopic species) and located between 0 and 22656 cm-1. The featured molecules are of interest in studies of the terrestrial as well as the other planetary atmospheres, especially those of the giant planets. GEISA-97 contains also a catalog of absorption cross-sections of molecules such as chlorofluorocarbons which exhibit unresolvable spectra. The modifications and improvements made to the earlier edition (GEISA-92) and the data management software are described.

  14. Single nanoparticle tracking spectroscopic microscope

    Science.gov (United States)

    Yang, Haw [Moraga, CA; Cang, Hu [Berkeley, CA; Xu, Cangshan [Berkeley, CA; Wong, Chung M [San Gabriel, CA

    2011-07-19

    A system that can maintain and track the position of a single nanoparticle in three dimensions for a prolonged period has been disclosed. The system allows for continuously imaging the particle to observe any interactions it may have. The system also enables the acquisition of real-time sequential spectroscopic information from the particle. The apparatus holds great promise in performing single molecule spectroscopy and imaging on a non-stationary target.

  15. Multi-pass spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Stehle, Jean-Louis [Sopralab, 7 rue du Moulin des Bruyeres, 92400 Courbevoie (France); Samartzis, Peter C., E-mail: sama@iesl.forth.gr [Institute of Electronic Structure and Laser, Foundation of Research and Technology-Hellas, Vassilika Vouton 71110, Heraklion Crete (Greece); Stamataki, Katerina [Institute of Electronic Structure and Laser, Foundation of Research and Technology-Hellas, Vassilika Vouton 71110, Heraklion Crete (Greece); Department of Chemistry, University of Crete, Voutes, 71003, Heraklion (Greece); Piel, Jean-Philippe [Sopralab, 7 rue du Moulin des Bruyeres, 92400 Courbevoie (France); Katsoprinakis, George E.; Papadakis, Vassilis [Institute of Electronic Structure and Laser, Foundation of Research and Technology-Hellas, Vassilika Vouton 71110, Heraklion Crete (Greece); Schimowski, Xavier [Sopralab, 7 rue du Moulin des Bruyeres, 92400 Courbevoie (France); Rakitzis, T. Peter [Institute of Electronic Structure and Laser, Foundation of Research and Technology-Hellas, Vassilika Vouton 71110, Heraklion Crete (Greece); Department of Physics, University of Crete, Voutes, 71003, Heraklion (Greece); Loppinet, Benoit [Institute of Electronic Structure and Laser, Foundation of Research and Technology-Hellas, Vassilika Vouton 71110, Heraklion Crete (Greece)

    2014-03-31

    Spectroscopic ellipsometry is an established technique, particularly useful for thickness measurements of thin films. It measures polarization rotation after a single reflection of a beam of light on the measured substrate at a given incidence angle. In this paper, we report the development of multi-pass spectroscopic ellipsometry where the light beam reflects multiple times on the sample. We have investigated both theoretically and experimentally the effect of sample reflectivity, number of reflections (passes), angles of incidence and detector dynamic range on ellipsometric observables tanΨ and cosΔ. The multiple pass approach provides increased sensitivity to small changes in Ψ and Δ, opening the way for single measurement determination of optical thickness T, refractive index n and absorption coefficient k of thin films, a significant improvement over the existing techniques. Based on our results, we discuss the strengths, the weaknesses and possible applications of this technique. - Highlights: • We present multi-pass spectroscopic ellipsometry (MPSE), a multi-pass approach to ellipsometry. • Different detectors, samples, angles of incidence and number of passes were tested. • N passes improve polarization ratio sensitivity to the power of N. • N reflections improve phase shift sensitivity by a factor of N. • MPSE can significantly improve thickness measurements in thin films.

  16. Spectroscopic neutron detection using composite scintillators

    Science.gov (United States)

    Jovanovic, I.; Foster, A.; Kukharev, V.; Mayer, M.; Meddeb, A.; Nattress, J.; Ounaies, Z.; Trivelpiece, C.

    2016-09-01

    Shielded special nuclear material (SNM), especially highly enriched uranium, is exceptionally difficult to detect without the use of active interrogation (AI). We are investigating the potential use of low-dose active interrogation to realize simultaneous high-contrast imaging and photofission of SNM using energetic gamma-rays produced by low-energy nuclear reactions, such as 11B(d,nγ)12C and 12C(p,p‧)12C. Neutrons produced via fission are one reliable signature of the presence of SNM and are usually identified by their unique timing characteristics, such as the delayed neutron die-away. Fast neutron spectroscopy may provide additional useful discriminating characteristics for SNM detection. Spectroscopic measurements can be conducted by recoil-based or thermalization and capture-gated detectors; the latter may offer unique advantages since they facilitate low-statistics and event-by-event neutron energy measurements without spectrum unfolding. We describe the results of the development and characterization of a new type of capture-gated spectroscopic neutron detector based on a composite of scintillating polyvinyltoluene and lithium-doped scintillating glass in the form of millimeter-thick rods. The detector achieves >108 neutron-gamma discrimination resulting from its geometric properties and material selection. The design facilitates simultaneous pulse shape and pulse height discrimination, despite the fact that no materials intrinsically capable of pulse shape discrimination have been used to construct the detector. Accurate single-event measurements of neutron energy may be possible even when the energy is relatively low, such as with delayed fission neutrons. Simulation and preliminary measurements using the new composite detector are described, including those conducted using radioisotope sources and the low-dose active interrogation system based on low-energy nuclear reactions.

  17. Antioxidant activities and infrared spectroscopic properties of extract from litchi seeds%荔枝核提取物抗氧化活性及红外光谱特性

    Institute of Scientific and Technical Information of China (English)

    江敏; 胡小军; 陈晓林; 李土珍

    2011-01-01

    以荔枝核为原料,以95%的乙醇为提取剂,在超声波的作用下得到荔枝核乙醇提取物。利用提取物对DPPH自由基和羟自由基的清除能力评价其抗氧化活性;同时测定了提取物的总还原能力和总的抗氧化性。最后通过红外光谱对提取物进行了定性分析。实验结果表明:荔枝核提取物具有很强的抗氧化活性,其抗氧化能力大5-BHT,小于维生素C;荔枝核提取物清除DPPH·和·OH的IC50分别为0.032、0.160mg/mL。每克荔枝核提取物总抗氧化能力相当于210mgVc的总抗氧化能力:从红外光谱的结果可知,荔枝核提取物主要为黄酮类物质。%The dried samples of litchi seeds were cut into small pieces and soaked in 95% (v/v) ethanolic aqueous solution under the ultrasonic for some time. The extract was decanted,filtered under vacuum, concentrated in a rotary evaporator,and then lyophilized. The resulting extracts were employed for the current study. DPPH radical and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. Total reducing power and antioxidant capacity of the extract were determined at the same time. Qualitative analysis of the extract was studied by infrared spectroscopic. The experiment results showed that the extract could play an important role in the antioxidant activity. The order of antioxidant was Vc〉 extract〉BHT. The IC50 values of extract against DPPH radical and hydroxyl radical were 0.032mg/mL and 0.160mg/mL, respectively. Total antioxidant capacity of per gram extract was equal to 210mg Vc. Main component of the extract was flavonoid from infrared spectroscopic.

  18. Role of nickel ion coordination on spectroscopic properties of multi-component CaF2-Bi2O3-P2O5-B2O3 glass-ceramics

    Science.gov (United States)

    Suresh, S.; Narendrudu, T.; Kumar, A. Suneel; Rao, M. V. Sambasiva; Ram, G. Chinna; Rao, D. Krishna

    2016-10-01

    Multi-component CaF2-Bi2O3-P2O5-B2O3 glasses doped with different concentrations of NiO were crystallized through heat treatment. The prepared glass ceramic samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), differential thermal analysis (DTA) as well as conventional spectroscopic studies viz., optical absorption, Fourier transform infrared (FTIR) and Raman. The XRD and SEM studies have indicated that the samples contain well defined and randomly distributed grains of different crystalline phases. The optical absorption studies together with FTIR and Raman measurements indicated the gradual transformation of nickel ions from tetrahedral sites to octahedral sites (lasing sites) as the concentration of NiO is increased beyond 1.5 mol%. All these investigations have indicated that the growing degree of disorder in the glass ceramic network at higher concentrations of NiO. Glass ceramics doped with NiO beyond 1.5 mol% appear to be suitable for getting laser emission due to 3T2(F) → 3A2(F) transition in NIR region. These glass-ceramics can be expected as an amplification medium for tunable lasers and broadband optical amplifiers for wavelength division multiplexing transmission system.

  19. The GEISA Spectroscopic Database System in its latest Edition

    Science.gov (United States)

    Jacquinet-Husson, N.; Crépeau, L.; Capelle, V.; Scott, N. A.; Armante, R.; Chédin, A.

    2009-04-01

    GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Spectroscopic Information)[1] is a computer-accessible spectroscopic database system, designed to facilitate accurate forward planetary radiative transfer calculations using a line-by-line and layer-by-layer approach. It was initiated in 1976. Currently, GEISA is involved in activities related to the assessment of the capabilities of IASI (Infrared Atmospheric Sounding Interferometer on board the METOP European satellite -http://earth-sciences.cnes.fr/IASI/)) through the GEISA/IASI database[2] derived from GEISA. Since the Metop (http://www.eumetsat.int) launch (October 19th 2006), GEISA/IASI is the reference spectroscopic database for the validation of the level-1 IASI data, using the 4A radiative transfer model[3] (4A/LMD http://ara.lmd.polytechnique.fr; 4A/OP co-developed by LMD and Noveltis with the support of CNES). Also, GEISA is involved in planetary research, i.e.: modelling of Titan's atmosphere, in the comparison with observations performed by Voyager: http://voyager.jpl.nasa.gov/, or by ground-based telescopes, and by the instruments on board the Cassini-Huygens mission: http://www.esa.int/SPECIALS/Cassini-Huygens/index.html. The updated 2008 edition of GEISA (GEISA-08), a system comprising three independent sub-databases devoted, respectively, to line transition parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols, will be described. Spectroscopic parameters quality requirement will be discussed in the context of comparisons between observed or simulated Earth's and other planetary atmosphere spectra. GEISA is implemented on the CNES/CNRS Ether Products and Services Centre WEB site (http://ether.ipsl.jussieu.fr), where all archived spectroscopic data can be handled through general and user friendly associated management software facilities. More than 350 researchers are

  20. Monte-Carlo Analysis of the Composition Dependence of the Flory-Huggins Interaction Parameter in PE-dPE Blends

    Science.gov (United States)

    Russell, Travis; Edwards, Brian; Khomami, Bamin

    2012-02-01

    Experimental SANS research displays a significant concentration dependence of the Flory-Huggins (χ) interaction parameter in isotopic polymer blends. At the extremes of the deuterated polymer concentration (φD 0.8), χ is shown to exhibit a greater than fourfold increase over its value at φD = 0.5. However, despite numerous attempts to theoretically describe the nature of this phenomenon, consensus is still lacking regarding the mechanisms at work in this system. This study uses free-space, spatially discretized Monte Carlo simulations to investigate the χ composition dependence of PE-dPE blends. Initial simulations are run on simple Lennard-Jones fluids to display the capability of the simulation method to track local concentration and energy across the discretized space as well as to investigate the concentration dependence of the radial distribution function, g(r), and structure factor, S(k). After which, MC simulations are performed on the PE-dPE system with varying φD. Both local and average system energies are tracked in addition to g(r) and S(k). The Flory-Huggins interaction parameter is then calculated using the Random Phase Approximation.

  1. Study of CoFeB thickness and composition dependence in a modified CoFeB/MgO/CoFeB perpendicular magnetic tunnel junction

    Science.gov (United States)

    Zhu, M.; Chong, H.; Vu, Q. B.; Brooks, R.; Stamper, H.; Bennett, S.

    2016-02-01

    We studied the CoFeB thickness and composition dependence of tunneling magnetoresistance (TMR) and resistance-area product (RA) in a modified CoFeB/MgO/CoFeB perpendicular magnetic tunnel junction (MTJ), in which the bottom CoFeB is coupled to an in-plane exchange biased magnetic layer. This stack structure allows us to measure TMR and RA of the MTJs in sheet film format without patterning them, using current-in-plane-tunneling (CIPT) technique. The thickness ranges for both top and bottom CoFeB to exhibit perpendicular magnetic anisotropy are similar to what are seen in each single magnetic film stack. However, CIPT measurement revealed that there exists an optimal thickness for both top and bottom CoFeB to achieve the highest TMR value. Magnetic hysteresis loops also suggest the thickness-dependent coupling between the top and bottom CoFeB layers. We studied MTJs with two CoFeB compositions (Co40Fe40B20 and Co20Fe60B20) and found that Co20Fe60B20 MTJs give higher TMR and also wider perpendicular thickness range when used at the top layer.

  2. Simultaneous tracer diffusion and interdiffusion in a sandwich-type configuration to provide the composition dependence of the tracer diffusion coefficients

    Science.gov (United States)

    Belova, I. V.; Kulkarni, N. S.; Sohn, Y. H.; Murch, G. E.

    2014-11-01

    In this paper, a new formalism of a combined tracer and interdiffusion experiment for a binary interdiffusion couple is developed. The analysis requires an interdiffusion couple that initially contains a thin layer of tracers of one or both of the constituent elements at the original interface of the couple (sandwich interdiffusion experiment). This type of interdiffusion experiment was first performed in 1958 by J.R. Manning. The theoretical analysis presented in this paper is based on a newly developed phenomenological theory of isotopic interdiffusion combined with the Boltzmann-Matano formalism. This new analysis now provides the means to obtain the composition dependent interdiffusion coefficient and tracer diffusion coefficients simultaneously from analysis of the interdiffusion and tracer profiles in a single sandwich interdiffusion experiment. The new analysis is successfully applied to the results of Manning's original 'sandwich interdiffusion' experiment in the Ag-Cd system (six couples in total) and is validated with an independent determination of the Ag and Cd tracer diffusion coefficients by Schoen using the conventional thin film technique. Suggestions for further development of the sandwich interdiffusion experiment and analysis to the case of multicomponent alloys are provided.

  3. Chiral Ionic Liquids in Chromatographic Separation and Spectroscopic Discrimination

    Science.gov (United States)

    Li, Min; Bwambok, David K.; Fakayode, Sayo O.; Warner, Isiah M.

    Chiral ionic liquids (CILs) are a subclass of ionic liquids (ILs) in which the cation, anion, or both may be chiral. The chirality can be central, axial, or planar. CILs possess a number of unique advantageous properties which are inherited from ionic liquids including negligible vapor pressure, wide liquidus temperature range, high thermal stability, and high tunability. Due to their dual functionalities as chiral selectors and chiral solvents simultaneously, CILs recently have been widely used both in enantiomeric chromatographic separation and in chiral spectroscopic discrimination. In this chapter, the various applications of CILs in chiral chromatographic separations such as GC, HPLC, CE, and MEKC are reviewed. The applications of CILs in enantiomeric spectroscopic discrimination using techniques such as NMR, fluorescence, and NIR are described. In addition, chiral recognition and separation mechanism using the CILs as chiral selectors or chiral solvents is also discussed.

  4. Spectroscopic Studies of the Several Isomers of UO3

    Energy Technology Data Exchange (ETDEWEB)

    Sweet, Lucas E.; Reilly, Dallas D.; Abrecht, David G.; Buck, Edgar C.; Meier, David E.; Su, Yin-Fong; Brauer, Carolyn S.; Schwantes, Jon M.; Tonkyn, Russell G.; Szecsody, James E.; Blake, Thomas A.; Johnson, Timothy J.

    2013-09-26

    Uranium trioxide is known to adopt seven different structural forms. While these structural forms have been well characterized using x-ray or neutron diffraction techniques, little work has been done to characterize their spectroscopic properties, particularly of the pure phases. Since the structural isomers of UO3 all have similar thermodynamic stabilities and most tend to hydrolyze under open atmospheric conditions, mixtures of UO3 phases and the hydrolysis products are common. Much effort went into isolating pure phases of UO3. Utilizing x-ray diffraction as a sample identification check, UV/Vis/NIR spectroscopic signatures of α-UO3, β-UO3, γ-UO3 and UO2(OH)2 products were obtained. The spectra of the pure phases can now be used to characterize typical samples of UO3, which are often mixtures of isomers.

  5. The spectroscopic Hertzsprung-Russell diagram of Galactic massive stars

    CERN Document Server

    Castro, N; Langer, N; Simón-Díaz, S; Schneider, F R N; Izzard, R G

    2014-01-01

    The distribution of stars in the Hertzsprung-Russell diagram narrates their evolutionary history and directly assesses their properties. Placing stars in this diagram however requires the knowledge of their distances and interstellar extinctions, which are often poorly known for Galactic stars. The spectroscopic Hertzsprung-Russell diagram (sHRD) tells similar evolutionary tales, but is independent of distance and extinction measurements. Based on spectroscopically derived effective temperatures and gravities of almost 600 stars, we derive for the first time the observational distribution of Galactic massive stars in the sHRD. While biases and statistical limitations in the data prevent detailed quantitative conclusions at this time, we see several clear qualitative trends. By comparing the observational sHRD with different state-of-the-art stellar evolutionary predictions, we conclude that convective core overshooting may be mass-dependent and, at high mass ($\\geq 15\\,M_\\odot$), stronger than previously thou...

  6. Spectroscopic investigation of local mechanical impedance of living cells

    CERN Document Server

    Costa, Luca; Benseny-Cases, Núria; Mayeaux, Véronique; Chevrier, Joël; Comin, Fabio

    2013-01-01

    The mechanical properties of PC12 living cells have been studied at the nanoscale with a Force Feedback Microscope using two experimental approaches. Firstly, the local mechanical impedance of the cell membrane has been mapped simultaneously to the cell morphology at constant force. As the force of the interaction is gradually increased, we observed the appearance of the sub-membrane cytoskeleton. We shall compare the results obtained with this method with the measurement of other existing techniques. Secondly, a spectroscopic investigation has been performed varying the indentation of the tip in the cell membrane and consequently the force applied on it. In contrast with conventional dynamic atomic force microscopy techniques, here the small oscillation amplitude of the tip is not necessarily imposed at the cantilever first eigenmode. This allows the user to arbitrarily choose the excitation frequency in developing spectroscopic AFM techniques. The mechanical response of the PC12 cell membrane is found to be...

  7. Synthesis, structure, and spectroscopic properties of chiral oxorhenium(V) complexes incorporating polydentate ligands derived from L-amino acids: a density functional theory/time-dependent density functional theory investigation.

    Science.gov (United States)

    Basak, Sucharita; Rajak, Kajal Krishna

    2008-10-06

    The oxorhenium(V) complexes [Re (V)O(L A)Cl 2] bearing the (N-2-pyridylmethyl) of l-valine (HL A (1)), l-leucine (HL A (2)), and l-phenylalanine (HL A (3)) and [Re (V)O(L B)Cl] containing the {(N-2pyridylmethyl)-(N-(5-nitro-2-hydroxybenzyl)} of l-valine (H 2L B (1)), l-leucine (H 2L B (2)), and l-phenylalanine (H 2L B (3)) are presented in this article. The complexes are isolated in enantiomeric pure form examined from X-ray structure determination. The complexes are characterized by spectroscopic and electrochemical methods. The molecular structures observed in the solid state are grossly preserved in solution ( (1)H, (13)C, and circular dichroism spectra). Gas-phase geometry optimization and the electronic structures of [Re (V)O(L A (1))Cl 2], [Re (V)O(L A (2))Cl 2], and [Re (V)O(L B (2))Cl] have been investigated with the framework of density functional theory. The absorption and circular dichroism spectra of the complexes were also calculated applying time-dependent density functional theory (TDDFT) using the conductor-like polarizable continuum solvent model to understand the origin of the electronic excitations. The chemical shift ( (1)H and (13)C) as well as (1)H- (1)H spin-spin coupling constant were also computed by the gauge-independent atomic orbital method, and the computed values are consistent with the experimental data.

  8. Synthesis and electrical, spectroscopic and nonlinear optical properties of cobalt molecular materials obtained from PcCo(CN)L (L = ethylenediamine, 1,4-diaminebutane, 1,12-diaminododecane and 2,6-diamineanthraquinone)

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Saavedra, O.G., E-mail: omar.morales@ccadet.unam.mx [Lab. of Nonlinear Optics, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, CCADET-UNAM, Apdo, Postal 70-186, C.P. 04510 Coyoacan, Cd. Universitaria, Mexico D. F. (Mexico); Sanchez-Vergara, M.E. [Coordinacion de Ingenieria Mecatronica, Facultad de Ingenieria, Universidad Anahuac del Norte, Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786 Huixquilucan, Estado de Mexico (Mexico); Rodriguez-Rosales, A.A.; Ortega-Martinez, R. [Lab. of Nonlinear Optics, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, CCADET-UNAM, Apdo, Postal 70-186, C.P. 04510 Coyoacan, Cd. Universitaria, Mexico D. F. (Mexico); Ortiz-Rebollo, A. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, IIM-UNAM, A.P. 70-360 Coyoacan, 04510 Mexico D. F. (Mexico); Frontana-Uribe, B.A. [Centro Conjunto de Investigacion en Quimica Sustentable UAEM-UNAM Km. 14.5, Carretera Toluca-Atlacomulco, C.P. 50200 Toluca, Estado de Mexico (Mexico); Garcia-Montalvo, V. [Instituto de Quimica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico D. F. 04510 (Mexico)

    2010-10-01

    Novel PcCo(CN)L monomeric complexes were synthesized from [PcCoCN]{sub n} compounds and bidentate axial ligands (L) such as ethylenediamine, 1,4-diaminebutane, 1,12-diaminedodecane and 2,6-diamineanthraquinone. These complexes were implemented to fabricate pellets and thin films by the vacuum thermal evaporation technique. The obtained compounds and deposited thin films were characterized by different spectroscopic techniques. Measurements of the electrical conductivity and the electrical current as a function of temperature were also carried out. IR-spectroscopy studies showed that the ligand attaches to the [PcCoCN]{sub n} unit. The C=N vibrational band is found in the PcCo(et)CN and PcCo(bu)CN molecular solids, although it is displaced with respect to other reported values. Compounds PcCo(do){sub 2} and PcCo(an){sub 2} do not show C=N vibrational bands. This fact suggests a double bond between the ligand and the macrocycle and a coordination at the fifth and sixth position on the Co(III) atom. UV-vis spectra of the thin films exhibited higher conjugation degree for the CN-based samples. Electrical conductivity for the PcCo(an){sub 2} complex was consistently low for all temperature ranges under measurement, whereas the other synthesized compounds showed a semiconductor-like dependence of electric current with temperature. Additionally, cubic nonlinear optical (NLO) characterizations of the film samples were performed with the Z-Scan and third harmonic generation (THG) techniques, all samples exhibit outstandingly high nonlinear activity.

  9. The TNG EROs Spectroscopic Identification Survey (TESIS)

    CERN Document Server

    Saracco, P; Ceca, R D; Severgnini, P; Braito, V; Bender, R; Drory, N; Feulner, G; Hopp, U; Mannucci, F; Maraston, C

    2003-01-01

    We are carrying on a near-IR very low resolution spectroscopic follow-up in parallel with XMM-Newton observations of a complete sample of ~30 bright (K'<18.5) Extremely Red Objects (EROs) selected over an area of 360 arcmin^2 of the MUNICS survey. We here present the preliminary results of the spectroscopic and X-ray data analysis.

  10. Raman Spectroscopic Studies of Methane Gas Hydrates

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.

    2009-01-01

    A brief review of the Raman spectroscopic studies of methane gas hydrates is given, supported by some new measurements done in our laboratory.......A brief review of the Raman spectroscopic studies of methane gas hydrates is given, supported by some new measurements done in our laboratory....

  11. The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Continuum Number Counts, Resolved 1.2 mm Extragalactic Background, and Properties of the Faintest Dusty Star-forming Galaxies

    Science.gov (United States)

    Aravena, M.; Decarli, R.; Walter, F.; Da Cunha, E.; Bauer, F. E.; Carilli, C. L.; Daddi, E.; Elbaz, D.; Ivison, R. J.; Riechers, D. A.; Smail, I.; Swinbank, A. M.; Weiss, A.; Anguita, T.; Assef, R. J.; Bell, E.; Bertoldi, F.; Bacon, R.; Bouwens, R.; Cortes, P.; Cox, P.; Gónzalez-López, J.; Hodge, J.; Ibar, E.; Inami, H.; Infante, L.; Karim, A.; Le Le Fèvre, O.; Magnelli, B.; Ota, K.; Popping, G.; Sheth, K.; van der Werf, P.; Wagg, J.

    2016-12-01

    We present an analysis of a deep (1σ = 13 μJy) cosmological 1.2 mm continuum map based on ASPECS, the ALMA