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Sample records for spectroscopic ellipsometry studies

  1. Albumin adsorption on oxide thin films studied by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Silva-Bermudez, P., E-mail: suriel21@yahoo.com [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, C.U., 04510, Mexico D.F. (Mexico); Unidad de Posgrado, Facultad de Odontologia, Universidad Nacional Autonoma de Mexico, CU, 04510, Mexico D.F. (Mexico); Rodil, S.E.; Muhl, S. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, C.U., 04510, Mexico D.F. (Mexico)

    2011-12-15

    Thin films of tantalum, niobium, zirconium and titanium oxides were deposited by reactive magnetron sputtering and their wettability and surface energy, optical properties, roughness, chemical composition and microstructure were characterized using contact angle measurements, spectroscopic ellipsometry, profilometry, X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The purpose of the work was to correlate the surface properties of the films to the Bovine Serum Albumin (BSA) adsorption, as a first step into the development of an initial in vitro test of the films biocompatibility, based on standardized protein adsorption essays. The films were immersed into BSA solutions with different protein concentrations and protein adsorption was monitored in situ by dynamic ellipsometry; the adsorption-rate was dependent on the solution concentration and the immersion time. The overall BSA adsorption was studied in situ using spectroscopic ellipsometry and it was found to be influenced by the wettability of the films; larger BSA adsorption occurred on the more hydrophobic surface, the ZrO{sub 2} film. On the Ta{sub 2}O{sub 5}, Nb{sub 2}O{sub 5} and TiO{sub 2} films, hydrophilic surfaces, the overall BSA adsorption increased with the surface roughness or the polar component of the surface energy.

  2. Mueller matrix spectroscopic ellipsometry study of chiral nanocrystalline cellulose films

    Science.gov (United States)

    Mendoza-Galván, Arturo; Muñoz-Pineda, Eloy; Ribeiro, Sidney J. L.; Santos, Moliria V.; Järrendahl, Kenneth; Arwin, Hans

    2018-02-01

    Chiral nanocrystalline cellulose (NCC) free-standing films were prepared through slow evaporation of aqueous suspensions of cellulose nanocrystals in a nematic chiral liquid crystal phase. Mueller matrix (MM) spectroscopic ellipsometry is used to study the polarization and depolarization properties of the chiral films. In the reflection mode, the MM is similar to the matrices reported for the cuticle of some beetles reflecting near circular left-handed polarized light in the visible range. The polarization properties of light transmitted at normal incidence for different polarization states of incident light are discussed. By using a differential decomposition of the MM, the structural circular birefringence and dichroism of a NCC chiral film are evaluated.

  3. Multi-pass spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Stehle, Jean-Louis; Samartzis, Peter C.; Stamataki, Katerina; Piel, Jean-Philippe; Katsoprinakis, George E.; Papadakis, Vassilis; Schimowski, Xavier; Rakitzis, T. Peter; Loppinet, Benoit

    2014-01-01

    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

  4. Spectroscopic ellipsometry study of gold nanostructures for LSPR bio-sensing applications

    Directory of Open Access Journals (Sweden)

    Ali Ghamin Al-Rubaye

    2017-02-01

    Full Text Available This main aim of this work is the development of optical biosensors based on the LSPR phenomenon in nano-structured gold films suitable for detection of low molecular weight analytes such as mycotoxins. A simple technology of annealing thin gold films was utilized for the formation of gold nano-islands exhibiting the LSPR effect. The morphology of gold nano-structures produced was studied with SEM and AFM, and their optical properties were analysed with UV-visible absorption spectroscopy and spectroscopic ellipsometry (SE. The position of LSPR band appeared to depend on the dimensions of gold nano-islands. The dependence of the LSPR band spectral shift on the refractive index of a medium was studied with both UV-vis absorption and SE, and the refractive index sensitivity (RIS was evaluated. The method of SE gave from two to three times higher values of RIS as compared to those obtained by absorption spectroscopy. LSPR bio-sensing tests were attempted using total internal reflection ellipsometry (TIRE; a noticeable spectral shift was recorded on course of immune binding of Aflatoxin B1 to specific antibodies immobilized on the surface of gold.

  5. Optical functions and critical points of dilute bismide alloys studied by spectroscopic ellipsometry

    Science.gov (United States)

    Bushell, Z. L.; Joseph, R. M.; Nattermann, L.; Ludewig, P.; Volz, K.; Keddie, J. L.; Sweeney, S. J.

    2018-01-01

    Critical point transition energies and optical functions of the novel GaAs-based dilute bismide alloys GaAsBi, GaNAsBi, and GaPAsBi were determined using spectroscopic ellipsometry. The ellipsometry data were analyzed using a parameterized semiconductor model to represent the dielectric function of the alloys as the sum of Gaussian oscillators centered on critical points in the band structure, and from this extracting the energies of those critical points. The band gap and spin-orbit splitting were measured for samples for a range of alloy compositions. The first experimental measurements of the spin-orbit splitting in the GaNAsBi quaternary alloy were obtained, which showed that it is approximately independent of N content, in agreement with theory. The real component of the refractive index in the transparent region below the band gap was found to decrease as the band gap increased for all of the alloys studied, following the usual relations for conventional semiconductors. This work provides key electronic and optical parameters for the development of photonic devices based on these novel alloys.

  6. Spectroscopic ellipsometry studies of as-prepared and annealed CdS:O thin films

    Energy Technology Data Exchange (ETDEWEB)

    Khalilova, Khuraman; Hasanov, Ilham; Mamedov, Nazim [Institute of Physics, Azerbaijan National Academy of Sciences, 1143 Baku (Azerbaijan); Shim, YongGu [Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531 (Japan); Asaba, Ryo; Wakita, Kazuki [Department of Electronics and Computer Engineering, Chiba Institute of Technology, Chiba 275-0016 (Japan)

    2015-06-15

    Cadmium sulfide thin films on soda lime substrates were obtained by rf-magnetron sputtering in argon-oxygen atmosphere. As-prepared and vacuum annealed films were then studied by spectroscopic ellipsometry at room temperature over photon energy range from 0.5 to 6 eV. The obtained ellipsometric data were treated using optical dispersion models based on Gaussian type oscillators. Dielectric function of oxygen-free films, as well as those obtained under 3% of O/Ar partial pressure was reliably restored. At the same time, dielectric function obtained for 5% CdS:O can be regarded only as an average over several materials since our XPS examination disclosed presence of several compounds in thin films deposited at O/Ar ratios higher than 3%. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. The oxidation kinetics of nickel thin films studied by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Lopez-Beltran, A.M.; Mendoza-Galvan, A.

    2006-01-01

    Thin nickel films deposited by d.c. magnetron sputtering on glass substrates were thermally annealed in air at temperatures in the range of 380-530 deg. C. The annealed samples were analyzed by ex situ spectroscopic ellipsometry. X-ray diffraction data reveal that during the oxidation process only the Ni and NiO phases are present. Thus, using an appropriate model that describes the ellipsometric spectra, the thickness of the NiO layer was obtained as a function of annealing temperature with an activation energy of 1.74 eV. Furthermore, a parabolic kinetics was found for the NiO thickness dependence on annealing time

  8. Optical properties of ultrathin CIGS films studied by spectroscopic ellipsometry assisted by chemical engineering

    Science.gov (United States)

    Loubat, Anaïs; Eypert, Céline; Mollica, Fabien; Bouttemy, Muriel; Naghavi, Negar; Lincot, Daniel; Etcheberry, Arnaud

    2017-11-01

    CIGS (Cu(In1-x,Gax)Se2) based devices are very efficient for photovoltaic conversion. A non-destructive optical study of CIGS is an important challenge as for evaluation of the material quality, and for device modeling. Spectroscopic Ellipsometry (SE) is well adapted for a quantitative characterization only if the handicaps of the roughness limitation, the oxidized surface, or the compositional gradient are minimized. For this SE study, ungraded and thin CIGS samples are prepared with GGI (x) ratio (=[Ga]/([Ga] + [In])) ranging from 0.15 to 0.60. Thanks to chemical engineering based on acidic bromine solution etching and/or HCl de-oxidation, the SE experiments are performed on flattened surfaces, and also, on as grown de-oxidized samples. Using assumptions based on XPS, AFM and SEM complementary characterizations, we give proof of oxide free flattening surfaces and chemical homogeneity in depth. Using these observations, the SE data are modeled on the basis of a three layer model using an Adachi/Tauc-Lorentz formula for the CIGS dispersion. The optical gap values are determined in good agreement with the x ratio measured by the other characterization techniques. SE is able to well estimate the thickness and roughness variations on each sample. Furthermore, the CIGS optical constant extracted on such reference flat surfaces are then applied to the as grown-de-oxidized surfaces, enabling to describe the SE data obtained on rougher surfaces. A complete consistency of the proposed model is shown as well as the capability of SE to be sensitive to the chemistry of the surface.

  9. Optical Properties of GaN and Other III-Nitride Semiconductor Materials Studied by Variable Angle Spectroscopic Ellipsometry

    National Research Council Canada - National Science Library

    Yao, Huade

    2000-01-01

    .... It is for the first time, the ordinary and extraordinary optical constants of the important III-Nitride materials, GaN, AlN and sapphire, have been determined by variable angle spectroscopic ellipsometry (VASE...

  10. Spectroscopic ellipsometry studies of index profile of indium tin oxide films prepared by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    El Rhaleb, H.; Benamar, E.; Rami, M.; Roger, J.P.; Hakam, A.; Ennaoui, A

    2002-11-30

    Spectroscopic ellipsometry (SE) has proven to be a very powerful diagnostic for thin film characterisation. It was used to determine thin film parameters such as film thickness and optical functions of polycrystalline tin-doped indium oxide (ITO) films deposited by spray pyrol onto Pyrex substrates. Dielectric ITO films often present microstructures which give rise to a variation of the refractive index with the distance from substrate. In this work, it was found that the fit between ellipsometric data and optical models results could be significantly improved when it was assumed that the refractive index of ITO films varied across the upper 60 nm near the film surface. Also, the surface roughness was modelled and compared with that given by the atomic force microscope (AFM)

  11. Spectroscopic ellipsometry studies of index profile of indium tin oxide films prepared by spray pyrolysis

    International Nuclear Information System (INIS)

    El Rhaleb, H.; Benamar, E.; Rami, M.; Roger, J.P.; Hakam, A.; Ennaoui, A.

    2002-01-01

    Spectroscopic ellipsometry (SE) has proven to be a very powerful diagnostic for thin film characterisation. It was used to determine thin film parameters such as film thickness and optical functions of polycrystalline tin-doped indium oxide (ITO) films deposited by spray pyrolysis onto Pyrex substrates. Dielectric ITO films often present microstructures which give rise to a variation of the refractive index with the distance from substrate. In this work, it was found that the fit between ellipsometric data and optical models results could be significantly improved when it was assumed that the refractive index of ITO films varied across the upper 60 nm near the film surface. Also, the surface roughness was modelled and compared with that given by the atomic force microscope (AFM)

  12. Spectroscopic ellipsometry studies of index profile of indium tin oxide films prepared by spray pyrolysis

    Science.gov (United States)

    El Rhaleb, H.; Benamar, E.; Rami, M.; Roger, J. P.; Hakam, A.; Ennaoui, A.

    2002-11-01

    Spectroscopic ellipsometry (SE) has proven to be a very powerful diagnostic for thin film characterisation. It was used to determine thin film parameters such as film thickness and optical functions of polycrystalline tin-doped indium oxide (ITO) films deposited by spray pyrolysis onto Pyrex substrates. Dielectric ITO films often present microstructures which give rise to a variation of the refractive index with the distance from substrate. In this work, it was found that the fit between ellipsometric data and optical models results could be significantly improved when it was assumed that the refractive index of ITO films varied across the upper 60 nm near the film surface. Also, the surface roughness was modelled and compared with that given by the atomic force microscope (AFM).

  13. Spectroscopic ellipsometry study of Cu{sub 2}ZnSnSe{sub 4} bulk crystals

    Energy Technology Data Exchange (ETDEWEB)

    León, M., E-mail: maximo.leon@uam.es; Lopez, N.; Merino, J. M.; Caballero, R. [Department of Applied Physics M12, Universidad Autónoma de Madrid, Madrid (Spain); Levcenko, S.; Gurieva, G. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany); Serna, R. [Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, 28006 Madrid (Spain); Bodnar, I. V. [Department of Chemistry, Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus); Nateprov, A.; Guc, M.; Arushanov, E. [Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau MD 2028 (Moldova, Republic of); Schorr, S. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany); Institute of Geological Sciences, Free University Berlin, Malteserstr. 74-100, Berlin (Germany); Perez-Rodriguez, A. [IREC, Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, 08930 Sant Adrià del Besòs (Barcelona) (Spain); IN2UB, Departament d' Electrònica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain)

    2014-08-11

    Using spectroscopic ellipsometry we investigated and analyzed the pseudo-optical constants of Cu{sub 2}ZnSnSe{sub 4} bulk crystals, grown by the Bridgman method, over 0.8–4.5 eV photon energy range. The structures found in the spectra of the complex pseudodielectric functions were associated to E{sub 0}, E{sub 1A}, and E{sub 1B} interband transitions and were analyzed in frame of the Adachi's model. The interband transition parameters such as strength, threshold energy, and broadening were evaluated by using the simulated annealing algorithm. In addition, the pseudo-complex refractive index, extinction coefficient, absorption coefficient, and normal-incidence reflectivity were derived over 0.8–4.5 eV photon energy range.

  14. Influence of the graphene substrate on morphology of the gold thin film. Spectroscopic ellipsometry study

    International Nuclear Information System (INIS)

    Kostruba, A.M.

    2013-01-01

    In metal optics gold assumes a special status because of its practical importance in optoelectronic and nanooptical devices, and its role huge increases when occurs combination of gold with two-dimension materials. We performed spectroscopic ellipsometry measurements on evaporated gold, and gold–graphene nanostructures to determine the optical dielectric function across a broad spectral range from 250 to 1000 nm. It was found that the deposition of gold film on the quartz substrate covered by graphene flake leads to significant changes in structural and dielectric properties of thin gold layer. Such changes can be explained by increasing of the gold cluster size. The model fit of the ellipsometric data demonstrates that the bilayer “graphene-gold” nanostructure can be described as a uniform optically homogeneous layer with modified optical properties. We can suggest that graphene flake creates a matrix for epitaxial alignment of the crystalline structure of the gold film during its growing. Effective doping of the graphene by free electrons of the gold clusters tends to decrease the optical contrast at the graphene-gold interface.

  15. Spectroscopic ellipsometry study of N+ ion-implanted ethylene-norbornene films

    Science.gov (United States)

    Šiljegović, M.; Kačarević-Popović, Z. M.; Stchakovsky, M.; Radosavljević, A. N.; Korica, S.; Novaković, M.; Popović, M.

    2014-05-01

    The optical properties of 150 keV N+ implanted ethylene-norbornene (TOPAS 6017S-04) copolymer were investigated using phase modulated spectroscopic ellipsometry (PMSE) and ultraviolet-visible (UV-Vis) spectroscopy in the ranges of 0.6-6.5 eV and of 1.5-6.2 eV, respectively. The single-effective-oscillator model was used to fit the calculated data to the experimental ellipsometric spectra. The results show that the oscillator and dispersion energies decrease with increasing ion fluence up to 1015 cm-2, and then these parameters increase with further fluence increasing. Analysis of the UV-Vis absorption spectra revealed the presence of indirect electronic transitions with the band gap energy in the range of 1.3 to 2.8 eV. It was found that both the band gap energy and the energy width of the distribution of localized band tail states decrease, while the values of Tauc coefficient increase with increasing the ion fluence. From the ellipsometric data we found that the real part of the dielectric function increased about 7% after irradiation with 1015 cm-2, and decreased about 10% in samples modified with 1016 cm-2.

  16. Study of oxide/metal/oxide thin films for transparent electronics and solar cells applications by spectroscopic ellipsometry

    Directory of Open Access Journals (Sweden)

    Mihaela Girtan

    2017-05-01

    Full Text Available A comprehensive study of a class of Oxide/Metal/Oxide (Oxide = ITO, AZO, TiO2 and Bi2O3, Metal = Au thin films was done by correlating the spectrophotometric studies with the ellispometric models. Films were deposited by successive sputtering from metallic targets In:Sn, Zn:Al, Ti and Bi in reactive atmosphere (for the oxide films and respective inert atmosphere (for the metallic Au interlayer films on glass substrates. The measurements of optical constants n—the refractive index and k—the extinction coefficient, at different incident photon energies for single oxide films and also for the three layers films oxide/metal/oxide samples were made using the spectroscopic ellipsometry (SE technique. The ellipsometry modelling process was coupled with the recorded transmission spectra data of a double beam spectrophotometer and the best fitting parameters were obtained not only by fitting the n and k experimental data with the dispersion fitting curves as usual is practiced in the most reported data in literature, but also by comparing the calculated the transmission coefficient from ellipsometry with the experimental values obtained from direct spectrophotometry measurements. In this way the best dispersion model was deduced for each sample. Very good correlations were obtained for the other different thin films characteristics such as the films thickness, optical band gap and electrical resistivity obtained by other measurements and calculation techniques. The ellipsometric modelling, can hence give the possibility in the future to predict, by ellipsometric simulations, the proper device architecture in function of the preferred optical and electrical properties.

  17. 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.

  18. Characterization of plasmonic effects in thin films and metamaterials using spectroscopic ellipsometry

    NARCIS (Netherlands)

    Oates, T.W.H.; Wormeester, Herbert; Arwin, H.

    2011-01-01

    In this article, spectroscopic ellipsometry studies of plasmon resonances at metal–dielectric interfaces of thin films are reviewed. We show how ellipsometry provides valuable non-invasive amplitude and phase information from which one can determine the effective dielectric functions, and how these

  19. Spectroscopic ellipsometry studies on ZnCdO thin films with different Cd concentrations grown by pulsed laser deposition

    Science.gov (United States)

    Chen, Shuai; Li, Qingxuan; Ferguson, Ian; Lin, Tao; Wan, Lingyu; Feng, Zhe Chuan; Zhu, Liping; Ye, Zhizhen

    2017-11-01

    A set of Zn1-xCdxO thin films with different Cd concentrations was deposited on quartz substrates by Pulsed Laser Deposition (PLD). The properties of these films were investigated by variable angle and temperature dependent spectroscopic ellipsometry (SE). The experimental Zn1-xCdxO thin films showed a red shift in the absorption edge with increasing Cd contents at room temperature. For ZnCdO films with the similar Cd concentration, it has been found that the film thickness has important effects on the optical constants (n, k). The variations of optical constants (n, k) and the band gap, E0, with temperature (T) in 25 °C-600 °C for a typical Zn0.95Cd0.05O sample were obtained. The E0 vs T relationship is described by a T- quadratic equation.

  20. Nanostructure characterization of high k materials by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Pereira, L.; Aguas, H.; Fortunato, E.; Martins, R.

    2006-01-01

    In this work, the optical and structural properties of high k materials such as tantalum oxide and titanium oxide were studied by spectroscopic ellipsometry, where a Tauc-Lorentz dispersion model based in one (amorphous films) or two oscillators (microcrystalline films) was used. The samples were deposited at room temperature by radio frequency magnetron sputtering and then annealed at temperatures from 100 to 500 deg. C. Concerning the tantalum oxide films, the increase of the annealing temperature, up to 500 deg. C does not change the amorphous nature of the films, increasing, however, their density. The same does not happen with the titanium oxide films that are microcrystalline, even when deposited at room temperature. Data concerning the use of a four-layer model based on one and two Tauc-Lorentz dispersions is also discussed, emphasizing its use for the detection of an amorphous incubation layer, normally present on microcrystalline films grown by sputtering

  1. 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.

  2. Stability of UV exposed RR-P3BT films by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Diware, Mangesh S.; Byun, J. S.; Hwang, S. Y.; Kim, T. J.; Kim, Y. D.

    2013-01-01

    Stability of regioregular poly(3-butylthiophene) (RR-P3BT) films under irradiation of ultra-violet (UV) light has been studied by spectroscopic ellipsometry at room temperature. Consistent decrease in dielectric function with UV exposure time showed the degree of degradation of polymer. This work suggests that, protective methods are mandatory to use this kind of material in optical devices.

  3. Localization effects in the disordered Ta interlayer of multilayer Ta–FeNi films: Evidence from dc transport and spectroscopic ellipsometry study

    Czech Academy of Sciences Publication Activity Database

    Kovaleva, Natalia; Chvostová, Dagmar; Pacherová, Oliva; Fekete, Ladislav; Kugel, K.I.; Pudonin, F.A.; Dejneka, Alexandr

    2017-01-01

    Roč. 111, č. 18 (2017), s. 1-5, č. článku 183104. ISSN 0003-6951 R&D Projects: GA ČR GA15-13778S Institutional support: RVO:68378271 Keywords : dc transport * wide-band * spectroscopic ellipsometry techniques * disordered metallic Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.411, year: 2016

  4. Rotatable broadband retarders for far infrared spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Kang, T.D.; Carr, G.; Zhou, T.; Kotelyanskii, M.; Sirenko, A.A.

    2010-12-09

    Rotatable retarders have been developed for applications in spectroscopic, full Mueller Matrix ellipsometry in the far-IR spectral range. Several materials, such as silicon, KRS-5, and a commercial polymer plastic (TOPAS) have been utilized to achieve a fully adjustable retardation between 0{sup o} and 90{sup o}. Experimental characteristics of the rotatable retarders that utilize three- and four-bounce designs are compared with calculations. We discuss the effect of light focusing on the performance of these rotatable retarders. Broadband optical retarders are required for spectroscopic ellipsometry in its full Mueller matrix (MM) realization. Performance of the MM ellipsometer depends on the capability to produce substantially linearly-independent Stokes vectors for the light incident onto the sample. As has been shown, the errors in the measuredMMof the sample are proportional to the condition number of the 4 x 4 matrix composed of the Stokes vectors of four polarization states incident at the sample. It can be proven that it is impossible to cover the Poincare sphere with linearly-independent Stokes vectors by only changing the linear polarization at the input surface of a stationary retarder. As we will illustrate further in this paper, total coverage of the Poincare sphere is possible by rotating a tandem of a linear polarizer and a retarder with a retardation of 90{sup o}. It is this goal that we are trying to achieve in the retarder designs described in this paper.

  5. Spectroscopic ellipsometry and UV-vis studies at room temperature of the novel organic-inorganic hybrid of salt Bis (4-acetylanilinium) tetrachlorocadmiate

    Science.gov (United States)

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

    2016-05-01

    The optical properties of Bis (4-acetylanilinium) tetrachlorocadmiate compound were studied using phase modulated spectroscopic ellipsometry (PMSE) and ultraviolet-visible (UV-Vis) spectroscopy in the range 200-800 nm. The optical absorbance were measured in order to deduce the absorption coefficient α and optical band gap Eg, thus the Tauc model was used to determine the optical gap energy of the synthesized (C8H10NO)2CdCl4 compound. The analysis of the data revealed the existence of optical allowed direct transition mechanisms with the band gap energy equal to 3.17 eV. On the other hand the single-effective-oscillator model was used to fit the calculated data to the experimental ellipsometric spectra. Thus the values of the dispersion energy and single-oscillator strength are determined. Also, the extinction coefficient, refractive index, dispersion parameter and both the real εr and imaginary parts εi of the dielectric permittivity of Bis (4-acetylanilinium) tetrachlorocadmiate compound were calculated and the results are discussed.

  6. Characterisation of thin films by phase modulated spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Bhattacharyya, D.; Das, N.C.

    1998-07-01

    A wide variety of thin film coatings, deposited by different techniques and with potential applications in various important areas, have been characterised by the Phase Modulated Spectroscopic Ellipsometer, installed recently in the Spectroscopy Division, B.A.R.C. The Phase Modulated technique provides a faster and more accurate data acquisition process than the conventional ellipsometry. The measured Ellipsometry spectra are fitted with theoretical spectra generated assuming an appropriate model regarding the sample. The fittings have been done objectively by minimising the squared difference (χ 2 ) between the measured and calculated values of the ellipsometric parameters and thus accurate information have been derived regarding the thickness and optical constants (viz, the refractive index and extinction coefficient) of the different layers, the surface roughness and the inhomogeneities present in the layers. Measurements have been done on (i) ion-implanted Si-wafers to investigate the formation of SiC layers, (ii) phenyl- silane coating on glass to investigate the surface modifications achieved for better adsorption of rhodamine dye on glass, (iii) GaN films on quartz to investigate the formation of high quality GaN layers by sputtering of GaAs targets, (iv) Diamond-like-coating (DLC) samples prepared by Chemical Vapour Deposition (CVD) to investigate the optical properties which would ultimately lead to an accurate estimation of the ratio of sp 3 and sp 2 bonded carbon atoms in the films and (v) SS 304 under different surface treatments to investigate the growth of different passive films. (author)

  7. Non-destructive characterization of nitrogen-implanted silicon-on-insulator structures by spectroscopic ellipsometry

    NARCIS (Netherlands)

    Fried, M.; Lohner, T.; de Nijs, J.M.M.; van Silfhout, Arend; Hanekamp, L.J.; Khanh, N.Q.; Laczik, Z.; Gyulai, J.

    1989-01-01

    Silicon-on-insulator (SOI) structures implanted with 200 or 400 keV N+ ions at a dose of 7.5 × 1017cm−2 were studied by spectroscopic ellipsometry (SE). The SE measurements were carried out in the 300–700 nm wavelength (4.13-1.78 eV photon energy) range. The SE data were analysed by the conventional

  8. Optical properties of Au–TiO{sub 2} and Au–SiO{sub 2} granular metal thin films studied by Spectroscopic Ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Bakkali, H., E-mail: hicham.bakkali@mail.uca.es [Departamento de Física de la Materia Condensada and Instituto de Microscopía Electrónica y Materiales (IMEYMAT), Universidad de Cadiz, 11510 Puerto Real, Cádiz (Spain); Centro de Ciencias Aplicadas y Desarrollo Tecnológico (CCADET), Universidad Nacional Autónoma de México (UNAM), México, D.F. 04510 (Mexico); Blanco, E.; Dominguez, M. [Departamento de Física de la Materia Condensada and Instituto de Microscopía Electrónica y Materiales (IMEYMAT), Universidad de Cadiz, 11510 Puerto Real, Cádiz (Spain); Mora, M.B. de la [CONACyT Research Fellow-CCADET, Universidad Nacional Autónoma de México (UNAM), México, D.F. 04510 (Mexico); Sánchez-Aké, C.; Villagrán-Muniz, M. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico (CCADET), Universidad Nacional Autónoma de México (UNAM), México, D.F. 04510 (Mexico)

    2017-05-31

    Highlights: • Gold NPs embedded in TiO{sub 2} or SiO{sub 2} are fabricated by single RF magnetron sputtering. • Films thickness and optical constants are determined by Spectroscopic Ellipsometry. - Abstract: We report on the optical properties in the dielectric regime of gold nanostructured granular thin films fabricated through sputter deposition with a composite target at room temperature and over a wide photon energy range (0.62–4.13 eV) by means of Spectroscopic Ellipsometry. The thickness and the films effective optical constants are successfully determined using an approach based on multiple Gaussian oscillators. In the quasi-static regime, i.e., 2R ≪ λ, and in the dipole approximation, examining the real and imaginary parts, ε{sub 1}, ε{sub 2}, of the dielectric function, it is shown that the dc optical conductivity is almost negligible (σ = ωε{sub 0}ε{sub 2} ≪ 10{sup −5} Ω cm{sup −1}) and only the capacitive contribution holds for the electron-phonon relaxation in localized surface plasmon of the gold particles. Furthermore, we find that the resonant frequencies ω{sub p} becomes red-shifted when the particles are electromagnetically coupled to each other or when the surrounding medium dielectric constant, ε{sub m}, increases, thus exhibiting a wide spectral tuning range of 1.95–2.24 eV.

  9. Spectroscopic Ellipsometry Studies of Thin Film a-Si:H/nc-Si:H Micromorph Solar Cell Fabrication in the p-i-n Superstrate Configuration

    Science.gov (United States)

    Huang, Zhiquan

    Spectroscopic ellipsometry (SE) is a non-invasive optical probe that is capable of accurately and precisely measuring the structure of thin films, such as their thicknesses and void volume fractions, and in addition their optical properties, typically defined by the index of refraction and extinction coefficient spectra. Because multichannel detection systems integrated into SE instrumentation have been available for some time now, the data acquisition time possible for complete SE spectra has been reduced significantly. As a result, real time spectroscopic ellipsometry (RTSE) has become feasible for monitoring thin film nucleation and growth during the deposition of thin films as well as during their removal in processes of thin film etching. Also because of the reduced acquisition time, mapping SE is possible by mounting an SE instrument with a multichannel detector onto a mechanical translation stage. Such an SE system is capable of mapping the thin film structure and its optical properties over the substrate area, and thereby evaluating the spatial uniformity of the component layers. In thin film photovoltaics, such structural and optical property measurements mapped over the substrate area can be applied to guide device optimization by correlating small area device performance with the associated local properties. In this thesis, a detailed ex-situ SE study of hydrogenated amorphous silicon (a-Si:H) thin films and solar cells prepared by plasma enhanced chemical vapor deposition (PECVD) has been presented. An SE analysis procedure with step-by-step error minimization has been applied to obtain accurate measures of the structural and optical properties of the component layers of the solar cells. Growth evolution diagrams were developed as functions of the deposition parameters in PECVD for both p-type and n-type layers to characterize the regimes of accumulated thickness over which a-Si:H, hydrogenated nanocrystalline silicon (nc-Si:H) and mixed phase (a

  10. Spectroscopic Ellipsometry analysis of a thin film composite membrane consisting of polysulfone on a porous α-alumina support

    NARCIS (Netherlands)

    Ogieglo, Wojciech; Wormeester, Herbert; Wessling, Matthias; Benes, Nieck Edwin

    2012-01-01

    Exposure of a thin polymer film to a fluid can affect properties of the film such as the density and thickness. In particular in membrane technology, these changes can have important implications for membrane performance. Spectroscopic ellipsometry is a convenient technique for in situ studies of

  11. Effects of oxygen partial pressure, deposition temperature, and annealing on the optical response of CdS:O thin films as studied by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Junda, Maxwell M.; Grice, Corey R.; Subedi, Indra; Yan, Yanfa; Podraza, Nikolas J. [Department of Physics & Astronomy and The Wright Center for Photovoltaics Innovation & Commercialization, University of Toledo, Toledo, Ohio 43606 (United States)

    2016-07-07

    Ex-situ spectroscopic ellipsometry measurements are made on radio frequency magnetron sputtered oxygenated cadmium sulfide (CdS:O) thin films. Films are deposited onto glass substrates at room temperature and at 270 °C with varying oxygen to total gas flow ratios in the sputtering ambient. Ellipsometric spectra from 0.74 to 5.89 eV are collected before and after annealing at 607 °C to simulate the thermal processes during close-space sublimation of overlying cadmium telluride in that solar cell configuration. Complex dielectric function (ε = ε{sub 1} + iε{sub 2}) spectra are extracted for films as a function of oxygen gas flow ratio, deposition temperature, and post-deposition annealing using a parametric model accounting for critical point transitions and an Urbach tail for sub-band gap absorption. The results suggest an inverse relationship between degree of crystallinity and oxygen gas flow ratio, whereas annealing is shown to increase crystallinity in all samples. Direct band gap energies are determined from the parametric modeling of ε and linear extrapolations of the square of the absorption coefficient. As-deposited samples feature a range of band gap energies whereas annealing is shown to result in gap energies ranging only from 2.40 to 2.45 eV, which is close to typical band gaps for pure cadmium sulfide.

  12. Observation of Frenkel and charge transfer excitons in pentacene single crystals using spectroscopic generalized ellipsometry

    NARCIS (Netherlands)

    Qi, Dongchen; Su, Haibin; Bastjan, M.; Jurchescu, O. D.; Palstra, T. M.; Wee, Andrew T. S.; Ruebhausen, M.; Rusydi, A.; Rübhausen, M.

    2013-01-01

    We report on the emerging and admixture of Frenkel and charge transfer (CT) excitons near the absorption onset in pentacene single crystals. Using high energy-resolution spectroscopic generalized ellipsometry with in-plane polarization dependence, the excitonic nature of three lowest lying

  13. Optical characterization of varnish films by spectroscopic ellipsometry for application in artwork conservation.

    Science.gov (United States)

    Polikreti, Kyriaki; Othonos, Andreas; Christofides, Constantinos

    2005-01-01

    The specific aim of this paper is to measure the optical constants of fresh varnish layers up to a thickness of 10 mum by spectroscopic ellipsometry. It is the first time that this technique has been used in artwork conservation and it may prove very promising due to its nondestructive character. Samples of fresh dammar varnish (natural resin) and Paraloid B72 (synthetic resin) applied on glass and carbon black acrylic paint were analyzed. Both varnishes were considered as perfect dielectrics, and the real part of their refractive index was described by the Cauchy model: n (lambda) = A + B/lambda(2) + C/lambda(4). The Cauchy coefficients for dammar varnish and Paraloid B72 were then determined for layers of known thickness. The ellipsometric data were fitted to a model, which includes a mixed varnish-air layer. The optical properties of this layer were calculated by the Bruggeman effective medium approximation. In the case of carbon black acrylic paint, another mixed layer (paint-varnish) was added to the model. The results are very close to the values given in the literature. Given the measurement reproducibility, the results show that ellipsometry can discriminate between dammar varnish and Paraloid B72. This is very important in artwork conservation studies, because it has been done by time-consuming, destructive techniques up to now. Future work includes measurements of other types of natural and synthetic varnishes, in an attempt to introduce a nondestructive method for picture varnish identification and aging studies.

  14. Development of InN metalorganic vapor phase epitaxy using in-situ spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Drago, M.; Werner, C.; Pristovsek, M.; Pohl, U.W. [Technische Universitaet Berlin, Institut fuer Festkoerperphysik, Hardenbergstrasse 36, 10623 Berlin (Germany); Richter, W. [Universita di Roma ' ' Torvergata' ' , Dipartimento di Fisica, Via della ricerca scientifica 1, I-00133 Roma (Italy)

    2005-11-01

    Metalorganic vapor phase epitaxy of InN layers on sapphire was studied in-situ by spectroscopic ellipsometry (SE), ex-situ atomic force microscopy and optical microscopy. Surface morphology has been largely improved by using nitrogen instead of hydrogen as carrier gas during sapphire nitridation. Using the sensitivity of in-situ SE with respect to roughness we established a new growth procedure with low V/III ratio (10{sup 4}) at high temperature (580 C) and growth rates as high as 350 nm/h, leading to improved electronic layer properties and allowing for growth of comparably thick layers. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. 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.

  16. Pulsed-source MOCVD of high-k dielectric thin films with in situ monitoring by spectroscopic ellipsometry

    CERN Document Server

    Tsuchiya, Y; Tung, R T; Oda, S; Kurosawa, M; Hattori, T

    2003-01-01

    The formation of high-k thin films by pulsed-source metal-organic chemical vapor deposition (MOCVD) has been investigated with in situ spectroscopic ellipsometry. It is demonstrated that spectroscopic ellipsometry is an effective method for in situ monitoring of the fabrication of high-k dielectric thin films with thicknesses of several nm's. Thin yttrium oxide films with average roughnesses smaller than the thickness of a single molecular layer, and with a capacitance equivalent thickness approx 1.7 nm were obtained. Thicknesses and optical properties of each individual layer were also extracted from spectroscopic ellipsometry, by fitting to appropriate structural models. (author)

  17. Fourier-transform far-infrared spectroscopic ellipsometry for standoff material identification

    Energy Technology Data Exchange (ETDEWEB)

    Ortolani, Michele, E-mail: michele.ortolani@ifn.cnr.i [Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Via Cineto Romano 42, I-00156 Rome (Italy); Schade, Ulrich [Helmholtz Zentrum Berlin fuer Materialen und Energie, Albert-Einstein-Strasse 15, D-12489 Berlin (Germany)

    2010-11-11

    The ellipsometry is an efficient method to determine the optical properties of matter. It has been largely employed with grating spectrometers in the visible, UV and near-infrared ranges for the characterization of thin films, surfaces and interfaces. In the mid- and far-infrared, where most substance-specific absorption lines are present, spectroscopic ellipsometry with Fourier-transform spectrometers is still not extended as a routine method. In particular, the lack of powerful sources in the far-infrared/terahertz range has prevented standoff application of this method. We will show that it is possible to measure the complex dielectric constant of a solid in the far-infrared and terahertz range by a reflection experiment with polarized light and ellipsometric analysis with a suitable calibration procedure. Extraction of terahertz synchrotron radiation from storage rings provides a suitable source for research-grade experiments. The optical constants determined by ellipsometry compare well with those obtained by Kramers-Kronig procedures, a method which, however, requires broader frequency range and absolute reflectance standard. We will present the case of remote spectroscopic identification of explosive materials, which is relevant for forthcoming security applications.

  18. 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.

  19. The optical characterization of organometallic complex thin films by spectroscopic ellipsometry and photovoltaic diode application

    Energy Technology Data Exchange (ETDEWEB)

    Özaydın, C. [Batman University, Engineering Faculty, Department of Computer Eng., Batman (Turkey); Güllü, Ö., E-mail: omergullu@gmail.com [Batman University, Science and Art Faculty, Department of Physics, Batman (Turkey); Pakma, O. [Batman University, Science and Art Faculty, Department of Physics, Batman (Turkey); Ilhan, S. [Siirt University, Science and Art Faculty, Department of Chemistry, Siirt (Turkey); Akkılıç, K. [Dicle University, Education Faculty, Department of Physics Education, Diyarbakır (Turkey)

    2016-05-15

    Highlights: • Optical properties and thickness of the A novel organometallic complex (OMC) film were investigated by spectroscopic ellipsometry (SE). • Au/OMC/n-Si metal/interlayer/semiconductor (MIS) diode has been fabricated • This paper presents the I–V analysis of Au/OMC/n-Si MIS diode. • Current–voltage and photovoltaic properties of the diode were investigated. - Abstract: In this work, organometallic complex (OMC) films have been deposited onto glass or silicon substrates by spin coating technique and their photovoltaic application potential has been investigated. Optical properties and thickness of the film have been investigated by spectroscopic ellipsometry (SE). Also, transmittance spectrum has been taken by UV/vis spectrophotometer. The optical method has been used to determine the band gap value of the films. Also, Au/OMC/n-Si metal/interlayer/semiconductor (MIS) diode has been fabricated. Current–voltage and photovoltaic properties of the structure were investigated. The ideality factor (n) and barrier height (Φ{sub b}) values of the diode were found to be 2.89 and 0.79 eV, respectively. The device shows photovoltaic behavior with a maximum open-circuit voltage of 396 mV and a short circuit current of 33.8 μA under 300 W light.

  20. The optical characterization of organometallic complex thin films by spectroscopic ellipsometry and photovoltaic diode application

    International Nuclear Information System (INIS)

    Özaydın, C.; Güllü, Ö.; Pakma, O.; Ilhan, S.; Akkılıç, K.

    2016-01-01

    Highlights: • Optical properties and thickness of the A novel organometallic complex (OMC) film were investigated by spectroscopic ellipsometry (SE). • Au/OMC/n-Si metal/interlayer/semiconductor (MIS) diode has been fabricated • This paper presents the I–V analysis of Au/OMC/n-Si MIS diode. • Current–voltage and photovoltaic properties of the diode were investigated. - Abstract: In this work, organometallic complex (OMC) films have been deposited onto glass or silicon substrates by spin coating technique and their photovoltaic application potential has been investigated. Optical properties and thickness of the film have been investigated by spectroscopic ellipsometry (SE). Also, transmittance spectrum has been taken by UV/vis spectrophotometer. The optical method has been used to determine the band gap value of the films. Also, Au/OMC/n-Si metal/interlayer/semiconductor (MIS) diode has been fabricated. Current–voltage and photovoltaic properties of the structure were investigated. The ideality factor (n) and barrier height (Φ b ) values of the diode were found to be 2.89 and 0.79 eV, respectively. The device shows photovoltaic behavior with a maximum open-circuit voltage of 396 mV and a short circuit current of 33.8 μA under 300 W light.

  1. Multichannel Spectroscopic Ellipsometry for CdTe Photovoltaics: from Materials and Interfaces to Solar Cells

    Science.gov (United States)

    Koirala, Prakash

    Spectroscopic ellipsometry (SE) in the mid-infrared to ultraviolet range has been implemented in order to develop and evaluate optimization procedures for CdTe solar cells at the different stages of fabrication. In this dissertation research, real time SE (RT-SE) has been applied during the fabrication of the as-deposited CdS/CdTe solar cell. Two areas of background research were addressed before undertaking the challenging RT-SE analysis procedures. First, optical functions were parameterized versus temperature for the glass substrate and its overlayers, including three different SnO2 layers. This database has applications not only for RT-SE analysis but also for on-line monitoring of the coated glass itself at elevated temperature. Second, post-deposition modifications of substrate have been studied by infrared spectroscopic ellipsometry (IR-SE) prior to the RT-SE analysis in order to evaluate the need for such modification in the analysis. With support from these background studies, RT-SE has been implemented in analyses of the evolution of the thin film structural properties during sputter deposition of polycrystalline CdS/CdTe solar cells on the transparent conducting oxide (TCO) coated glass substrates. The real time optical spectra collected during CdS/CdTe deposition were analyzed using the optical property database for all substrate components as a function of measurement temperature. RT-SE enables characterization of the filling process of the surface roughness modulations on the top-most SnO2 substrate layer, commonly referred to as the high resistivity transparent (HRT) layer. In this filling process, the optical properties of this surface layer are modified in accordance with an effective medium theory. In addition to providing information on interface formation to the substrate during film growth, RT-SE also provides information on the bulk layer CdS growth, its surface roughness evolution, as well as overlying CdTe interface formation and bulk layer

  2. Characterisation of different single and multilayer films using phase modulated spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Das, N.C.; Bhattacharyya, D.; Thakur, S.

    1998-06-01

    Different single layers and multilayer coatings deposited by e-beam evaporation and r.f. sputtering techniques have been characterised by the Phase Modulated Spectroscopic Ellipsometer, installed recently in the Spectroscopy Division, B.A.R.C. The Phase Modulated technique provides a faster and more accurate data acquisition process than the conventional ellipsometry. Measurements have been done on single layers of Cu, Si and ZrO 2 films and on multilayer thin films devices e.g., high reflectivity mirror, beam combiner, beam splitter, narrow band filter etc. consisting of several bilayers of TiO 2 /SiO 2 . The measured Ellipsometry spectra is then fitted with a theoretical spectra generated assuming an appropriate model regarding the sample. The layer thickness and composition have been used as fitting parameters. The optical constants of the substrates have been supplied and a trial dispersion relation have been used for the layers. In case of inhomogeneous layers, trial compositions have been given for the individual components for each layer. The roughness of the layers has been taken into account by assuming the film to be an inhomogeneous mixture of material and voids. The fittings have been done objectively by minimising the squared difference (χ 2 ) between the measured and calculated values of the ellipsometric parameters and thus accurate information have been derived regarding the thickness and optical constants (viz, the refractive index and extinction coefficient) of the different layers, the surface roughness and the inhomogeneities present in the layers. (author)

  3. NIR-Vis-UV permittivity of nanoporous C-Pd thin films determined using spectroscopic ellipsometry

    Science.gov (United States)

    Wronkowska, Aleksandra A.; Czerniak, GraŻyna; Wronkowski, Andrzej; Czerwosz, ElŻbieta; Kowalska, Ewa

    2013-10-01

    In this work, spectroscopic ellipsometry combined with transmittance measurements in a spectral range of 0.6 - 6.5eV (2.2μm - 193nm) have been used to determine the thickness and optical constants of carbon-palladium thin films. The C-Pd nanocomposite samples are synthesised by physical vapour deposition and chemical vapour deposition methods on to fused silica substrates. The C60 fullerene and palladium acetate are used as the source materials. The effective complex dielectric functions [equation-see manuscript] of the particulate films are found to depend strongly on preparation technology and concentration of Pd nanoparticles embedded in the carbon matrix. Optical parameterisation with a Drude-Lorentz model of the dielectric functions has been applied to match the experimental data. Influence of chemical treatment and Pd nanoparticles on structural disorder and relevant optical and electronic properties of the C-Pd samples is analysed.

  4. Probing the carrier concentration profiles in phosphorus-implanted germanium using infrared spectroscopic ellipsometry

    Science.gov (United States)

    D'Costa, Vijay Richard; Yeo, Yee-Chia

    2015-02-01

    Spectroscopic ellipsometry with photon energy in the 0.045-0.65 eV range was used to investigate germanium samples implanted with 30 keV phosphorus ions and annealed at 700 °C. The infrared response of implanted layers is dominated by free carrier absorption which is modeled using a Drude oscillator. The carrier concentration profiles were modeled using an error function, and compared with those obtained by electrochemical capacitance-voltage profiling and secondary ion mass spectrometry. In the flat region of the carrier concentration profile, average carrier concentration and mobility of 1.40 × 1019 cm-3 and 336 cm2V-1s-1, respectively, were obtained. A phosphorus diffusivity of ˜1.2 × 10-13 cm2/s was obtained. The mobility versus carrier concentration relationships obtained for the implanted samples are close to the empirical relationship for bulk Ge.

  5. Investigation of optical properties of benzocyclobutene wafer bonding layer used for 3D interconnects via infrared spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Kamineni, Vimal K.; Singh, Pratibha; Kong, LayWai; Hudnall, John; Qureshi, Jamal; Taylor, Chris; Rudack, Andy; Arkalgud, Sitaram; Diebold, Alain C.

    2011-01-01

    Benzocyclobutene (BCB) used for bonding silicon wafers to enable 3D interconnect technology is characterized using spectroscopic ellipsometry (SE). SE is a non-destructive technique that has been used to characterize the thickness and dielectric properties of BCB. The infrared (IR) absorption spectrum was used to calculate the percentage of curing of BCB on 300 mm bare and bonded wafers. The percentage of curing in BCB is a key parameter that impacts the bond strength and bond quality. This study presents the potential application of IRSE for measurements on bonded wafers to characterize the chemical information, curing percentage, bond quality and thickness of the BCB bonding layer. One of the key issues in the process development and characterization of BCB bonding for 3D interconnects of 300 mm wafers is the presence of dendrites and voids between the bonded wafers. The presence of dendrites and voids was identified by using scanning acoustic microscopy (SAM) and imaged by scanning electron microscope (SEM).

  6. Investigation of optical properties of benzocyclobutene wafer bonding layer used for 3D interconnects via infrared spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Kamineni, Vimal K., E-mail: vkamineni@uamail.albany.ed [College of Nanoscale Science and Engineering, University at Albany, Albany, NY 12203 (United States); Singh, Pratibha [GLOBALFOUNDRIES Inc., Albany, NY 12203 (United States); SEMATECH, Albany, NY 12203 (United States); Kong, LayWai [College of Nanoscale Science and Engineering, University at Albany, Albany, NY 12203 (United States); Hudnall, John [SEMATECH, Albany, NY 12203 (United States); Qureshi, Jamal [College of Nanoscale Science and Engineering, University at Albany, Albany, NY 12203 (United States); SEMATECH, Albany, NY 12203 (United States); Taylor, Chris [SEMATECH, Albany, NY 12203 (United States); Hewlett-Packard Company, Corvallis, OR (United States); Rudack, Andy; Arkalgud, Sitaram [SEMATECH, Albany, NY 12203 (United States); Diebold, Alain C. [College of Nanoscale Science and Engineering, University at Albany, Albany, NY 12203 (United States)

    2011-02-28

    Benzocyclobutene (BCB) used for bonding silicon wafers to enable 3D interconnect technology is characterized using spectroscopic ellipsometry (SE). SE is a non-destructive technique that has been used to characterize the thickness and dielectric properties of BCB. The infrared (IR) absorption spectrum was used to calculate the percentage of curing of BCB on 300 mm bare and bonded wafers. The percentage of curing in BCB is a key parameter that impacts the bond strength and bond quality. This study presents the potential application of IRSE for measurements on bonded wafers to characterize the chemical information, curing percentage, bond quality and thickness of the BCB bonding layer. One of the key issues in the process development and characterization of BCB bonding for 3D interconnects of 300 mm wafers is the presence of dendrites and voids between the bonded wafers. The presence of dendrites and voids was identified by using scanning acoustic microscopy (SAM) and imaged by scanning electron microscope (SEM).

  7. Investigating organic multilayers by spectroscopic ellipsometry: specific and non-specific interactions of polyhistidine with NTA self-assembled monolayers

    Directory of Open Access Journals (Sweden)

    Ilaria Solano

    2016-04-01

    Full Text Available Background: A versatile strategy for protein–surface coupling in biochips exploits the affinity for polyhistidine of the nitrilotriacetic acid (NTA group loaded with Ni(II. Methods based on optical reflectivity measurements such as spectroscopic ellipsometry (SE allow for label-free, non-invasive monitoring of molecule adsorption/desorption at surfaces.Results: This paper describes a SE study about the interaction of hexahistidine (His6 on gold substrates functionalized with a thiolate self-assembled monolayer bearing the NTA end group. By systematically applying the difference spectra method, which emphasizes the small changes of the ellipsometry spectral response upon the nanoscale thickening/thinning of the molecular film, we characterized different steps of the process such as the NTA-functionalization of Au, the adsorption of the His6 layer and its eventual displacement after reaction with competitive ligands. The films were investigated in liquid, and ex situ in ambient air. The SE investigation has been complemented by AFM measurements based on nanolithography methods (nanografting mode.Conclusion: Our approach to the SE data, exploiting the full spectroscopic potential of the method and basic optical models, was able to provide a picture of the variation of the film thickness along the process. The combination of δΔi+1,i(λ, δΨi+1,i(λ (layer-addition mode and δΔ†i',i+1(λ, δΨ†i',i+1(λ (layer-removal mode difference spectra allowed us to clearly disentangle the adsorption of His6 on the Ni-free NTA layer, due to non specific interactions, from the formation of a neatly thicker His6 film induced by the Ni(II-loading of the NTA SAM.

  8. Optical properties and surface characterization of pulsed laser-deposited Cu2ZnSnS4 by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Crovetto, Andrea; Cazzaniga, Andrea; Ettlinger, Rebecca B.; Schou, Jørgen; Hansen, Ole

    2015-01-01

    Cu 2 ZnSnS 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 2 ZnSnS 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 2 ZnSnS 4 films

  9. Characterization of μc-Si:H/a-Si:H tandem solar cell structures by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Murata, Daisuke; Yuguchi, Tetsuya; Fujiwara, Hiroyuki

    2014-01-01

    In order to perform the structural characterization of Si thin-film solar cells having submicron-size rough textured surfaces, we have developed an optical model that can be utilized for the spectroscopic ellipsometry (SE) analysis of a multilayer solar cell structure consisting of hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon (μc-Si:H) layers fabricated on textured SnO 2 :F substrates. To represent the structural non-uniformity in the textured structure, the optical response has been calculated from two regions with different thicknesses of the Si layers. Moreover, in the optical model, the interface layers are modeled by multilayer structures assuming two-phase composites and the volume fractions of the phases in the layers are controlled by the structural curvature factor. The polarized reflection from the μc-Si:H layer that shows extensive surface roughening during the growth has also been modeled. In this study, a state-of-the-art solar cell structure with the textured μc-Si:H (2000 nm)/ZnO (100 nm)/a-Si:H (200 nm)/SnO 2 :F/glass substrate structure has been characterized. The μc-Si:H/a-Si:H textured structure deduced from our SE analysis shows remarkable agreement with that observed by transmission electron microscopy. From the above results, we have demonstrated the high-precision characterization of highly-textured μc-Si:H/a-Si:H solar cell structures. - Highlights: • Characterization of textured μc-Si:H/a-Si:H solar cell structures by ellipsometry • A new optical model using surface area and multilayer models • High precision characterization of submicron-range rough interface structures

  10. Spectroscopic ellipsometry characterization of interface reactivity in GaAs-based superlattices

    International Nuclear Information System (INIS)

    Losurdo, M.; Giuva, D.; Giangregorio, M.M.; Bruno, G.; Brown, A.S.

    2004-01-01

    Pseudodielectric function spectra of GaAs/GaSb 1-y As y , GaSb/GaAs y Sb 1-y and GaAs/GaP y As 1-y superlattices have been measured by spectroscopic ellipsometry in the 0.75-5.5 eV photon energy range. The analysis of the E 1 interband critical point and modeling of spectra has been carried out to investigate the chemistry of the anion exchange reaction and abruptness of interface composition in the superlattices. It has been found that a ternary compound GaP y As 1-y forms in the case of the P-for-As anion exchange reaction. In the case of As-for-Sb anion exchange reaction for (GaSb/GaAs y Sb 1-y ) 20 SLs, SE data show that this anion exchange results in the formation not only of a ternary alloy GaAs y Sb 1-y , but also in the formation of isoelectronic compounds AsSb x that segregate at the GaSb/GaAs interface. In the case of Sb-for-As anion exchange for (GaAs/GaSbyAs 1-y ) 20 SLs, Sb segregates at the GaAs surface

  11. Spectroscopic ellipsometry of columnar porous Si thin films and Si nanowires

    Science.gov (United States)

    Fodor, Bálint; Defforge, Thomas; Agócs, Emil; Fried, Miklós; Gautier, Gaël; Petrik, Péter

    2017-11-01

    Columnar mesoporous Si thin films and dense nanowire (SiNW) carpets were investigated by spectroscopic ellipsometry in the visible-near-infrared wavelength range. Porous Si layers were formed by electrochemical etching while structural anisotropy was controlled by the applied current. Layers of highly oriented SiNWs, with length up to 4.1 μm were synthesized by metal-assisted chemical etching. Ellipsometric spectra were fitted with different multi-layered, effective medium approximation-based (EMA) models. Isotropic, in-depth graded, anisotropic and hybrid EMA models were investigated with the help of the root mean square errors obtained from the fits. Ellipsometric-fitted layer thicknesses were also cross-checked by scanning electron microscopy showing an excellent agreement. Furthermore, in the case of mesoporous silicon, characterization also revealed that, at low current densities (100 mA/cm2) this behavior turns around, and anisotropy becomes the dominant feature describing the spectra. Characterization of SiNW layers showed a very high geometrical anisotropy. However, the highest fitted geometrical anisotropy was obtained for the layer composed of ∼1 μm long SiNWs indicating that for thicker layers, collapse of the nanowires occurs.

  12. Spectroscopic ellipsometry characterization of interface reactivity in GaAs-based superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Losurdo, M.; Giuva, D.; Giangregorio, M.M.; Bruno, G.; Brown, A.S

    2004-05-01

    Pseudodielectric function spectra of GaAs/GaSb{sub 1-y}As{sub y}, GaSb/GaAs{sub y}Sb{sub 1-y} and GaAs/GaP{sub y}As{sub 1-y} superlattices have been measured by spectroscopic ellipsometry in the 0.75-5.5 eV photon energy range. The analysis of the E{sub 1} interband critical point and modeling of spectra has been carried out to investigate the chemistry of the anion exchange reaction and abruptness of interface composition in the superlattices. It has been found that a ternary compound GaP{sub y}As{sub 1-y} forms in the case of the P-for-As anion exchange reaction. In the case of As-for-Sb anion exchange reaction for (GaSb/GaAs{sub y}Sb{sub 1-y}){sub 20} SLs, SE data show that this anion exchange results in the formation not only of a ternary alloy GaAs{sub y}Sb{sub 1-y}, but also in the formation of isoelectronic compounds AsSb{sub x} that segregate at the GaSb/GaAs interface. In the case of Sb-for-As anion exchange for (GaAs/GaSbyAs{sub 1-y}){sub 20} SLs, Sb segregates at the GaAs surface.

  13. Optical properties and surface characterization of pulsed laser-deposited Cu2ZnSnS4 by spectroscopic ellipsometry

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Cazzaniga, Andrea Carlo; Ettlinger, Rebecca Bolt

    2015-01-01

    Cu2ZnSnS4 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 dielect......Cu2ZnSnS4 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 surface features observed by scanning electron microscopy and atomic force microscopy are accurately...

  14. Spectroscopic ellipsometry and polarimetry for materials and systems analysis at the nanometer scale: state-of-the-art, potential, and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Losurdo, Maria, E-mail: maria.losurdo@ba.imip.cnr.i [National Council of Research-Institute of Inorganic Methodologies and of Plasmas, CNR-IMIP (Italy); Bergmair, Michael [Johannes Kepler University Linz, Christian Doppler Laboratory for Surface Optics, Center for Surface- and Nanoanalytics (Austria); Bruno, Giovanni [National Council of Research-Institute of Inorganic Methodologies and of Plasmas, CNR-IMIP (Italy); Cattelan, Denis, E-mail: denis.cattelan@horiba.co [HORIBA Scientific, Thin Film Division (France); Cobet, Christoph [ISAS Institute for Analytical Sciences, Department Berlin (Germany); Martino, Antonello de [Ecole Polytechnique, Centre National de la Recherche Scientique (CNRS-LPICM) (France); Fleischer, Karsten [ISAS Institute for Analytical Sciences, Department Berlin (Germany); Dohcevic-Mitrovic, Zorana [Institute of Physics, Center for Solid State Physics and New Materials (Serbia); Esser, Norbert [ISAS Institute for Analytical Sciences, Department Berlin (Germany); Galliet, Melanie, E-mail: melanie.gaillet@horiba.co [HORIBA Scientific, Thin Film Division (France); Gajic, Rados [Institute of Physics, Center for Solid State Physics and New Materials (Serbia); Hemzal, Dusan; Hingerl, Kurt [Johannes Kepler University Linz, Christian Doppler Laboratory for Surface Optics, Center for Surface- and Nanoanalytics (Austria); Humlicek, Josef; Ossikovski, Razvigor [Ecole Polytechnique, Centre National de la Recherche Scientique (CNRS-LPICM) (France); Popovic, Zoran V. [Institute of Physics, Center for Solid State Physics and New Materials (Serbia); Saxl, Ottilia [Institute of Nanotechnology (United Kingdom)

    2009-10-15

    This paper discusses the fundamentals, applications, potential, limitations, and future perspectives of polarized light reflection techniques for the characterization of materials and related systems and devices at the nanoscale. These techniques include spectroscopic ellipsometry, polarimetry, and reflectance anisotropy. We give an overview of the various ellipsometry strategies for the measurement and analysis of nanometric films, metal nanoparticles and nanowires, semiconductor nanocrystals, and submicron periodic structures. We show that ellipsometry is capable of more than the determination of thickness and optical properties, and it can be exploited to gain information about process control, geometry factors, anisotropy, defects, and quantum confinement effects of nanostructures.

  15. Spectroscopic ellipsometry and polarimetry for materials and systems analysis at the nanometer scale: state-of-the-art, potential, and perspectives

    Science.gov (United States)

    Bergmair, Michael; Bruno, Giovanni; Cattelan, Denis; Cobet, Christoph; de Martino, Antonello; Fleischer, Karsten; Dohcevic-Mitrovic, Zorana; Esser, Norbert; Galliet, Melanie; Gajic, Rados; Hemzal, Dušan; Hingerl, Kurt; Humlicek, Josef; Ossikovski, Razvigor; Popovic, Zoran V.; Saxl, Ottilia

    2009-01-01

    This paper discusses the fundamentals, applications, potential, limitations, and future perspectives of polarized light reflection techniques for the characterization of materials and related systems and devices at the nanoscale. These techniques include spectroscopic ellipsometry, polarimetry, and reflectance anisotropy. We give an overview of the various ellipsometry strategies for the measurement and analysis of nanometric films, metal nanoparticles and nanowires, semiconductor nanocrystals, and submicron periodic structures. We show that ellipsometry is capable of more than the determination of thickness and optical properties, and it can be exploited to gain information about process control, geometry factors, anisotropy, defects, and quantum confinement effects of nanostructures. PMID:21170135

  16. Spectroscopic ellipsometry and polarimetry for materials and systems analysis at the nanometer scale: state-of-the-art, potential, and perspectives

    International Nuclear Information System (INIS)

    Losurdo, Maria; Bergmair, Michael; Bruno, Giovanni; Cattelan, Denis; Cobet, Christoph; Martino, Antonello de; Fleischer, Karsten; Dohcevic-Mitrovic, Zorana; Esser, Norbert; Galliet, Melanie; Gajic, Rados; Hemzal, Dusan; Hingerl, Kurt; Humlicek, Josef; Ossikovski, Razvigor; Popovic, Zoran V.; Saxl, Ottilia

    2009-01-01

    This paper discusses the fundamentals, applications, potential, limitations, and future perspectives of polarized light reflection techniques for the characterization of materials and related systems and devices at the nanoscale. These techniques include spectroscopic ellipsometry, polarimetry, and reflectance anisotropy. We give an overview of the various ellipsometry strategies for the measurement and analysis of nanometric films, metal nanoparticles and nanowires, semiconductor nanocrystals, and submicron periodic structures. We show that ellipsometry is capable of more than the determination of thickness and optical properties, and it can be exploited to gain information about process control, geometry factors, anisotropy, defects, and quantum confinement effects of nanostructures.

  17. Spectroscopic study

    International Nuclear Information System (INIS)

    Flores, M.; Rodriguez, R.; Arroyo, R.

    1999-01-01

    This work is focused about the spectroscopic properties of a polymer material which consists of Polyacrylic acid (Paa) doped at different concentrations of Europium ions (Eu 3+ ). They show that to stay chemically joined with the polymer by a study of Nuclear Magnetic Resonance (NMR) of 1 H, 13 C and Fourier Transform Infrared Spectroscopy (Ft-IR) they present changes in the intensity of signals, just as too when this material is irradiated at λ = 394 nm. In according with the results obtained experimentally in this type of materials it can say that is possible to unify chemically the polymer with this type of cations, as well as, varying the concentration of them, since that these are distributed homogeneously inside the matrix maintaining its optical properties. These materials can be obtained more quickly and easy in solid or liquid phase and they have the best conditions for to make a quantitative analysis. (Author)

  18. Optical constants of CH3NH3PbBr3 perovskite thin films measured by spectroscopic ellipsometry

    KAUST Repository

    Alias, Mohd Sharizal

    2016-07-14

    The lack of optical constants information for hybrid perovskite of CH3NH3PbBr3 in thin films form can delay the progress of efficient LED or laser demonstration. Here, we report on the optical constants (complex refractive index and dielectric function) of CH3NH3PbBr3 perovskite thin films using spectroscopic ellipsometry. Due to the existence of voids, the refractive index of the thin films is around 8% less than the single crystals counterpart. The energy bandgap is around 2.309 eV as obtained from photoluminescence and spectrophotometry spectra, and calculated from the SE analysis. The precise measurement of optical constants will be useful in designing optical devices using CH3NH3PbBr3 thin films.

  19. Spectroscopic imaging ellipsometry for automated search of flakes of mono- and n-layers of 2D-materials

    Science.gov (United States)

    Funke, S.; Wurstbauer, U.; Miller, B.; Matković, A.; Green, A.; Diebold, A.; Röling, C.; Thiesen, P. H.

    2017-11-01

    Spectroscopic imaging ellipsometry (SIE) is used to localize and characterize flakes of conducting, semi-conducting and insulating 2D-materials. Although the research in the field of monolayers of 2D-materials increased the last years, it is still challenging to look for small flakes and distinguish between different layer numbers. Special substrates are used to enhance optical contrast for the conventional light microscopy (LM). In case when other functional support from the substrate is essential, an additional transfer step needs to be employed, bringing the drawbacks as contamination, cracking and wrinkling of the 2D materials. Furthermore it is time-consuming and not yet fully automatically to search for monolayers by contrast with the LM. Here we present a method, that is able to automatically localize regions with desired thicknesses, e.g. monolayers, of the different materials on arbitrary substrates.

  20. Analyzing optical properties of thin vanadium oxide films through semiconductor-to-metal phase transition using spectroscopic ellipsometry

    Science.gov (United States)

    Sun, Jianing; Pribil, Greg K.

    2017-11-01

    We investigated the optical behaviors of vanadium dioxide (VO2) films through the semiconductor-to-metal (STM) phase transition using spectroscopic ellipsometry. Correlations between film thickness and refractive index were observed resulting from the absorbing nature of these films. Simultaneously analyzing data at multiple temperatures using Kramers-Kronig consistent oscillator models help identify film thickness. Nontrivial variations in resulting optical constants were observed through STM transition. As temperature increases, a clear increase is observed in near infrared absorption due to Drude losses that accompany the transition from semiconducting to metallic phases. Thin films grown on silicon and sapphire substrate present different optical properties and thermal hysteresis due to lattice stress and compositional differences.

  1. Real time spectroscopic ellipsometry investigation of homoepitaxial GaN grown by plasma assisted molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tong-Ho; Choi, Soojeong; Wu, Pae; Brown, April [Department of Electrical and Computer Engineering, Duke University, 128 Hudson Hall, Durham, NC (United States); Losurdo, Maria; Giangregorio, Maria M.; Bruno, Giovanni [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM UdR Bari, via Orabona, 4, 70126 Bari (Italy); Moto, Akihiro [Innovation Core SEI, Inc., 3235 Kifer Road, Santa Clara, CA 95051 (United States)

    2006-06-15

    The growth of GaN by plasma assisted molecular beam epitaxy on GaN template substrates (GaN on sapphire) is investigated with in-situ multi-channel spectroscopic ellipsometry. Growth is performed under various Ga/N flux ratios at growth temperatures in the range 710-780 C. The thermal roughening of the GaN template caused by decomposition of the surface is investigated through the temporal variation of the GaN pseudodielectric function over the temperature range of 650 C to 850 C. The structural, morphological, and optical properties are also discussed. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Determination of the optical model of the MOS structure with spectroscopic ellipsometry

    Science.gov (United States)

    Kudla, Andrzej; Brzezinska, Danuta; Wagner, Thomas; Sawicki, Zbigniew

    1997-04-01

    The internal photo injection phenomena in a semitransparent gate metal-oxide-semiconductor (MOS) structure were described among others by the Przewlocki formula. This formula describes the dependence between external voltage applied to the gate to get zero photoelectric current and the light absorption in both electrodes. To study optical properties of the MOS structure, ellipsometric measurements and calculations for the Al-SiO2-Si system were done using J.A. Woolam spectroscopic ellipsometer VASE. The optical model of this structure was determined and used to calculate the dependence of the voltage on the light wavelength (lambda) in Przewlocki's formula.

  3. Mueller-matrix ellipsometry studies of optically active structures in scarab beetles

    Directory of Open Access Journals (Sweden)

    Arwin H.

    2010-06-01

    Full Text Available The complexity of multilayers, photonic crystals, metamaterials and other artificial materials has promoted the use of spectroscopic, variable angle, generalized and Mueller-matrix ellipsometry. Naturally occurring structures may show even higher complexity than artificial structures but with a more narrow range of constituent materials. Fascinating reflection properties result from intricate photonic structures in, for instance, the wing scales and cuticles of insects. Currently there is a large interest to explore such functional supramolecular architectures for exploitation in nanotechnology. In this study, Mueller-matrix spectroscopic ellipsometry is applied in the spectral range of 250 to 1000 nm to investigate optical response and structures of the cuticle of Scarab beetles of the Cetoniinae subfamily. The cuticle of Cetonia aurata (the rose chafer, la cétoine dorée is green with a metallic appearance and reflects left-handed circular/elliptically polarized light. It has been suggested that the polarization of this metallic gloss is caused by a helical structure in the chitinous cuticle. We find that the polarization effect is limited to the narrow spectral range 470-550 nm whereas for shorter or longer wavelengths the reflection properties are similar to those from a near-dielectric material. Model calculations and parameterization of the nanostructure employing a heliocoidal structure are discussed. As a comparison the polarization effects from light reflected from two other beetles will be presented. Coptomia laevis has a similar appearance as Cetonia aurata but has very different polarization properties. The golden Plusiotis argentiola has very interesting properties showing both left and right-handed polarization depending on incidence angle and wavelength.

  4. Spectroscopic ellipsometry for analysis of polycrystalline thin-film photovoltaic devices and prediction of external quantum efficiency

    Science.gov (United States)

    Ibdah, Abdel-Rahman; Koirala, Prakash; Aryal, Puruswottam; Pradhan, Puja; Marsillac, Sylvain; Rockett, Angus A.; Podraza, Nikolas J.; Collins, Robert W.

    2017-11-01

    Complete polycrystalline thin-film photovoltaic (PV) devices employing CuIn1-xGaxSe2/CdS and CdS/CdTe heterojunctions have been studied by ex situ spectroscopic ellipsometry (SE). In this study, layer thicknesses have been extracted along with photon energy independent parameters such as compositions that describe the dielectric function spectra ε(E) of the individual layers. For accurate ex situ SE analysis of these PV devices, a database of ε(E) spectra is required for all thin film component materials used in each of the two absorber technologies. When possible, database measurements are performed by applying SE in situ immediately after deposition of the thin film materials and after cooling to room temperature in order to avoid oxidation and surface contamination. Determination of ε(E) from the resulting in situ SE data requires structural information that can be obtained from analysis of SE data acquired in real time during the deposition process. From the results of ex situ analysis of the complete CuIn1-xGaxSe2 (CIGS) and CdTe PV devices, the deduced layer thicknesses in combination with the parameters describing ε(E) can be employed in further studies that simulate the external quantum efficiency (EQE) spectra of the devices. These simulations have been performed here by assuming that all electron-hole pairs generated within the active layers, i.e. layers incorporating a dominant absorber component (either CIGS or CdTe), are separated and collected. The active layers may include not only the bulk absorber but also window and back contact interface layers, and individual current contributions from these layers have been determined in the simulations. In addition, the ex situ SE analysis results enable calculation of the absorbance spectra for the inactive layers and the overall reflectance spectra, which lead to quantification of all optical losses in terms of a current density deficit. Mapping SE can be performed given the high speed of multichannel

  5. 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

  6. Optical gradients in a-Si:H thin films detected using real-time spectroscopic ellipsometry with virtual interface analysis

    Science.gov (United States)

    Junda, Maxwell M.; Karki Gautam, Laxmi; Collins, Robert W.; Podraza, Nikolas J.

    2018-04-01

    Virtual interface analysis (VIA) is applied to real time spectroscopic ellipsometry measurements taken during the growth of hydrogenated amorphous silicon (a-Si:H) thin films using various hydrogen dilutions of precursor gases and on different substrates during plasma enhanced chemical vapor deposition. A procedure is developed for optimizing VIA model configurations by adjusting sampling depth into the film and the analyzed spectral range such that model fits with the lowest possible error function are achieved. The optimal VIA configurations are found to be different depending on hydrogen dilution, substrate composition, and instantaneous film thickness. A depth profile in the optical properties of the films is then extracted that results from a variation in an optical absorption broadening parameter in a parametric a-Si:H model as a function of film thickness during deposition. Previously identified relationships are used linking this broadening parameter to the overall shape of the optical properties. This parameter is observed to converge after about 2000-3000 Å of accumulated thickness in all layers, implying that similar order in the a-Si:H network can be reached after sufficient thicknesses. In the early stages of growth, however, significant variations in broadening resulting from substrate- and processing-induced order are detected and tracked as a function of bulk layer thickness yielding an optical property depth profile in the final film. The best results are achieved with the simplest film-on-substrate structures while limitations are identified in cases where films have been deposited on more complex substrate structures.

  7. Characterization of thermochromic VO2 (prepared at 250 °C) in a wide temperature range by spectroscopic ellipsometry

    Science.gov (United States)

    Houska, J.; Kolenaty, D.; Rezek, J.; Vlcek, J.

    2017-11-01

    The paper deals with thermochromic VO2 prepared by reactive high-power impulse magnetron sputtering and characterized by spectroscopic ellipsometry. We focus on the dispersion of optical constants in a wide temperature range and on the transmittance predicted using the optical constants. While the thermochromic behavior of VO2 in itself has been reported previously (particularly above the room temperature, RT), in this paper we present (i) optical properties achieved at a low deposition temperature of 250 °C and without any substrate bias voltage (which dramatically increases the application potential of the coating) and (ii) changes of these properties not only above but also below RT (down to -30 °C). The properties include very low (for VO2) extinction coefficient at RT (0.10 at 550 nm), low transition temperature of around or even below 50 °C (compared to the frequently cited 68 °C) and high modulation of the predicted infrared transmittance (e.g. 39% at -30 °C, 30% at RT and 3.4% above the transition temperature at 2000 nm for a 100 nm thick coating on glass). The results are important for the design of thermochromic coatings, and pathways for their preparation under industry-friendly conditions, for various technological applications.

  8. Spectroscopic Ellipsometry Measurements of Wurtzite Gallium Nitride Surfaces as a Function of Buffered Oxide Etch Substrate Submersion

    Science.gov (United States)

    Szwejkowski, Chester; Constantin, Costel; Duda, John; Hopkins, Patrick; Optical Studies of GaN interfaces Collaboration

    2013-03-01

    Gallium nitride (GaN) is considered the most important semiconductor after the discovery of silicon. Understanding the optical properties of GaN surfaces is imperative in determining the utility and applicability of this class of materials to devices. In this work, we present preliminary results of spectroscopic ellipsometry measurements as a function of surface root mean square (RMS). We used commercially available 5mm x 5mm, one side polished GaN (3-7 μm)/Sapphire (430 μm) substrates that have a wurtzite crystal structure and they are slightly n-type doped. The GaN substrates were cleaned with Acetone (20 min)/Isopropanol(20 min)/DI water (20 min) before they were submerged into Buffered Oxide Etch (BOE) for 10s - 60s steps. This BOE treatment produced RMS values of 1-30 nm as measured with an atomic force microscope. Preliminary qualitative ellipsometric measurements show that the complex refractive index and the complex dielectric function decrease with an increase of RMS. More measurements need to be done in order to provide explicit quantitative results. This work was supported by the 4-VA Collaborative effort between James Madison University and University of Virginia.

  9. Identification of optimal ALD process conditions of Nd{sub 2}O{sub 3} on Si by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xiaojiao; Liu, Hongxia; Zhang, Xujie [Xidian University, School of Microelectronics, Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, Xi' an (China)

    2014-02-15

    Variable angle spectroscopic ellipsometry (VASE) is used to investigate the thickness and optical properties of Nd{sub 2}O{sub 3} films deposited by atomic layer deposition (ALD) at various process conditions. It is found that the films exhibit good thickness uniformity and an almost constant growth rate of 0.42 aa/cycle in the temperature region of 290-330 C. Further examination of the imaginary part of the dielectric functions of the selected samples demonstrates that all optically observable dielectric-related defects are located in the interface layer between the silicon substrate and the native oxide rather than in the bulk Nd{sub 2}O{sub 3} layer. And, the defects within the band gap of the interface are found to be strongly affected by the deposition temperature. In the deposition temperature range of 300-320 C, only one absorption peak of 3.53 eV besides the silicon substrate's critical features is observed, indicating that the Si/SiO{sub 2}/Nd{sub 2}O{sub 3} stacks contain the fewest interfacial defects. Then the optimal ALD process condition for Nd{sub 2}O{sub 3} is determined as Nd(thd){sub 3} (thd = 2,2,6,6,-tetramethyl-3,5-heptanedionato) evaporation temperature: 185 C, deposition temperature: 300-320 C, saturation condition: Nd(thd){sub 3} and pulse time longer than 0.5 s. (orig.)

  10. Etching of a-Si:H thin films by hydrogen plasma: A view from in situ spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Hadjadj, Aomar, E-mail: aomar.hadjadj@univ-reims.fr; Larbi, Fadila; Gilliot, Mickaël [Laboratoire d’Ingénierie et Sciences des Matériaux (LISM, EA 4695), Université de Reims Champagne-Ardenne (France); Roca i Cabarrocas, Pere [Laboratoire de Physique des Interfaces et Couches Minces (LPICM, CNRS UMR 7647), Ecole Polytechnique (France)

    2014-08-28

    When atomic hydrogen interacts with hydrogenated amorphous silicon (a-Si:H), the induced modifications are of crucial importance during a-Si:H based devices manufacturing or processing. In the case of hydrogen plasma, the depth of the modified zone depends not only on the plasma processing parameters but also on the material. In this work, we exposed a-Si:H thin films to H{sub 2} plasma just after their deposition. In situ UV-visible spectroscopic ellipsometry measurements were performed to track the H-induced changes in the material. The competition between hydrogen insertion and silicon etching leads to first order kinetics in the time-evolution of the thickness of the H-modified zone. We analyzed the correlation between the steady state structural parameters of the H-modified layer and the main levers that control the plasma-surface interaction. In comparison with a simple doped layer, exposure of a-Si:H based junctions to the same plasma treatment leads to a thinner H-rich subsurface layer, suggesting a possible charged state of hydrogen diffusing.

  11. Complex refractive indices of thin films of secondary organic materials by spectroscopic ellipsometry from 220 to 1200 nm.

    Science.gov (United States)

    Liu, Pengfei; Zhang, Yue; Martin, Scot T

    2013-01-01

    The complex refractive indices of three different types of secondary organic material (SOM) were obtained for 220 to 1200 nm using a variable angle spectroscopic ellipsometer. Aerosol particles were produced in a flow tube reactor by ozonolysis of volatile organic compounds, including the monoterpenes α-pinene and limonene and the aromatic catechol (benzene-1,2-diol). Optically reflective thin films of SOM were grown by electrostatic precipitation of the aerosol particles onto silicon substrates. The ellipsometry analysis showed that both the real and imaginary components of the refractive indices decreased with increasing wavelength. The real part n(λ) could be parametrized by the three-term form of Cauchy's equation, as follows: n(λ) = B + C/λ(2) + D/λ(4) where λ is the wavelength and B, C, and D are fitting parameters. The real refractive indices of the three SOMs ranged from 1.53 to 1.58, 1.49-1.52, and 1.48-1.50 at 310, 550, and 1000 nm, respectively. The catechol-derived SOM absorbed light in the ultraviolet (UV) range. By comparison, the UV absorption of the monoterpene-derived SOMs was negligible. On the basis of the measured refractive indices, optical properties were modeled for a typical atmospheric particle population. The results suggest that the wavelength dependence of the refractive indices can vary the Angstrom exponent by up to 0.1 across the range 310 to 550 nm. The modeled single-scattering albedo can likewise vary from 0.97 to 0.85 at 310 nm (UV-B). Variability in the optical properties of different types of SOMs can imply important differences in the relative effects of atmospheric particles on tropospheric photochemistry, as well as possible inaccuracies in some satellite-retrieved properties such as optical depth and mode diameter.

  12. Analysis of the early growth mechanisms during the chemical deposition of CdS thin films by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval-Paz, M.G., E-mail: myrnasandoval@udec.c [Centro de Investigacion y Estudios Avanzados del IPN. Unidad Queretaro, Apdo. postal 1-798, Queretaro, Qro., 76001 (Mexico); Departamento de Fisica, Facultad de Ciencias Fisicas y Matematicas, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile); Ramirez-Bon, R. [Centro de Investigacion y Estudios Avanzados del IPN. Unidad Queretaro, Apdo. postal 1-798, Queretaro, Qro., 76001 (Mexico)

    2009-10-30

    Chemically deposited CdS thin films were analyzed in this work by means of the spectroscopic ellipsometry technique. The CdS thin films were deposited from an ammonia-free process at short durations in order to obtain information about the layer microstructure and kinetic growth process. We found that the conditions of the ammonia-free reaction solution promote the ion-by-ion deposition process at the early growth stages yielding a compact, high refraction index and highly crystalline oriented CdS layers. Using a concentration of 1.82 mg/ml of cadmium in the reaction solution, the resulting films possess a double layer microstructure which consists of an inner compact layer and an external porous one. The inner layer is developed during the first 15 min of deposition time and it reaches a thickness around of 80 nm. After this time and on this inner layer of CdS, it grows an external porous layer whose thickness increases with the deposition time. The formation of the CdS compact layer at the early stages is related with the ion-by-ion growth mechanism. The subsequent CdS porous layer is formed during the cluster-by-cluster growth stage at longer deposition times. By reducing the cadmium concentration in reaction solution down to 0.76 mg/ml, maintaining constant molar ratio concentrations of Cd/complexing and Cd/thiourea, the chemically deposited CdS films develop only the inner compact layer with a thickness of about 80 nm after 35 min of deposition time.

  13. Application of ellipsometry techniques to biological materials

    Energy Technology Data Exchange (ETDEWEB)

    Arwin, Hans, E-mail: han@ifm.liu.s

    2011-02-28

    Ellipsometry is well-suited for bioadsorption studies and numerous reports, mainly using null ellipsometry, are found on this subject whereas investigations addressing structural properties of thin biolayers are few. Here two examples based on the use of spectroscopic ellipsometry (SE) on the latter are briefly discussed. In the first example, time evolution of thickness, spectral refractive index and surface mass density of a fibrinogen matrix forming on a silicon substrate are investigated with SE and a structural model of the protein matrix is discussed. In the second example a model dielectric function concept for protein monolayers is presented. The model allows parameterization of the optical properties which facilitates monitoring of temperature induced degradation of a protein layer. More recently, photonic structures in beetles have been studied with SE. It is shown here that full Mueller-matrix SE can resolve very complex nanostructures in scarab beetles, more specifically chiral structures causing reflected light to become circularly polarized.

  14. Temperature-dependent and anisotropic optical response of layered Pr0.5Ca1.5MnO4 probed by spectroscopic ellipsometry

    NARCIS (Netherlands)

    Majidi, M. A.; Thoeng, E.; Gogoi, P. K.; Wendt, F.; Wang, S. H.; Santoso, I.; Asmara, T. C.; Handayani, I. P.; van Loosdrecht, P. H. M.; Nugroho, A. A.; Ruebhausen, M.; Rusydi, A.; Rübhausen, M.

    2013-01-01

    We study the temperature dependence as well as anisotropy of optical conductivity (sigma(1)) in the pseudocubic single crystal Pr0.5Ca1.5MnO4 using spectrocopic ellipsometry. Three transition temperatures are observed and can be linked to charge-orbital (T-CO/OO similar to 320 K),

  15. Investigation of Bovine Serum Albumin (BSA) Attachment onto Self-Assembled Monolayers (SAMs) Using Combinatorial Quartz Crystal Microbalance with Dissipation (QCM-D) and Spectroscopic Ellipsometry (SE)

    Science.gov (United States)

    Phan, Hanh T. M.; Bartelt-Hunt, Shannon; Rodenhausen, Keith B.; Schubert, Mathias; Bartz, Jason C.

    2015-01-01

    Understanding protein adsorption kinetics to surfaces is of importance for various environmental and biomedical applications. Adsorption of bovine serum albumin to various self-assembled monolayer surfaces including neutral and charged hydrophilic and hydrophobic surfaces was investigated using in-situ combinatorial quartz crystal microbalance with dissipation and spectroscopic ellipsometry. Adsorption of bovine serum albumin varied as a function of surface properties, bovine serum albumin concentration and pH value. Charged surfaces exhibited a greater quantity of bovine serum albumin adsorption, a larger bovine serum albumin layer thickness, and increased density of bovine serum albumin protein compared to neutral surfaces at neutral pH value. The quantity of adsorbed bovine serum albumin protein increased with increasing bovine serum albumin concentration. After equilibrium sorption was reached at pH 7.0, desorption of bovine serum albumin occurred when pH was lowered to 2.0, which is below the isoelectric point of bovine serum albumin. Our data provide further evidence that combinatorial quartz crystal microbalance with dissipation and spectroscopic ellipsometry is a sensitive analytical tool to evaluate attachment and detachment of adsorbed proteins in systems with environmental implications. PMID:26505481

  16. Investigation of Bovine Serum Albumin (BSA Attachment onto Self-Assembled Monolayers (SAMs Using Combinatorial Quartz Crystal Microbalance with Dissipation (QCM-D and Spectroscopic Ellipsometry (SE.

    Directory of Open Access Journals (Sweden)

    Hanh T M Phan

    Full Text Available Understanding protein adsorption kinetics to surfaces is of importance for various environmental and biomedical applications. Adsorption of bovine serum albumin to various self-assembled monolayer surfaces including neutral and charged hydrophilic and hydrophobic surfaces was investigated using in-situ combinatorial quartz crystal microbalance with dissipation and spectroscopic ellipsometry. Adsorption of bovine serum albumin varied as a function of surface properties, bovine serum albumin concentration and pH value. Charged surfaces exhibited a greater quantity of bovine serum albumin adsorption, a larger bovine serum albumin layer thickness, and increased density of bovine serum albumin protein compared to neutral surfaces at neutral pH value. The quantity of adsorbed bovine serum albumin protein increased with increasing bovine serum albumin concentration. After equilibrium sorption was reached at pH 7.0, desorption of bovine serum albumin occurred when pH was lowered to 2.0, which is below the isoelectric point of bovine serum albumin. Our data provide further evidence that combinatorial quartz crystal microbalance with dissipation and spectroscopic ellipsometry is a sensitive analytical tool to evaluate attachment and detachment of adsorbed proteins in systems with environmental implications.

  17. Dielectric functions and carrier concentrations of Hg{sub 1−x}Cd{sub x}Se films determined by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A. J.; Peiris, F. C., E-mail: peirisf@kenyon.edu [Department of Physics, Kenyon College, Gambier, Ohio 43022 (United States); Brill, G.; Doyle, K. [U.S. Army Research Laboratory, Adelphi, Maryland 20783-1197 (United States); Myers, T. H. [Department of Physics, Texas State University, San Marcos, Texas 78666 (United States)

    2015-08-17

    Spectroscopic ellipsometry, ranging from 35 meV to 6 eV, was used to determine the dielectric functions of a series of molecular beam epitaxy-grown Hg{sub 1−x}Cd{sub x}Se thin films deposited on both ZnTe/Si(112) and GaSb(112) substrates. The fundamental band gap as well as two higher-order electronic transitions blue-shift with increasing Cd composition in Hg{sub 1−x}Cd{sub x}Se, as expected. Representing the free carrier absorption with a Drude oscillator, we found that the effective masses of Hg{sub 1−x}Cd{sub x}Se (grown on ZnTe/Si) vary between 0.028 and 0.050 times the free electron mass, calculated using the values of carrier concentration and the mobility obtained through Hall measurements. Using these effective masses, we determined the carrier concentrations of Hg{sub 1−x}Cd{sub x}Se samples grown on GaSb, which is of significance as films grown on such doped-substrates posit ambiguous results when measured by conventional Hall experiments. These models can serve as a basis for monitoring Cd-composition during sample growth through in-situ spectroscopic ellipsometry.

  18. Ellipsometry at the nanoscale

    CERN Document Server

    Hingerl, Kurt

    2013-01-01

    This book presents and introduces ellipsometry in nanoscience and nanotechnology making a bridge between the classical and nanoscale optical behaviour of materials. It delineates the role of the non-destructive and non-invasive optical diagnostics of ellipsometry in improving science and technology of nanomaterials and related processes by illustrating its exploitation, ranging from fundamental studies of the physics and chemistry of nanostructures to the ultimate goal of turnkey manufacturing control. This book is written for a broad readership: materials scientists, researchers, engineers, as well as students and nanotechnology operators who want to deepen their knowledge about both basics and applications of ellipsometry to nanoscale phenomena. It starts as a general introduction for people curious to enter the fields of ellipsometry and polarimetry applied to nanomaterials and progresses to articles by experts on specific fields that span from plasmonics, optics, to semiconductors and flexible electronics...

  19. Spectroscopic ellipsometry on Si/SiO2/graphene tri-layer system exposed to downstream hydrogen plasma: Effects of hydrogenation and chemical sputtering

    International Nuclear Information System (INIS)

    Eren, Baran; Fu, Wangyang; Marot, Laurent; Calame, Michel; Steiner, Roland; Meyer, Ernst

    2015-01-01

    In this work, the optical response of graphene to hydrogen plasma treatment is investigated with spectroscopic ellipsometry measurements. Although the electronic transport properties and Raman spectrum of graphene change after plasma hydrogenation, ellipsometric parameters of the Si/SiO2/graphene tri-layer system do not change. This is attributed to plasma hydrogenated graphene still being electrically conductive, since the light absorption of conducting 2D materials does not depend on the electronic band structure. A change in the light transmission can only be observed when higher energy hydrogen ions (30 eV) are employed, which chemically sputter the graphene layer. An optical contrast is still apparent after sputtering due to the remaining traces of graphene and hydrocarbons on the surface. In brief, plasma treatment does not change the light transmission of graphene; and when it does, this is actually due to plasma damage rather than plasma hydrogenation

  20. Nucleation and initial growth of atomic layer deposited titanium oxide determined by spectroscopic ellipsometry and the effect of pretreatment by surface barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, David C., E-mail: dccameron@mail.muni.cz [R& D Centre for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 267/2, 611 37 Brno (Czech Republic); Krumpolec, Richard, E-mail: richard.krumpolec@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 842 4 Bratislava (Slovakia); Ivanova, Tatiana V., E-mail: tatiana.ivanova@lut.fi [ASTRaL team, Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Homola, Tomáš, E-mail: tomas.homola@mail.muni.cz [R& D Centre for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 267/2, 611 37 Brno (Czech Republic); Černák, Mirko, E-mail: cernak@physics.muni.cz [R& D Centre for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 267/2, 611 37 Brno (Czech Republic)

    2015-08-01

    Highlights: • Spectroscopic ellipsometry shows initial nucleation and growth process in atomic layer deposited titanium dioxide. • Quantum confinement effects were used to measure evolution of crystallite size. • Crystallite surface density can be extracted from ellipsometric surface roughness data and crystallite size. • Pretreatment of silicon substrates by diffuse coplanar surface barrier discharge has only minor effects on titanium dioxide film nucleation and growth. - Abstract: This paper reports on the use of spectroscopic ellipsometry to characterise the initial nucleation stage of the atomic layer deposition of the anatase phase of titanium dioxide on silicon substrates. Careful control and analysis of the ellipsometric measurements enables the determination of the evolution of crystallite diameter and surface density in the nucleation stage before a continuous film is formed. This growth behaviour is in line with atomic force microscopy measurements of the crystallite size. The crystallite diameter is a linear function of the number of ALD cycles with a slope of approximately 1.7 Å cycle{sup −1} which is equivalent to a layer growth rate of 0.85 Å cycle{sup −1} consistent with a ripening process which increases the crystallite size while reducing their density. The crystallite density decreases from ∼3 × 10{sup 17} m{sup −3} in the initial nucleation stages to ∼3 × 10{sup 15} m{sup −3} before the film becomes continuous. The effect of exposing the substrate to a diffuse coplanar surface barrier discharge in an air atmosphere before deposition was measured and only small differences were found: the plasma treated samples were slightly rougher in the initial stages and required a greater number of cycles to form a continuous film (∼80) compared to the untreated films (∼50). A thicker layer of native oxide was found after plasma treatment.

  1. Modeling approach to derive the anisotropic complex refractive index of polymer:fullerene blends for organic solar cells utilizing spectroscopic ellipsometry

    Science.gov (United States)

    Klein, Michael F. G.; de Medeiros, Gustavo Q. Glasner; Kapetana, Panagiota; Lemmer, Uli; Colsmann, Alexander

    2015-01-01

    The knowledge of the complex refractive indices of all thin layers in organic solar cells (OSCs) is a prerequisite for comprehensive optical device simulations that are particularly important for sophisticated device architectures, such as tandem OSCs. Therefore, refractive indices are often determined via spectroscopic ellipsometry and subsequent time-consuming modeling. Here, we investigate a modeling approach that allows for the determination of complex refractive indices of bulk-heterojunctions by superimposing the optical models of the respective fullerenes and polymers. The optical constants of neat [6,6]-phenyl C71-butyric acid methyl ester (PC71BM), poly{[4,4'-bis(2-ethylhexyl)dithieno(3,2-b2',3'-d)silole]-2,6-diyl-alt-(2,1,3-benzothidiazole)-4,7-diyl} (PSBTBT) and poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b3,4-b‧‧]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole) (PCPDTBT) are determined, covering the OSC relevant spectral region from 250 to 1,000 nm. Then the blends PSBTBT:PC71BM and PCPDTBT:PC71BM are described within an effective medium approximation. From this approximation, the mass density ratio of polymer and fullerene can be derived. This approach furthermore allows for a uniaxial anisotropic optical description of the polymers and provides insight into thin-film morphology. In contrast to x-ray diffraction experiments, this method also allows for probing amorphous materials. Spectroscopic ellipsometry can be a valuable tool for the investigation of bulk-heterojunction morphologies of the latest high-performance OSC materials that exhibit a low degree of crystallinity.

  2. Phonon and free-charge carrier properties in group-III nitride heterostructures investigated by spectroscopic ellipsometry and optical Hall effect

    Science.gov (United States)

    Schoeche, Stefan

    The material class of group-III nitrides gained tremendous technological importance for optoelectronic and high-power/high-frequency amplification devices. Tunability of the direct band gap from 0.65 eV (InN) to 6.2 eV (AlN) by alloying, high breakthrough voltages and intrinsic mobilities, as well as the formation of highly mobile 2d electron gases (2DEG) at heterointerfaces make these compounds ideal for many applications. GaN and Ga-rich alloys are well studied and current research is mainly device-oriented. For example, choice and quality of the gate dielectric significantly influence device performance in high-electron mobility transistors (HEMT) which utilize highly mobile 2DEGs at heterointerfaces. Experimental access to the 2DEG channel properties without influence from parasitic currents or contact properties are desirable. In- and Al-rich ternary alloys are less explored than Ga-rich compounds. For InN and In-rich alloys, while many material parameters such as stiffness constants or effective mass values are largely unknown, reliable p-type doping is a major challenge, also because p-type conducting channels are buried within highly conductive n-type material formed at the surface and interfaces preventing electrical characterization. For AlN and high-Al content alloys, doping mechanisms are not understood and reliable fabrication of material with high free-charge carrier (FCC) concentrations was achieved just recently. Difficulties to form ohmic contacts impair electrical measurements and optical characterization is impeded by lack of high-energy excitation sources. In this work, spectroscopic ellipsometry over the wide spectral range from the THz to VUV in combination with optical Hall effect (generalized ellipsometry with applied magnetic field) from THz to MIR are applied in order to investigate the phonon modes and FCC properties in group-III nitride heterostructures. Adequate model descriptions and analysis strategies are introduced which allow

  3. Interferometric snapshot spectro-ellipsometry.

    Science.gov (United States)

    Dembele, Vamara; Jin, Moonseob; Choi, Inho; Chegal, Won; Kim, Daesuk

    2018-01-22

    We propose a snapshot spectroscopic ellipsometry and its applications for real-time thin-film thickness measurement. The proposed system employs an interferometric polarization-modulation module that can measure the spectroscopic ellipsometric phase for thin-film deposited on a substrate with a measurement speed of around 20 msec. It requires neither moving parts nor time dependent modulation devices. The accuracy of the proposed interferometric snapshot spectro-ellipsometer is analyzed through comparison with commercial equipment results.

  4. Optical characterization of the coloration process in electrochromic amorphous and crystalline WO3 films by spectroscopic ellipsometry

    Science.gov (United States)

    Yuan, Guangzhong; Hua, Chenzheng; Huang, Li; Defranoux, Christophe; Basa, Peter; Liu, Yong; Song, Chenlu; Han, Gaorong

    2017-11-01

    Amorphous and crystalline electrochromic WO3 films exhibit quite different optical properties during coloration process. In the present work, amorphous and crystalline electrochromic WO3 films prepared by a solution method were characterized using X-ray diffraction, scanning electron microscope, and transmission electron microscope techniques. A double-layer model with sharp interfaces was established for the fitting of the ellipsometry parameters. The results show that the proton favors amorphous films more than crystalline WO3 films. The refractive indices of both amorphous and polycrystalline WO3 films decrease while extinction coefficients increase with the inserting of H+ during the coloration process. But the optical parameters of the latter are much more sensitive to the H+ ions injected compared to the amorphous WO3 during the coloration process. That is the refractive index modulation of the crystalline WO3 films is about 53% at 633 nm while that of the amorphous films about 15% at the same wavelength. The Drude-like free electron model for crystalline WO3 and hopping mechanism of small polaron for amorphous WO3 are used to explain the difference in detail. These results are very helpful for the better understanding of the coloration process and for the design of electrochromic devices.

  5. Spectroscopic ellipsometry, optical, structural and electrical investigation of sprayed pure and Sn-doped ZnO thin films

    Directory of Open Access Journals (Sweden)

    Attaf N.

    2013-03-01

    Full Text Available In this work, we report the transparent pure and Sn-doped zinc oxide (ZnO. The films were deposited onto microscope glass substrate which was heated at 350±5C° by ultrasonic spray pyrolysis (U S P deposition technique. The concentrations of Sn were selected within the range of 0-3% by step of 0.5% and the time deposition is kept at 5 min. A (002-oriented wurtzite crystal structure was confirmed by X-rays patterns; and grain size varied within the range 7.37-14.84nm, and cristanillity is calculated goes from14.4 to 45.9%. Based on UV-VIS-IR analysis, the results revealed the high transparency of the sprayed films which exceeds 90%. The band gap energy was of 3.26-3.30 eV. The film thickness was estimated by spectroscopy ellipsometry and the found values were of 165-270nm. The refractive index is in the range of 2.75.The obtained electrical parameters were around 1018 cm−3, 3.6 cm2/Vs, 1.6Ω.cm; 5.8cm3/C. finally the Sn-doping has influenced the physical parameters of asground ZnO films

  6. Efficient thin-film stack characterization using parametric sensitivity analysis for spectroscopic ellipsometry in semiconductor device fabrication

    International Nuclear Information System (INIS)

    Likhachev, D.V.

    2015-01-01

    During semiconductor device fabrication, control of the layer thicknesses is an important task for in-line metrology since the correct thickness values are essential for proper device performance. At the present time, ellipsometry is widely used for routine process monitoring and process improvement as well as characterization of various materials in the modern nanoelectronic manufacturing. The wide recognition of this technique is based on its non-invasive, non-intrusive and non-destructive nature, high measurement precision, accuracy and speed, and versatility to characterize practically all types of materials used in modern semiconductor industry (dielectrics, semiconductors, metals, polymers, etc.). However, it requires the use of one of the multi-parameter non-linear optimization methods due to its indirect nature. This fact creates a big challenge for analysis of multilayered structures since the number of simultaneously determined model parameters, for instance, thin film thicknesses and model variables related to film optical properties, should be restricted due to parameter cross-correlations. In this paper, we use parametric sensitivity analysis to evaluate the importance of various model parameters and to suggest their optimal search ranges. In this work, the method is applied practically for analysis of a few structures with up to five-layered film stack. It demonstrates an evidence-based improvement in accuracy of multilayered thin-film thickness measurements which suggests that the proposed approach can be useful for industrial applications. - Highlights: • An improved method for multilayered thin-film stack characterization is proposed. • The screening-type technique based on so-called “elementary effects” was employed. • The model parameters were ranked according to relative importance for model output. • The method is tested using two examples of complex thin-film stack characterization. • The approach can be useful in many practical

  7. Smooth and rough Proteus mirabilis lipopolysaccharides studied by total internal reflection ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Gleńska-Olender, J., E-mail: joannaglenska@wp.pl [Institute of Biology, Jan Kochanowski University, 25-406 Kielce (Poland); Świętokrzyski Biobank, Regional Science and Technology Center, 26-060 Chęciny (Poland); Dworecki, K. [Institute of Physics, Jan Kochanowski University, 25-406 Kielce (Poland); Sęk, S. [Department of Chemistry, University of Warsaw, 02-093 Warsaw (Poland); Kwinkowski, M.; Kaca, W. [Institute of Biology, Jan Kochanowski University, 25-406 Kielce (Poland)

    2013-12-02

    Total internal reflection ellipsometry (TIRE), a label-free optical detection technique for studying interactions between biomolecules, was used to examine the adsorption of various forms of lipopolysaccharides (LPSs) isolated from Proteus mirabilis S1959, R110, and R45 strains on a gold surface. The thickness of the adsorbed layers was determined by TIRE, with the average values for S1959, R110, and R45 LPS layers being 78 ± 5, 39 ± 3, and 12 ± 2 nm, respectively. The thickness of LPS layers corresponds to the presence and length of O-specific parts in P. mirabilis LPS molecules. Atomic force microscopy was used as a complementary technique for visualizing lipopolysaccharides on the surface. Force measurements seem to confirm the data obtained from TIRE experiments. - Highlights: • Proteus mirabilis lipopolysaccharides were adsorbed on the gold surface. • Thickness of adsorbed layers was determined by total internal reflection ellipsometry. • Atomic force microscopy was used to visualize lipopolysaccharide build-up on gold surface. • Time is important in the evolution of biomolecular film thickness created on gold surface.

  8. Spectroscopic ellipsometry characterization of amorphous and crystalline TiO2 thin films grown by atomic layer deposition at different temperatures

    Science.gov (United States)

    Saha, D.; Ajimsha, R. S.; Rajiv, K.; Mukherjee, C.; Gupta, M.; Misra, P.; Kukreja, L. M.

    2014-10-01

    TiO2 thin films of widely different structural and morphological characteristics were grown on Si (1 0 0) substrates using Atomic Layer Deposition (ALD) by varying the substrate temperature (Ts) in a wide range (50 °C ≤ Ts ≤ 400 °C). Spectroscopic ellipsometry (SE) measurements were carried out to investigate the effect of growth temperature on the optical properties of the films. Measured SE data were analyzed by considering double layer optical model for the sample together with the single oscillator Tauc-Lorentz dispersion relation. Surface roughness was taken into consideration due to the columnar growths of grains in crystalline films. The refractive index was found to be increased from amorphous (Ts ≤ 150 °C) to the nanocrystalline films (2500 < Ts ≤ 400 °C). The pronounced surface roughening for the large-grained anatase film obtained at the amorphous to crystalline phase transformation temperature of 200 °C, impeded SE measurement. The dispersions of refractive indices below the interband absorption edge were found to be strongly correlated with the single oscillator Wemple-DiDomenico (WD) model. The increase in dispersion energy parameter in WD model from disordered amorphous to the more ordered nanocrystalline films was found to be associated with the increase in the film density and coordination number.

  9. A note on the use of ellipsometry for studying the kinetics of ...

    Indian Academy of Sciences (India)

    Ellipsometry is currently one of the most important techniques for characterization of the deposition and growth mode of ultra thin organic films. However, it is well known that for thicknesses normally encountered in organic monolayer films, as would occur for example in self-assembled monolayers, ellipsometry cannot be ...

  10. Etching and ellipsometry studies on CL-VPE grown GaN epilayer

    Directory of Open Access Journals (Sweden)

    Puviarasu P.

    2017-02-01

    Full Text Available The surface morphological characteristics of wet chemical etched GaN layers grown at different temperatures on (0 0 0 1 sapphire substrates by Chloride-Vapor Phase Epitaxy (Cl-VPE have been studied using optical microscope. Significant surface morphology changes have been observed in correlation to the growth temperature and etching time. Also optical properties of the as grown and high-energy silicon (Si ion irradiated gallium nitride (GaN epilayers were studied using monochromatic ellipsometry. The effect of ion fluences on the refractive index of the GaN has been investigated and it has been found to decrease with an increase of ion fluence. This decrease is attributed to irradiation-induced defects and polycrystallization which plays an important role in determining the optical properties of silicon (Si ion irradiated GaN layers.

  11. Initial stages of anodic oxidation of silver in sodium hydroxide solution studied by potential sweep voltammetry and ellipsometry

    NARCIS (Netherlands)

    Droog, J.M.M.; Alderliesten, P.T.; Bootsma, G.A.

    1979-01-01

    The first stages of the oxidation of polycrystalline silver electrodes in NaOH solutions were studied by potential sweep voltammetry and ellipsometry. Formation of bulk Ag2O was found to be preceded by dissolution of silver species and deposition of a surface oxide. The equilibrium oxide coverage

  12. Optical investigations of La0.7Ca0.3-xKxMnO3 (x = 0.00, 0.05 and 0.10 probed by spectroscopic ellipsometry

    Directory of Open Access Journals (Sweden)

    N. Sdiri

    2012-07-01

    Full Text Available Using spectroscopic ellipsometry, we have studied the optical properties of doped manganites at the paramagnetic state in polycrystalline La0.7Ca0.3-xKxMnO3 samples for (x = 0.00, 0.05 and 0.10 in the energy range of 3.2-5.5 eV at room temperature. The surface morphology of the samples was obtained by using atomic force microscopy (AFM. Refractive indices, extinction coefficients, the transmission ellipsometric parameters Ψ and Δ are investigated at different wavelengths. The study of the optical conductivity σ reveals that optical behaviour and the activated transport in the paramagnetic state of these materials are consistent with Jahn-Teller small polaron. In addition, the spectrum of the complex dielectric constant ε reveals peaks for all samples, the results may be explained by the presence of space charges from the strongly dipole-allowed O(2p−Mn(3d transition.

  13. Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn1−xGaxSe2 Growth: Indium-Gallium Selenide Co-Evaporation

    Directory of Open Access Journals (Sweden)

    Puja Pradhan

    2018-01-01

    Full Text Available Real time spectroscopic ellipsometry (RTSE has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV devices. The first stage entails the growth of indium-gallium selenide (In1−xGax2Se3 (IGS on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to achieve the optimum performance of the resulting CIGS solar cell. RTSE is sensitive to monolayer level film growth processes and can provide accurate measurements of bulk and surface roughness layer thicknesses. These in turn enable accurate measurements of the bulk layer optical response in the form of the complex dielectric function ε = ε1 − iε2, spectra. Here, RTSE has been used to obtain the (ε1, ε2 spectra at the measurement temperature of 400 °C for IGS thin films of different Ga contents (x deduced from different ranges of accumulated bulk layer thickness during the deposition process. Applying an analytical expression in common for each of the (ε1, ε2 spectra of these IGS films, oscillator parameters have been obtained in the best fits and these parameters in turn have been fitted with polynomials in x. From the resulting database of polynomial coefficients, the (ε1, ε2 spectra can be generated for any composition of IGS from the single parameter, x. The results have served as an RTSE fingerprint for IGS composition and have provided further structural information beyond simply thicknesses, for example information related to film density and grain size. The deduced IGS structural evolution and the (ε1, ε2 spectra have been interpreted as well in relation to observations from scanning electron microscopy, X

  14. Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn1-xGaxSe₂ Growth: Indium-Gallium Selenide Co-Evaporation.

    Science.gov (United States)

    Pradhan, Puja; Aryal, Puruswottam; Attygalle, Dinesh; Ibdah, Abdel-Rahman; Koirala, Prakash; Li, Jian; Bhandari, Khagendra P; Liyanage, Geethika K; Ellingson, Randy J; Heben, Michael J; Marsillac, Sylvain; Collins, Robert W; Podraza, Nikolas J

    2018-01-16

    Real time spectroscopic ellipsometry (RTSE) has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS) thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV) devices. The first stage entails the growth of indium-gallium selenide (In 1- x Ga x )₂Se₃ (IGS) on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to achieve the optimum performance of the resulting CIGS solar cell. RTSE is sensitive to monolayer level film growth processes and can provide accurate measurements of bulk and surface roughness layer thicknesses. These in turn enable accurate measurements of the bulk layer optical response in the form of the complex dielectric function ε = ε₁ - iε₂, spectra. Here, RTSE has been used to obtain the (ε₁, ε₂) spectra at the measurement temperature of 400 °C for IGS thin films of different Ga contents ( x ) deduced from different ranges of accumulated bulk layer thickness during the deposition process. Applying an analytical expression in common for each of the (ε₁, ε₂) spectra of these IGS films, oscillator parameters have been obtained in the best fits and these parameters in turn have been fitted with polynomials in x . From the resulting database of polynomial coefficients, the (ε₁, ε₂) spectra can be generated for any composition of IGS from the single parameter, x . The results have served as an RTSE fingerprint for IGS composition and have provided further structural information beyond simply thicknesses, for example information related to film density and grain size. The deduced IGS structural evolution and the (ε₁, ε₂) spectra have been interpreted as well in relation to observations from scanning

  15. Thermal atomic layer deposition and oxidation of TiN monitored by in-situ spectroscopic ellipsometry

    NARCIS (Netherlands)

    Van Hao, B.; Aarnink, Antonius A.I.; Kovalgin, Alexeij Y.; Wolters, Robertus A.M.; Schmitz, Jurriaan

    2009-01-01

    Thin TiN films have many important applications in Integrated Circuit (IC) technology. In spite of its chemical inertness, it is reported that TiN can be oxidized when exposed to oxidants (O2, H2O, etc.). To avoid an undesired oxidation of the metal-nitride layers, a study on this process is

  16. A note on the use of ellipsometry for studying the kinetics of ...

    Indian Academy of Sciences (India)

    Unknown

    practice is to assume a reasonable value for the film refractive index and calculate an effective 'ellipsometric thickness'. This communication seeks to ... tive index, n) from a single ellipsometry measurement. Recognizing this problem, the .... uptake with time curve indicates an initial rapid chemi- sorption of the ODT molecule ...

  17. Ellipsometry study of optical parameters of AgIn{sub 5}S{sub 8} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Isik, Mehmet, E-mail: mehmet.isik@atilim.edu.tr [Department of Electrical and Electronics Engineering, Atilim University, 06836 Ankara (Turkey); Gasanly, Nizami [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey); Virtual International Scientific Research Centre, Baku State University, 1148 Baku (Azerbaijan)

    2015-12-01

    AgIn{sub 5}S{sub 8} crystals grown by Bridgman method were characterized for optical properties by ellipsometry measurements. Spectral dependence of optical parameters; real and imaginary parts of the pseudodielectric function, pseudorefractive index, pseudoextinction coefficient, reflectivity and absorption coefficient were obtained from ellipsometry experiments carried out in the 1.2–6.2 eV range. Direct band gap energy of 1.84 eV was found from the analysis of absorption coefficient vs. photon energy. The oscillator energy, dispersion energy and zero-frequency refractive index, high-frequency dielectric constant values were found from the analysis of the experimental data using Wemple-DiDomenico and Spitzer-Fan models. Crystal structure and atomic composition ratio of the constituent elements in the AgIn{sub 5}S{sub 8} crystal were revealed from structural characterization techniques of X-ray diffraction and energy dispersive spectroscopy.

  18. The negative thermo-optic effect in KTa0.sub.3./sub. : an ellipsometry study

    Czech Academy of Sciences Publication Activity Database

    Trepakov, Vladimír; Dejneka, Alexandr; Jastrabík, Lubomír; Lynnyková, Anna; Chvostová, Dagmar; Syrnikov, P.; Markovin, P.

    2015-01-01

    Roč. 88, č. 10 (2015), s. 991-1000 ISSN 0141-1594 R&D Projects: GA ČR GAP108/12/1941; GA MŠk(CZ) LM2011029 Grant - others:SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 Keywords : KTa0 3 ellipsometry * band-edge optical transitions * thermo-optics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.858, year: 2015

  19. Infrared-spectroscopic single-shot laser mapping ellipsometry: Proof of concept for fast investigations of structured surfaces and interactions in organic thin films

    Science.gov (United States)

    Furchner, Andreas; Kratz, Christoph; Gkogkou, Dimitra; Ketelsen, Helge; Hinrichs, Karsten

    2017-11-01

    We present a novel infrared-spectroscopic laser mapping ellipsometer based on a single-shot measurement concept. The ellipsometric set-up employs multiple analyzers and detectors to simultaneously measure the sample's optical response under different analyzer azimuths. An essential component is a broadly tunable quantum cascade laser (QCL) covering the important marker region of 1800-1540 cm-1. The ellipsometer allows for fast single-wavelength as well as spectroscopic studies with thin-film sensitivity at temporal resolutions of 60 ms per wavelength. We applied the single-shot mapping ellipsometer for the characterization of metal-island enhancement surfaces as well as of molecular interactions in organic thin films. In less than 3 min, a linescan with 1600 steps revealed profile and infrared-enhancement properties of a gradient gold-island film for sensing applications. Spectroscopic measurements were performed to probe the amide I band of thin films of poly(N-isopropylacrylamide) [PNIPAAm], a stimuli-responsive polymer for bioapplications. The QCL spectra agree well with conventional FT-IR ellipsometric results, showing different band components associated with hydrogen-bond interactions between polymer and adsorbed water. Multi-wavelength ellipsometric maps were used to analyze homogeneity and surface contaminations of the polymer films.

  20. Study of CdTe surface by SIMS and RBS ellipsometry

    International Nuclear Information System (INIS)

    Stuck, R.; Hage-Ali, M.; Grob, A.; Siffert, P.

    1978-01-01

    For a better understanding of the mechanisms involved in the rectification of metal-cadmium telluride contacts, the surface of bromine-methanol etched CdTe crystals by means of ellipsometry, secondary ions mass spectroscopy (SIMS) and Rutherford backscattering of charged particles (RBS) has been investigated. The results show that these surfaces are contaminated with bromine and that a tellurium surface oxide layer grows, its thickness increasing with time. This surface layer composition has been analyzed at different steps of its evolution [fr

  1. Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al2O3-films

    Directory of Open Access Journals (Sweden)

    Jörg Haeberle

    2013-11-01

    Full Text Available We report on results on the preparation of thin (2O3 films on silicon substrates using thermal atomic layer deposition (T-ALD and plasma enhanced atomic layer deposition (PE-ALD in the SENTECH SI ALD LL system. The T-ALD Al2O3 layers were deposited at 200 °C, for the PE-ALD films we varied the substrate temperature range between room temperature (rt and 200 °C. We show data from spectroscopic ellipsometry (thickness, refractive index, growth rate over 4” wafers and correlate them to X-ray photoelectron spectroscopy (XPS results. The 200 °C T-ALD and PE-ALD processes yield films with similar refractive indices and with oxygen to aluminum elemental ratios very close to the stoichiometric value of 1.5. However, in both also fragments of the precursor are integrated into the film. The PE-ALD films show an increased growth rate and lower carbon contaminations. Reducing the deposition temperature down to rt leads to a higher content of carbon and CH-species. We also find a decrease of the refractive index and of the oxygen to aluminum elemental ratio as well as an increase of the growth rate whereas the homogeneity of the film growth is not influenced significantly. Initial state energy shifts in all PE-ALD samples are observed which we attribute to a net negative charge within the films.

  2. In-situ study of molecular dynamics in a water environment by using imaging ellipsometry

    International Nuclear Information System (INIS)

    Hwang, Soon Yong; Kim, Tae Jung; Diware, Mangesh S; Kim, Young Dong

    2010-01-01

    We report on the dynamics of bio molecules and a high polymer in a water environment by using imaging ellipsometry (IE). The morphology of collapsed films of arachidic acid (AA) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) Langmuir monolayers in a liquid solution is investigated. The IE images clearly show that the multilayer domains and thickness of the collapsed region change sensitively depending on Langmuir compression. Also, the adsorption of bovine serum albumin is observed by using total internal reflection resonance IE (TIRIE), which has the advantage of IE and surface plasmon resonance. We believe that IE is a powerful technique for analysis and applications of bio materials

  3. Nuclear spectroscopic studies

    International Nuclear Information System (INIS)

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1994-01-01

    The Nuclear Physics group at UTK is involved in heavy-ion physics including both nuclear structure and reaction mechanisms. During the last year experimental work has been in 3 broad areas: structure of nuclei at high angular momentum, structure of nuclei far from stability, and ultra-relativistic heavy-ion physics. Results in these areas are described in this document under: properties of high-spin states, study of low-energy levels of nuclei far from stability, and high-energy heavy-ion physics (PHENIX, etc.). Another important component of the work is theoretical interpretation of experimental results (Joint Institute for Heavy Ion Research)

  4. Nuclear spectroscopic studies

    International Nuclear Information System (INIS)

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1993-01-01

    The Nuclear Physics group at the University of Tennessee, Knoxville is involved in several aspects of heavy-ion physics including both nuclear structure and reaction mechanisms. While our main emphasis is on experimental problems involving heavy-ion accelerators, we have maintained a strong collaboration with several theorists in order to best pursue the physics of our measurements. During the last year we have led several experiments at the Holifield Heavy Ion Research Facility and participated in others at Argonne National Laboratory. Also, we continue to be very active in the collaboration to study ultra-relativistic heavy ion physics utilizing the SPS accelerator at CERN in Geneva, Switzerland and in a RHIC detector R ampersand D project. Our experimental work is in four broad areas: (1) the structure of nuclei at high angular momentum, (2) heavy-ion induced transfer reactions, (3) the structure of nuclei far from stability, and (4) ultra-relativistic heavy-ion physics. The results of studies in these particular areas will be described in this document in sections IIA, IIB, IIC, and IID, respectively. Areas (1), (3), and (4) concentrate on the structure of nuclear matter in extreme conditions of rotational motion, imbalance of neutrons and protons, or very high temperature and density. Area (2) pursues the transfer of nucleons to states with high angular momentum, both to learn about their structure and to understand the transfer of particles, energy, and angular momentum in collisions between heavy ions. An important component of our program is the strong emphasis on the theoretical aspects of nuclear structure and reactions

  5. Nuclear spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1993-02-08

    The Nuclear Physics group at the University of Tennessee, Knoxville is involved in several aspects of heavy-ion physics including both nuclear structure and reaction mechanisms. While our main emphasis is on experimental problems involving heavy-ion accelerators, we have maintained a strong collaboration with several theorists in order to best pursue the physics of our measurements. During the last year we have led several experiments at the Holifield Heavy Ion Research Facility and participated in others at Argonne National Laboratory. Also, we continue to be very active in the collaboration to study ultra-relativistic heavy ion physics utilizing the SPS accelerator at CERN in Geneva, Switzerland and in a RHIC detector R D project. Our experimental work is in four broad areas: (1) the structure of nuclei at high angular momentum, (2) heavy-ion induced transfer reactions, (3) the structure of nuclei far from stability, and (4) ultra-relativistic heavy-ion physics. The results of studies in these particular areas will be described in this document in sections IIA, IIB, IIC, and IID, respectively. Areas (1), (3), and (4) concentrate on the structure of nuclear matter in extreme conditions of rotational motion, imbalance of neutrons and protons, or very high temperature and density. Area (2) pursues the transfer of nucleons to states with high angular momentum, both to learn about their structure and to understand the transfer of particles, energy, and angular momentum in collisions between heavy ions. An important component of our program is the strong emphasis on the theoretical aspects of nuclear structure and reactions.

  6. Nuclear spectroscopic studies

    International Nuclear Information System (INIS)

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1988-01-01

    The Nuclear Physics group at the University of Tennessee, Knoxville is involved in several aspects of heavy-ion physics including both nuclear structure and reaction mechanisms. While our main emphasis is on experimental problems involving heavy-ion accelerators, we have maintained a strong collaboration with several theorists in order to best pursue the physics of our measurements. During the last year we have led experiments at the Holifield Heavy Ion Research Facility, the SuperHILAC at Berkeley, and Chalk River Tandem Accelerator. Also, we have joined a collaboration to study ultra-relativistic heavy ion physics and one of our group has spent all of 1987 at CERN to work on the WA80 experiment. Our experimental work is in four broad areas: (1) the structure of nuclei at high angular momentum, (2) heavy-ion induced transfer reactions, (3) the structure of nuclei far from stability, and (4) ultra-relativistic heavy-ion physics. These results will be described in this document in sections 2A, 2B, 2C, and 2D, respectively. Areas (1), (3), and (4) concentrate on the structure of nuclear matter in extreme conditions of rotational motion, imbalance of neutrons and protons or very high temperature and density. Area (2) pursues the transfer of nucleons to states with high angular momentum, both to learn about their structure and to understand the transfer of particles, energy and angular momentum in collisions between heavy ions. An important component of our program is the strong emphasis on the theoretical aspects of nuclear structure and reactions

  7. Mossbauer spectroscopic studies in ferroboron

    Science.gov (United States)

    Yadav, Ravi Kumar; Govindaraj, R.; Amarendra, G.

    2017-05-01

    Mossbauer spectroscopic studies have been carried out in a detailed manner on ferroboron in order to understand the local structure and magnetic properties of the system. Evolution of the local structure and magnetic properties of the amorphous and crystalline phases and their thermal stability have been addressed in a detailed manner in this study. Role of bonding between Fe 4s and/or 4p electrons with valence electrons of boron (2s,2p) in influencing the stability and magnetic properties of Fe-B system is elucidated.

  8. In-situ spectroscopic ellipsometry for studies of thin films and membranes

    NARCIS (Netherlands)

    Ogieglo, Wojciech

    2014-01-01

    The properties of a thin polymer film can be significantly affected by the presence of a penetrant. It is also known that the behavior of ultra-thin polymer films (<100 nm) may deviate from the bulk behavior. This sole impact of film thickness reduction is often referred to as a nano-confinement

  9. Enhanced sensitivity to dielectric function and thickness of absorbing thin films by combining total internal reflection ellipsometry with standard ellipsometry and reflectometry

    International Nuclear Information System (INIS)

    Lizana, A; Foldyna, M; Garcia-Caurel, E; Stchakovsky, M; Georges, B; Nicolas, D

    2013-01-01

    High sensitivity of spectroscopic ellipsometry and reflectometry for the characterization of thin films can strongly decrease when layers, typically metals, absorb a significant fraction of the light. In this paper, we propose a solution to overcome this drawback using total internal reflection ellipsometry (TIRE) and exciting a surface longitudinal wave: a plasmon-polariton. As in the attenuated total reflectance technique, TIRE exploits a minimum in the intensity of reflected transversal magnetic (TM) polarized light and enhances the sensitivity of standard methods to thicknesses of absorbing films. Samples under study were stacks of three films, ZnO : Al/Ag/ZnO : Al, deposited on glass substrates. The thickness of the silver layer varied from sample to sample. We performed measurements with a UV–visible phase-modulated ellipsometer, an IR Mueller ellipsometer and a UV–NIR reflectometer. We used the variance–covariance formalism to evaluate the sensitivity of the ellipsometric data to different parameters of the optical model. Results have shown that using TIRE doubled the sensitivity to the silver layer thickness when compared with the standard ellipsometry. Moreover, the thickness of the ZnO : Al layer below the silver layer can be reliably quantified, unlike for the fit of the standard ellipsometry data, which is limited by the absorption of the silver layer. (paper)

  10. Effect of elastic strain on the band gaps, band alignment, and electronic structure of epitaxial ASnO3 (A = Ca, Sr, and Ba) films and heterostructures revealed through in situ photoemission, spectroscopic ellipsometry, and density functional theory

    Science.gov (United States)

    Baniecki, John; Yamazaki, Takashi; Aso, Hiroyuki; Imanaka, Yoshihiko; Ricinschi, Dan

    The alkaline earth stannates ASnO3 (A = Ba, Sr, and Ca) are emerging as important materials. Band gaps in stannates are remarkably dependent on volumetric strain with a decrease in volumetric strain of 3 percent in SrSnO3 resulting in an increase in the band gap of 0.35 eV. However, little understanding of volumetric strain dependence on the valence band (VB) electronic structure and band alignments between stannates and other oxides exits. In this talk we will examine the effect of elastic strain on the band gaps, band alignment, and electronic structure of stannate films and heterostructures through in situ photoemission, spectroscopic ellipsometry, scanning transmission electron microscopy with geometric phase analysis, and density functional theory. CaSnO3 (CSO), SrSnO3 (SSO) and La-doped BaSnO3 (BLSO) thin films were grown by pulsed laser epitaxy with strain control via epitaxial buffer layers. While the VB electronic structure is strain dependent VB offsets do not vary significantly with strain, which resulted in ascribing most of the difference in band alignment to the conduction band (CB) edge. Significantly, strain-induced tuning of CB offset differences are as large as 0.6 eV for SSO and may provide a pathway to enhance stannate-based devices.

  11. 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....

  12. Real time study of amalgam formation and mercury adsorption on thin gold film by total internal reflection ellipsometry

    Science.gov (United States)

    Paulauskas, A.; Selskis, A.; Bukauskas, V.; Vaicikauskas, V.; Ramanavicius, A.; Balevicius, Z.

    2018-01-01

    Total internal reflection ellipsometry (TIRE) was utilized in its dynamic data acquisition mode to reveal the percentage of mercury present in an amalgam surface layer. In determining the optical constants of the amalgam film, the non-homogeneities of the formed surface layer were taken into account. The composition of the amalgam layer by percentage was determined using the EMA Bruggemann model for the analysis of the TIRE data. Regression results showed that amalgam layer consisted of mercury 16.00 ± 0.43% and gold 84.00 ± 0.43%. This real time TIRE analysis has shown that for these studies method can detect 0.6 ± 0.4% of mercury on a gold surface, proving that this is a suitable optical technique for obtaining real time readouts. The structural analysis of SEM and AFM have shown that the amalgam layer had a dendritic structure, which formation was determined by the weak adhesion of the gold atoms onto its surface.

  13. Synthesis, Spectroscopic and Pharmacological Studies of Bivalent ...

    African Journals Online (AJOL)

    Synthesis, Spectroscopic and Pharmacological Studies of Bivalent Copper, Zinc and Mercury Complexes of Thiourea. ... All the metal complexes were characterized by elemental chemical analysis, molar conductance, magnetic susceptibility measurements and IR spectroscopy. Cu(II) complexes were additionally ...

  14. A note on the use of ellipsometry for studying the kinetics of ...

    Indian Academy of Sciences (India)

    Unknown

    an optically flat surface (Azzam and Bashara 1977), is one of the most versatile and commonly used techniques for studying various processes such as the kinetics of. SAM formation on metal surfaces (Tillman et al 1988;. Bain et al 1989; Wasserman et al 1989), formation of multilayer Langmuir Blodgett films (Honig and De ...

  15. Heavy-ion ERDA and spectroscopic ellipsometry characterization of a SiOC:H layered structure as functional coating on polymeric lenses

    Science.gov (United States)

    Kreissig, U.; Gago, R.; Vinnichenko, M.; Fernández-Hidalgo, P.; Martín-Palma, R. J.; Martínez-Duart, J. M.

    2004-06-01

    In order to improve the optical and mechanical performance of plastic ophthalmic lenses the use of surface coatings is necessary. However, the application of such coatings can be limited by bad adhesion to the substrate. One way to overcome this drawback is the use of a layered structure consisting of an adherent layer, an abrasion resistant hard layer and an antireflective (AR) multilayer (ML) stack. In this work we study the preparation of SiO xC y:H layered coatings to increase the mechanical durability of polymeric substrates and to accommodate gradually an external dielectric SiO 2/TiO 2 AR-ML. The coatings were grown by plasma assisted chemical vapor deposition (PACVD) using a mixture of hexamethyldisiloxane (HMDSO) and O 2. The possibility of producing the whole layered stack by adjusting the HMDSO:O 2 ratio was demonstrated. The composition and elemental profiles of the different layers were measured by ERDA using 35 MeV Cl-ions. A polymeric-like gradient layer could be formed followed by a buffer layer Si 28O 47C 15H 10 with a nearly constant composition. The variation of the elemental composition does not affect significantly the optical properties, which are close to that of SiO 2.

  16. Competitive adsorption from mixed hen egg-white lysozyme/surfactant solutions at the air-water interface studied by tensiometry, ellipsometry, and surface dilational rheology.

    Science.gov (United States)

    Alahverdjieva, V S; Grigoriev, D O; Fainerman, V B; Aksenenko, E V; Miller, R; Möhwald, H

    2008-02-21

    The competitive adsorption at the air-water interface from mixed adsorption layers of hen egg-white lysozyme with a non-ionic surfactant (C10DMPO) was studied and compared to the mixture with an ionic surfactant (SDS) using bubble and drop shape analysis tensiometry, ellipsometry, and surface dilational rheology. The set of equilibrium and kinetic data of the mixed solutions is described by a thermodynamic model developed recently. The theoretical description of the mixed system is based on the model parameters for the individual components.

  17. Time resolved spectroscopic studies on some nanophosphors

    Indian Academy of Sciences (India)

    Wintec

    Abstract. Time resolved spectroscopy is an important tool for studying photophysical processes in phosphors. Present work investigates the steady state and time resolved photoluminescence (PL) spectroscopic characteristics of ZnS, ZnO and (Zn, Mg)O nanophosphors both in powder as well as thin film form.

  18. Synthesis, Spectroscopic and Pharmacological Studies of Bivalent ...

    African Journals Online (AJOL)

    NICO

    Synthesis, Spectroscopic and Pharmacological Studies of. Bivalent Copper, Zinc and Mercury Complexes of Thiourea. Shikha Parmar*, Yatendra Kumar and Ashu Mittal. I.T.S Paramedical College (Pharmacy), Delhi Meerut Road, Muradnagar, Ghaziabad 201206, India. Received 4 June 2010, revised 14 June 2010, ...

  19. Crystallization and spectroscopic studies of manganese malonate

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The preparation of manganese malonate crystals by gel method and its spectroscopic studies are reported. X-ray diffraction (XRD) pattern reveals the crystalline nature. The FTIR and FT Raman spectra of the crystals are recorded and the vibrational assignments are given with possible explanations. Diffuse reflec-.

  20. Spectroscopic studies of hydrogen collisions

    International Nuclear Information System (INIS)

    Kielkopf, J.

    1991-01-01

    Low energy collisions involving neutral excited states of hydrogen are being studied with vacuum ultraviolet spectroscopy. Atomic hydrogen is generated by focusing an energetic pulse of ArF, KrF, or YAG laser light into a cell of molecular hydrogen, where a plasma is created near the focal point. The H 2 molecules in and near this region are dissociated, and the cooling atomic hydrogen gas is examined with laser and dispersive optical spectroscopy. In related experiments, we are also investigating neutral H + O and H + metal - atom collisions in these laser-generated plasmas

  1. Nuclear spectroscopic studies. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1993-02-08

    The Nuclear Physics group at the University of Tennessee, Knoxville is involved in several aspects of heavy-ion physics including both nuclear structure and reaction mechanisms. While our main emphasis is on experimental problems involving heavy-ion accelerators, we have maintained a strong collaboration with several theorists in order to best pursue the physics of our measurements. During the last year we have led several experiments at the Holifield Heavy Ion Research Facility and participated in others at Argonne National Laboratory. Also, we continue to be very active in the collaboration to study ultra-relativistic heavy ion physics utilizing the SPS accelerator at CERN in Geneva, Switzerland and in a RHIC detector R&D project. Our experimental work is in four broad areas: (1) the structure of nuclei at high angular momentum, (2) heavy-ion induced transfer reactions, (3) the structure of nuclei far from stability, and (4) ultra-relativistic heavy-ion physics. The results of studies in these particular areas will be described in this document in sections IIA, IIB, IIC, and IID, respectively. Areas (1), (3), and (4) concentrate on the structure of nuclear matter in extreme conditions of rotational motion, imbalance of neutrons and protons, or very high temperature and density. Area (2) pursues the transfer of nucleons to states with high angular momentum, both to learn about their structure and to understand the transfer of particles, energy, and angular momentum in collisions between heavy ions. An important component of our program is the strong emphasis on the theoretical aspects of nuclear structure and reactions.

  2. Nuclear spectroscopic studies: Progress report

    International Nuclear Information System (INIS)

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1989-01-01

    The Nuclear Physics Group at the University of Tennessee, Knoxville (UTK) is involved in several aspects of heavy-ion physics including both nuclear structure and reaction mechanisms. While our main emphasis is on experimental problems involving heavy-ion accelerators, we have maintained a strong collaboration with several theorists in order to best pursue the physics of our measurements. During the last year we have led experiments at the Holifield Heavy Ion Research Facility (HHIRF) and the Niels Bohr Institute Tandem Accelerator. Also, we are active in a collaboration (WA80) to study ultra-relativistic heavy ion physics utilizing the SPS accelerator at CERN in Geneva, Switzerland. Our experimental work is four broad areas: (1) the structure of nuclei at high angular momentum, (2) heavy-ion induced transfer reactions, (3) the structure of nuclei far from stability, and (4) ultra-relativistic heavy-ion physics. These results will be described in this document. Areas (1), (3), and (4) concentrate on the structure of nuclear matter in extreme conditions of rotational motion, imbalance of neutrons and protons, or very high temperature and density. Area (2) pursues the transfer of nucleons to states with high angular momentum, both to learn about their structure and to understand the transfer of particles, energy, and angular momentum in collisions between heavy ions. An important component of our program is the strong emphasis on the theoretical aspects of nuclear structure and reactions

  3. An ellipsometry study on the effect of aluminium chloride and ferric chloride formulations on mucin layers adsorbed at hydrophobic surfaces.

    Science.gov (United States)

    Hamit-Eminovski, Jildiz; Eskilsson, Krister; Arnebrant, Thomas

    2010-07-01

    Ellipsometry was used to investigate the effect of polyaluminium chloride (PAC) formulations of different degrees of hydrolysation on an adsorbed mucin film. The results were compared to the effect of aluminium chloride (AlCl(3)) and ferric chloride. A compaction of the mucin film took place upon addition of the formulations and this occurred to different extents and at different concentrations for the different formulations. The compaction of PAC of a low degree of hydrolysis behaved similarly to AlCl(3). PAC of a high degree of hydrolysis showed a greater compaction effect than the other aluminium formulations. The initial compaction concentration was found to be 0.001 mM which is less than previously found for aluminium-mucin complex formation in bulk. The reversibility of the compaction was also investigated. The compaction of the mucin film was found to be partly reversible for AlCl(3) and PAC of low degree of hydrolysis. No reversibility was observed for the formulations of PAC of high hydrolysis grade or for ferric chloride. The results are consistent with previously observed effects of PAC of a low degree of hydrolysis on bacterial surfaces where a compaction of surface polymers was indicated by the reduced range of repulsive steric interactions.

  4. Interplay of electron correlations and localization in disordered β-tantalum films: evidence from dc transport and spectroscopic ellipsometry study

    Czech Academy of Sciences Publication Activity Database

    Kovaleva, Natalia; Chvostová, Dagmar; Bagdinov, A.V.; Petrova, M.G.; Demikhov, E.I.; Pudonin, F.A.; Dejneka, Alexandr

    2015-01-01

    Roč. 106, č. 5 (2015), "051907-1"-"051907-5" ISSN 0003-6951 R&D Projects: GA ČR GA15-13778S Institutional support: RVO:68378271 Keywords : diffusion * absence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.142, year: 2015

  5. Studies on Inx(As2Se31-x thin films using variable angle spectroscopic ellipsometry (VASE

    Directory of Open Access Journals (Sweden)

    Amin G. A. M.

    2015-09-01

    Full Text Available The results of multi-angle ellipsometrical measurements of thermally evaporated Inx(As2Se31-x (x = 0, 0.01,0.05 films are presented. Optical parameters n and Es of thin Inx(As2Se31-x films show that indium atoms were incorporated into the host matrix of As2Se3 forming distinct features depending on the indium concentration. Refractive index, n, was found to decrease with the addition of In to the binary As2Se3. The real and imaginary parts of the dielectric function, ε' and ε" were also calculated from the obtained data and correlated with In concentration. It was found that e' decreases with the increase of In content while ε" increases with the increase of In content. Absorption edge is shifted towards lower photon energy with the increase of In content. As a result, the optical energy gap decreases with increasing In content. This has been correlated with the chemical character of the additive as well as with the structural and bonding aspects of the amorphous composition. Nonlinear optical constants (χ(3 and n2 were determined from linear optical parameters using semi-empirical relations in the long wavelength limit.

  6. Exploratory multivariate spectroscopic study on human skin.

    Science.gov (United States)

    Lauridsen, Rikke Kragh; Everland, Hanne; Nielsen, Lene Feldskov; Engelsen, Søren Balling; Nørgaard, Lars

    2003-05-01

    Spectroscopy on human skin is a field that is being adopted increasingly because of its rapidity and high reproducibility. Infrared reflectance (IR), near-infrared reflectance (NIR), and fluorescence spectroscopy have previously been applied to human skin in vivo to compare healthy and sick skin, including skin cancer, atopy, and leprosy. Exploratory data analysis/chemometrics is a tool for evaluating multivariate data such as spectroscopic measurements. The objective of this study was to explore the spectral variance spanned by people with normal integument, and to demonstrate the advantages of multivariate analysis to skin research. IR, NIR and fluorescence spectroscopy have been carried out in vivo on 216 volunteers' forearms before and after four tape strippings. The subjects were asked to fill in a questionnaire regarding factors suspected to influence the measurement results. Principal Component Analysis (PCA) was used to investigate whether the population can be divided into groups on the basis of their skin chemistry. Unless otherwise stated, the results are from the measurements prior to stripping. In contrast to IR and fluorescence spectra, NIR spectra proved able to detect gender differences. By use of PCA, classifications on male and female subjects were observed from the IR and NIR measurements, and as an indication from the fluorescence measurements. The NIR and fluorescence measurements varied between elderly and young subjects. The largest variance in the fluorescence landscapes was seen between pigmented and non-pigmented skin. No connection was found between the spectroscopic measurements and smoking or drinking habits. Future spectroscopic skin investigations should be balanced as regards to gender and age, as these can possibly affect the measurement results. Chemometrics proved to be superior to traditional attempts of interpreting the spectra.

  7. Spectroscopic studies of pulsed-power plasmas

    International Nuclear Information System (INIS)

    Maron, Y.; Arad, R.; Dadusc, G.; Davara, G.; Duvall, R.E.; Fisher, V.; Foord, M.E.; Fruchtman, A.; Gregorian, L.; Krasik, Ya.

    1993-01-01

    Recently developed spectroscopic diagnostic techniques are used to investigate the plasma behavior in a Magnetically Insulated Ion Diode, a Plasma Opening Switch, and a gas-puffed Z-pinch. Measurements with relatively high spectral, temporal, and spatial resolutions are performed. The particle velocity and density distributions within a few tens of microns from the dielectric-anode surface are observed using laser spectroscopy. Collective fluctuating electric fields in the plasma are inferred from anisotropic Stark broadening. For the Plasma Opening Switch experiment, a novel gaseous plasma source was developed which is mounted inside the high-voltage inner conductor. The properties of this source, together with spectroscopic observations of the electron density and particle velocities of the injected plasma, are described. Emission line intensities and spectral profiles give the electron kinetic energies during the switch operation and the ion velocity distributions. Secondary plasma ejection from the electrodes is also studied. In the Z-pinch experiment, spectral emission-line profiles are studied during the implosion phase. Doppler line shifts and widths yield the radial velocity distributions for various charge states in various regions of the plasma. Effects of plasma ejection from the cathode are also studied

  8. Spectroscopic study of natural quartz samples

    International Nuclear Information System (INIS)

    Nunes, Eduardo H.M.; Lameiras, Fernando S.; Houmard, Manuel; Vasconcelos, Wander L.

    2013-01-01

    In this work we performed a spectroscopic characterization of natural amethyst, citrine, and prasiolite samples from different localities. These materials were examined by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–vis), electron paramagnetic resonance (EPR), and inductively coupled plasma atomic emission spectrometry (ICP-AES). Samples were used in this study in as-received, gamma-irradiated, UV-irradiated, and heat-treated conditions. We observed the changes in the FTIR, UV–vis, and EPR spectra of these samples as a function of the condition they were analyzed. We noticed that gamma radiation had a great effect on the color of amethyst and citrine samples used in this work. It was observed that light colored samples showed a deepening of their colors upon gamma-irradiation and a bleaching upon heat treatment at 450 °C. However, we observed that gamma radiation had a slight effect on the color of citrine. UV-irradiations revealed that the coloration of both amethyst and prasiolite can be bleached by UV radiation. On the other hand, the color of citrine was not affected by UV radiation. - Highlights: • Spectroscopic characterization of natural amethyst, citrine, and prasiolite samples. • Gamma radiation had a great effect on the color of amethyst and citrine samples. • The coloration of citrine was not affected by UV radiation. • Resonance lines observed in EPR spectra of some samples were associated to Fe 3+ . • Broad resonance signal observed in EPR spectra of citrine samples

  9. Preparation of cesium targets for gamma-spectroscopic studies

    Science.gov (United States)

    Bhattacharyya, S.; Basu, S. K.; Chanda, S.; Deb, P.; Eqbal, Md; Kundu, S.; Joseph, D.

    2000-11-01

    A procedure to prepare monoisotopic cesium compound targets for gamma-spectroscopic experiments is described. Using this procedure, uniform targets up to thicknesses of 0.6-1.2 mg/cm 2 were prepared and used for in-beam spectroscopic studies. The purity of the target was tested by energy dispersive X-ray fluorescence (EDXRF) measurements.

  10. Fundamental spectroscopic studies of carbenes and hydrocarbon radicals

    Energy Technology Data Exchange (ETDEWEB)

    Gottlieb, C.A.; Thaddeus, P. [Harvard Univ., Cambridge, MA (United States)

    1993-12-01

    Highly reactive carbenes and carbon-chain radicals are studied at millimeter wavelengths by observing their rotational spectra. The purpose is to provide definitive spectroscopic identification, accurate spectroscopic constants in the lowest vibrational states, and reliable structures of the key intermediates in reactions leading to aromatic hydrocarbons and soot particles in combustion.

  11. Deformed shell model studies of spectroscopic properties of Zn and ...

    Indian Academy of Sciences (India)

    2014-04-05

    Apr 5, 2014 ... the generating coordinate method framework (GCM+PNAMP), (v) projected Hartree– ... shall first study its spectroscopic properties using deformed shell model (DSM) to test the effectiveness of the model for ... Section. 3 gives DSM results for 64Zn for spectroscopic properties and then the results for both 2ν.

  12. A user's guide to ellipsometry

    CERN Document Server

    Tompkins, Harland G

    1992-01-01

    This book is specifically designed for the user who wishes expanded use of ellipsometry beyond the relatively limited number of turn-key applications. The book provides a concise discussion of theory and instrumentation before describing how to use optical parameters to determine material properties and optical parameters for inaccessible substrates and unknown films, and how to measure extremely thin films. The book also addresses polysilicon, a material commonly used in the microelectronics industry, and the effect of substrate roughness. This book's concepts and applications are reinforced

  13. Spectral ellipsometry of nanodiamond composite

    International Nuclear Information System (INIS)

    Yastrebov, S.G.; Ivanov-Omskij, V.I.; Gordeev, S.K.; Garriga, M.; Alonso, I.A.

    2006-01-01

    Methods of spectral ellipsometry were applied for analysis of optical properties of nanodiamond based composite in spectral region 1.4-5 eV. The nanocomposite was synthesized by molding of ultradispersed nanodiamond powder in the course of heterogeneous chemical reaction of decomposition of methane, forming pyrocarbon interconnecting nanodiamond grains. The energy of σ + π plasmon of pyrocarbon component of nanodiamond composite was restored which proves to be ∼ 24 eV; using this value, an estimation was done of pyrocarbon matrix density, which occurs to be 2 g/cm 3 [ru

  14. Spectroscopic study of ohmically heated Tokamak discharges

    International Nuclear Information System (INIS)

    Breton, C.; Michelis, C. de; Mattioli, M.

    1980-07-01

    Tokamak discharges interact strongly with the wall and/or the current aperture limiter producing recycling particles, which penetrate into the discharge and which can be studied spectroscopically. Working gas (hydrogen or deuterium) is usually studied observing visible Balmer lines at several toroidal locations. Absolute measurements allow to obtain both the recycling flux and the global particle confinement time. With sufficiently high resolution the isotopic plasma composition can be obtained. The impurity elements can be divided into desorbed elements (mainly oxygen) and eroded elements (metals from both walls and limiter) according to the plasma-wall interaction processes originating them. Space-and time-resolved emission in the VUV region down to about 20 A will be reviewed for ohmically-heated discharges. The time evolution can be divided into four phases, not always clearly separated in a particular discharge: a) the initial phase, lasting less than 10 ms (the so-called burn-out phase), b) the period of increasing plasma current and electron temperature, lasting typically 10 - 100 ms, c) an eventual steady state (plateau of the plasma current with almost constant density and temperature), d) the increase of the electron density up to or just below the maximum value attainable in a given device. For all these phases the results reported from different devices will be described and compared

  15. Expanded beam (macro-imaging) ellipsometry

    International Nuclear Information System (INIS)

    Fried, M.; Juhasz, G.; Major, C.; Petrik, P.; Polgar, O.; Horvath, Z.; Nutsch, A.

    2011-01-01

    Our aim was to make possible to use spectroscopic ellipsometry for mapping purposes during one measuring cycle (minimum one rotation period of polarizer or analyzer) on many sample points. Our new technique uses non-collimated (non-parallel, mostly diffuse) illumination with an angle of incidence sensitive pinhole camera detector system and it works as an unusual kind of imaging ellipsometry. Adding multicolour supplemets, it provides spectral (a few wavelengths on a 2D image or a full spectrum along a line) information from rapid measurements of many points on a large (several dm2) area. This technique can be expanded by upscaling the geometry (upscaling the dimensions of the instrument, and characteristic imaging parameters such as focal lengths, distances, etc.). The lateral resolution is limited by the minimum resolved-angle determined by the detector system, mainly by the diameter of the pinhole. (The diameter of the pinhole is a compromise between the light intensity and the lateral resolution.) Small-aperture (25 mm diameter) polarizers are incorporated into both the polarization state generator (PSG) and polarization state detection (PSD) components of the instrument. The detection is almost without background because the pinhole serves as a filter against the scattered light. One rapid measuring cycle (less than 10 s) is enough to determine the polarization state at all the points inside the illuminated area. The collected data can be processed very fast (seconds) providing nearly real-time thicknesses and/or refractive index maps over many points of the sample surface even in the case of multilayer samples. The speed of the measuring system makes it suitable for using even on production lines. The necessary (in each sample-point different) angle-of-incidence and the mirror-effect calibration are made via well-known and optimized structures such as silicon/silicon-dioxide samples. The precision is suitable for detecting sub-nanometer thickness and a

  16. Submillimeter Spectroscopic Study of Semiconductor Processing Plasmas

    Science.gov (United States)

    Helal, Yaser H.

    Plasmas used for manufacturing processes of semiconductor devices are complex and challenging to characterize. The development and improvement of plasma processes and models rely on feedback from experimental measurements. Current diagnostic methods are not capable of measuring absolute densities of plasma species with high resolution without altering the plasma, or without input from other measurements. At pressures below 100 mTorr, spectroscopic measurements of rotational transitions in the submillimeter/terahertz (SMM) spectral region are narrow enough in relation to the sparsity of spectral lines that absolute specificity of measurement is possible. The frequency resolution of SMM sources is such that spectral absorption features can be fully resolved. Processing plasmas are a similar pressure and temperature to the environment used to study astrophysical species in the SMM spectral region. Many of the molecular neutrals, radicals, and ions present in processing plasmas have been studied in the laboratory and their absorption spectra have been cataloged or are in the literature for the purpose of astrophysical study. Recent developments in SMM devices have made its technology commercially available for applications outside of specialized laboratories. The methods developed over several decades in the SMM spectral region for these laboratory studies are directly applicable for diagnostic measurements in the semiconductor manufacturing industry. In this work, a continuous wave, intensity calibrated SMM absorption spectrometer was developed as a remote sensor of gas and plasma species. A major advantage of intensity calibrated rotational absorption spectroscopy is its ability to determine absolute concentrations and temperatures of plasma species from first principles without altering the plasma environment. An important part of this work was the design of the optical components which couple 500 - 750 GHz radiation through a commercial inductively coupled plasma

  17. Spectroscopic studies on colloid-borne uranium

    International Nuclear Information System (INIS)

    Ulrich, K.U.; Weiss, S.; Foerstendorf, H.; Brendler, V.; Zaenker, H.; Rossberg, A.; Scheinost, A.C.

    2005-01-01

    Full text of publication follows: Information on molecular speciation provides a basis for the reliable assessment of actinide migration in the environment. We use several methods for the separation of colloids from liquids (e.g. ultracentrifugation, ultrafiltration) in combination with spectroscopic techniques (EXAFS, ATR-FTIR, Moessbauer) and modeling of surface complexation reactions. This enables us to investigate the speciation of colloid-borne uranium in waters occurring in or escaping from abandoned uranium mines during the remediation process. Mine flooding was simulated on a 100 L scale by mixing acid mine water of elevated U concentration with oxic, near-neutral groundwater until pH ∼ 5.5 was reached. The freshly formed colloids adsorbed 95% of the total uranium and consisted mainly of 2-line ferri-hydrite (Fh) besides traces of aluminum, sulfur, silica, and carbon compounds. EXAFS analysis at the U-LIII absorption edge suggested a bidentate surface complex of UO 2 2+ on FeO 6 octahedra, but two minor backscattering contributions in close vicinity to the absorber remained unexplained. Since only Al could be excluded as backscattering atom, we studied U sorption on Fh at pH 5.5 in presence and in absence of sulfate, silicate, and atmospheric CO 2 to clarify the bond structure. EXAFS showed the unknown backscattering contributions in all the sorption samples regardless of the presence or absence of the tested components. Contrary to structural models proposed in the literature, bi-dentately complexed carbonate ligands do not explain our experimental EXAFS data. But ATR-IR spectra showed that U-carbonato complexes must be involved in the sorption of uranyl on Fh. These results are not contradictory if the carbonate ligands were bound mono-dentately. Nevertheless, carbon cannot act as backscattering atom in carbonate-free samples prepared in N 2 atmosphere. We propose a new structural model including exclusively Fe, H, and O atoms in which the bi

  18. Spectroscopic techniques to study the immune response in human saliva

    Science.gov (United States)

    Nepomnyashchaya, E.; Savchenko, E.; Velichko, E.; Bogomaz, T.; Aksenov, E.

    2018-01-01

    Studies of the immune response dynamics by means of spectroscopic techniques, i.e., laser correlation spectroscopy and fluorescence spectroscopy, are described. The laser correlation spectroscopy is aimed at measuring sizes of particles in biological fluids. The fluorescence spectroscopy allows studying of the conformational and other structural changings in immune complex. We have developed a new scheme of a laser correlation spectrometer and an original signal processing algorithm. We have suggested a new fluorescence detection scheme based on a prism and an integrating pin diode. The developed system based on the spectroscopic techniques allows studies of complex process in human saliva and opens some prospects for an individual treatment of immune diseases.

  19. Characterization of silicon-oxide interfaces and organic monolayers by IR-UV ellipsometry and FTIR spectroscopy

    Science.gov (United States)

    Hess, P.; Patzner, P.; Osipov, A. V.; Hu, Z. G.; Lingenfelser, D.; Prunici, P.; Schmohl, A.

    2006-08-01

    VUV-laser-induced oxidation of Si(111)-(1×1):H, Si(100):H, and a-Si:H at 157 nm (F II laser) in pure O II and pure H IIO atmospheres was studied between 30°C and 250°C. The oxidation process was monitored in real time by spectroscopic ellipsometry (NIR-UV) and FTIR spectroscopy. The ellipsometric measurements could be simulated with a three-layer model, providing detailed information on the variation of the suboxide interface with the nature of the silicon substrate surface. Besides the silicon-dioxide and suboxide layer, a dense, disordered, roughly monolayer thick silicon layer was included, as found previously by molecular dynamics calculations. The deviations from the classical Deal-Grove mechanism and the self-limited growth of the ultrathin dioxide layers (TMS) groups and n-alkylthiol monolayers on gold-coated silicon. The C-H stretching vibrations of the methylene and methyl groups could be identified by FTIR spectroscopy and IR ellipsometry.

  20. Spectroscopic and antimicrobial studies of polystyrene films under ...

    Indian Academy of Sciences (India)

    Spectroscopic and antimicrobial studies of polystyrene films under air plasma and He-Ne laser treatment ... The parameters such as (1) surface area by contact angle measurements, (2) quality of material before and after treatment by SEM and FTIR spectra and (3) material characterization by UV-vis spectra were studied.

  1. A spectroscopic study of southern binary Cepheids

    Science.gov (United States)

    Petterson, O. K. L.; Albrow, Michael D.; Cottrell, P. L.; Fokin, A.

    2004-05-01

    High-resolution spectroscopic observations have been made of a number of southern binary Cepheids to determine their dynamical masses. The stars are part of a long-term program to observe southern variable starsf or which a valuable long-term database has been obtained. The most recent radial velocities have a precision of ~300 ms-1, allowing the detection of velocity differences of ~1 kms-1 with confidence. Masses were determined for three systems: the 9-day Cepheid S Mus (6.0±0.4 MSolar), the double-mode Cepheid Y Car (4.5±1.8 MSolar) and the 5-day Cepheid V350 Sgr (6.0±0.9 MSolar). For five Cepheids (YZ Car, AX Cir, V636 Sco, W Sgr and T Mon) new or improved orbital solutions were found. Line level effects have been observed in several species of lines. Most Cepheids were observed to show the same progression of line level effects. Using non-linear radiative hydrodynamical models, we have compared the results of these models with our observations. These have shown that AX Cir and YZ Car have the following properties: L = 2050 LSolar, M = 4.8 MSolar, Teff = 5900 K and L = 9350 LSolar, M = 7.7 MSolar, Teff = 5590 K. Our models show no strong shockwaves being produced. Good agreement was found between the observed and modelled spectral lines Fe I 5576Å, SiII 6347Å, BaII 5853Å and CaII 8542Å.

  2. Spectroscopic study of low-lying 16N levels

    International Nuclear Information System (INIS)

    Bardayan, Daniel W.; O'Malley, Patrick; Blackmon, Jeff C.; Chae, K.Y.; Chipps, K.; Cizewski, J.A.; Hatarik, Robert; Jones, K.L.; Kozub, R. L.; Matei, Catalin; Moazen, Brian; Nesaraja, Caroline D.; Pain, Steven D.; Paulauskas, Stanley; Peters, W.A.; Pittman, S.T.; Schmitt, Kyle; Shriner, J.F. Jr.; Smith, Michael Scott

    2008-01-01

    The magnitude of the 15N(n,gamma)16N reaction rate in asymptotic giant branch stars depends directly on the neutron spectroscopic factors of low-lying 16N levels. A new study of the 15N(d,p)16N reaction is reported populating the ground and first three excited states in 16N. The measured spectroscopic factors are near unity as expected from shell model calculations, resolving a long-standing discrepancy with earlier measurements that had never been confirmed or understood. Updated 15N(n,gamma)16N reaction rates are presented

  3. Moessbauer spectroscopic study of South Italic Greek-type pottery

    International Nuclear Information System (INIS)

    Moessbauer spectroscopic (M.S.) study of 19 South Italic Greek-type ceramics was carried out. Two groups can be distinguished, on the grounds of Fe 3+ -sites content. However, the results of archeological and neutron activation analysis run contrary to this classification. (author)

  4. Comparative study of spectroscopic properties of the low-lying ...

    Indian Academy of Sciences (India)

    985–994. c Indian Academy of Sciences. Comparative study of spectroscopic properties of the low-lying electronic states of 2,4-pentadien-1-iminium cation and its N-substituted analogues. ANJAN CHATTOPADHYAY. Department of Chemistry, Birla Institute of Technology and Science (BITS), Pilani –KK Birla Goa Campus,.

  5. Structural, spectroscopic and electrochemical study of V 5 ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 37; Issue 4. Structural, spectroscopic and electrochemical study of V5+ substituted LiTi2(PO4)3 solid electrolyte for lithium-ion batteries. A Venkateswara Rao V Veeraiah A V Prasada Rao B Kishore Babu B Swarna Latha K Rama Rao. Volume 37 Issue 4 June 2014 pp ...

  6. 129I Moessbauer spectroscopic study of metallocene-iodine adducts

    International Nuclear Information System (INIS)

    Nakashima, Satoru; Sakai, Hiroshi; Watanabe, Masanobu; Maeda, Yutaka

    1994-01-01

    A 129 I Moessbauer spectroscopic study of iodine adducts of ferrocenophane, biruthenocene, and osmocene is reported. The spectra show the existence of iodine bonded to the central metals of metallocenes in addition to triiodide anions. The valence state of iron in the ferrocenophane-iodine adduct is the same as those of ruthenium and osmium in their adducts. (orig.)

  7. AC impedance and dielectric spectroscopic studies of Mg ion ...

    Indian Academy of Sciences (India)

    Mater. Sci., Vol. 34, No. 5, August 2011, pp. 1063–1067. c Indian Academy of Sciences. AC impedance and dielectric spectroscopic studies of Mg. 2+ ion conducting PVA–PEG blended polymer electrolytes. ANJI REDDY POLU. ∗ and RANVEER KUMAR. Department of Physics, Dr H S Gour University, Sagar 470 003, India.

  8. A novel DNA biosensor based on ellipsometry

    Science.gov (United States)

    Demirel, Gökhan; Çağlayan, Mustafa O.; Garipcan, Bora; Pişkin, Erhan

    In this study, we have firstly investigated the effects of dipping time, solution concentration and solvent types on the formation of self-assembled monolayers (SAMs) with 3-mercaptopropyltrimethoxysilane (MPTS) molecules on the Si(0 0 1) surfaces. Ellipsometric measurements showed that monolayers with a thickness of about 0.73 nm were formed when the dipping time is about 1 h, while more profound agglomerations were observed for longer time periods and MPTS solutions with higher concentrations. Monolayers were formed with solvents having larger dielectric constants. Contact angle measurements were in good correlation with the ellipsometric data. 5'-Thiolated oligodeoxynucleotides (ODNs) probes were immobilized onto these thiol-terminated SAMs by disulfide bond formation. The thickness of the ODN-layer on the MPTS modified surfaces reached almost a constant value of about 2.5 nm in 1 h. Target ODNs were detected by monitoring hybridization onto the surfaces by ellipsometry. The analytical signal (the delta ( Δ) value) measured was correlated with the target ODNs concentration.

  9. Time resolved spectroscopic studies on some nanophosphors

    Indian Academy of Sciences (India)

    Wintec

    . 1. Introduction. Time resolved spectroscopy is an important tool for study- ing energy and charge transfer processes, coupling of electronic and vibrational degrees of freedom, vibrational and conformational relaxation, isomerization, etc. The.

  10. On-line monitoring of solar cell module production by ellipsometry technique

    International Nuclear Information System (INIS)

    Fried, M.

    2014-01-01

    Non-destructive analyzing tools are needed at all stages of thin film photovoltaic (PV) development, and on production lines. In thin film PV, layer thicknesses, micro-structure, composition, layer optical properties, and their uniformity (because each elementary cell is connected electrically in series within a big panel) serve as an important starting point in the evaluation of the performance of the cell or module. An important focus is to express the dielectric functions of each component material in terms of a handful of wavelength independent parameters whose variation can cover all process variants of that material. With the resulting database, spectroscopic ellipsometry coupled with multilayer analysis can be developed for on-line point-by-point mapping and on-line line-by-line imaging. This work tries to review the investigations of different types of PV-layers (anti-reflective coating, transparent-conductive oxide (TCO), multi-diode-structure, absorber and window layers) showing the existing dielectric function databases for the thin film components of CdTe, CuInGaSe 2 , thin Si, and TCO layers. Off-line point-by-point mapping can be effective for characterization of non-uniformities in full scale PV panels in developing labs but it is slow in the on-line mode when only 15 points can be obtained (within 1 min) as a 120 cm long panel moves by the mapping station. In the last years [M. Fried et al., Thin Solid Films 519, 2730 (2011)], instrumentation was developed that provides a line image of spectroscopic ellipsometry (wl = 350–1000 nm) data. Up to now a single 30 point line image can be collected in 10 s over a 15 cm width of PV material. This year we are building a 30 and a 60 cm width expanded beam ellipsometer the speed of which will be increased by 10 ×. Then 1800 points can be mapped in a 1 min traverse of a 60 ∗ 120 cm PV panel or flexible roll-to-roll substrate. - Highlights: • Instrumentation developed provides a line image of

  11. Inhibition of urinary calculi -- a spectroscopic study

    Science.gov (United States)

    Manciu, Felicia; Govani, Jayesh; Durrer, William; Reza, Layra; Pinales, Luis

    2008-10-01

    Although a considerable number of investigations have already been undertaken and many causes such as life habits, metabolic disorders, and genetic factors have been noted as sources that accelerate calculi depositions and aggregations, there are still plenty of unanswered questions regarding efficient inhibition and treatment mechanisms. Thus, in an attempt to acquire more insights, we propose here a detailed scientific study of kidney stone formation and growth inhibition based on a traditional medicine approach with Rotula Aquatica Lour (RAL) herbal extracts. A simplified single diffusion gel growth technique was used for synthesizing the samples for the present study. The unexpected Zn presence in the sample with RAL inhibitor, as revealed by XPS measurements, explains the inhibition process and the dramatic reflectance of the incident light observed in the infrared transmission studies. Raman data demonstrate potential binding of the inhibitor with the oxygen of the kidney stone. Photoluminescence results corroborate to provide additional evidence of Zn-related inhibition.

  12. INFRARED AND RAMAN SPECTROSCOPIC STUDY OF ION ...

    African Journals Online (AJOL)

    Infrared and Raman spectroscopy techniques have been used to study the ionic interactions of strontium(II) and barium(II) with thiocyanate ion in liquid ammonia. A number of bands were observed in both n (CN) and n (CS) regions of infrared and Raman spectra and these were assigned to 1:1 contact ion pair, ...

  13. PREPARATION, SPECTROSCOPIC STUDIES AND X-RAY ...

    African Journals Online (AJOL)

    Molar conductance measurements in dmf indicate 1:3 electrolytes in all cases. Magnetic moment values are close proximity of the Van Vleck values. IR studies suggest the coordination of the ligand is through the azomethine, the phenolic oxygen atom and the carbonyl oxygen of the hydrazonic moiety. The nitrate ion is also ...

  14. Synthesis, spectroscopic, electrochemical and luminescence studies ...

    Indian Academy of Sciences (India)

    Unknown

    with hydrazine to form its N2 complex which is of great interest in the chemistry of N2 fixation. Triazoles are also the subject of extensive studies in view of their synthetic properties and other theoretical aspects 9. Ruthenium (II) polypyridyl complexes have opened a new door for enthusiastic researchers since they act as ...

  15. IR spectroscopic techniques to study isolated biomolecules

    NARCIS (Netherlands)

    Rijs, A.M.; Oomens, J.; Rijs, A.M.; Oomens, J.

    2015-01-01

    The combination of mass spectrometry, infrared action spectroscopy and quantum-chemical calculations provides a variety of approaches to the study of the structure of biologically relevant molecules in vacuo. This chapter reviews some of the experimental methods that are currently in use, which can

  16. Spectroscopic study of gamma irradiated bovine hemoglobin

    International Nuclear Information System (INIS)

    Maghraby, Ahmed Mohamed; Ali, Maha Anwar

    2007-01-01

    In the present study, the effects of ionizing radiation of Cs-137 and Co-60 from 4.95 to 743.14 Gy and from 40 Gy to 300 kGy, respectively, on some bovine hemoglobin characteristics were studied. Such an effect was evaluated using electron paramagnetic resonance (EPR) spectroscopy, and infra-red (IR) spectroscopy. Bovine hemoglobin EPR spectra were recorded and analyzed before and after irradiation and changes were explained in detail. IR spectra of unirradiated and irradiated Bovine hemoglobin were recorded and analyzed also. It was found that ionizing radiation may lead to the increase of free radicals production, the decrease in α-helices contents, which reflects the degradation of hemoglobin molecular structure, or at least its incomplete performance. Results also show that the combined application of EPR and FTIR spectroscopy is a powerful tool for determining structural modification of bovine hemoglobin samples exposed to gamma irradiation

  17. SPECTROSCOPIC STUDY OF SEA BUCKTHORN EXTRACTS

    Directory of Open Access Journals (Sweden)

    Carmen Mihaela Topală

    2014-11-01

    Full Text Available The application of sea buckthorn oil is to incorporate the oil into foodstuffs such as milk, yoghurt, cheese, butter, juice and snacks which represents new opportunities for food manufacturers, food supplements and nutraceuticals providing nutritional supports. The FTIR spectroscopy is a powerful technique for assessing food production and studied materials provides fundamental information on the behavior of the spectral metabolites and bio product. The extracts were studied from two varieties of sea buckthorn oil Pitesti I and II. Oil obtained from peel and seeds by the Soxhlet extraction with hexane solvent and CO2 supercriticalwas analyzed by FTIR spectroscopy. The concentration of fatty acids in oil extracted from seeds and peels was similar in both extraction techniques.

  18. Spectroscopic analysis of bones for forensic studies

    Energy Technology Data Exchange (ETDEWEB)

    Tofanelli, Mirko [Applied and Laser Spectroscopy Laboratory, Institute of Chemistry of Organometallic Compounds, Research Area of CNR, Via G. Moruzzi, 1, 56124 Pisa (Italy); Pardini, Lorenzo [Institut für Physik und IRIS Adlershof, Humboldt-Universität zu Berlin, Zum Großen Windkanal 6, 12489 Berlin (Germany); Borrini, Matteo [Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool (United Kingdom); Bartoli, Fulvio; Bacci, Alessandra [Department of Biology, University of Pisa, Via A. Volta, 4, 56126 Pisa (Italy); D’Ulivo, Alessandro; Pitzalis, Emanuela; Mascherpa, Marco Carlo; Legnaioli, Stefano; Lorenzetti, Giulia; Pagnotta, Stefano [Applied and Laser Spectroscopy Laboratory, Institute of Chemistry of Organometallic Compounds, Research Area of CNR, Via G. Moruzzi, 1, 56124 Pisa (Italy); Holanda Cavalcanti, Gildo de [Instituto de Fìsica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/no Campus da Praia Vermelha, CEP 24210-346, Niterói, Rio de Janeiro (Brazil); Lezzerini, Marco [Department of Earth Sciences, University of Pisa, Via Santa Maria, 53, 56126 Pisa (Italy); Palleschi, Vincenzo, E-mail: vincenzo.palleschi@cnr.it [Applied and Laser Spectroscopy Laboratory, Institute of Chemistry of Organometallic Compounds, Research Area of CNR, Via G. Moruzzi, 1, 56124 Pisa (Italy)

    2014-09-01

    The elemental analysis of human bones can give information about the dietary habits of the deceased, especially in the last years of their lives, which can be useful for forensic studies. The most important requirement that must be satisfied for this kind of analysis is that the concentrations of analyzed elements are the same as ante mortem. In this work, a set of bones was analyzed using Laser-Induced Breakdown Spectroscopy (LIBS) and validated using Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP-OES), in order to compare those two techniques and to investigate the effect of possible alterations in the elemental concentrations' proportion resulting from the treatment usually applied for preparing the bones for traditional forensic analysis. The possibility that elemental concentrations' changes would occur after accidental or intentional burning of the bones was also studied. - Highlights: • The LIBS analysis of (animal) bones is presented, to establish its feasibility for forensic studies. • Untreated bones and bones subjected to high temperatures (boiled, burned) were analyzed. • A simple calibration, using a single reference sample, gave reasonable quantitative results. • The comparison of the results demonstrates that LIBS analysis can provide nutritional information. • The nutritional information obtained are the same on untreated, boiled and burned bones.

  19. Spectroscopic analysis of bones for forensic studies

    International Nuclear Information System (INIS)

    Tofanelli, Mirko; Pardini, Lorenzo; Borrini, Matteo; Bartoli, Fulvio; Bacci, Alessandra; D’Ulivo, Alessandro; Pitzalis, Emanuela; Mascherpa, Marco Carlo; Legnaioli, Stefano; Lorenzetti, Giulia; Pagnotta, Stefano; Holanda Cavalcanti, Gildo de; Lezzerini, Marco; Palleschi, Vincenzo

    2014-01-01

    The elemental analysis of human bones can give information about the dietary habits of the deceased, especially in the last years of their lives, which can be useful for forensic studies. The most important requirement that must be satisfied for this kind of analysis is that the concentrations of analyzed elements are the same as ante mortem. In this work, a set of bones was analyzed using Laser-Induced Breakdown Spectroscopy (LIBS) and validated using Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP-OES), in order to compare those two techniques and to investigate the effect of possible alterations in the elemental concentrations' proportion resulting from the treatment usually applied for preparing the bones for traditional forensic analysis. The possibility that elemental concentrations' changes would occur after accidental or intentional burning of the bones was also studied. - Highlights: • The LIBS analysis of (animal) bones is presented, to establish its feasibility for forensic studies. • Untreated bones and bones subjected to high temperatures (boiled, burned) were analyzed. • A simple calibration, using a single reference sample, gave reasonable quantitative results. • The comparison of the results demonstrates that LIBS analysis can provide nutritional information. • The nutritional information obtained are the same on untreated, boiled and burned bones

  20. Combined reflection and transmission thin-film ellipsometry: a unified linear analysis.

    Science.gov (United States)

    Azzam, R M; Elshazly-Zaghloul, M; Bashara, N M

    1975-07-01

    A scheme of combined reflection and transmission ellipsometry on light-transmitting ambient-film-substrate systems is proposed and the required sample design and instrument operation are investigated. A comparative study of the sensitivity of external and internal reflection and transmission ellipsometry is carried out based on unified linear approximations of the exact equations. These approximations are general in that an arbitrary initial film thickness is assumed. They are simple, because a complex sensitivity function is introduced whose real and imaginary projections determine the psi (Psi) and delta (Delta) sensitivity factors. Among the conclusions of this paper are the following. (1) External reflection ellipsometry near the Brewster angle of a transparent ambient-substrate system is extremely sensitive to the presence of very thin interfacial films. For example, films as thin as 10(-5) A of gold are readily detectable on glass substrates at an angle of incidence 0.3 degrees below the Brewster angle, assuming a measuring wavelength of 5461 A with an ellipsometer of 0.05 degrees precision. (2) The formation of thin nonabsorbing films at the interface between transparent ambient and substrate media is not detectable, to first order, as a change in the ellipsometric angle Psi by either internal or external reflection or transmission ellipsometry. (3) The film-detection sensitivity of transmission ellipsometry increases monotonically with angle of incidence. (4) For each angle of external incidence there is a corresponding angle of internal incidence that leads to the same values of the reflection and transmission sensitivity functions. These angles are interrelated by Snell's law. (5) The ranges of validity of the linear approximation in reflection and transmission ellipsometry are comparable. The case of total internal reflection ellipsometry may lead to strong nonlinear behavior of Psi and Delta as functions of the film thickness in the range below 0.05 of

  1. Nonlinear spectroscopic studies of interfacial molecular ordering

    International Nuclear Information System (INIS)

    Superfine, R.

    1991-07-01

    The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful new probes of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the nonlinear susceptibility. In particular, infrared-visible sum frequency generation (SFG) can obtain the vibrational spectrum of sub-monolayer coverages of molecules. In this thesis, we explore the unique information that can be obtained from SFG. We take advantage of the sensitivity of SFG to the conformation of alkane chains to study the interaction between adsorbed liquid crystal molecules and surfactant treated surfaces. The sign of the SFG susceptibility depends on the sign of the molecular polarizability and the orientation, up or down, of the molecule. We experimentally determine the sign of the susceptibility and use it to determine the absolute orientation to obtain the sign of the molecular polarizability and show that this quantity contains important information about the dynamics of molecular charge distributions. Finally, we study the vibrational spectra and the molecular orientation at the pure liquid/vapor interface of methanol and water and present the most detailed evidence yet obtained for the structure of the pure water surface. 32 refs., 4 figs., 2 tabs

  2. The optical properties of transferred graphene and the dielectrics grown on it obtained by ellipsometry

    Science.gov (United States)

    Kasikov, Aarne; Kahro, Tauno; Matisen, Leonard; Kodu, Margus; Tarre, Aivar; Seemen, Helina; Alles, Harry

    2018-04-01

    Graphene layers grown by chemical vapour deposition (CVD) method and transferred from Cu-foils to the oxidized Si-substrates were investigated by spectroscopic ellipsometry (SE), Raman and X-Ray Photoelectron Spectroscopy (XPS) methods. The optical properties of transferred CVD graphene layers do not always correspond to the ones of the exfoliated graphene due to the contamination from the chemicals used in the transfer process. However, the real thickness and the mean properties of the transferred CVD graphene layers can be found using ellipsometry if a real thickness of the SiO2 layer is taken into account. The pulsed laser deposition (PLD) and atomic layer deposition (ALD) methods were used to grow dielectric layers on the transferred graphene and the obtained structures were characterized using optical methods. The approach demonstrated in this work could be useful for the characterization of various materials grown on graphene.

  3. Spectroscopic studies of silver boro tellurite glasses

    Science.gov (United States)

    Kumar, E. Ramesh; Kumari, K. Rajani; Rao, B. Appa; Bhikshamaiah, G.

    2014-04-01

    The FTIR absorption and Raman scattering studies were used to obtain the structural information of AgI-Ag2O-[(1-x)B2O3-xTeO2] (x=0 to 1 mol% in steps of 0.2) glasses. The glassy nature of the compounds has been confirmed by X-ray diffraction. FTIR and Raman spectra were recorded for all samples at room temperature. FTIR spectra which provides the information about the change in bond structure of the glasses. Raman spectra provide the effect of TeO2 on SBT glass system is that as increasing the concentration of TeO2 the band intensity at 707 cm-1 increase.

  4. Spectroscopic studies of silver boro tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, E. Ramesh, E-mail: apparao.bojja@gmail.com; Kumari, K. Rajani, E-mail: apparao.bojja@gmail.com; Rao, B. Appa, E-mail: apparao.bojja@gmail.com; Bhikshamaiah, G., E-mail: apparao.bojja@gmail.com [Department of Physics, Osmania University, Hyderabad-500007 (India)

    2014-04-24

    The FTIR absorption and Raman scattering studies were used to obtain the structural information of AgI−Ag{sub 2}O−[(1−x)B{sub 2}O{sub 3}−xTeO{sub 2}] (x=0 to 1 mol% in steps of 0.2) glasses. The glassy nature of the compounds has been confirmed by X-ray diffraction. FTIR and Raman spectra were recorded for all samples at room temperature. FTIR spectra which provides the information about the change in bond structure of the glasses. Raman spectra provide the effect of TeO{sub 2} on SBT glass system is that as increasing the concentration of TeO{sub 2} the band intensity at 707 cm{sup −1} increase.

  5. Spectroscopic Studies of Exotic Nuclei at ISOLDE

    CERN Multimedia

    2002-01-01

    Experiment IS50 is designed to: a) Investigate the full range of the @b strength function of heavy (A~$>$~48)~K nuclei b)~Study the decay of isomeric states in n-deficient bromine nuclei (A~=~72 and 70). The heavy K isotopes appeared to have complex decay schemes, including feeding by the @b-decay of levels having open neutron channels (Beta decay energy Q(@b) exceeds neutron binding energy S^n); in addition, a large fraction of the delayed transitions populate excited levels in the daughter nuclei. The allowed @b-decay selects states in the daughter nucleus with wave functions having a large overlap with the initial state. Hence, the @b strength functions, deduced from these deca reveal simple structures correlated to the particle-hole excitation energies in the Ca nuclei. These results are valuable for the application of the shell-model calculations far from stability. The delayed neutron spectra are measured with a large area curved scintillator in coincidence either with high resolution Ge(Li) detectors, ...

  6. Spectroscopic Studies of the Nucleus GOLD-195

    Science.gov (United States)

    Fischer, Susan Marie

    The nucleus ^{195}Au has been studied via in-beam gamma -ray and electron spectroscopy with the reactions ^{196}Pt(p,2n)^ {195}Au at beam energies of 12 and 16 MeV, and the reaction ^{rm nat }Ir(alpha,2n) ^{195}Au at a beam energy of 26 MeV. All experiments were performed at the University of Notre Dame tandem accelerator facility and utilized elements of the University of Pittsburgh multi-detector gamma-array and ICEBall mini-orange electron spectrometer. Fifty-five new transitions and thirty-six new energy levels have been observed. The U(6/4) supersymmetric algebra has been proposed to provide a simultaneous description for the positive parity states of the pair of nuclei ^{194 }Pt and ^{195}Au. The observed energy spectra for these nuclei show satisfactory agreement with the U(6/4) predicted spectra. The collective properties including relative B(E2) values for the Pt and Au nuclei in this mass region are also consistent with theoretical predictions. However, the measured E2/M1 mixing ratios for transitions in ^{195} Au indicate that the single particle description for the odd-A nucleus is incomplete. The new data for ^{195}Au is further combined with the existing data for ^{194} Pt and ^{195}Pt within the context of the larger U_{ nu}(6/12) otimes U_{pi}(6/4) supersymmetry. A consistent fit to the energy eigenvalue equation is obtained and a modified prediction for the negative parity states in the odd-odd nucleus ^{196} Au is made. Thus, the proposal of an underlying supersymmetry for the quartet of nuclei ^ {194}Pt-^{195} Pt-^{195}Au- ^{196}Au also appears valid. New transitions and levels involved in the negative parity h_{11/2} decoupled band in ^{195}Au have also been observed. The band appears to be much more fragmented at high spins than the analogous structures in the lighter odd-A Au nuclei, but it is unclear what the source of this difference is. It is, however, proposed that a consistent description for both the positive and negative parity

  7. Ellipsometry of functional organic surfaces and films

    CERN Document Server

    Hinrichs, Karsten

    2013-01-01

    Ellipsometry is the method of choice to determin the properties of surfaces and thin films. It provides comprehensive and sensitive characterization in a contactless and non-invasive measurements. This book gives a state-of-the-art survey of ellipsometric investigations of organic films and surfaces, from laboratory to synchrotron applications, with a special focus on in-situ use in processing environments and at solid-liquid interfaces.

  8. The intertwined history of polarimetry and ellipsometry

    International Nuclear Information System (INIS)

    Azzam, R.M.A.

    2011-01-01

    Ellipsometry and reflection polarimetry are almost synonymous. Therefore it is not surprising that ellipsometry and polarimetry share a common history which is that of optical polarization. The discoveries in the late 1600s by Bartholinus and Huyghens of double refraction by Iceland spar and the unusual properties of the twin beams thus generated presented insurmountable difficulties for the entrenched corpuscular-ray theory of Newton and caused research on polarization to remain stagnant in the 1700s. Major breakthroughs came in the early 1800s when Malus discovered polarization of light by reflection and his cosine-squared law and Fresnel and Arago enunciated their laws of interference of polarized light that helped establish the transverse vector nature of luminous vibrations. Important further research immediately followed on optical rotatory power by Arago, Biot, and Pasteur that ushered fundamental and practical applications of polarimetry in chemistry and biology. Fresnel deserves to be recognized as a founder of ellipsometry by virtue of his laws of reflection of polarized light at interfaces between dissimilar media and his identification and production of circular and elliptical polarization. The later part of the 19th century witnessed significant discoveries of magneto-optic and electro-optic effects by Faraday, Kerr, and Pockels that greatly enriched polarization optics and physics. The 1896 discovery of the Zeeman effect launched the exciting field of solar polarimetry. The 1864 crown achievement of Maxwell's electromagnetic (EM) theory provided a unified framework for the analysis of polarization phenomena across the entire EM spectrum.

  9. Spectroscopic and dynamical studies of highly energized small polyatomic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Field, R.W.; Silbey, R.J. [Massachusetts Institute of Technology, Cambridge (United States)

    1993-12-01

    The authors have initiated a program to perform spectroscopic and dynamic studies of small molecules. Large amplitude motions in excited acetylene were discussed along with plans to record the dispersed fluorescence (DF) and the stimulated emission pumping (SEP) spectra. SEP spectra were reported for the formyl radical. A Fourier transform spectrometer was discussed with respect to its ability to probe the structure of radicals. This instrument is capable of performing studies using various techniques such as magnetic rotation spectroscopy and sub-Doppler sideband-OODR Zeman (SOODRZ) spectroscopy.

  10. Spectroscopic studies of carbon impurities in PISCES-A

    International Nuclear Information System (INIS)

    Ra, Y.; Hirooka, Y.; Leung, W.K.; Conn, R.W.; Pospieszczyk, A.

    1989-08-01

    The graphite used for the limiter of the tokamak reactor produces carbon-containing molecular impurities as a result of the interactions with the edge plasma. The behavior of these molecular impurities has been studied using emission spectroscopy. The present study includes: finding molecular bands and atomic lines in the visible spectral range which can be used for the study of the molecular impurities, studying the breakup processes of the molecular impurities on their way from the source into the plasma, developing a spectroscopic diagnostic method for the absolute measurement of the molecular impurity flux resulting from graphite erosion. For these studies, carbon-containing molecules such as CH 4 , C 2 H 2 , C 2 H 4 , and CO 2 were injected into the tokamak-boundary,like plasma generated by PISCES-A. The spectrograms of these gases were taken. Many useful bands and lines were determined from the spectrograms. The breakup processes of these gases were studied by observing the spatial profiles of the emission of the molecules and their radicals for different plasma conditions. For the absolute measurement of the eroded molecular impurity flux, the photon efficiency of the lines and bands were found by measuring the absolute number of the emitted photons and injected gas molecules. The chemical sputtering yield of graphite by hydrogen plasma was spectroscopically measured using the previously obtained photon efficiencies. It showed good agreement with results obtained by weight loss measurements. 16 refs., 7 figs., 1 tab

  11. Weighted averaging in spectroscopic studies improves statistical power

    OpenAIRE

    Miller, JJ; Cochlin, L; Clarke, K; Tyler, D

    2017-01-01

    Purpose In vivo MRS is often characterized by a spectral signal‐to‐noise ratio (SNR) that varies highly between experiments. A common design for spectroscopic studies is to compare the ratio of two spectral peak amplitudes between groups, e.g. individual PCr/γ‐ATP ratios in 31P‐MRS. The uncertainty on this ratio is often neglected. We wished to explore this assumption. Theory The canonical theory for the propagation of uncertainty on the ratio of two spectral peaks and its incorporation in th...

  12. In situ nanoparticle diagnostics by multi-wavelength Rayleigh-Mie scattering ellipsometry

    CERN Document Server

    Gebauer, G

    2003-01-01

    We present and discuss the method of multiple-wavelength Rayleigh-Mie scattering ellipsometry for the in situ analysis of nanoparticles. It is applied to the problem of nanoparticles suspended in low-pressure plasmas. We discuss experimental results demonstrating that the size distribution and the complex refractive index can be determined with high accuracy and present a study on the in situ analysis of etching of melamine-formaldehyde nanoparticles suspended in an oxygen plasma. It is also shown that particles with a shell structure (core plus mantle) can be analysed by Rayleigh-Mie scattering ellipsometry. Rayleigh-Mie scattering ellipsometry is also applicable to in situ analysis of nanoparticles under high gas pressures and in liquids.

  13. Real time ellipsometry for monitoring plasma-assisted epitaxial growth of GaN

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Giovanni [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM UdR Bari, via Orabona, 4, 70126 Bari (Italy); Losurdo, Maria [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM UdR Bari, via Orabona, 4, 70126 Bari (Italy)]. E-mail: maria.losurdo@ba.imip.cnr.it; Giangregorio, Maria M. [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM UdR Bari, via Orabona, 4, 70126 Bari (Italy); Capezzuto, Pio [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM UdR Bari, via Orabona, 4, 70126 Bari (Italy); Brown, April S. [Department of Electrical and Computer Engineering, Duke University, 128 Hudson Hall, Durham, NC (United States); Kim, Tong-Ho [Department of Electrical and Computer Engineering, Duke University, 128 Hudson Hall, Durham, NC (United States); Choi, Soojeong [Department of Electrical and Computer Engineering, Duke University, 128 Hudson Hall, Durham, NC (United States)

    2006-10-31

    GaN is grown on Si-face 4H-SiC(0 0 0 1) substrates using remote plasma-assisted methods including metalorganic chemical vapour deposition (RP-MOCVD) and molecular beam epitaxy (MBE). Real time spectroscopic ellipsometry is used for monitoring all the steps of substrate pre-treatments and the heteroepitaxial growth of GaN on SiC. Our characterization emphasis is on understanding the nucleation mechanism and the GaN growth mode, which depend on the SiC surface preparation.

  14. Application of Fourier transform infrared ellipsometry to assess the concentration of biological molecules

    Science.gov (United States)

    Garcia-Caurel, Enric; Drevillon, Bernard; De Martino, Antonello; Schwartz, Laurent

    2002-12-01

    Spectroscopic ellipsometry is a noninvasive optical characterization technique mainly used in the semiconductor field to characterize bare substrates and thin films. In particular, it allows the gathering of information concerning the physical structure of the sample, such as roughness and film thickness, as well as its optical response. In the mid-infrared (IR) range each molecule exhibits a characteristic absorption fingerprint, which makes this technique chemically selective. Phase-modulated IR ellipsometry does not require a baseline correction procedure or suppression of atmospheric CO2 and water-vapor absorption bands, thus greatly reducing the subjectivity in data analysis. We have found that ellipsometric measurements of thin films, such as the solid residuals left on a plane surface after evaporation of a liquid drop containing a given compound in solution, are particularly favorable for dosing purposes because the intensity of IR absorptions shows a linear behavior along a wide range of solution concentrations of the given compound. Our aim is to illustrate with a concrete example and to justify theoretically the linearity experimentally found between radiation absorption and molecule concentration. For the example, we prepared aqueous solutions of glycogen, a molecule of huge biological importance currently tested in biochemical analyses, at concentrations ranging from 1 mg/l to 1 g/l, which correspond to those found in physiological conditions. The results of this example are promising for the application of ellipsometry for dosing purposes in biochemistry and biomedicine.

  15. Spectroscopic Studies on Complex Formation of U(VI)-thiosalicylate

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Wan Sik; Cho, Hye Ryun; Park, Kyoung Kyun; Jung, Euo Chang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-05-15

    The dynamic interaction between radionuclides and organic ligands is largely dependent on the composition of functional groups in a ligand chemical structure. Therefore, the structural mimics of natural ligands possessing specific functional groups, such as hydroxy, phenol, carboxyl, thiol and amine groups, have been studied to understand their influence on the migration of radionuclides including actinide species under geological groundwater conditions. In previous studies, we demonstrated that the fraction of hydrolyzed U(VI) species occurring in weak acidic solutions (pH {approx}4.5) is significantly influenced by the presence of salicylate (Sal) ligand due to the simultaneous participation of both phenol and carboxyl groups in the formation of U(VI)-complexes. Thiosalicylic acid (TSalH{sub 2}) is a good model compound for studying the effects of both carboxyl and thiol (-SH) groups. The fraction of di-anionic ligand form (TSal{sup 2-}) is higher at near neutral pH due to the lower pKa ({approx} 8) of the thiol group than the case of salicylic acid (pKa, {approx}13 for salicylic -OH), despite the structural similarity. In addition, the redox capability of the thiol group is expected to influence the reducible radiouclides and the chemical structures of natural ligands by creating cross-linkage (-S-S-) upon oxidation. The goal of the present study is to investigate aqueous U(VI)-TSal complexation equilibrium via laser-based spectroscopic techniques including time resolved laser-induced fluorescence spectroscopy (TRLFS). In this preliminary work, we report the results of spectroscopic studies using conventional UVVis absorbance and fluorescence (FL) measurement methods. The photo-stability of U(VI)-TSal complex or ligand itself upon exposure to a series of laser pulses is estimated by monitoring the change in their absorption bands. Additionally, TSal FL-quenching effect by U(VI) ions is discussed in comparison with that of Sal FL-quenching

  16. In-situ Mueller matrix ellipsometry of silicon nanowires grown by plasma-enhanced vapor-liquid-solid method for radial junction solar cells

    Science.gov (United States)

    Mrazkova, Z.; Foldyna, M.; Misra, S.; Al-Ghzaiwat, M.; Postava, K.; Pištora, J.; Roca i Cabarrocas, P.

    2017-11-01

    In-situ Mueller matrix spectroscopic ellipsometry was applied for monitoring the silicon nanowire growth by plasma-enhanced vapor-liquid-solid method. The technique is proposed as a real-time, non-destructive, and non-invasive characterization of the deposition process in a plasma-enhanced chemical vapor deposition reactor. The data have been taken by spectrally resolved Mueller matrix ellipsometer every 1 min during the 8-10 min long nanowire growth process. We have developed an easy-to-apply optical model to fit the experimental data, which enables to study the evolution of the parameters of the structure during initial stages of the growth. The first results provide information about the effective deposition rate determined from the linear increase of the deposited silicon volume with the deposition time.

  17. Spectroscopic studies on the photochemical decarboxylation mechanisms of synthetic pyrethroids.

    Science.gov (United States)

    Suzuki, Yusuke; Ishizaka, Shoji; Kitamura, Noboru

    2012-12-01

    A novel radical trapping technique combined with a fluorescence spectroscopic analysis has been employed to investigate the radical intermediates produced by photodecarboxylation of four synthetic pyrethroids: fenvalerate (SMD), fenpropathrin (DTL), cyphenothrin (GKL), and cypermethrin (AGT). Under photoirradiation at >290 nm, all pyrethroids underwent direct photolysis via homolytic cleavage of the carbon-oxygen bonds in the ester groups. The consumed amount of a nitroxide free radical, as a trapping agent for the intermediate radical of a pyrethroid, was determined by ESR, which was the measure of the reaction yield of a photochemically generated α-cyano-3-phenoxybenzyl radical common to all pyrethroids. The reactivities of the pyrethroids studied was in the sequence of SMD > DTL > GKL > AGT. Furthermore, nanosecond transient absorption spectroscopy demonstrated that geminate recombination of the radical pair within a solvent cage is the main deactivation route of the photochemically generated α-cyano-3-phenoxybenzyl radical common for all pyrethroids studied.

  18. [Raman spectroscopic study on silicone fluid as pressure gauge].

    Science.gov (United States)

    Liu, Jin; Sun, Qiang

    2010-09-01

    Within a diamond-anvil cell, the in-situ Raman spectroscopic study of silicone fluid was operated at room temperature 298. 1 K and under pressures from 0.1 to 5140.2 MPa. The present study analyzed the correlation of the modes 2906 and 2967 cm(-1) with different pressures, indicating that their wavenumbers linearly increased with increasing pressure. Therefore, this provided the potential to consider the pressure medium silicone fluid as a pressure gauge. The result suggested that silicone fluid could be used as a reliable pressure gauge in high-pressure experiments using diamond-anvil cells with Raman spectrometer, and the correlations between pressure and (delta nu p)2906, (delta nu p)2967 are, p = -0.05[(delta nu p)2967]2 + 73.07 (delta nu p)2967 + 91.54 and p = 0.14 [(delta nu p)2906]2 + 81.9 (delta nu p)2906 + 92.01, respectively.

  19. Velocity Curve Studies of Spectroscopic Binary Stars V380 Cygni ...

    Indian Academy of Sciences (India)

    Abstract. Using measured radial velocity data of five double lined spectroscopic binary systems V380 Cygni, V401 Cyg, V523 Cas, V373 Cas and V2388 Oph, we find corresponding orbital and spectroscopic elements via the method introduced by Karami & Mohebi (2007) and Karami &. Teimoorinia (2007). Our numerical ...

  20. Ellipsometry of anodic film growth

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.G.

    1978-08-01

    An automated computer interpretation of ellisometer measurements of anodic film growth was developed. Continuous mass and charge balances were used to utilize more fully the time dependence of the ellipsometer data and the current and potential measurements. A multiple-film model was used to characterize the growth of films which proceeds via a dissolution--precipitation mechanism; the model also applies to film growth by adsorption and nucleation mechanisms. The characteristic parameters for film growth describe homogeneous and heterogeneous crystallization rates, film porosities and degree of hydration, and the supersaturation of ionic species in the electrolyte. Additional descriptions which may be chosen are patchwise film formation, nonstoichiometry of the anodic film, and statistical variations in the size and orientation of secondary crystals. Theories were developed to describe the optical effects of these processes. An automatic, self-compensating ellipsometer was used to study the growth in alkaline solution of anodic films on silver, cadmium, and zinc. Mass-transport conditions included stagnant electrolyte and forced convection in a flow channel. Multiple films were needed to characterize the optical properties of these films. Anodic films grew from an electrolyte supersatuated in the solution-phase dissolution product. The degree of supersaturation depended on transport conditions and had a major effect on the structure of the film. Anodic reaction rates were limited by the transport of charge carriers through a primary surface layer. The primary layers on silver, zinc, and cadmium all appeared to be nonstoichiometric, containing excess metal. Diffusion coefficients, transference numbers, and the free energy of adsorption of zinc oxide were derived from ellipsometer measurements. 97 figures, 13 tables, 198 references.

  1. Microscopic imaging ellipsometry of submicron-scale bacterial cells

    African Journals Online (AJOL)

    community. With this notation, the sign convention of Δ in both optics and physics communities become consistent [5]. Microscopic Imaging Ellipsometry (MIE) combines the capabilities of ellipsometry in measuring thin film thickness accurately with the high spatial resolution of optical microscopy in lateral directions [6].

  2. Gas detection by means of surface plasmon resonance enhanced ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Nooke, Alida

    2012-11-01

    This thesis investigated gas sensing by means of surface plasmon resonance enhanced ellipsometry. Surface plasmons were excited in a 40 - 50 nm gold layer by a He-Ne-laser using the Kretschmann configuration, which was arranged on a self-made copper measuring cell. A fixed angle of incidence and the ellipsometric parameter {Delta} as the measured value were used to monitor changes in the gas phase. Different types of gases were investigated: flammable (hydrocarbons and hydrogen), oxidising (oxygen and ozone), toxic (carbon monoxide) and inert (helium and nitrogen). The gas types can be distinguished by their refractive indices, whereas the sensor responds instantly relative to the reference gas with an increase or a decrease in {Delta}. Diluting the analyte gas with a reference gas (nitrogen or air) allowed the detection limits to be determined, these lay in the low % range. The sensor stability was also enhanced as well as the sensitivity by modifying the gold layers with a 3-10 nm additional layer. These additional layers consisted of the inorganic materials TiO{sub 2}, ZrO{sub 2}, MgF{sub 2} and Fe: SnO{sub 2} which were deposited by different coating processes. Surface investigations were made of every utilised layer: scanning electron microscope and atomic force microscope measurements for surface topology and spectroscopic ellipsometry mapping to determine the optical constants and the layer thicknesses. All applied materials protected the gold layer from contaminations and thus prolonged the life span of the sensor. Furthermore, the detection limits were reduced significantly, to the low ppm range. The material Fe: SnO{sub 2} demonstrates a special behaviour in reaction with the toxic gas carbon monoxide: Due to the iron doping, the response to carbon monoxide is extraordinary and concentrations below 1 ppm were detected. In order to approach a future application in industry, the sensor system was adapted to a stainless steel tube. With this measuring

  3. Spectroscopic study of photo and thermal destruction of riboflavin

    Science.gov (United States)

    Astanov, Salikh; Sharipov, Mirzo Z.; Fayzullaev, Askar R.; Kurtaliev, Eldar N.; Nizomov, Negmat

    2014-08-01

    Influence of temperature and light irradiation on the spectroscopic properties of aqueous solutions of riboflavin was studied using linear dichroism method, absorption and fluorescence spectroscopy. It was established that in a wide temperature range 290-423 K there is a decline of absorbance and fluorescence ability, which is explained by thermodestruction of riboflavin. It is shown that the proportion of molecules, which have undergone degradation, are in the range of 4-28%, and depends on the concentration and quantity of temperature effects. Introduction of hydrochloric and sulfuric acids, as well as different metal ions leads to an increase in the photostability of riboflavin solutions by 2-2.5 times. The observed phenomena are explained by the formation protonation form of riboflavin and a complex between the metal ions and oxygen atoms of the carbonyl group of riboflavin, respectively.

  4. Ultrasonic and spectroscopic studies on photoactivation of euglena

    Science.gov (United States)

    Saito, Mitsunori; Morita, Shin

    2006-12-01

    We studied the effect of the irradiation wavelength on the activity of photosynthetic euglena. The ultrasonic manipulation technique was used for both the activity evaluation and the movement restriction in the spectral measurements. Euglenas that had been preserved in darkness became inactive, and accordingly most of them were trapped by the ultrasonic standing wave (0.8mW/mm2). However, when they were exposed to light of 500 or 700nm wavelength (0.13W/m2), they became active enough to escape from the trapping. By contrast, irradiation at 550, 600, or 650nm wavelength had no effect on their activity. Spectroscopic measurements, which used to be difficult for locomotive microorganisms, were conducted successfully by trapping euglena at a node of the ultrasonic standing wave. The absorption bands were observed at around 500 or 700nm, which corresponded to the irradiation wavelengths that activated euglena.

  5. Raman spectroscopic study of cyclohexane at pressures below 1000 MPa

    Science.gov (United States)

    Qiao, Erwei; Zheng, Haifei

    2017-10-01

    At present, the room temperature freezing pressure of cyclohexane is still uncertain, and the phase transition pressure of solid I - solid III is not reliable at ambient temperature. In this work, we have performed a Raman spectroscopic study of cyclohexane in a Moissanite anvil cell at pressures below 1000 MPa at 25 °C, and analyzed the characteristic of Raman brands νs(CH2), νas(CH2) and νb(Ring). Two phase transition pressures 80 MPa and 550 MPa were determined by a quartz pressure gauge, and they are the room temperature freezing pressure of cyclohexane and the phase transition pressure of solid I to solid III, respectively. Furthermore, from the phase diagram of cyclohexane, it is inferred that pressure plays an important role on the stability of cyclohexane as the main constituent of oil, and it can be beneficial to understanding the formation, migration and preservation of petroleum in subterranean rock strata.

  6. Raman spectroscopic study of "The Malatesta": a Renaissance painting?

    Science.gov (United States)

    Edwards, Howell G M; Vandenabeele, Peter; Benoy, Timothy J

    2015-02-25

    Raman spectroscopic analysis of the pigments on an Italian painting described as a "Full Length Portrait of a Gentleman", known also as the "Malatesta", and attributed to the Renaissance period has established that these are consistent with the historical research provenance undertaken earlier. Evidence is found for the early 19th Century addition of chrome yellow to highlighted yellow ochre areas in comparison with a similar painting executed in 1801 by Sir Thomas Lawrence of John Kemble in the role of Hamlet, Prince of Denmark. The Raman data are novel in that no analytical studies have previously been made on this painting and reinforces the procedure whereby scientific analyses are accompanied by parallel historical research. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Combined ellipsometry and refractometry technique for characterisation of liquid crystal based nanocomposites.

    Science.gov (United States)

    Warenghem, Marc; Henninot, Jean François; Blach, Jean François; Buchnev, Oleksandr; Kaczmarek, Malgosia; Stchakovsky, Michel

    2012-03-01

    Spectroscopic ellipsometry is a technique especially well suited to measure the effective optical properties of a composite material. However, as the sample is optically thick and anisotropic, this technique loses its accuracy for two reasons: anisotropy means that two parameters have to be determined (ordinary and extraordinary indices) and optically thick means a large order of interference. In that case, several dielectric functions can emerge out of the fitting procedure with a similar mean square error and no criterion to discriminate the right solution. In this paper, we develop a methodology to overcome that drawback. It combines ellipsometry with refractometry. The same sample is used in a total internal reflection (TIR) setup and in a spectroscopic ellipsometer. The number of parameters to be determined by the fitting procedure is reduced in analysing two spectra, the correct final solution is found by using the TIR results both as initial values for the parameters and as check for the final dielectric function. A prefitting routine is developed to enter the right initial values in the fitting procedure and so to approach the right solution. As an example, this methodology is used to analyse the optical properties of BaTiO(3) nanoparticles embedded in a nematic liquid crystal. Such a methodology can also be used to analyse experimentally the validity of the mixing laws, since ellipsometry gives the effective dielectric function and thus, can be compared to the dielectric function of the components of the mixture, as it is shown on the example of BaTiO(3)/nematic composite.

  8. Protein adsorption monitored by plasmon-enhanced semi-cylindrical Kretschmann ellipsometry

    Science.gov (United States)

    Kalas, B.; Nador, J.; Agocs, E.; Saftics, A.; Kurunczi, S.; Fried, M.; Petrik, P.

    2017-11-01

    The Kretschmann-Raether geometry is widely used to investigate the properties of various biological samples and their behavior on different substrates [1] (mostly on gold surface with/without different functionalization). In this configuration the surface plasmon polaritons (SPPs) are used to enhance the sensitivity of the measurement. Recently, the combination of this method with spectroscopic ellipsometry (SE) became more and more popular. In our work protein adsorption was monitored in situ using this configuration. The performance of the configuration was investigated for different thicknesses of the plasmonic layer. The best measurement parameters were identified in terms of layer thickness, angle of incidence (AOI) and wavelength range. It was shown that the spectroscopic capability over a broad wavelength range, the possibility to adjust the AOI accurately, as well as the phase information from the measurement proves to be a significant advantage compared to standard configuration and surface plasmon resonance configurations.

  9. In situ ellipsometry — A powerful tool for monitoring alkali doping of organic thin films

    International Nuclear Information System (INIS)

    Haidu, F.; Ludemann, M.; Schäfer, P.; Gordan, O.D.; Zahn, D.R.T.

    2014-01-01

    The changes of the optical properties of several organic thin films induced by potassium doping were monitored using in situ spectroscopic ellipsometry. The samples were prepared in a high vacuum chamber by organic molecular deposition. Then, potassium (K) was evaporated by passing current through K getters. The three different organic molecules used, show very distinct and different spectral behaviour upon doping. While for Tris-(8-hydroxyquinoline)-aluminium(III) and N,N′-Di-[(1-naphthyl)-N,N′-diphenyl]-(1,1′-biphenyl)-4,4′-diamine only small shifts of the spectral features were noticed, Manganese Phthalocyanine revealed significant changes of the optical properties induced by the K doping. This work indicates that the K doping process can have a dramatic effect on the electronic and the optical properties of the organic molecules, but the effect on the optical spectra remains specific for each organic molecule used, and cannot be easily predicted. - Highlights: • Monitoring organic film growth and doping with in situ spectroscopic ellipsometry • K doped organic thin films • Optical properties of organic thin films change by K doping. • The changes in the optical spectra remain specific for each organic molecule used

  10. Insight into excimer laser crystallization exploiting ellipsometry: Effect of silicon film precursor

    Energy Technology Data Exchange (ETDEWEB)

    Losurdo, Maria [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM sez. Bari, Via Orabona 4, 70125 Bari (Italy)], E-mail: maria.losurdo@ba.imip.cnr.it; Giangregorio, Maria M.; Sacchetti, Alberto; Capezzuto, Pio; Bruno, Giovanni [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM sez. Bari, Via Orabona 4, 70125 Bari (Italy); Mariucci, Luigi; Fortunato, Guglielmo [IFN-CNR, Via Cineto Romano, 42 - 00156 Rome (Italy)

    2007-07-16

    The optical diagnostic of spectroscopic ellipsometry is shown to be an effective tool to investigate the mechanism of excimer laser crystallization (ELC) of silicon thin films. A detailed spectroscopic ellipsometric investigation of the microstructures of polycrystalline Si films obtained on SiO{sub 2}/Si wafers by ELC of a-Si:H and nc-Si films deposited, respectively, by SiH{sub 4} plasma enhanced chemical vapor deposition (PECVD) and SiF{sub 4}-PECVD is presented. It is shown that ellipsometric spectra of the pseudodielectric function of polysilicon thin films allows to discern the three different ELC regimes of partial melting, super lateral growth and complete melting. Exploiting ellipsometry and atomic force microscopy, it is shown that ELC of nc-Si has very low energy density threshold of 95 mJ/cm{sup 2} for complete melting, and that re-crystallization to large grains of {approx} 2 {mu}m can be achieved by multi-shot irradiation at an energy density as low as 260 mJ/cm{sup 2} when using nc-Si when compared to 340 mJ/cm{sup 2} for the ELC of a-Si films.

  11. Raman spectroscopic study of some chalcopyrite-xanthate flotation products

    CSIR Research Space (South Africa)

    Andreev, GN

    2003-12-16

    Full Text Available of normal vibrations of the corresponding individual compounds. The latter facilitated the Raman spectroscopic elucidation of the reaction products formed on the chalcopyrite surface in real industrial flotation conditions with a sodium isopropyl xanthate...

  12. 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…

  13. A spectroscopic study of uranium species formed in chloride melts

    International Nuclear Information System (INIS)

    Volkovich, Vladimir A.; Bhatt, Anand I.; May, Iain; Griffiths, Trevor R.; Thied, Robert C.

    2002-01-01

    The chlorination of uranium metal or uranium oxides in chloride melts offers an acceptable process for the head-end of pyrochemical reprocessing of spent nuclear fuels. The reactions of uranium metal and ceramic uranium dioxide with chlorine and with hydrogen chloride were studied in the alkali metal chloride melts, NaCl-KCl at 973K, NaCl-CsCl between 873 and 923K and LiCl-KCl at 873K. The uranium species formed therein were characterized from their electronic absorption spectra measured in situ. The kinetic parameters of the reactions depend on melt composition, temperature and chlorinating agent used. The reaction of uranium dioxide with oxygen in the presence of alkali metal chlorides results in the formation of alkali metal uranates. A spectroscopic study, between 723 and 973K, on their formation and their solutions was undertaken in LiCl, LiCl-KCl eutectic and NaCl-CsCl eutectic melts. The dissolution of uranium dioxide in LiCl-KCl eutectic at 923K containing added aluminium trichloride in the presence of oxygen has also been investigated. In this case, the reaction leads to the formation of uranyl chloride species. (author)

  14. Spectroscopic Studies of Molecular Systems relevant in Astrobiology

    Science.gov (United States)

    Fornaro, Teresa

    2016-01-01

    In the Astrobiology context, the study of the physico-chemical interactions involving "building blocks of life" in plausible prebiotic and space-like conditions is fundamental to shed light on the processes that led to emergence of life on Earth as well as to molecular chemical evolution in space. In this PhD Thesis, such issues have been addressed both experimentally and computationally by employing vibrational spectroscopy, which has shown to be an effective tool to investigate the variety of intermolecular interactions that play a key role in self-assembling mechanisms of nucleic acid components and their binding to mineral surfaces. In particular, in order to dissect the contributions of the different interactions to the overall spectroscopic signals and shed light on the intricate experimental data, feasible computational protocols have been developed for the characterization of the spectroscopic properties of such complex systems. This study has been carried out through a multi-step strategy, starting the investigation from the spectroscopic properties of the isolated nucleobases, then studying the perturbation induced by the interaction with another molecule (molecular dimers), towards condensed phases like the molecular solid, up to the case of nucleic acid components adsorbed on minerals. A proper modeling of these weakly bound molecular systems has required, firstly, a validation of dispersion-corrected Density Functional Theory methods for simulating anharmonic vibrational properties. The isolated nucleobases and some of their dimers have been used as benchmark set for identifying a general, reliable and effective computational procedure based on fully anharmonic quantum mechanical computations of the vibrational wavenumbers and infrared intensities within the generalized second order vibrational perturbation theory (GVPT2) approach, combined with the cost-effective dispersion-corrected density functional B3LYP-D3, in conjunction with basis sets of

  15. Spectroscopic studies of anthracyclines: Structural characterization and in vitro tracking.

    Science.gov (United States)

    Szafraniec, Ewelina; Majzner, Katarzyna; Farhane, Zeineb; Byrne, Hugh J; Lukawska, Malgorzata; Oszczapowicz, Irena; Chlopicki, Stefan; Baranska, Malgorzata

    2016-12-05

    A broad spectroscopic characterization, using ultraviolet-visible (UV-vis) and Fourier transform infrared absorption as well as Raman scattering, of two commonly used anthracyclines antibiotics (DOX) daunorubicin (DNR), their epimers (EDOX, EDNR) and ten selected analogs is presented. The paper serves as a comprehensive spectral library of UV-vis, IR and Raman spectra of anthracyclines in the solid state and in solution. The particular advantage of Raman spectroscopy for the measurement and analysis of individual antibiotics is demonstrated. Raman spectroscopy can be used to monitor the in vitro uptake and distribution of the drug in cells, using both 488nm and 785nm as source wavelengths, with submicrometer spatial resolution, although the cellular accumulation of the drug is different in each case. The high information content of Raman spectra allows studies of the drug-cell interactions, and so the method seems very suitable for monitoring drug uptake and mechanisms of interaction with cellular compartments at the subcellular level. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Near-Infrared Spectroscopic Study of Chlorite Minerals

    Directory of Open Access Journals (Sweden)

    Min Yang

    2018-01-01

    Full Text Available The mineral chemistry of twenty chlorite samples from the United States Geological Survey (USGS spectral library and two other regions, having a wide range of Fe and Mg contents and relatively constant Al and Si contents, was studied via infrared (IR spectroscopy, near-infrared (NIR spectroscopy, and X-ray fluorescence (XRF analysis. Five absorption features of the twenty samples near 4525, 4440, 4361, 4270, and 4182 cm−1 were observed, and two diagnostic features at 4440 and 4280 cm−1 were recognized. Assignments of the two diagnostic features were made for two combination bands (ν+δAlAlO−OH and ν+δSiAlO−OH by regression with IR fundamental absorptions. Furthermore, the determinant factors of the NIR band position were found by comparing the band positions with relative components. The results showed that Fe/(Fe + Mg values are negatively correlated with the two NIR combination bands. The findings provide an interpretation of the NIR band formation and demonstrate a simple way to use NIR spectroscopy to discriminate between chlorites with different components. More importantly, spectroscopic detection of mineral chemical variations in chlorites provides geologists with a tool with which to collect information on hydrothermal alteration zones from hyperspectral-resolution remote sensing data.

  17. Spectroscopic and electrochemical study of polynuclear clusters from ruthenium acetate

    International Nuclear Information System (INIS)

    Cipriano, C.

    1989-01-01

    The chemistry of the trinuclear clusters [Ru sub(3) O (CH sub(3) CO sub(2)) sub(4) L sub(3)] where L = imidazole, pyridine or pyrazine type of ligands, was investigated based on spectroscopic and electrochemical techniques. These complexes are of great interest from the point of view of their electronic and redox properties, providing multisite species for electron transfer processes. They were isolated in solid state, and characterized by means of elementary analyses and infrared spectra. The electrochemical behaviour in acetonitrile solution was typically reversible; the cyclic voltammograms exhibited a series of four or five mono electronic waves ascribed to the sucessive Ru sup(IV) Ru sup(III) Ru sup(III) / Ru sup(III) Ru sup(III) Ru sup(III)/ --- Ru sup(II) Ru sup(II) Ru sup(II) redox couples. The differences between the successive redox potentials were about 1 V, indicating strong metal-metal interaction in the trinuclear Ru sub(3) centre. The E values were strongly sensitive to the nature of the N-heterocyclic ligand, increasing with the pi-acceptor properties of the pyridine and pyrazine derivatives, but in a much less pronounced way in the case of the imidazole derivatives. Resonance Raman studies for the pyrazine cluster showed selective intensification of the vibrational modes of the Ru-pyrazine chromophore, and the trinuclear centre, using excitation wavelengths coinciding with the metal-to-pyrazine and metal-metal bands, respectively. (author)

  18. Spectroscopic study of small absorptions in optical coatings

    Science.gov (United States)

    Hansen, W. N.

    1982-07-01

    This report concerns research performed by the Utah University surface physics group for the Air Force Weapons Laboratory (AFWL), Kirtland Air Force Base, New Mexico. It is a supplement to AFWL-TR-79-197. It reports the continued study of thorium fluoride (ThF4) as an optical coating, showing that the moisture found in the ThF4 films probably originated from the preparation itself, and that ThF4 may not degrade by moisture absorption from the atmosphere as rapidly as previously thought. Further advances are reported in the characterization procedures themselves, including computer methods for data handling. New procedures were instituted for determining the optical constants of liquids. To test the procedures, the optical constants of liquid water were determined and compared with values found in literature. The procedures used are reported. A sample of Si3N4 film on germanium was analyzed spectroscopically. The dominant feature was a large infrared band revealing the presence of large amounts of silicon hydride. Finally, new procedures are reported for determining impurity concentrations in optical thin films which takes into account the local electromagnetic field strength seen by an impurity in a known optical material as matrix.

  19. Molecular docking, spectroscopic studies and quantum calculations on nootropic drug.

    Science.gov (United States)

    Uma Maheswari, J; Muthu, S; Sundius, Tom

    2014-04-05

    A systematic vibrational spectroscopic assignment and analysis of piracetam [(2-oxo-1-pyrrolidineacetamide)] have been carried out using FT-IR and FT-Raman spectral data. The vibrational analysis was aided by an electronic structure calculation based on the hybrid density functional method B3LYP using a 6-311G++(d,p) basis set. Molecular equilibrium geometries, electronic energies, IR and Raman intensities, and harmonic vibrational frequencies have been computed. The assignments are based on the experimental IR and Raman spectra, and a complete assignment of the observed spectra has been proposed. The UV-visible spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies and the maximum absorption wavelengths λmax were determined by the time-dependent DFT (TD-DFT) method. The geometrical parameters, vibrational frequencies and absorption wavelengths were compared with the experimental data. The complete vibrational assignments are performed on the basis of the potential energy distributions (PED) of the vibrational modes in terms of natural internal coordinates. The simulated FT-IR, FT-Raman, and UV spectra of the title compound have been constructed. Molecular docking studies have been carried out in the active site of piracetam by using Argus Lab. In addition, the potential energy surface, HOMO and LUMO energies, first-order hyperpolarizability and the molecular electrostatic potential have been computed. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Molecular spectroscopic study for suggested mechanism of chrome tanned leather.

    Science.gov (United States)

    Nashy, Elshahat H A; Osman, Osama; Mahmoud, Abdel Aziz; Ibrahim, Medhat

    2012-03-01

    Collagen represents the structural protein of the extracellular matrix, which gives strength of hides and/or skin under tanning process. Chrome tan is the most important tanning agent all over the world. The methods for production of leather evolved over several centuries as art and engineering with little understanding of the underlying science. The present work is devoted to suggest the most probable mechanistic action of chrome tan on hide proteins. First the affect of Cr upon hide protein is indicated by the studied mechanical properties. Then the spectroscopic characterization of the hide protein as well as chrome tanned leather was carried out with Horizontal Attenuated Total Reflection (HATR) FT-IR. The obtained results indicate how the chromium can attached with the active sites of collagen. Molecular modeling confirms that chromium can react with amino as well as carboxylate groups. Four schemes were obtained to describe the possible interactions of chrome tan with hide proteins. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Ultrafast dynamic ellipsometry and spectroscopies of laser shocked materials

    Energy Technology Data Exchange (ETDEWEB)

    Mcgrane, Shawn David [Los Alamos National Laboratory; Bolme, Cindy B [Los Alamos National Laboratory; Whitley, Von H [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory

    2010-01-01

    Ultrafast ellipsometry and transient absorption spectroscopies are used to measure material dynamics under extreme conditions of temperature, pressure, and volumetric compression induced by shock wave loading with a chirped, spectrally clipped shock drive pulse.

  2. Study of the spectroscopic characteristics of methyl (ligand ...

    Indian Academy of Sciences (India)

    TECS

    Abstract. Spectroscopic characterization (IR, NMR and electronic spectra) of methyl (ligand) coba- loxime was done, where ligand = pyrazole, dimethyl pyrazole, alanine and alanine methyl ester. The fre- quency changes in the IR spectra and shifts in the NMR were explained on the basis of basicity of the ligand, steric ...

  3. Deformed shell model studies of spectroscopic properties of 64 Zn ...

    Indian Academy of Sciences (India)

    2014-04-05

    Apr 5, 2014 ... 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 ...

  4. Ion-beam spectroscopic studies of the 69As nucleus

    International Nuclear Information System (INIS)

    Badica, T.; Cojocaru, V.; Olariu, A.; Petre, M.; Popescu, I. V.; Gheboianu, A.

    2009-01-01

    Excited state of the neutron deficient 69 As nucleus were investigated in the 58 Ni( 14 N,2pn) reaction by ion-beam γ spectroscopic methods (excitation functions, γγ-coincidences, angular distributions and linear polarization gated with neutrons). A new more complete level scheme of 69 As has been proposed with spin-parity values. The structure of the nucleus is discussed in the framework of the interaction boson-fermion model (IBFM). (authors)

  5. Spectroscopic Tools for Quantitative Studies of DNA Structure and Dynamics

    DEFF Research Database (Denmark)

    Preus, Søren

    The main objective of this thesis is to develop quantitative fluorescence-based, spectroscopic tools for probing the 3D structure and dynamics of DNA and RNA. The thesis is founded on six peer-reviewed papers covering mainly the development, characterization and use of fluorescent nucleobase...... analogues. In addition, four software packages is presented for the simulation and quantitative analysis of time-resolved and steady-state UV-Vis absorption and fluorescence experiments....

  6. Study of various spectroscopic properties of the Ds meson

    Directory of Open Access Journals (Sweden)

    Kher Virendrasinh H.

    2015-01-01

    Full Text Available Spectroscopic parameters of the Ds (cs̄ meson are obtained using phenomenological quark antiquark potential(coulomb plus power model consisting of O(1/m correction to the potential. Within Variational scheme Gaussian wave function is employed with a hamiltonian incorporating kinematic relativistic corrections to obtain various properties such as the mass spectra, decay constants, electromagnetic transitions. The results are compared with various experimental measurement as well as other theoretical predictions.

  7. Infrared optical constants of liquid palm oil and palm oil biodiesel determined by the combined ellipsometry-transmission method.

    Science.gov (United States)

    Wang, C C; Tan, J Y; Ma, Y Q; Liu, L H

    2017-06-20

    The optical constants of vegetable oils and biodiesels are the basic input parameters in the study of the thermal radiation transfer and monitoring the productivity of vegetable oils converting to biodiesels. In this work, a combined ellipsometry-transmission method is presented to obtain the optical constants of palm oil and palm oil biodiesel between 20°C and 150°C in the spectral range 600-4100  cm -1 and to study the temperature effect on the optical constants. In the combined method, a modified ellipsometry method is used to measure the optical constants of palm oil and palm oil biodiesel for the whole researched wave bands. For the weak absorption regions in which the ellipsometry method cannot give precise absorption indices, the transmission method is conducted to get the absorption indices using the refractive indices obtained by the proposed ellipsometry method. Deionized water and methanol are taken as examples to verify the combined ellipsometry-transmission method. It is shown that the combined method can overcome the deficiencies of the traditional ellipsometry and transmission method, which can be used for the measurements of both strong and weak absorption wave bands. The experimental analyses indicate that temperature exerts a noticeable influence on the infrared optical constants of palm oil and palm oil biodiesel. With the increase of temperature, the refractive indices at certain wavenumbers decrease nearly linearly, and the amplitudes of dominant absorption peaks show a decreasing trend. The absorption peaks located around 3550  cm -1 show blueshift trends as temperature increases. Comparing these two kinds of oils, palm oil presents larger values in refractive indices and dominant absorption peaks.

  8. Spectral ellipsometry of a nanodiamond composite

    International Nuclear Information System (INIS)

    Yastrebov, S. G.; Gordeev, S. K.; Garriga, M.; Alonso, I. A.; Ivanov-Omskii, V. I.

    2006-01-01

    Optical properties of a nanodiamond composite were analyzed by methods of spectral ellipsometry in the range of photon energies 1.4-5 eV, which are characteristic of π-π* transitions in amorphous carbon. The nanocomposite was synthesized by molding nanodiamond powder with subsequent binding of diamond nanoparticles by pyrocarbon formed as a result of the heterogeneous chemical reaction of methane decomposition. The dispersion curves of the imaginary and real parts of the dielectric function were reconstructed. It is shown that the imaginary part of the dielectric function can be represented as the sum of two components generated by the two types of π-π* optical transitions. The maximum contribution of the transitions of the first and second types manifests itself at energies of 2.6 and 5.6 eV, respectively, which correspond to peaks in optical density at 2.9 and 6.11 eV. It was established that the main specific features of the normalized optical density of the nanodiamond composite almost coincide with those for poly(para-phenylenevinylene). It was found that the energy of a σ + π plasmon of the pyrocarbon component of the nanodiamond composite is 24.2 eV. On the basis on this value, the pyrocarbon density matrix was estimated to be 2 g/cm 3 . Within the concepts of optimum filling of an elementary volume by carbon atoms in an amorphous material with such a density, the allotropic composition of the pyrocarbon matrix was restored

  9. Transport and spectroscopic studies of liquid and polymer electrolytes

    Science.gov (United States)

    Bopege, Dharshani Nimali

    trifluoromethanesulfonate, LiCF3SO3, abbreviated here as lithium triflate(LiTf). The molar absorption coefficients of nus(SO3), deltas(CF3), and deltas(SO3) vibrational modes of triflate anion in the LiTf-2-pentanone system were found to be 6708+/-89, 5182+/-62, and 189+/-2 kg mol-1 cm-1, respectively using Beer-Lambert law. Our results show that there is strong absorption by nu s(SO3) mode and weak absorption by deltas(CF 3) mode. Also, the absorptivity of each mode is independent of the ionic association with Li ions. This work allows for the direct quantitative comparison of calculated concentrations in different samples and different experimental conditions. In addition, this dissertation reports the temperature-dependent vibrational spectroscopic studies of pure poly(ethylene oxide) and LiTf-poly(ethylene oxide) complexes. A significant portion of this dissertation focuses on crystallographic studies of ketone-salt (LiTf:2-pentanone and NaTf:2-hexanone) and amine-acid (diethyleneamine: H3PO4, N,N'-dimethylethylenediamine:H 3PO4, and piperazine:H3PO4) systems. Here, sodium trifluoromethanesulfonate, NaCF3SO3 is abbreviated as NaTf. As model compounds, these systems provide valuable information about ion-ion interactions, which are helpful for understanding complex polymer systems. During this study, five crystal structures were solved using single X-ray diffractometry, and their vibrational modes were studied in the mid-infrared region. In the secondary amine/phosphoric acid systems, the nature of hydrogen-bonding network was examined.

  10. Application of Ellipsometry to Control the Plasmachemical Synthesis of Thin TiONx Layers

    Directory of Open Access Journals (Sweden)

    F. N. Dultsev

    2015-01-01

    Full Text Available Ellipsometry is often used to determine the characteristics of films. Ellipsometric studies may turn out to be ineffective because several solutions correspond to the same polarization angles. It is demonstrated that the ambiguity is not due to the physical limitations of the method but it has a purely mathematical character. So, additional information about the film is necessary to determine the absolute values of refractive index, attenuation, and thickness.

  11. Spectroscopic studies of the cytochrome P450 reaction mechanisms.

    Science.gov (United States)

    Mak, Piotr J; Denisov, Ilia G

    2018-01-01

    The cytochrome P450 monooxygenases (P450s) are thiolate heme proteins that can, often under physiological conditions, catalyze many distinct oxidative transformations on a wide variety of molecules, including relatively simple alkanes or fatty acids, as well as more complex compounds such as steroids and exogenous pollutants. They perform such impressive chemistry utilizing a sophisticated catalytic cycle that involves a series of consecutive chemical transformations of heme prosthetic group. Each of these steps provides a unique spectral signature that reflects changes in oxidation or spin states, deformation of the porphyrin ring or alteration of dioxygen moieties. For a long time, the focus of cytochrome P450 research was to understand the underlying reaction mechanism of each enzymatic step, with the biggest challenge being identification and characterization of the powerful oxidizing intermediates. Spectroscopic methods, such as electronic absorption (UV-Vis), electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), electron nuclear double resonance (ENDOR), Mössbauer, X-ray absorption (XAS), and resonance Raman (rR), have been useful tools in providing multifaceted and detailed mechanistic insights into the biophysics and biochemistry of these fascinating enzymes. The combination of spectroscopic techniques with novel approaches, such as cryoreduction and Nanodisc technology, allowed for generation, trapping and characterizing long sought transient intermediates, a task that has been difficult to achieve using other methods. Results obtained from the UV-Vis, rR and EPR spectroscopies are the main focus of this review, while the remaining spectroscopic techniques are briefly summarized. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Photometric and Spectroscopic studies of Ap star Cyg V1584

    Directory of Open Access Journals (Sweden)

    D. M. Z Jassur

    2001-06-01

    Full Text Available   UBV photometric observations of Ap star Cyg V1584 have been presented. To find the rotational period of the star, a sinusoidal wave function has been fitted to the noramal points of UBV filters. Assuming that a circular hot spot located at the magnetic pole of the star is responsible for the observed light variations, both physical an geometrical parameters of the spot have been determined. Finally, the angle between the magnetic and the rotational axis has been calculated from combining the spectroscopic and photometric data and the magnetic structure of the star has been discussed.

  13. Expanded beam spectro-ellipsometry for big area on-line monitoring

    Science.gov (United States)

    Fried, M.; Major, C.; Juhasz, G.; Petrik, P.; Horvath, Z.

    2015-05-01

    Non-destructive analysing tools are needed at all stages of thin film process-development, especially photovoltaic (PV) development, and on production lines. In the case of thin films, layer thicknesses, micro-structure, composition, layer optical properties, and their uniformity are important parameters. An important focus is to express the dielectric functions of each component material in terms of a handful of wavelength independent parameters whose variation can cover all process variants of that material. With the resulting database, spectroscopic ellipsometry coupled with multilayer analysis can be developed for on-line point-by-point mapping and on-line line-by-line imaging. Off-line point-by-point mapping can be effective for characterization of non-uniformities in full scale PV panels or big area (even 450 mm diameter) Si-wafers in developing labs but it is slow in the on-line mode when only 15 points can be obtained (within 1 min) as a 120 cm long panel moves by the mapping station. Last years [M. Fried et al, Thin Solid Films 519, 2730 (2011)], a new instrumentation was developed that provides a line image of spectroscopic ellipsometry (wl=350- 1000 nm) data. Earlier a single 30 point line image could be collected in 10 s over a 15 cm width of PV material. Recent years we have built a 30, a 45 and a 60 cm width expanded beam ellipsometer which speed is increased by 10x. Now, 1800 points can be mapped in a 1 min traverse of a 60*120 cm PV panel or flexible roll-to-roll substrate.

  14. Acquisition of Infrared Variable Angle Spectroscopic Ellipsometer (IR-VASE)

    Science.gov (United States)

    2016-04-22

    SECURITY CLASSIFICATION OF: This award was used to acquire a J.A. Woollam Infrared Variable Angle Spectroscopic Ellipsometer ( IR -VASE). The IR -VASE...unit is capable of obtaining crucial IR information of ultrathin films whilst being complemented with ellipsometry data. This powerful and versatile...Unlimited UU UU UU UU 22-04-2016 1-Feb-2015 31-Jan-2016 Final Report: Acquisition of Infrared Variable Angle Spectroscopic Ellipsometer ( IR -VASE) The

  15. Spectroscopic study on the stability of morin in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Bark, Ki Min [Dept. of Chemical Education and Research Institute of Life Science, Gyeongsang National University, Chinju (Korea, Republic of); Im, Seo Eun; Seo, Jung Ja; Park, Ok Hyun; Park, Hyoung Ryun [Dept. of Chemistry, Chonnam National University, Gwangju (Korea, Republic of); Park, Chul Ho [Dept. of Cosmetic Science, Nambu University, Gwangju (Korea, Republic of)

    2015-02-15

    Morin (3,2,4,5,7-pentahydroxyflavone) is a flavonol conjugated to a resorcinol moiety at the C-2 position, different from many other flavonoids. The UV–vis spectrum of morin in neat water reveals two major absorption bands with maxima at 265 and 387 nm. The substance is stable in acidic solution and neat water. However, its absorption maximum at 387 nm continuously shifts to longer wavelengths and new peaks appeared at wavelengths of 312 nm with increasing pH of the solution. The shape of the absorption spectrum of morin depends on the storage time at a given pH, indicating the occurrence of other successive chemical reactions. The fluorescence spectroscopic results also prove that new conjugated double bonds are formed in the deaerated basic solution at the initial state and decompose with time. This behavior indicates that morin is very unstable, and therefore its decomposition occurs by a sequence of multistep reactions in basic solution. Probable reaction pathways for the reaction are suggested based on the spectroscopic results.

  16. Strontium titanate (100) surfaces monitoring by high temperature in situ ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Hrabovsky, D.; Berini, B. [Groupe d’Étude de la Matière Condensée (GEMaC), (UMR8635) Université de Versailles Saint-Quentin-en-Yvelines – CNRS, 45 Av. des États-Unis, 78035 Versailles (France); Fouchet, A., E-mail: fouchet@physique.uvsq.fr [Groupe d’Étude de la Matière Condensée (GEMaC), (UMR8635) Université de Versailles Saint-Quentin-en-Yvelines – CNRS, 45 Av. des États-Unis, 78035 Versailles (France); Aureau, D. [Institut Lavoisier de Versailles, (UMR 8180) Université de Versailles-Saint-Quentin-en-Yvelines – CNRS, 45 Av. des États-Unis, 78035 Versailles (France); Keller, N. [Groupe d’Étude de la Matière Condensée (GEMaC), (UMR8635) Université de Versailles Saint-Quentin-en-Yvelines – CNRS, 45 Av. des États-Unis, 78035 Versailles (France); Etcheberry, A. [Institut Lavoisier de Versailles, (UMR 8180) Université de Versailles-Saint-Quentin-en-Yvelines – CNRS, 45 Av. des États-Unis, 78035 Versailles (France); and others

    2016-03-30

    Graphical abstract: SrTiO{sub 3} surface contamination evidenced by in situ ellipsometry monitoring. Temperature dependence of overlayer thickness d of HF-treated SrTiO{sub 3} substrate: (1) The sample was heated up (full circles) then (2) cooled down (empty square). (3) The sample was out from the chamber on air for several weeks. (4) Heating up process was repeated. Irreversible behavior during heating up and cooling down indicate the desorption process leaving clean surface with only sub-nanometric roughness. Inset is AFM topographic images of atomic steps (500 nm × 500 nm) of as HF-treated substrate, with the 1 nm height scale. This demonstrates the necessity of in situ sensitive monitoring of the surface before thin film growth and surface analysis in particularly for low temperature deposition process. - Highlights: • In situ spectroscopic ellipsometry monitoring of the contamination layer with different atmosphere and temperature. • Evidence of desorption process of the contaminated layer until 550 °C for both random and TiO{sub 2} termination. • Confirmation of water and carbon contamination layer by XPS. - Abstract: We report monitoring and analysis of the contamination overlayer on the surface of different SrTiO{sub 3} (STO) substrates by in situ spectroscopic ellipsometry (SE) and ex situ X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Substrates of STO with different terminations, random and TiO{sub 2} terminated, were heated from room temperature up to 720 °C under oxygen pressure in UHV chamber similar to conditions commonly used for epitaxial growth of perovskite oxides. Contamination layer on the substrate was modeled as an equivalent dielectric overlayer with a thickness of 2 nm at room temperature which decreases progressively during the heating up to reach its minimum (around 1 unit cell) at the temperature around 550 °C. After exposition to air, surface recovers a contamination layer on both types of

  17. Ellipsometry based imaging techniques for nanoscale characterization of heterogeneous polymer films

    NARCIS (Netherlands)

    Cumurcu, Aysegul

    2014-01-01

    In this thesis, hybrid methods for nanoscale characterization of heterogeneous thin polymer films were discussed. Essentially two ellipsometry based hybrid methods were established or further developed, respectively, namely electrochemical imaging ellipsometry (EC-IE) and scanning near field

  18. Structural and spectroscopic studies of a commercial glassy carbon

    Science.gov (United States)

    Parker, Stewart F.; Imberti, Silvia; Callear, Samantha K.; Albers, Peter W.

    2013-12-01

    Glassy carbon is a form of carbon made by heating a phenolic resin to high temperature in an inert atmosphere. It has been suggested that it is composed of fullerene-like structures. The aim of the present work was to characterize the material using both structural (neutron diffraction and transmission electron microscopy) and spectroscopic (inelastic neutron scattering, Raman and X-ray photoelectron spectroscopies) methods. We find no evidence to support the suggestion of fullerene-like material being present to a significant extent, rather the model that emerges from all of the techniques is that the material is very like amorphous carbon, consisting of regions of small graphite-like basic structural units of partly stacked but mismatched structure with the edges terminated by hydrogen or hydroxyls. We do find evidence for the presence of a small quantity of water trapped in the network and suggest that this may account for batch-to-batch variation in properties that may occur.

  19. Raman spectroscopic study of a genetically altered kidney cell

    Science.gov (United States)

    Joshi, Joel; Garcia, Francisco; Centeno, Silvia P.; Joshi, N. V.

    2008-02-01

    A Raman spectroscopic investigation of a genetically altered Human Embryonic Kidney Cell (HEK293) along with a pathologically normal cell has been carried out by a conventional method. The genetic alteration was carried out with a standard protocol by using a Green Fluorescence Protein (GFP). Raman spectra show that there are dramatic differences between the spectrum obtained from a genetically altered cell and that obtained from a pathologically normal cell. The former shows three broad bands; meanwhile the latter shows several sharp peaks corresponding to the ring vibrational modes of Phen, GFP and DNA. The present analysis provides an indication that the force field near Phen located at 64, 65 and 66 was altered during the genetic transformation. The Raman spectrum could be a direct experimental evidence for substantial modifications triggered due to the expression of specific genes.

  20. Electrochemical and spectroscopic studies of uranium(IV), -(V), and -(VI) in carbonate-bicarbonate buffers

    International Nuclear Information System (INIS)

    Wester, D.W.; Sullivan, J.C.

    1980-01-01

    Recently a need for more detailed knowledge of the chemistry of actinide ions in basic media has arisen in connection with deducing their chemistry in the environment. In this work the results of polarographic, cyclic voltammetric, and spectroscopic studies of U(IV), -(V), and -(VI) in carbonate and bicarbonate media are reported. Polarographic studies were in excellent agreement with those reported previously. Cyclic voltammetric scans confirmed the irreversible reduction to U(V) in both solutions, but disproportionation of the U(V) was observed only in the bicarbonate solutions. The oxidation of U(V) in carbonate was followed spectroscopically for the first time. Reduction in bicarbonate produced U(IV), the spectrum of which is now reported and the oxidation of which was also followed spectroscopically for the first time

  1. Dielectric and impedance spectroscopic studies of neodymium gallate

    Energy Technology Data Exchange (ETDEWEB)

    Sakhya, Anup Pradhan, E-mail: npshakya31@gmail.com [Department of Physics, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009 (India); Dutta, Alo [Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Sinha, T.P. [Department of Physics, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009 (India)

    2016-05-01

    The AC electrical properties of a polycrystalline neodymium gallate, NdGaO{sub 3} (NGO), synthesized by the sol–gel method have been investigated by employing impedance spectroscopy in the frequency range from 42 Hz to 5 MHz and in the temperature range from 323 K to 593 K. The X-ray diffraction analysis shows that the compound crystallizes in the orthorhombic phase with Pbnm space group at room temperature. Two relaxation processes with different relaxation times are observed from the impedance as well as modulus spectroscopic measurements, which have been attributed to the grain and the grain boundary effects at different temperatures in NGO. The complex impedance data are analyzed by an electrical equivalent circuit consisting of a resistance and a constant phase element in parallel. It has been observed that the value of the capacitance and the resistance associated with the grain boundary is higher than those associated with the grain. The temperature dependent electrical conductivity shows the negative temperature coefficient of resistance. The frequency dependent conductivity spectra are found to follow the power law.

  2. Elastic properties and spectroscopic studies of Na 2 O–ZnO–B 2 O 3 ...

    Indian Academy of Sciences (India)

    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.

  3. Elastic properties and spectroscopic studies of Na2O–ZnO–B2O3 ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. 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.

  4. SKIN RESEARCH BY SCATTERING ELLIPSOMETRY METHOD A.B.

    Directory of Open Access Journals (Sweden)

    Anastasiya B. Bulykina

    2017-09-01

    Full Text Available Application possibility of quantitative ellipsometry method for studies of optical anisotropy and structural heterogeneity of the skin in vivo is shown. To describe the polarization properties of the depolarizing optically-active biotissue medium, the Mueller matrix algebra is used. Based on comparative analysis of the technical options and their application in experiments with biotissue, a setup for recording of the polarization state of the backscattered radiation was developed. It is proposed tо use the emitting channel of the LEF-3 ellipsometer in the optical scheme of the stand to have a uniform intensity distribution along the cross section of the input radiation beam, and also to form the polarization states necessary for the study. Radiation source wavelength selection in the spectral range (He-Ne laser, 632 nm is justified, when scattering of radiation in turbid biological media predominates over absorption that makes it possible to estimate the structural parameters of the sample by the change of the output radiation polarization state. The receiving channel of the output polarization state analyzer was developed; it contains a video information block based on a color matrix sensor with a unified analysis field providing the possibility of further multispectral studying of the skin surface structure. The method of ellipsometric examination of the skin is proposed based on the distribution visualization of the polarization state parameters along the cross section of the output radiation beam and on its following analysis. An algorithm and software are developed with a Python language for image processing and calculation of the polarization characteristics of the sample. The distributions of the polarization

  5. Conformational Heterogeneity of Methyl 4-Hydroxycinnamate: A Gas-Phase UV-IR Spectroscopic Study

    NARCIS (Netherlands)

    Tan, E.M.M.; Amirjalayer, S.; Smolarek, S.; Vdovin, A.; Rijs, A.M.; Buma, W.J.

    2013-01-01

    UV excitation and IR absorption spectroscopy on Jet cooled molecules is used to study the conformational heterogeneity of methyl 4-hydroxycinnamate, a model chromophore of the Photoactive Yellow Protein (PYP), and to determine the spectroscopic properties of the various conformers UV-UV depletion

  6. [sup 129]I Moessbauer spectroscopic study of metallocene-iodine adducts

    Energy Technology Data Exchange (ETDEWEB)

    Nakashima, Satoru (Dept. of Chemistry, Faculty of Science, Hiroshima Univ. (Japan)); Sakai, Hiroshi (Dept. of Chemistry, Faculty of Science, Hiroshima Univ. (Japan)); Watanabe, Masanobu (Dept. of Chemistry, Coll. of Arts and Sciences, Univ. of Tokyo (Japan)); Maeda, Yutaka (Research Reactor Inst., Kyoto Univ., Osaka (Japan))

    1994-05-01

    A [sup 129]I Moessbauer spectroscopic study of iodine adducts of ferrocenophane, biruthenocene, and osmocene is reported. The spectra show the existence of iodine bonded to the central metals of metallocenes in addition to triiodide anions. The valence state of iron in the ferrocenophane-iodine adduct is the same as those of ruthenium and osmium in their adducts. (orig.)

  7. A comparative study of the spectroscopic features of the low-lying ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 122; Issue 2. A comparative study of the spectroscopic features ... Both of them are having bent ground state (1A1) equilibrium geometries, but there is a huge difference (∼ 1.93 eV) between their energy barrier to linearity. Their first two excited states are found to be ...

  8. SECTIONING METHOD APPLICATION AT ELLIPSOMETRY OF INHOMOGENEOUS REFLECTION SYSTEMS

    Directory of Open Access Journals (Sweden)

    A. N. Gorlyak

    2014-05-01

    Full Text Available The paper deals with investigation of application peculiarities of ellipsometry methods and UF spectrophotometry at mechanical and chemical processing of optical engineering surface elements made of quartz glass. Ellipsometer LEF–3M–1, spectrophotometer SF–26 and interferometer MII–4 are used as experiment tools; they obtain widely known technical characteristics. Polarization characteristics of reflected light beam were measured by ellipsometry method; spectrophotometry method was used for measuring radiation transmission factor in UF spectrum area; by interference method surface layer thickness at quartz glass etching was measured. A method for HF–sectioning of inhomogeneous surface layer of polished quartz glass is developed based on ellipsometry equation for reflection system «inhomogeneous layer – inhomogeneous padding». The method makes it possible to carry out the measuring and analysis of optical characteristics for inhomogeneous layers system on inhomogeneous padding and to reconstruct optical profile of surface layers at quartz glass chemical processing. For definition of refractive index change along the layer depth, approximation of experimental values for polarization characteristics of homogeneous layers system is used. Inhomogeneous surface layer of polished quartz glass consists of an area (with thickness up to 20 nm and layer refractive index less than refractive index for quartz glass and an area (with thickness up to 0,1 μm and layer refractive index larger than refractive index for quartz glass. Ellipsometry and photometry methods are used for definition of technological conditions and optical characteristics of inhomogeneous layers at quartz glass chemical processing for optical elements with minimum radiation losses in UF spectrum area.

  9. Bioactive Phenothiazines and Benzo[a]phenothiazines: Spectroscopic Studies, and Biological and Biomedical Properties and Applications

    Science.gov (United States)

    Aaron, J. J.; Gaye Seye, M. D.; Trajkovska, S.; Motohashi, N.

    Recent progress in spectroscopic, photophysical, photochemical and analytical studies, as well as in the biological and biomedical properties of bioactive phenothiazines and benzophenothiazines, is reviewed. Their electronic absorption and luminescence properties, and their complexation and interactions in organized media are discussed. Various applications, including analytical studies, relative to phenothiazines and benzophenothiazines are described. Among the important biological and biomedical properties of these compounds, their neurological effects, their antibacterial, antifungal, antiviral, antiparasitic and antitumour activities, and their cytotoxicity are particularly reviewed.

  10. Spectroscopic and time domain reflectometry studies on acetonitrile - Ethylene glycol binary solutions

    Science.gov (United States)

    Mahendraprabu, A.; Kumbharkhane, A. C.; Joshi, Y. S.; Shaikh, S. S.; Kannan, P. P.; Karthick, N. K.; Arivazhagan, G.

    2017-05-01

    Spectroscopic (FTIR and 13C NMR) and time domain reflectometry (in the frequency range from 10 MHz to 25 GHz) studies have been carried out on the binary solutions of acetonitrile (AN) with ethylene glycol (EG). The presence of EG-EG multimers of various orders in neat EG has been confirmed by spectroscopic studies. AN-EG association through the formation of ∁ ≡ N ⋯ H - O , ∁ ≡ N ⋯ H - C(EG) and (EG) C - O ⋯ H - C(AN) hydrogen bonds have been identified using spectral studies. The principal relaxation process of the heteromolecular entities that involve higher order alcohol association in ethylene glycol rich solutions is found to be relatively slower than that in acetonitrile rich solutions in which lower order alcohol association involves in heterointeraction. The angular correlation among the dipoles appears to be described more precisely when the experimental ε∞ values rather than ε∞ =n2 are used for the calculation of geff .

  11. Spectroscopic and antimicrobial studies of polystyrene films under ...

    Indian Academy of Sciences (India)

    microorganisms such as bacteria and yeast were used. Untreated PS films show very fast rate of growth of bacteria within few hours. The study involves developments of polymer surfaces with bacterial growth and further studies after giving antibacterial treatment such as plasma treatment. Major emphasis has been given to ...

  12. DC conductivity and spectroscopic studies of polyaniline doped with ...

    Indian Academy of Sciences (India)

    Doped samples are characterized using various techniques such as – characteristics, UV-visible spectroscopy, X-ray diffractometry (XRD), FTIR and photoluminescence (PL) studies. A significant enhancement in d.c. conductivity has been observed with the introduction of binary dopant. UV-visible study shows that ...

  13. Synthesis and spectroscopic study of nitroxide mono- and bi- radicals

    International Nuclear Information System (INIS)

    Michon, Pierre

    1970-01-01

    Synthesis and study of nitroxide mono- and bi- radicals derived from oxazolidine: - The first part is the synthesis of amines and radicals, and the I.R. U.V., E.P.R. spectroscopy study. - Conformational analysis of two biradicals has been carried out by measurement of dipolar interaction, on the E.P.R. spectra in the second part. - The final part is an application of N.M.R. study to the determination of the sign and magnitude of nuclear-electron spin-spin couplings and conformations analysis in five mono-radicals. (author) [fr

  14. SPECTROSCOPIC STUDIES OF MATERIALS FOR ELECTROCHEMICAL ENERGY STORAGE

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, Steven G.

    2014-03-01

    Several battery materials research projects were undertaken, suing NMR spectroscopy as a primary analytical tool. These include transport proerties of liquid and solid electrolytes and structural studies of Li ion electrodes.

  15. PHOSPHATO AND PHOSPHONATO ADDUCTS: SYNTHESIS AND SPECTROSCOPIC STUDY

    Directory of Open Access Journals (Sweden)

    Mouhamadou Birame Diop

    2014-05-01

    Full Text Available Two new adducts have been synthesized and studied by infrared and NMR spectroscopy. The suggested structures are discrete or of infinite chain type with a phosphate behaving as a bidentate ligand, a phosphonate acting as a monodentate ligand, the environments around the tin centre being tetrahedral or trigonal bipyramidal. In all the studied compounds, supramolecular architectures are obtained when hydrogen bonds are considered.

  16. Spectroscopic, thermal and biological studies on some trivalent ruthenium and rhodium NS chelating thiosemicarbazone complexes.

    Science.gov (United States)

    Sharma, Vinod K; Srivastava, Shipra; Srivastava, Ankita

    2007-01-01

    The synthetic, spectroscopic, and biological studies of sixteen ring-substituted 4-phenylthiosemicarbazones and 4-nitrophenyl-thiosemicarbazones of anisaldehyde, 4-chlorobenzaldehyde, 4-fluorobenzaldehyde, and vanillin with ruthenium(III) and rhodium(III) chlorides are reported here. Their structures were determined on the basis of the elemental analyses, spectroscopic data (IR, electronic, (1)H and (13)C NMR) along with magnetic susceptibility measurements, molar conductivity and thermogravimetric analyses. Electrical conductance measurement revealed a 1 : 3 electrolytic nature of the complexes. The resulting colored products are monomeric in nature. On the basis of the above studies, three ligands were suggested to be coordinated to each metal atom by thione sulphur and azomethine nitrogen to form low-spin octahedral complexes with ruthenium(III) while forming diamagnetic complexes with rhodium(III). Both ligands and their complexes have been screened for their bactericidal activities and the results indicate that they exhibit a significant activity.

  17. Excitation induced spectroscopic study and quenching effect in cerium samarium codoped lithium aluminoborate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Parvinder; Kaur, Simranpreet [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Singh, Gurinder Pal [Department of Physics, Khalsa College, Amritsar 143002 (India); Arora, Deepawali; Kumar, Sunil [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Singh, D.P., E-mail: dpsinghdr@yahoo.com [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)

    2016-08-15

    Lithium aluminium borate host has been codoped with cerium and samarium to prepare glass by conventional melt quench technique. Their structural and spectroscopic investigation has been carried out using XRD, FTIR and density measurements. The UV‐Vis absorption spectra and fluorescence spectra (λ{sub exc}.=380 nm and 400 nm) have been studied for spectroscopic analysis. The amorphous nature of the prepared samples is shown by XRD. The density is increasing with addition of cerium at the expense of aluminium, keeping other components constant. FTIR study also shows the presence of compact and stable tetrahedral BO{sub 4} units thus supporting the density results. The UV‐ Vis absorption spectra show a shift of optical absorption edge towards longer wavelength along with an increase in intensity of peaks with rising samarium concentration. The fluorescence spectra show a blue shift and subsequent suppression of cerium peaks with addition of samarium.

  18. Spectrochemistry of Solutions: A Vibrational Spectroscopic Study of ...

    African Journals Online (AJOL)

    Ion pairing and upper stage transition of magnesium (II) and calcium (II) with thiocyanate ion has been studied by Infrared and Raman spectroscopy. A complete picture of species present in thiocyanate solutions has been established. The spectral profile consists of five thiocyanate species namely; a triple-ion, [SCN - M ...

  19. Comparative study of spectroscopic properties of the low-lying ...

    Indian Academy of Sciences (India)

    due to the substitutions by methyl (II), isopropyl (III) and fluoromethyl (IV) groups on nitrogen. Some theo- retical studies on PSB (I) have been earlier reported at different level of calculations. AM1/CISD, MP4, MRCI calculations have been carried out by Dobado and. Nonella,25 while MNDO-CI method has been applied.

  20. Spectroscopic Studies of the Electron Donor-Acceptor Interaction of ...

    African Journals Online (AJOL)

    Purpose: The electron donor-acceptor interaction between drugs which act as electron donors and some electron-deficient compounds (π acceptors) has severally been utilized as an analytical tool for the quantitation and qualitative assessment of such drugs. The objective of this study, therefore, was to develop an assay ...

  1. Synthesis and spectroscopic study of high quality alloy Cdx S ...

    Indian Academy of Sciences (India)

    Wintec

    Abstract. In the present study, we report the synthesis of high quality CdxZn1–xS nanocrystals alloy at. 150°C with changing the composition. The shifting of absorption and emission peak in shorter wave- length is obtained with increasing the mole fraction of zinc. The quantum yield (QY) value decreases with increasing the ...

  2. Spectroscopic studies of some lanthanide(III) nitrate complexes ...

    African Journals Online (AJOL)

    ... chemical analysis, conductance, magnetic moment measurements and infrared spectra. Infrared study indicates that the ligand behaves both as neutral and ionic O donors and as neutral N donors. KEY WORDS: Lanthanide(III) complexes, Schiff base, 2,6-bis-(Salicylaldehydehydrazone)-4-chlorophenol, Infrared spectra, ...

  3. preparation, spectroscopic studies and x-ray structure of ...

    African Journals Online (AJOL)

    Administrator

    Molar conductance measurements in dmf indicate 1:3 electrolytes in all cases. Magnetic moment values are close proximity of the Van Vleck values. IR studies suggest the coordination of the ligand is through the azomethine, the phenolic oxygen atom and the carbonyl oxygen of the hydrazonic moiety. The nitrate ion is also ...

  4. Fundamental spectroscopic studies of carbenes and hydrocarbon radicals

    Energy Technology Data Exchange (ETDEWEB)

    None

    1999-03-12

    Determination of bond dissociation energies and heats of formation of hydrocarbon radicals and carbenes requires knowledge of their structures, but this is not provided by standard mass spectrometric studies; what is needed is high-resolution spectroscopy, often best achieved at centimeter and millimeter wavelengths. Nearly 60 reactive organic molecules were investigated in the period from 1988--1998.

  5. Infrared absorption spectroscopic study of Nd substituted Zn–Mg ...

    Indian Academy of Sciences (India)

    Unknown

    dependent behaviour of force constant are attributed to the cation oxygen bond distances. The structural distortion in case of chromium substituted nickel ferrites was studied by Ghatage et al (1996) and the existence of fine structure is attributed to the Jahn-Teller effect. The IR spectra of Cd, Co, Mg, Ni, Zn, Cu etc containing ...

  6. Synthesis and Spectroscopic, Thermal and Crystal Structure Studies ...

    African Journals Online (AJOL)

    NICO

    The salt undergoes melting followed by decomposition to give gaseous products. KEYWORDS. Hydrazine, succinic acid, hydrazinium hydrogensuccinate, crystal structure, thermal studies. 1. Introduction. Dibasic acids are known to form N2H5HA, (N2H5)2A and. N2H5HA.H2A type salts (H2A = dibasic acid) with hydrazine.

  7. DC conductivity and spectroscopic studies of polyaniline doped with ...

    Indian Academy of Sciences (India)

    study shows structural modifications in functional groups with doping in PANI. Photoluminescence spectra exhibit emission properties of the samples. Keywords. Polyaniline; D.C. conductivity; UV-visible; XRD; FTIR; PL. 1. Introduction. Polymers are typically utilized in electrical, optical and electronic devices as insulators ...

  8. Fluorescence spectroscopic studies on binding of a flavonoid ...

    Indian Academy of Sciences (India)

    Binding of quercetin to human serum albumin (HSA) was studied and the binding constant measured by following the red-shifted absorption spectrum of quercetin in the presence of HSA and the quenching of the intrinsic protein fluorescence in the presence of different concentrations of quercetin. Fluorescence lifetime ...

  9. Infrared absorption spectroscopic study of Nd substituted Zn–Mg ...

    Indian Academy of Sciences (India)

    Unknown

    results from IR absorption study can be used to interpret the electrical and magnetic properties of the ferrites. (Braber 1969). The absorption bands, from which the details regarding functional groups and their linkages can be explored, are found to be dependent on atomic mass, cationic radius, cation–anion bond distances, ...

  10. Spectroscopic Studies of the Electron Donor-Acceptor Interaction of ...

    African Journals Online (AJOL)

    Erah

    The objective of this study, therefore, was to develop an assay procedure for dosage forms of chloroquine phosphate based on its reaction with chloranilic acid which resulted in the formation of a charge-transfer complex. Methods: The complex formation between chloroquine phosphate and chloranilc acid as evidenced by.

  11. Thermophysical and spectroscopic studies of room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate in Tritons

    International Nuclear Information System (INIS)

    Chaudhary, Ganga Ram; Bansal, Shafila; Mehta, S.K.; Ahluwalia, A.S.

    2012-01-01

    Highlights: ► Thermophysical studies of new formulations of [BMIM][PF 6 ]+TX(45,100) have been made. ► Strong intermolecular interactions between [BMIM][PF 6 ] and TX (45, 100) is observed. ► Magnitude of interactions increases with the addition of oxyethylene groups in TX. ► With rise in temperature, intermolecular interactions increases. ► Spectroscopic studies show that interactions are via aromatic rings of RTIL and TX. - Abstract: The thermophysical properties viz. density ρ, speed of sound u, and specific conductivity κ of pure room temperature ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and its binary formulations with Triton X-45 and Triton X-100 have been studied over the entire composition range at different temperatures (293.15 to 323.15) K. Excess molar volume V E , deviation in isentropic compressibility ΔK S , partial molar excess volume V i E , deviation in partial molar isentropic compressibility ΔK S,i , deviation in specific conductivity Δκ have also been estimated and analysed. Spectroscopic properties (IR, 1 H and 13 C NMR) of these mixtures have been investigated in order to understand the structural and interactional behaviour of formulations studied. The magnitude of interactions between the two components increases with addition of number of oxyethylene groups in Tritons and with rise in temperature. Spectroscopic measurements indicate that interactions are mainly taking place through the five member ring of room temperature ionic liquid and six member ring of Tritons.

  12. Spectroscopic studies with the use of deep-inelastic heavy-ion reactions

    International Nuclear Information System (INIS)

    Broda, R

    2006-01-01

    Gamma spectroscopic studies exploiting deep-inelastic heavy-ion reactions in thick target experiments are reviewed. The description of physical motivation, history of early experiments, analysis of the N/Z equilibration process as well as the outline of the experimental method and data analysis are followed by the presentation of main results obtained in various regions of the nuclide chart. Brief comments on thin target spectroscopy experiments involving fragment detection and future outlook are summarized. (topical review)

  13. Isolation and spectroscopic studies of curcumin from Philippine Curcuma longa L

    International Nuclear Information System (INIS)

    Torres, Rosalinda C.; Bonifacio, Teresita S.; Herrera, Celia L.; Lanto, Eduardo A.

    1998-01-01

    Curcumin, the yellow coloring matter was isolated from the rhizomes of Philippine Curcuma longa L. (turmeric) by Soxhlet extraction with toluene followed by concentration and slow crystallization. The isolated curcumin was then subjected to chromatographic and spectroscopic studies with the Merck curcumin standard. The infra red and UV-vis spectra of both compounds were found to be almost identical indicating a high purity of the isolate. The % yield obtained was 2-3%. (Author)

  14. Spectroscopic study of silicate glass structure. Application to the case of iron and magnesium

    International Nuclear Information System (INIS)

    Rossano, Stephanie

    2008-01-01

    During the last 10 years, I focused my research topics on silicate glass structure. More specifically I have been interested by two main components of natural and technological silicate glasses, Fe and Mg. Using solid state spectroscopic methods adapted to the disordered nature of glass coupled to molecular dynamics simulation and modeling or ab initio calculation, I have studied the environment of iron and magnesium and their impact on glass properties. Information on the distribution of environments in glasses have been extracted. (author)

  15. Spectroscopic and transport studies of Cu 2 ion doped in (40–x ...

    Indian Academy of Sciences (India)

    The preparation of (40 – )Li2O–LiF–60Bi2O3 glassy system and spectroscopic and transport studies of this system are reported. IR results show that this glass consists of [BiO3] units and indicate formation of Bi–F bonds with the addition of LiF. From the ESR spectra of Cu2+ ion, the effective values are found to vary ...

  16. Studies of tropical fruit ripening using three different spectroscopic techniques.

    Science.gov (United States)

    Zhang, Hao; Huang, Jing; Li, Tianqi; Wu, Xiuxiang; Svanberg, Sune; Svanberg, Katarina

    2014-06-01

    We present a noninvasive method to study fruit ripening. The method is based on the combination of reflectance and fluorescence spectroscopies, as well as gas in scattering media absorption spectroscopy (GASMAS). Chlorophyll and oxygen are two of the most important constituents in the fruit ripening process. Reflectance and fluorescence spectroscopies were used to quantify the changes of chlorophyll and other chromophores. GASMAS, based on tunable diode laser absorption spectroscopy, was used to measure free molecular oxygen in the fruit tissue at 760 nm, based on the fact that the free gases have much narrower spectral imprints than those of solid materials. The fruit maturation and ripening processes can be followed by studying the changes of chlorophyll and oxygen contents with these three techniques.

  17. Spectroscopic studies of laser ablation plumes of artwork materials

    Science.gov (United States)

    Oujja, M.; Rebollar, E.; Castillejo, M.

    2003-04-01

    Studies on the plasma plume created during KrF laser (248 nm) ablation of dosimeter tempera samples in vacuum have been carried out to investigate the basic interactions of the laser with paint materials. Time resolved optical emission spectroscopy (OES) was used to measure the translational velocity of electronically excited transients in the plasma plume. Laser-induced fluorescence (LIF) studies using a probe dye laser, allowed to determine the velocities of non-emitting species. The propagation velocities of C 2 in the a 3π u and d 3π g electronic states and of excited atomic species are indicative of a high translational temperature. Differences between the velocities of organic and inorganic species and between emissions from the tempera systems and from the pigments as pellets allow to discuss the participation of photochemical mechanisms in the laser irradiation of the paint systems.

  18. FT-IR spectroscopic studies of polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Salisbury, D.W.; Allen, J.E. Jr.; Donn, B.; Moore, W.J.; Khanna, R.K.

    1990-01-01

    Proper assessment of the hypothesis which correlates polycyclic aromatic hydrocarbons (PAHs) with the unidentified infrared emission bands requires additional experimental laboratory data. In order to address this need, thermal infrared emission studies were performed on a subset of PAHs suggested to be of astrophysical importance. It was proposed that infrared emission from interstellar PAHs occurs following absorption of an ultraviolet photon. Since energy transfer to the ground electronic state can be rapid for a species in which intersystem crossing is negligible, the emission spectrum may be viewed as resulting from an equilibrium vibrational temperature (Leger and d'Hendecourt, 1987). This has been the basis for using infrared absorption spectra to calculate the corresponding emission spectra at various temperatures. These calculations were made using room temperature infrared absorption coefficients instead of those at the temperature of interest because of the latter's unavailability. The present studies are designed to address the differences between the calculated and experimental thermal emission spectra and to provide information which will be useful in future ultraviolet induced infrared fluorescence studies. The emission spectra have been obtained for temperatures up to 825K using an emission cell designed to mount against an external port of an FT-IR spectrometer. These spectra provide information concerning relative band intensities and peak positions which is unavailable from previous calculations

  19. Near-Infrared Spectroscopic Study of Chlorite Minerals

    OpenAIRE

    Min Yang; Meifang Ye; Haihui Han; Guangli Ren; Ling Han; Zhuan Zhang

    2018-01-01

    The mineral chemistry of twenty chlorite samples from the United States Geological Survey (USGS) spectral library and two other regions, having a wide range of Fe and Mg contents and relatively constant Al and Si contents, was studied via infrared (IR) spectroscopy, near-infrared (NIR) spectroscopy, and X-ray fluorescence (XRF) analysis. Five absorption features of the twenty samples near 4525, 4440, 4361, 4270, and 4182 cm−1 were observed, and two diagnostic features at 4440 and 4280 cm−1 we...

  20. Iron Complexes of Peptide Conjugates: Theoretical and Spectroscopic Study

    Czech Academy of Sciences Publication Activity Database

    Šebestík, Jaroslav; Šafařík, Martin; Bouř, Petr

    2011-01-01

    Roč. 96, č. 4 (2011), s. 506-506 ISSN 1097-0282. [ American Peptide Symposium /22./. 25.06.2011-30.06.2011, San Diego] R&D Projects: GA ČR GA203/07/1517; GA MŠk(CZ) LH11033; GA ČR GAP208/11/0105 Grant - others:AV ČR(CZ) M200550902 Institutional research plan: CEZ:AV0Z40550506 Keywords : deferipron * ferric complexes * Raman spectra * DFT study * peptide Subject RIV: CF - Physical ; Theoretical Chemistry

  1. Impedance and modulus spectroscopic study of nano hydroxyapatite

    Science.gov (United States)

    Jogiya, B. V.; Jethava, H. O.; Tank, K. P.; Raviya, V. R.; Joshi, M. J.

    2016-05-01

    Hydroxyapatite (Ca10 (PO4)6 (OH)2, HAP) is the main inorganic component of the hard tissues in bones and also important material for orthopedic and dental implant applications. Nano HAP is of great interest due to its various bio-medical applications. In the present work the nano HAP was synthesized by using surfactant mediated approach. Structure and morphology of the synthesized nano HAP was examined by the Powder XRD and TEM. Impedance study was carried out on pelletized sample in a frequency range of 100Hz to 20MHz at room temperature. The variation of dielectric constant, dielectric loss, and a.c. conductivity with frequency of applied field was studied. The Nyquist plot as well as modulus plot was drawn. The Nyquist plot showed two semicircle arcs, which indicated the presence of grain and grain boundary effect in the sample. The typical behavior of the Nyquist plot was represented by equivalent circuit having two parallel RC combinations in series.

  2. Spectroscopic, structural and drug docking studies of carbocysteine

    Science.gov (United States)

    Manivannan, M.; Rajeshwaran, K.; Govindhan, R.; Karthikeyan, B.

    2017-09-01

    Carbocysteine or carbocisteine having the empirical formula C5H9NO4S,is one of the most therapeutically prescribed expectorant, sold under the brand name viz., Mucodyne (UK and India), Rhinathiol and Mucolite. In pediatric respiratory pathology, it can relieve the symptoms of obstructive pulmonary disease (COPD) and bronchiectasis. On the consideration of its extensive pharmaceutical usage and medicinal value, we have investigated its chemical structure and composition by employing various spectral techniques like 1H, 13C NMR, FT-IR,Raman, UV-Visible spectroscopy and powder X-ray diffraction method. Density Functional Theoretical (DFT) studies on its electronic structure is also carried out. Drug docking studies were carried out to ascertain the nature of molecular interaction with the biological protein system. Furthermore theoretical Raman spectrum of this molecule has been computed and compared with the experimental Raman spectrum. The forbidden energy gap between its frontier molecular orbitals, viz., HOMO-LUMO is calculated and correlated with its observed λmax value. Atomic orbitals which are mainly contributes to the frontier molecular orbitals were identified. Molecular electrostatic potential diagram has been mapped to explain its chemical activity. Based on the results, a suitable mechanism of its protein binding mode and drug action has been discussed.

  3. Divalent thulium triflate. A structural and spectroscopic study

    Energy Technology Data Exchange (ETDEWEB)

    Xemard, Mathieu; Jaoul, Arnaud; Cordier, Marie; Nocton, Gregory [Univ. Paris-Saclay, Palaiseau (France). LCM, Ecole polytechnique, CNRS; Molton, Florian; Duboc, Carole [Grenoble Univ., Saint Martin d' Heres (France). Dept. de Chimie Moleculaire; Cador, Olivier; Le Guennic, Boris [Univ. de Rennes 1 (France). Inst. des Sciences Chimique de Rennes, UMR 6226 CNRS; Maury, Olivier [Univ. Claude Bernard Lyon 1 (France). Lab. de Chimie; Clavaguera, Carine [Univ. Paris-Saclay, Palaiseau (France). LCM, Ecole polytechnique, CNRS; Univ. Paris Sud, Univ. Paris-Saclay, Orsay (France). Lab. de Chimie Physique, CNRS

    2017-04-03

    The first molecular Tm{sup II} luminescence measurements are reported along with rare magnetic, X and Q bands EPR studies. Access to simple and soluble molecular divalent lanthanide complexes is highly sought for small-molecule activation studies and organic transformations using single-electron transfer processes. However, owing to their low stability and propensity to disproportionate, these complexes are hard to synthetize and their electronic properties are therefore almost unexplored. Herein we present the synthesis of [Tm(μ-OTf){sub 2}(dme){sub 2}]{sub n}, a rare and simple coordination compound of divalent thulium that can be seen as a promising starting material for the synthesis of more elaborated complexes. This reactive complex was structurally characterized by X-ray diffraction analysis and its electronic structure has been compared with that of its halide cousin TmI{sub 2}(dme){sub 3}. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Lithium and sodium incorporation in zirconia: a spectroscopic study

    International Nuclear Information System (INIS)

    Bender, Alexandra

    2001-01-01

    Zircaloy is used as fuel cladding material. Lithium dissolved in the cooling water enhances its corrosion and incorporates into the oxide layer. It could substitute for zirconium atoms forming a solid solution or modify crystallographic structure of zirconia. The aim of this work is to determine the crystallographic structure and the local environment of dopant in Li and Na doped zirconia samples obtained by ionic implantation and coprecipitation route, and then to discuss their interest in term of 'lithium effect study'. Implanted zirconia samples are constituted by metallic aggregates oxidised at their surface. A third 'Na 2 ZrO 3 ' local environment has been detected probably due to Na dissolved in zirconia. An experimental procedure has been developed allowing Li and Na doping by a coprecipitation route. Lithium and sodium hydroxide helps the stabilisation of metastable zirconia. Stabilisation doesn't seem to be due to alkaline substitution for zirconium but it must be connected to the effect of both alkaline hydroxides on the first precipitation steps. Similarities between Li doped zirconia by coprecipitation route and zirconia obtained by oxidation of zirconium in the presence of LiOH should help to understand the so-called 'lithium effect'. Finally sodium seems to be relevant to simulate lithium when samples are elaborated and studied at room temperature. It is not the case for annealed samples. (author) [fr

  5. Ligand exchange in quaternary alloyed nanocrystals--a spectroscopic study.

    Science.gov (United States)

    Gabka, Grzegorz; Bujak, Piotr; Giedyk, Kamila; Kotwica, Kamil; Ostrowski, Andrzej; Malinowska, Karolina; Lisowski, Wojciech; Sobczak, Janusz W; Pron, Adam

    2014-11-14

    Exchange of initial, predominantly stearate ligands for pyridine in the first step and butylamine (BA) or 11-mercaptoundecanoic acid (MUA) in the second one was studied for alloyed quaternary Cu-In-Zn-S nanocrystals. The NMR results enabled us to demonstrate, for the first time, direct binding of the pyridine labile ligand to the nanocrystal surface as evidenced by paramagnetic shifts of the three signals attributed to its protons to 7.58, 7.95 and 8.75 ppm. XPS investigations indicated, in turn, a significant change in the composition of the nanocrystal surface upon the exchange of initial ligands for pyridine, which being enriched in indium in the 'as prepared' form became enriched in zinc after pyridine binding. This finding indicated that the first step of ligand exchange had to involve the removal of the surface layer enriched in indium with simultaneous exposure of a new, zinc-enriched layer. In the second ligand exchange step (replacement of pyridine with BA or MUA) the changes in the nanocrystal surface compositions were much less significant. The presence of zinc in the nanocrystal surface layer turned out necessary for effective binding of pyridine as shown by a comparative study of ligand exchange in Cu-In-Zn-S, Ag-In-Zn-S and CuInS2, carried out by complementary XPS and NMR investigations.

  6. Modified Learning Strategy for Neural Networks to Support Spectroscopic Ellipsometric Data Evaluation

    NARCIS (Netherlands)

    Redei, L.; Fried, Miklós; Barsony, I.; Barsony, István; Wallinga, Hans

    1998-01-01

    It has been shown that worst-case learning, a slightly modified strategy in backpropagation network (BPN) training, results in constrained maximal error at the expense of slightly increased root mean squared error (RMSE) using BPN in spectroscopic ellipsometry (SE). Traditionally the evaluation of

  7. Moessbauer spectroscopic studies of iron-storage proteins

    Energy Technology Data Exchange (ETDEWEB)

    St. Pierre, T.G.

    1986-01-01

    /sup 57/Fe Moessbauer spectroscopy was used to study iron storage proteins. Various cryostats and a superconducting magnet were used to obtain sample environment temperatures from 1.3 to 200K and applied magnetic fields of up to 10T. The Moessbauer spectra of ferritins isolated from iron-overloaded human spleen, limpet (Patella vulgata), giant limpet (Patella laticostata) and chiton (Clavarizona hirtosa) hemolymph, and bacterial (Pseudomonas aeruginosa) cells are used to gain information on the magnetic ordering- and superparamagnetic transition temperatures of the microcrystalline cores of the proteins. Investigations were made about the cause of the difference in the magnetic anisotropy constants of the cores of iron-overloaded human spleen ferritin and hemosiderin. Livers taken from an iron-overloaded hornbill and artificially iron-loaded rats showed no component with a superparamagnetic transition temperature approaching that of the human spleen hemosiderin.

  8. Tertiary phosphine complexes of rhenium: a spectroscopic study

    International Nuclear Information System (INIS)

    Fergusson, J.E.; Heveldt, P.F.

    1976-01-01

    Complexes of the type ReOX 3 L 2 , ReNX 2 L 3 , ReX 3 (NO)L 2 and ReX 2 (NO)L 3 have been studied using, UV visible, IR and H 1 , C 13 NMR spectroscopy. (X is a halogen, Cl, Br, I and L is a tertiary phosphine Et 3 P and Et 2 PhP). Evidence obtained on the blue cis isomer ReOCl 3 L 2 suggests that the halogens are arranged on a face of the octahedral complex. Assignments of ν(Re-X) and ν(Re-P) vibrations have been made. Three complexes of technetium, [TcCl 4 (Ph 3 P) 2 ], [TcCl 3 (Et 2 PhP) 3 ] and [TcCl 3 (NO)(Et 2 PhP) 2 ] have been isolated. (author)

  9. Raman spectroscopic study of plasma-treated salmon DNA

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Geon Joon; Kim, Yong Hee; Choi, Eun Ha [Plasma Bioscience Research Center, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Kwon, Young-Wan [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of)

    2013-01-14

    In this research, we studied the effect of plasma treatment on the optical/structural properties of the deoxyribonucleic acid (DNA) extracted from salmon sperm. DNA-cetyltrimethylammonium (CTMA) films were obtained by complexation of DNA with CTMA. Circular dichroism (CD) and Raman spectra indicated that DNA retained its double helical structure in the solid film. The Raman spectra exhibited several vibration modes corresponding to the nuclear bases and the deoxyribose-phosphate backbones of the DNA, as well as the alkylchains of CTMA. Dielectric-barrier-discharge (DBD) plasma treatment induced structural modification and damage to the DNA, as observed by changes in the ultraviolet-visible absorption, CD, and Raman spectra. The optical emission spectra of the DBD plasma confirmed that DNA modification was induced by plasma ions such as reactive oxygen species and reactive nitrogen species.

  10. In-beam spectroscopic studies of the 44S nucleus

    Science.gov (United States)

    Cáceres, L.; Sohler, D.; Grévy, S.; Sorlin, O.; Dombrádi, Zs.; Bastin, B.; Achouri, N. L.; Angélique, J. C.; Azaiez, F.; Baiborodin, D.; Borcea, R.; Bourgeois, C.; Buta, A.; Bürger, A.; Chapman, R.; Dalouzy, J. C.; Dlouhy, Z.; Drouard, A.; Elekes, Z.; Franchoo, S.; Gaudefroy, L.; Iacob, S.; Laurent, B.; Lazar, M.; Liang, X.; Liénard, E.; Mrazek, J.; Nalpas, L.; Negoita, F.; Nowacki, F.; Orr, N. A.; Penionzhkevich, Y.; Podolyák, Zs.; Pougheon, F.; Poves, A.; Roussel-Chomaz, P.; Saint-Laurent, M. G.; Stanoiu, M.; Stefan, I.

    2012-02-01

    The structure of the 44S nucleus has been studied at GANIL through the one proton knock-out reaction from a 45Cl secondary beam at 42 A·MeV. The γ rays following the de-excitation of 44S were detected in flight using the 70 BaF2 detectors of the Château de Cristal array. An exhaustive γγ-coincidence analysis allowed an unambiguous construction of the level scheme up to an excitation energy of 3301 keV. The existence of the spherical 22+ state is confirmed and three new γ-ray transitions connecting the prolate deformed 21+ level were observed. Comparison of the experimental results to shell model calculations further supports a prolate and spherical shape coexistence with a large mixing of states built on the ground state band in 44S.

  11. Conformational analysis and vibrational spectroscopic studies on dapsone

    Science.gov (United States)

    Ildiz, Gulce Ogruc; Akyuz, Sevim

    2012-11-01

    In this study, the theoretical conformation analysis of free dapsone has been performed by single point energy calculations at both semi-empirical PM3 and DFT/B3LYP-3-21G theory levels and three stable conformers were determined. Both the IR and Raman spectra of the molecule in solid phase have been recorded. The IR intensities and harmonic vibrational wavenumbers of each conformer were calculated by DFT method at B3LYP/6-31++G(d,p) theory level. For the fundamental characterization, the total energy distribution (TED) calculations of the vibrational modes were done using parallel quantum mechanic solution program (SQM) and the fundamental modes were assigned. The theoretical results are in agreement with the experimental ones.

  12. A spectroscopic study of interaction of cationic dyes with heparin

    Directory of Open Access Journals (Sweden)

    R. Nandini

    2010-01-01

    Full Text Available The interaction of two cationic dyes namely, acridine orange and pinacyanol chloride with an anionic polyelectrolyte, heparin, has been investigated by spectrophotometric method.The polymer induced metachromasy in the dyes resulting in the shift of the absorption maxima of the dyes towards shorter wavelengths. The stability of the complexes formed between acridine orange and heparin was found to be lesser than that formed between pinacyanol chloride and heparin. This fact was further confirmed by reversal studies using alcohols, urea and surfactants. The interaction of acridine orange with heparin has also been investigated fluorimetrically.The interaction parameters revealed that binding between acridine orange and heparin arises due to electrostatic interaction while that between pinacyanol chloride and heparin is found to involve both electrostatic and hydrophobic forces. The effect of the structure of the dye in inducing metachromasy has also been discussed.

  13. NMR spectroscopic studies of membrane-bound biological systems

    International Nuclear Information System (INIS)

    Hohlweg, W.

    2013-01-01

    In the course of this thesis, biological NMR spectroscopy was employed in studying membrane-bound peptides and proteins, for which structural information is still comparatively hard to obtain. Initial work focused on various model peptides bound to membrane-mimicking micelles, studying the protonation state of arginine in a membrane environment. Strong evidence for a cation-π complex was found in TM7, a peptide which forms the seventh transmembrane helix of subunit a of the vacuolar-type H+-ATPase (V-ATPase). V-ATPase is a physiologically highly relevant proton pump, which is present in intracellular membranes of all eukaryotic organisms, as well as the plasma membrane of several specialized cells. Loss of functional V-ATPase is associated with human diseases such as osteopetrosis, distal renal tubular acidosis or the spreading of cancer. V-ATPase is considered a potential drug target in the treatment of osteoporosis and cancer, or in the development of novel contraceptives. Results from NMR solution structure determination, NMR titration experiments, paramagnetic relaxation enhancement experiments and tryptophan fluorescence spectroscopy confirm the existence of a buried cation-? complex formed between arginine residue R735, which is essential for proton transport, and neighbouring tryptophan and tyrosine residues. In vivo experiments in the yeast Saccharomyces cerevisiae using selective growth tests and fluorescence microscopy showed that formation of the cation-π complex is essential for V-ATPase function. Deletion of both aromatic residues, as well as only the one tryptophan residue leads to growth defects and inability to maintain vacuolar pH homeostasis. These findings shine new light on the still elusive mechanism of proton transport in V-ATPase, and show that arginine R735 may be directly involved in proton transfer across the membrane. (author) [de

  14. Experimental and theoretical spectroscopic studies of dye modification in synthetic Maya Blue pigment

    Science.gov (United States)

    Reza, Layra; Manciu, Felicia; Ramirez, Alejandra; Chianelli, Russell

    2009-03-01

    Maya pigments are hybrid organic/inorganic materials with multiple technology applications that possess unprecedented stability with respect to harsh environment conditions. In this investigation, we address the question of how the organic indigo dye modifies as it binds to the inorganic palygorskite clay to form a pigment similar to Maya Blue after a heating treatment is applied. Both infrared and Raman spectroscopic data demonstrate the disappearance of nitrogen-hydrogen (N-H) bonding, as the indigo molecule incorporates into the inorganic palygorskite material. This effect suggests a transformation of the dye from indigo to dehydroindigo. Furthermore, the Raman and infrared absorption results demonstrate partial elimination of the selection rules for the centrosymmetric indigo, which provides further evidence for this conversion. Theoretical spectroscopic studies are also addressed in this investigation to confirm the transformation of the dye into dehydroindigo.

  15. Ir Spectroscopic Studies on Microsolvation of HCl by Water

    Science.gov (United States)

    Mani, Devendra; Schwan, Raffael; Fischer, Theo; Dey, Arghya; Kaufmann, Matin; Redlich, Britta; van der Meer, Lex; Schwaab, Gerhard; Havenith, Martina

    2016-06-01

    Acid dissociation reactions are at the heart of chemistry. These reactions are well understood at the macroscopic level. However, a microscopic level understanding is still in the early stages of development. Questions such as 'how many H_2O molecules are needed to dissociate one HCl molecule?' have been posed and explored both theoretically and experimentally.1-5 Most of the theoretical calculations predict that four H_2O molecules are sufficient to dissociate one HCl molecule, resulting in the formation of a solvent separated H_3O+(H_2O)3Cl- cluster.1-3 IR spectroscopy in helium nanodroplets has earlier been used to study this dissociation process.3-5 However, these studies were carried out in the region of O-H and H-Cl stretch, which is dominated by the spectral features of undissociated (HCl)m-(H_2O)n clusters. This contributed to the ambiguity in assigning the spectral features arising from the dissociated cluster.4,5 Recent predictions from Bowman's group, suggest the presence of a broad spectral feature (1300-1360 wn) for the H_3O+(H_2O)3Cl- cluster, corresponding to the umbrella motion of H_3O+ moiety.6 This region is expected to be free from the spectral features due to the undissociated clusters. In conjunction with the FELIX laboratory, we have performed experiments on the (HCl)m(H_2O)n (m=1-2, n≥4) clusters, aggregated in helium nanodroplets, in the 900-1700 wn region. Mass selective measurements on these clusters revealed the presence of a weak-broad feature which spans between 1000-1450 wn and depends on both HCl as well as H_2O concentration. Measurements are in progress for the different deuterated species. The details will be presented in the talk. References: 1) C.T. Lee et al., J. Chem. Phys., 104, 7081 (1996). 2) H. Forbert et al., J. Am. Chem. Soc., 133, 4062 (2011). 3) A. Gutberlet et al., Science, 324, 1545 (2009). 4) S. D. Flynn et al., J. Phys. Chem. Lett., 1, 2233 (2010). 5) M. Letzner et al., J. Chem. Phys., 139, 154304 (2013). 6) J. M

  16. Spectroscopic studies on native proteins, glycated and inhibited nonenzymatically

    International Nuclear Information System (INIS)

    Gil, H; Otero, V; Contreras, S

    1995-01-01

    The nonenzymatic glucation is an irreversible process whose speed depends on the concentration reducer sugar in plasma. The glycated albumins is higher in diabetic people. Up to now, this has been indicated as an important mechanism in the pathology of the the secondary complications associated with diabetes and the normal aging. Recently a lot of interest has been focused on the search of certain compounds (inhibitors) to prevent the glucation and / or the formation of ending products of advanced glucation, AGE. The reaction of glucose with the human albumin and γ globulins and the effects of acid acetylsalicylic and ascorbic acid were studied. The proteins were incubated with glucose in absence and in presence of inhibitors for one month. The solutions were dialysed and then lyophilizated. The absorption spectra were taken for native proteins, glycated and inhibited (2 mg/ml) in phosphate 10 mM buffer, p H 7.3. It is observed that the spectra of the acetylate proteins and native proteins are practically same. This can be interpreted as an inhibitor effect of acid acetylsalicylic on glucation. In all the observed cases the glycated proteins absorb more than the native ones and they present a line toward the visible region. The ascorbic acid absorbs below the native proteins and it doesn't present the same characteristics. The increase and / or the decrease in the absorption picks can be associated with environmental changes affecting the groups involved in the absorption process [es

  17. Spectroscopic study of the eclipsing binary V 367 Cygni

    International Nuclear Information System (INIS)

    Aydin, C.; Yilmaz, N.; Hack, M.

    1978-01-01

    Seventeen coude spectrograms (dispersion 20 A mm -1 ) of the β Lyrae-type eclipsing binary V 367 Cygni (P = 18.6 d) have been studied. The observations were made at the Haute Provence Observatory during a period of almost two years (May 1973-March 1975). An anomalous behavior for the radial velocities of the spectrograms taken during one cycle (406) was observed; it is suggested that gas eruption under form of prominences may explain it. The spectrum is dominated by shell lines very similar to those present in the spectrum of the supergiant A9 Ia epsilon Aurigae. The underlying stellar spectrum is classified as A5 I on the basis of the intensity of the sole clearly visible stellar line, lambda 4481 Mg II, of the wings of the stellar Balmer lines, and an estimate of the intensity of the stellar K line. The radial velocity curves for the shell lines of Ca II, H I, metallic ions and neutral iron, as well as the phase dependence of the microturbulence, indicate stratification in the shell. (Auth.)

  18. A theoretical and spectroscopic study of conformational structures of piroxicam

    Science.gov (United States)

    Souza, Kely Ferreira de; Martins, José A.; Pessine, Francisco B. T.; Custodio, Rogério

    2010-02-01

    Piroxicam (PRX) has been widely studied in an attempt to elucidate the causes and mechanisms of its side effects, mainly the photo-toxicity. In this paper fluorescence spectra in non-protic solvents and different polarities were carried out along with theoretical calculations. Preliminary potential surfaces of the keto and enol forms were obtained at AM1 level of theory providing the most stable conformers, which had their structure re-optimized through the B3LYP/CEP-31G(d,p) method. From the optimized structures, the electronic spectra were calculated using the TD-DFT method in vacuum and including the solvent effect through the PCM method and a single water molecule near PRX. A new potential surface was constructed to the enol tautomer at DFT level and the most stable conformers were submitted to the QST2 calculations. The experimental data showed that in apolar media, the solution fluorescence is raised. Based on conformational analysis for the two tautomers, keto and enol, the results indicated that the PRX-enol is the main tautomer related to the drug fluorescence, which is reinforced by the spectra results, as well as the interconvertion barrier obtained from the QST2 calculations. The results suggest that the PRX one of the enol conformers presents great possibility of involvement in the photo-toxicity mechanisms.

  19. Spectroscopic study of neodymium doped lead-bismuth-borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Pasha, Altaf; Dayani, P.; Negalur, Mahesh; Swamy, Manjunatha; Abhiram, J. [Dept of Post Graduate Studies & Research in Physics, The National Degree College, Bangalore (India); Rajaramakrishna, R. [Dept of Post Graduate Studies & Research in Physics, The National Degree College, Bangalore (India); Physics Department, Bangalore University, Bangalore (India)

    2016-05-06

    This paper reports on different physical and optical properties of rare earth doped heavy metal oxide glasses. The glass composition of 10Bi{sub 2}O{sub 3}-30PbO-60B{sub 2}O{sub 3}-xNd{sub 2}O{sub 3} where x = 0, 0.1, 0.2, 0.5 and 1 (in mol %) has been synthesized using melt-quenching technique. Refractive index measurements for these glasses were done and physical parameters were studied. Structural properties of these glasses were analysed through infrared spectra that was recorded between 1600cm{sup −1} and 300cm{sup −1} in transmission mode. The optical absorption spectra were recorded in the wavelength range from 300 to 700 nm. The transitions originated from ground state energy {sup 4}I{sub 9/2}. The energy level analysis has been carried out by considering absorption spectral bands. The results thus obtained are comparable with reports on similar glasses, indicating that the prepared glasses may have potential laser applications.

  20. Borax methylene blue: a spectroscopic and staining study.

    Science.gov (United States)

    Donaldson, P T; Russo, A; Reynolds, C; Lillie, R D

    1978-07-01

    Borax methylene blue is quite stable at room temperatures of 22-25 C. At 30 C polychroming is slow; during 50 days in a water bath at this temperature the absorption peak moves from 665 to 656 nm. At 35 C, the absorption peak reaches 660 nm in 7 days, 654 nm in 14. At 60 C polychroming is rapid, the absorption peak reaching 640-620 nm in 3 days. When the pH of the borax methylene blue solutions, normally about 9.0, is adjusted to pH 6.5, the absorption peak remains at 665 nm even when incubated at 60 C for extended periods. When used as a blood stain 0.4 ml borax methylene blue (1% methylene blue in 1% borax), 4 ml acetone, 2 ml borax-acid phosphate buffer to bring the solution to pH 6.5, and distilled water to make 40 ml, with 0.2 ml 1% eosin added just before using, an excellent Nocht-Giemsa type stain is achieved after 30 minutes staining. The material plasmodia P. falciparum, P. vivax, and P. berghei stain moderate blue with dark red chromatin and green to black pigment granules. The study confirms Malachowski's 1891 results and explains Gautier's 1896-98 failure to duplicate it.

  1. Spectroscopic studies on the antioxidant activity of ellagic acid

    Science.gov (United States)

    Kilic, Ismail; Yeşiloğlu, Yeşim; Bayrak, Yüksel

    2014-09-01

    Ellagic acid (EA, C14H6O8) is a natural dietary polyphenol whose benefits in a variety of diseases shown in epidemiological and experimental studies involve anti-inflammation, anti-proliferation, anti-angiogenesis, anticarcinogenesis and anti-oxidation properties. In vitro radical scavenging and antioxidant capacity of EA were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. EA inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α-tocopherol and ascorbic acid displayed 69.8%, 66.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, EA had an effective DPPH• scavenging, ABTSrad + scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that EA can be used in the pharmacological, food industry and medicine because of these properties.

  2. HPLC assisted Raman spectroscopic studies on bladder cancer

    Science.gov (United States)

    Zha, W. L.; Cheng, Y.; Yu, W.; Zhang, X. B.; Shen, A. G.; Hu, J. M.

    2015-04-01

    We applied confocal Raman spectroscopy to investigate 12 normal bladder tissues and 30 tumor tissues, and then depicted the spectral differences between the normal and the tumor tissues and the potential canceration mechanism with the aid of the high-performance liquid chromatographic (HPLC) technique. Normal tissues were demonstrated to contain higher tryptophan, cholesterol and lipid content, while bladder tumor tissues were rich in nucleic acids, collagen and carotenoids. In particular, β-carotene, one of the major types of carotenoids, was found through HPLC analysis of the extract of bladder tissues. The statistical software SPSS was applied to classify the spectra of the two types of tissues according to their differences. The sensitivity and specificity of 96.7 and 66.7% were obtained, respectively. In addition, different layers of the bladder wall including mucosa (lumps), muscle and adipose bladder tissue were analyzed by Raman mapping technique in response to previous Raman studies of bladder tissues. All of these will play an important role as a directive tool for the future diagnosis of bladder cancer in vivo.

  3. Luminescence and spectroscopic studies of halosulfate phosphors: a review.

    Science.gov (United States)

    Gedam, S C; Thakre, P S; Dhoble, S J

    2015-03-01

    This review discusses the photoluminescence (PL) characteristics of halosulfate phosphors developed by us. Halosulfate phosphors KCaSO4 Cl:X,Y (X = Eu or Ce; Y = Dy or Mn) and Na6 (SO4 )2 FCl (doped with Dy, Ce or Eu) were prepared using a solid-state diffusion method. The mechanism of energy transfer from Eu(2+) →Dy(3+) , Ce(3+) →Dy(3+) and Ce(3+) →Mn(2+) has also been studied. Dy(3+) emission in the host at 475 and 570 nm is observed due to (4) F9/2 →(6) H15/2 and (4) F9/2 →(6) H13/2 transition, whereas the PL emission spectra of Na6 (SO4 )2 FCl:Ce phosphor shows Ce(3+) emission at 322 nm due to 5d→4f transition of the Ce(3+) ion. The main property of KCaSO4 Cl is its very high sensitivity, particularly when doped by Dy, Mn or Pb activators. This review also discusses the PL characteristics of some new phosphors such as LiMgSO4 F, Na6 Pb4 (SO4 )6 Cl2 , Na21 Mg(SO4 )10 Cl3 and Na15 (SO4 )5 F4 Cl. Copyright © 2014 John Wiley & Sons, Ltd.

  4. [Spectroscopic studies on the interaction of nicotine and BSA].

    Science.gov (United States)

    Chen, Yun; Kong, Xiang-rong; Shen, Xinag-can; Liang, Hong

    2005-10-01

    The interaction of nicotine and bovine serum albumin(BSA) was investigated by fluorescence spectra and UV-vis spectra. The fluorescence spectrum showed that BSA fluorescence quench regularly with the addition of nicotine.The fluorescence quenching mechanisms were also studied in pH 5.0, pH 7.4 and pH 11.0 by Stern-Volmer equation, indicating dynamic quenching(pH 5.0) and static quenching(pH 7.4 and pH 11.0) respectively. Association constants (k) of nicotine and BSA at pH 7.4 and pH 11.0 at the temperatures of 20 and 37 degrees C were given by the Lineweaver-Buck equation, which are: k(20 degrees C) = 140.15 L x mol(-1) and k(37 degrees C) = 131.83 mol x L(-1) (pH 7.4), and k(20 degrees C) = 141.76 mol x L(-1), k(37 degrees C) = 27.79 mol x L(-1) (pH 11.0), suggesting that the association constant is effected by the temperature much more remarkably at pH 7.4 than that at pH 11.0 because of the different states of nicotine at different pHs. The UV-Vis spectra exhibit that the absorbance of BSA(210 nm) shifts to red and decreases gradually with the addition of nicotine, reflecting the transition of secondary structure of BSA, namely, the helix of BSA becomes looser. The UV-Vis second derivative spectra and synchronous spectra (delta wavelength = wavelength(em) - wavelength(ex) = 15 nm and delta wavelength = wavelength(em) - wavelength(ex) = 60 nm) imply the change of the microcircumstance of aromatic amino residues of BSA(Trp, Tyr and Phe) from hydrophobicity to hydrophilicity at high concentration of nicotine.

  5. 2-Ethynylpyridine dimers: IR spectroscopic and computational study

    Science.gov (United States)

    Bakarić, Danijela; Spanget-Larsen, Jens

    2018-04-01

    2-ethynylpyridine (2-EP) presents a multifunctional system capable of participation in hydrogen-bonded complexes utilizing hydrogen bond donating (tbnd Csbnd H, Aryl-H) and hydrogen bond accepting functions (N-atom, Ctbnd C and pyridine π-systems). In this work, IR spectroscopy and theoretical calculations are used to study possible 2-EP dimer structures as well as their distribution in an inert solvent such as tetrachloroethene. Experimentally, the tbnd Csbnd H stretching vibration of the 2-EP monomer absorbs close to 3300 cm-1, whereas a broad band with maximum around 3215 cm-1 emerges as the concentration rises, indicating the formation of hydrogen-bonded complexes involving the tbnd Csbnd H moiety. The Ctbnd C stretching vibration of monomer 2-EP close to 2120 cm-1 is, using derivative spectroscopy, resolved from the signals of the dimer complexes with maximum around 2112 cm-1. Quantum chemical calculations using the B3LYP + D3 model with counterpoise correction predict that the two most stable dimers are of the π-stacked variety, closely followed by dimers with intermolecular tbnd Csbnd H⋯N hydrogen bonding; the predicted red shifts of the tbnd Csbnd H stretching wavenumbers due to hydrogen bonding are in the range 54-120 cm-1. No species with obvious hydrogen bonding involving the Ctbnd C or pyridine π-systems as acceptors are predicted. Dimerization constant at 25 °C is estimated to be K2 = 0.13 ± 0.01 mol-1 dm3.

  6. Moessbauer spectroscopic study on inorganic compounds. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Masashi; Kitazawa, Takafumi; Nanba, Hiroshi; Yoshinaga, Tomohiro; Nakajima, Norio; Sumisawa, Yasuhiro; Takeda, Masuo [Toho Univ., Funabashi, Chiba (Japan). Faculty of Science; Sawahata, Hiroyuki; Ito, Yasuo

    1998-01-01

    {sup 166}Er and {sup 127}I Moessbauer spectra were observed. {sup 166}Er Moessbauer spectrum of Er metal and 9 compounds were measured by {sup 166}Ho/Y{sub 0.6}Ho{sub 0.4}H{sub 2} source at 12K and the parameters such as e{sup 2}qQ(mm s{sup -1}), Heff(T) and {tau}(ns) were determined. The relaxation time of ErCl{sub 3}{center_dot}6H{sub 2}O was 0.7ns, long, but that of ErCl{sub 3} was 10 ps, short time. {sup 127}I Moessbauer spectrum of PhI(O{sub 2}CR){sub 2} (R=CH{sub 3}, CHF{sub 2}, CH{sub 2}Cl, CHCl{sub 2}, CCl{sub 3}, CH{sub 2}Br, CHBr{sub 2} and CBr{sub 3}) were observed and compared with that of R`{sub 3}Sb(O{sub 2}CR){sub 2} was similar to that of PhI(O{sub 2}CR){sub 2}. The correlation coefficient between e{sup 2}qQ({sup 127}I) and Mulliken population of carboxylic hydrogen atom of R{sub 2}CO{sub 2}H was -0.87. The relation between the hypervalent bond of O-I-O and that of O-Sb-0 was shown by the equation: e{sup 2}qQ({sup 121}Sb)/mm s{sup -1} = -47.2 + 1.32 e{sup 2}qQ({sup 127}I)/mm s{sup -1}. Hypervalent iodine complex such as (PhI(py){sub 2}){sup 2+} salt and E-Sb-I (E=O, I, N and C) were studied, too. (S.Y.)

  7. Raman spectroscopic studies on exfoliated cells of oral and cervix

    Science.gov (United States)

    Hole, Arti; Sahu, Aditi; Shaikh, Rubina; Tyagi, Gunjan; Murali Krishna, C.

    2018-01-01

    Visual inspection followed by biopsy is the standard procedure for cancer diagnosis. Due to invasive nature of the current diagnostic methods, patients are often non-compliant. Hence, it is necessary to explore less invasive and rapid methods for early detection. Exfoliative cytology is a simple, rapid, and less invasive technique. It is thus well accepted by patients and is suitable for routine applications in population screening programs. Raman spectroscopy (RS) has been increasingly explored for disease diagnosis in the recent past. In vivo RS has previously shown promise in management of both oral and cervix cancers. In vivo applications require on-site instrumentation and stringent experimental conditions. Hence, RS of less invasive samples like exfoliated cells has been explored, as this facilitates collection at multiple screening centers followed by analysis at a centralized facility. In the present study, efficacy of Raman spectroscopy in classification of 15 normal and 29 abnormal oral exfoliated cells specimens and 28 normal and 38 abnormal cervix specimens were explored. Spectra were acquired by Raman microprobe (HE 785, Horiba-Jobin-Yvon, France) from several areas to span the pellet. Spectral acquisition parameters were: microscopic objective: 40X, power: 40 mW, acquisition time: 15 s and average: 3. PCA and PC-LDA of pre-processed spectra was carried out on a 4-model system of normal and tumor of both cervix and oral specimens. Leave-one-out-cross-validation findings indicate 73 % correct classification. Findings suggest RS of exfoliated cells may serve as a patient-friendly, non-invasive, rapid and objective method for management of cervix and oral cancers.

  8. Spectroscopic study of synthetic hydrothermal Fe3+-bearing beryl

    Science.gov (United States)

    Taran, Michail N.; Dyar, M. Darby; Khomenko, Vladimir M.

    2017-12-01

    A synthetic hydrothermal beryl Fe-4-51, investigated previously by Taran and Rossman (Am Miner 86:973-980, 2001), was additionally studied by microprobe, Mössbauer, optical absorption, Raman and IR spectroscopy. For comparison, polarized spectra of natural blue aquamarine and Cr3+, Fe3+-bearing alexandrite, both from Brazil, are also presented. Fe-4-51 is a nearly pure Fe3+-bearing beryl, with a homogeneous composition as shown by electron microprobe. Averaging over 22 points gives a formula of Be3.07(Al1.94,{Fe}_{{{0.07}}}^{{{3}+}} )Σ=2.01Si5.95O18, with Fe3+ replacing Al3+ in the octahedral site of the structure. The Mössbauer spectrum is dominated by a broad disordered pattern with beryl-suitable parameters; for Fe2+, IS = 1.21 mm/s, QS = 2.71 mm/s, area ≈ 5% and for Fe3+, IS = 0.34 mm/s, QS = 0.71 mm/s, and area ≈ 67%—are distinguished overlying a broad disordered continuum. The optical absorption spectrum is typical of octahedral Fe3+. From it, the crystal field strength Dq is derived as 1520 cm-1 and the values of Racah parameters of interelectronic repulsion B and C are found to be 665 and 3415 cm-1, respectively. This rather low B value, compared with that of a free Fe3+ ion, 814 cm-1, suggests a comparatively high degree of covalency in the octahedral Fe3+-O bond. Infrared spectra show the presence of channel H2O of both I and II structural type in comparable quantities, about 0.5 and 1 mass%, respectively. Raman data show the expected five bands in the energy range from 300 to 1200 cm-1.

  9. Synthesis, structural, spectroscopic and biological studies of Schiff base complexes

    Science.gov (United States)

    Diab, M. A.; El-Sonbati, A. Z.; Shoair, A. F.; Eldesoky, A. M.; El-Far, N. M.

    2017-08-01

    Schiff base ligand 4-((pyridin-2- yl)methyleneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (PDMP) and its complexes were prepared and characterized on the basis of elemental analysis, IR, mass spectra and thermogravimetric analysis. All results confirm that the complexes have 1:1 (M: PMDP) stoichiometric formula [M(PMDP)Cl2H2O ] (M = Cu(II), Co(II), Ni(II) and Mn(II)), [Cd(PMDP)Cl2] and the ligand behaves as a bi/tridentate forming five-membered chelating ring towards the metal ions, bonding through azomethine nitrogen/exocyclic carbonyl oxygen, azomethine pyridine nitrogen and exocyclic carbonyl oxygen. The shift in the band positions of the groups involved in coordination has been utilized to estimate the metal-nitrogen and/or oxygen bond lengths. The complexes of Co(II), Ni(II) and Cu(II) are paramagnetic and the magnetic as well as spectral data suggest octahedral geometry, whereas the Cd(II) complex is tetrahedral. The XRD studies show that both the ligand and its metal complexes (1 and 3) show polycrystalline with crystal structure. Molecular docking was used to predict the binding between PMDP ligand and the receptors. The corrosion inhibition of mild steel in 2 M HCl solution by PDMP was explored utilizing potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and (EFM) electrochemical frequency modulation method. Potentiodynamic polarization demonstrated that PDMP compound is mixed-type inhibitor. EIS spectra exhibit one capacitive loop and confirm the protective ability. The percentage of inhibition efficiency was found to increase with increasing the inhibitor concentration.

  10. Spectroscopic studies of molybdenum complexes as models for nitrogenase

    International Nuclear Information System (INIS)

    Walker, T.P.

    1981-05-01

    Because biological nitrogen fixation requires Mo, there is an interest in inorganic Mo complexes which mimic the reactions of nitrogen-fixing enzymes. Two such complexes are the dimer Mo 2 O 4 (cysteine) 2 2- and trans-Mo(N 2 ) 2 (dppe) 2 (dppe = 1,2-bis(diphenylphosphino)ethane). The H 1 and C 13 NMR of solutions of Mo 2 O 4 (cys) 2 2- are described. It is shown that in aqueous solution the cysteine ligands assume at least three distinct configurations. A step-wise dissociation of the cysteine ligand is proposed to explain the data. The Extended X-ray Absorption Fine Structure (EXAFS) of trans-Mo(N 2 ) 2 (dppe) 2 is described and compared to the EXAFS of MoH 4 (dppe) 2 . The spectra are fitted to amplitude and phase parameters developed at Bell Laboratories. On the basis of this analysis, one can determine (1) that the dinitrogen complex contains nitrogen and the hydride complex does not and (2) the correct Mo-N distance. This is significant because the Mo inn both complexes is coordinated by four P atoms which dominate the EXAFS. A similar sort of interference is present in nitrogenase due to S coordination of the Mo in the enzyme. This model experiment indicates that, given adequate signal to noise ratios, the presence or absence of dinitrogen coordination to Mo in the enzyme may be determined by EXAFS using existing data analysis techniques. A new reaction between Mo 2 O 4 (cys) 2 2- and acetylene is described to the extent it is presently understood. A strong EPR signal is observed, suggesting the production of stable Mo(V) monomers. EXAFS studies support this suggestion. The Mo K-edge is described. The edge data suggests Mo(VI) is also produced in the reaction. Ultraviolet spectra suggest that cysteine is released in the course of the reaction

  11. New trends in ellipsometry for thin film diagnostics

    International Nuclear Information System (INIS)

    Masetti, E.

    1987-01-01

    Ellipsometric technique is both instrumentation and method for surface characterization through light polarization change measurements. After the improvement of the technique due to electrooptical components (light polarization modulator) and personal computer, ellipsometry today is getting new interest in optical thin film diagnostics because of automatized ellipsometer availability. The realization of a new instrument for light polarization measurement, the FDP (Four Detector Photopolarimeter), will allow the production of ellipsometers with improved characteristics and low cost. A survey on ellipsometric technique trend and preliminary data on the first realized FDP are reported

  12. Binding Studies of Andrographolide with Human serum albumin: Molecular Docking, Chromatographic and Spectroscopic studies.

    Science.gov (United States)

    Godugu, Deepika; Rupula, Karuna; Beedu, Sashidhar Rao

    2018-02-11

    Andrographolide, sourced from Andrographis paniculata, is an established therapeutic agent with variety of pharmacological properties in treatment of various diseases. The present study is designed to evaluate the interaction and binding affinity of andrographolide with HSA by docking and spectral studies. The docking study for screening the interaction of andrographolide with HSA protein was carried out using Auto Dock Vina software and the binding score of andrographolide was -8.7 kcal mol-1 and formed one hydrogen bond with Arg 218 residue of HSA in sub-domains IIA region. The formation of HSA-andrographolide complex was characterized by spectroscopic methods - UV absorption, HPLC, CD and FTIR analysis. The UV spectral analysis revealed a decrease in the absorption peak of HSA due to its interaction with andrographolide. A new peak was observed at retention time 7.45 min by HPLC analysis and the Bmax was found to be 7.5 ± 0.4 mg protein with a Kd value of 1.89 mM, indicating interaction of andrographolide with HSA. The CD spectra results suggested, a marginal decrease in the negative ellipticity without any significant shift in peak, indicating the stabilization of the HSA-andrographolide complex. The FTIR analysis further confirmed, a shift of amide I groups from 1646 to 1637 cm-1 and a peak at 1016 cm-1 in andrographolide, was observed in the complex, indicating the interaction. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  13. Spectroscopic Study of L Hypernuclei with Electron Beams at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Satoshi [Tohoku Univ., Sendai (Japan); Gogami, Toshiyuki [Tohoku Univ., Sendai (Japan); Tang, Liguang [Hampton Univ., Hampton, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2017-07-01

    The missing mass spectroscopy of L hypernuclei with the (e, e'K^+) reaction was started from 2000 at Jefferson Lab. In this fifteen years, various hypernuclei (A = 7 - 52) including hyperon (L, S^0) productions have been studied with newly developed experimental techniques. The (e, e'K^+) reaction spectroscopy of L hypernuclei features its capability of absolute missing mass calibration and production of new species of hypernuclei which are the isospin partners of well studied hypernuclei by (K^-, pi-) and (pi^+, K^+) reactions. In this paper, we will review how we established the (e, e'K^+) spectroscopic study of hypernuclei.

  14. M-line spectroscopic, spectroscopic ellipsometric and microscopic measurements of optical waveguides fabricated by MeV-energy N{sup +} ion irradiation for telecom applications

    Energy Technology Data Exchange (ETDEWEB)

    Bányász, I., E-mail: banyasz@sunserv.kfki.hu [Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O.B. 49, H-1525, Budapest (Hungary); Berneschi, S. [“Enrico Fermi” Center for Study and Research, Piazza del Viminale 2, 00184 Roma (Italy); MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Fried, M.; Lohner, T. [Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O.B. 49, H-1525, Budapest (Hungary); Conti, G. Nunzi; Righini, G.C.; Pelli, S. [MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Zolnai, Z. [Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O.B. 49, H-1525, Budapest (Hungary)

    2013-08-31

    Irradiation with N{sup +} ions of the 1.5–3.5 MeV energy range was applied to optical waveguide formation. Planar and channel waveguides have been fabricated in an Er-doped tungsten–tellurite glass, and in both types of bismuth germanate (BGO) crystals: Bi{sub 4}Ge{sub 3}O{sub 12} (eulytine) and Bi{sub 12}GeO{sub 20} (sillenite). Multi-wavelength m-line spectroscopy and spectroscopic ellipsometry were used for the characterisation of the ion beam irradiated waveguides. Planar waveguides fabricated in the Er-doped tungsten–tellurite glass using irradiation with N{sup +} ions at 3.5 MeV worked even at the 1550 nm telecommunication wavelength. 3.5 MeV N{sup +} ion irradiated planar waveguides in eulytine-type BGO worked up to 1550 nm and those in sillenite-type BGO worked up to 1330 nm. - Highlights: ► Waveguides were fabricated in glass and crystals using MeV energy N{sup +} ions. ► SRIM simulation and spectroscopic ellipsometry yielded similar waveguide structures. ► Multi-wavelength m-line spectroscopy was used to study the waveguides. ► Waveguides fabricated in an Er-doped tungsten–tellurite glass worked up to 1.5 μm. ► Waveguides in Bi{sub 12}GeO{sub 20} remained operative up to 1.5 μm.

  15. Sensing of Streptococcus mutans by microscopic imaging ellipsometry

    Science.gov (United States)

    Khaleel, Mai Ibrahim; Chen, Yu-Da; Chien, Ching-Hang; Chang, Yia-Chung

    2017-05-01

    Microscopic imaging ellipsometry is an optical technique that uses an objective and sensing procedure to measure the ellipsometric parameters Ψ and Δ in the form of microscopic maps. This technique is well known for being noninvasive and label-free. Therefore, it can be used to detect and characterize biological species without any impact. Microscopic imaging ellipsometry was used to measure the optical response of dried Streptococcus mutans cells on a glass substrate. The ellipsometric Ψ and Δ maps were obtained with the Optrel Multiskop system for specular reflection in the visible range (λ=450 to 750 nm). The Ψ and Δ images at 500, 600, and 700 nm were analyzed using three different theoretical models with single-bounce, two-bounce, and multibounce light paths to obtain the optical constants and height distribution. The obtained images of the optical constants show different aspects when comparing the single-bounce analysis with the two-bounce or multibounce analysis in detecting S. mutans samples. Furthermore, the height distributions estimated by two-bounce and multibounce analyses of S. mutans samples were in agreement with the thickness values measured by AFM, which implies that the two-bounce and multibounce analyses can provide information complementary to that obtained by a single-bounce light path.

  16. Mg co-ordination with potential carcinogenic molecule acrylamide: Spectroscopic, computational and cytotoxicity studies

    Science.gov (United States)

    Singh, Ranjana; Mishra, Vijay K.; Singh, Hemant K.; Sharma, Gunjan; Koch, Biplob; Singh, Bachcha; Singh, Ranjan K.

    2018-03-01

    Acrylamide (acr) is a potential toxic molecule produced in thermally processed food stuff. Acr-Mg complex has been synthesized chemically and characterized by spectroscopic techniques. The binding sites of acr with Mg were identified by experimental and computational methods. Both experimental and theoretical results suggest that Mg coordinated with the oxygen atom of Cdbnd O group of acr. In-vitro cytotoxicity studies revealed significant decrease in the toxic level of acr-Mg complex as compared to pure acr. The decrease in toxicity on complexation with Mg may be a useful step for future research to reduce the toxicity of acr.

  17. Preparation and spectroscopic studies of PbS/nanoMCM-41 nanocomposite

    Directory of Open Access Journals (Sweden)

    A. Pourahmad

    2014-11-01

    Full Text Available The present work describes the preparation and characterization of nanosized PbS particles inside the mesopore channels of nanoMCM-41 silicate molecular sieves. The encapsulation of the lead sulfide was carried out at room temperature by ion-exchange method. Diffuse reflectance ultraviolet–visible spectroscopic studies showed a significant shift in the absorption band for the entrapped metal sulfide as compared to corresponding bulk sulfide. Thus, confirming the quantum confinement of the incorporated nanoparticles in nanoMCM-41.

  18. The interaction of new piroxicam analogues with lipid bilayers--a calorimetric and fluorescence spectroscopic study.

    Science.gov (United States)

    Maniewska, Jadwiga; Szczęśniak-Sięga, Berenika; Poła, Andrzej; Sroda-Pomianek, Kamila; Malinka, Wiesław; Michalak, Krystyna

    2014-01-01

    The purpose of the present paper was to assess the ability of new piroxicam analogues to interact with the lipid bilayers. The results of calorimetric and fluorescence spectroscopic experiments of two new synthesized analogues of piroxicam, named PR17 and PR18 on the phase behavior of phospholipid bilayers and fluorescence quenching of fluorescent probes (Laurdan and Prodan), which molecular location within membranes is known with certainty, are shown in present work. The presented results revealed that, depending on the details of chemical structure, the studied compounds penetrated the lipid bilayers.

  19. Thermal Physical, and Infrared Spectroscopic Studies on Glasses Prepared by Microwave Route

    International Nuclear Information System (INIS)

    Jagadeesha, N.; Gowda, V. C. Veeranna; Chakradhar, R. P. S.; Reddy, C. Narayana

    2011-01-01

    This paper describes thermal, physical and spectroscopic properties of glasses prepared by a novel micro wave method. These studies exhibited a strong compositional dependent trend and existence of characteristic boro-vanadate groups in these glasses. The scheme of modification of borate and vanadate groups is controlled by Sanderson's electronegativity principle. Analysis of density and glass transition temperatures suggests the presence of characteristic four coordinated borate and diboro - vanadate groups in these glasses. The presence of [BO 4/2 ] - and [B 2 V 2 O 9 ] 2- ) groups are confirmed by Infrared Spectroscopy of investigated glasses.

  20. Spectroscopic techniques in the study of human tissues and their components. Part I: IR spectroscopy.

    Science.gov (United States)

    Olsztyńska-Janus, Sylwia; Szymborska-Małek, Katarzyna; Gąsior-Głogowska, Marlena; Walski, Tomasz; Komorowska, Małgorzata; Witkiewicz, Wojciech; Pezowicz, Celina; Kobielarz, Magdalena; Szotek, Sylwia

    2012-01-01

    Among the currently used methods of monitoring human tissues and their components many types of research are distinguished. These include spectroscopic techniques. The advantage of these techniques is the small amount of sample required, the rapid process of recording the spectra, and most importantly in the case of biological samples - preparation of tissues is not required. In this work, vibrational spectroscopy: ATR-FTIR and Raman spectroscopy will be used. Studies are carried out on tissues: tendons, blood vessels, skin, red blood cells and biological components: amino acids, proteins, DNA, plasma, and deposits.

  1. Infrared and Raman spectroscopic studies on alkali borate glasses: evidence of mixed alkali effect.

    Science.gov (United States)

    Padmaja, G; Kistaiah, P

    2009-03-19

    A lithium-potassium-borate glass system containing manganese and iron cations has been thoroughly investigated in order to obtain information about the mixed alkali effect and the structural role of both the manganese and iron in such glass hosts. Mixed alkali borate glasses of the (30 - x)Li(2)O - xK(2)O - 10CdO/ZnO - 59B(2)O(3) (x = 0, 10, 15, 20, and 30) doped with 1MnO(2)/1Fe(2)O(3) system were prepared by a melt quench technique. The amorphous phase of the prepared glass samples was confirmed from their X-ray diffraction. The spectroscopic properties of glass samples were studied using infrared (IR) and Raman spectroscopic techniques. The density of all the prepared glasses was measured using Archimedes principle. Molar volumes were estimated from the density data. IR spectra of these glasses revealed a dramatic variation of three- and four-coordinated boron structures as a function of mixed alkali concentration. The vibrations due to Li-O, K-O, and MnO(4)/FeO(4) arrangements are consistent in all the compositions and show a nonlinear variation in the intensity with alkali content. Raman spectra of different alkali combinations with CdO and ZnO present drastic changes in the intensity of various Raman bands. The observation of disappearance and reappearance of IR and Raman bands as a function of various alkali concentrations is an important result pertaining to the mixed alkali effect in borate glasses. Acting as complementary spectroscopic techniques, both types of measurements, IR and Raman, revealed that the network structure of the studied glasses is mainly based on BO(3) and BO(4) units placed in different structural groups, the BO(3) units being dominant. The measured IR and Raman spectra of different glasses are used to clarify the optical properties of the present glasses correlating them with their structure and composition.

  2. Ellipsometric study of percolation in electroless deposited silver films

    NARCIS (Netherlands)

    de Vries, Anna Jo; Kooij, E. Stefan; Wormeester, Herbert; Mewe, Agnes A.; Poelsema, Bene

    2007-01-01

    Using spectroscopic ellipsometry in the visible and near-infrared spectral range we investigate the optical properties of a growing silver film starting from predeposited gold nanoparticles. The effective pseudodielectric functions, obtained by direct inversion of the ellipsometry spectra, reveal a

  3. Optical properties of γ- and α-Ce by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Joo Yull, Rhee.

    1992-01-01

    A rotating analyzer type ellipsometer with an ultra high vacuum sample chamber was built. The dielectric functions of γ- and α-Ce were measured in the energy range from 1.5 to 5.4 eV to investigate the role of the 4f electron in the isostructural phase transition. γ- and α-Ce were made by evaporation of Ce on sapphire substrates at room temperature and 25 K. All measurements were performed inside a UHV chamber at pressures lower than l x 10 -10 Torr. The measured dielectric functions showed a thickness dependence. The thicker sample has the smaller optical conductivities. Both overlayer thickness and void fraction increase as sample thickness increases. Repeating cooling-heating-cooling or heating-cooling-heating cycles causes the sample surface to become rougher but the relative volume fractions of both phases and the void fraction in the bulk remain unchanged. The optical conductivity increases upon entering the a-phase but the number of electrons per atom, N eff /N A , contributing to the optical conductivity does not change. The valence electrons lose oscillator strength in the above energy range due to volume collapse. This reduces N eff /NA but the increased 4f-sd valence band hybridization exactly compensates the reduced oscillator strength. Therefore the net effects of the γ→α isostructural phase transition are an increase of optical conductivity and constancy of N eff /N A

  4. Measurement of the surface susceptibility and the surface conductivity of atomically thin by spectroscopic ellipsometry

    KAUST Repository

    Jayaswal, Gaurav

    2017-10-01

    We show how to correctly extract from the ellipsometric data the surface susceptibility and the surface conductivity that describe the optical properties of monolayer $\\ m MoS_2$. Theoretically, these parameters stem from modelling a single-layer two-dimensional crystal as a surface current, a truly two-dimensional model. Currently experimental practice is to consider this model equivalent to a homogeneous slab with an effective thickness given by the interlayer spacing of the exfoliating bulk material. We prove that the error in the evaluation of the surface susceptibility of monolayer $\\ m MoS_2$, owing to the use of the slab model, is at least 10% or greater, a significant discrepancy in the determination of the optical properties of this material.

  5. Spectroscopic studies on chemical- and photo-responsive molecular machines and their bio-applications

    Science.gov (United States)

    Lau, Yuen Agnes

    2011-07-01

    The four chapters presented in this dissertation describe how various spectroscopic techniques are used: 1) to study the operation of molecular machines in solution, 2) to track the operation of molecular machines inside a single cell, and 3) to investigate the photo-decomposition pathway of a biological chromophore. Recent advances in nanotechnology have enriched the development of nano-scale molecular assemblies to be used as delivery platforms for biologically relevant molecules. Among all the molecular assemblies, molecular machines that are incorporated onto various domains of mesoporous silica nanoparticles (MSN) hold considerable potential as a reliable delivery system. Because the ease of functionalization enables chemical or photo-responsive molecular moieties to be covalently attached to the silica framework, these molecular assemblies, with defined mechanized properties, can perform specific functions under external stimuli (pH, redox, or light). While the primary function of these molecular machines is to deliver stored cargo molecules, the means of activation and the motif in which they operate are different. In the first and second chapters of this dissertation, two types of molecular machines, nanovalves and nanoimpellers, and their operations are studied. The ability to continuously monitor and image progression of molecular-based biological events in real-time can enhance our understanding of intracellular processes upon drug, protein and nucleic acid delivery. Using the photo-activated nanoimpeller described in the second chapter, the third chapter explores how it can be used to transport a nuclear staining agent, PI, inside a single cell. Nanoimpellers are made by functionalizing azobenzene molecules to the internal pore surface of MSN. The continuous cis/trans isomerizations are set in motion upon laser illumination at optimal wavelength(s), which facilitate cargo molecules to be expelled from the pores to the surrounding medium. By refining a

  6. THE DISTANCE TO THE MASSIVE GALACTIC CLUSTER WESTERLUND 2 FROM A SPECTROSCOPIC AND HST PHOTOMETRIC STUDY

    International Nuclear Information System (INIS)

    Vargas Álvarez, Carlos A.; Kobulnicky, Henry A.; Bradley, David R.; Kannappan, Sheila J.; Norris, Mark A.; Cool, Richard J.; Miller, Brendan P.

    2013-01-01

    We present a spectroscopic and photometric determination of the distance to the young Galactic open cluster Westerlund 2 using WFPC2 imaging from the Hubble Space Telescope (HST) and ground-based optical spectroscopy. HST imaging in the F336W, F439W, F555W, and F814W filters resolved many sources previously undetected in ground-based observations and yielded photometry for 1136 stars. We identified 15 new O-type stars, along with two probable binary systems, including MSP 188 (O3 + O5.5). We fit reddened spectral energy distributions based on the Padova isochrones to the photometric data to determine individual reddening parameters R V and A V for O-type stars in Wd2. We find average values (R V ) = 3.77 ± 0.09 and (A V ) = 6.51 ± 0.38 mag, which result in a smaller distance than most other spectroscopic and photometric studies. After a statistical distance correction accounting for close unresolved binaries (factor of 1.08), our spectroscopic and photometric data on 29 O-type stars yield that Westerlund 2 has a distance (d) = 4.16 ± 0.07 (random) +0.26 (systematic) kpc. The cluster's age remains poorly constrained, with an upper limit of 3 Myr. Finally, we report evidence of a faint mid-IR polycyclic aromatic hydrocarbon ring surrounding the well-known binary candidate MSP 18, which appears to lie at the center of a secondary stellar grouping within Westerlund 2.

  7. Spectroscopic and structural study of the newly synthesized heteroligand complex of copper with creatinine and urea.

    Science.gov (United States)

    Gangopadhyay, Debraj; Singh, Sachin Kumar; Sharma, Poornima; Mishra, Hirdyesh; Unnikrishnan, V K; Singh, Bachcha; Singh, Ranjan K

    2016-02-05

    Study of copper complex of creatinine and urea is very important in life science and medicine. In this paper, spectroscopic and structural study of a newly synthesized heteroligand complex of copper with creatinine and urea has been discussed. Structural studies have been carried out using DFT calculations and spectroscopic analyses were carried out by FT-IR, Raman, UV-vis absorption and fluorescence techniques. The copper complex of creatinine and the heteroligand complex were found to have much increased water solubility as compared to pure creatinine. The analysis of FT-IR and Raman spectra helps to understand the coordination properties of the two ligands and to determine the probable structure of the heteroligand complex. The LIBS spectra of the heteroligand complex reveal that the complex is free from other metal impurities. UV-visible absorption spectra and the fluorescence emission spectra of the aqueous solution of Cu-Crn-urea heteroligand complex at different solute concentrations have been analyzed and the complex is found to be rigid and stable in its monomeric form at very low concentrations. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Ellipsometry measurements of glass transition breadth in bulk films of random, block, and gradient copolymers.

    Science.gov (United States)

    Mok, M M; Kim, J; Marrou, S R; Torkelson, J M

    2010-03-01

    Bulk films of random, block and gradient copolymer systems were studied using ellipsometry to demonstrate the applicability of the numerical differentiation technique pioneered by Kawana and Jones for studying the glass transition temperature (T (g)) behavior and thermal expansivities of copolymers possessing different architectures and different levels of nanoheterogeneity. In a series of styrene/n -butyl methacrylate (S/nBMA) random copolymers, T (g) breadths were observed to increase from approximately 17( degrees ) C in styrene-rich cases to almost 30( degrees ) C in nBMA-rich cases, reflecting previous observations of significant nanoheterogeneity in PnBMA homopolymers. The derivative technique also revealed for the first time a substantial increase in glassy-state expansivity with increasing nBMA content in S/nBMA random copolymers, from 1.4x10(-4) K-1 in PS to 3.5x10(-4) K-1 in PnBMA. The first characterization of block copolymer T (g) 's and T (g) breadths by ellipsometry is given, examining the impact of nanophase-segregated copolymer structure on ellipsometric measurements of glass transition. The results show that, while the technique is effective in detecting the two T (g) 's expected in certain block copolymer systems, the details of the glass transition can become suppressed in ellipsometry measurements of a rubbery minor phase under conditions where the matrix is glassy; meanwhile, both transitions are easily discernible by differential scanning calorimetry. Finally, broad glass transition regions were measured in gradient copolymers, yielding in some cases extraordinary T (g) breadths of 69- 71( degrees ) C , factors of 4-5 larger than the T (g) breadths of related homopolymers and random copolymers. Surprisingly, one gradient copolymer demonstrated a slightly narrower T (g) breadth than the S/nBMA random copolymers with the highest nBMA content. This highlights the fact that nanoheterogeneity relevant to the glass transition response in selected

  9. Use of nearly neat 16O18O in spectroscopic studies of oxyhemerythrin and oxyhemoglobin

    International Nuclear Information System (INIS)

    Appelman, E.H.

    1985-01-01

    Klotz and Kurtz mention the use of nearly neat 16 O 18 O in a resonance Raman spectroscopic study of the bonding of O 2 in oxyhemerythyrin, citing unpublished work in a dissertation in their work on hemerythrin. A prior study of the O 2 bonding in oxyhemoglobin was carried out with the same 1 andO 18 O sample, and led to a similar conclusion, i.e., that the O 2 was bonded in such a way that the two oxygen atoms were not equivalent. To the best of the authors knowledge, this work constituted the first preparation of neat 16 O 18 O and its first use in spectroscopy. The work represents a collaboration between the group at Northwestern and a group at Argonne National Laboratory, where the 16 O 18 O was prepared by a rather laborious procedure that entailed the intermediate synthesis of 18 O-enriched hypofluorous acid. A more convenient synthesis of nearly neat 16 O 18 O that makes use of the recently isolated fluoroxysulfate ion, SO 4 F - was subsequently developed, and it is anticipated that this uniquely labeled oxygen molecule will now find application in a variety of spectroscopic measurements

  10. Thermal and spectroscopic studies on solid ibuprofen complexes of lighter trivalent lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Gálico, D.A.; Holanda, B.B.C.; Guerra, R.B.; Legendre, A.O.; Rinaldo, D. [UNESP – Univ Estadual Paulista, Faculdade de Ciências, Departamento de Química, São Paulo CEP 17033-260 (Brazil); Treu-Filho, O. [UNESP – Univ Estadual Paulista, Instituto de Química, São Paulo CEP 14800-900 (Brazil); Bannach, G., E-mail: gilbert@fc.unesp.br [UNESP – Univ Estadual Paulista, Faculdade de Ciências, Departamento de Química, São Paulo CEP 17033-260 (Brazil)

    2014-01-10

    Highlights: • Lighter trivalent lanthanide complexes of ibuprofen have been synthesized. • The TG-FTIR allowed the identification of propane as the gas evolved during the thermal decomposition of the neodymium compound. • The thermal analysis provided information about the composition, dehydration, thermal behavior and thermal decomposition of the samples. • The theoretical and experimental spectroscopic studies suggest that the carboxylate group of ibuprofen is coordinated to the metals by a bidentate bond. - Abstract: Solid-state compounds of general formula Ln(L){sub 3}, in which L is ibuprofen and Ln stands for trivalent La, Ce, Pr, Nd, Sm and Eu, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), X-ray powder diffractometry (DRX), complexometry, Fourier-transformed infrared spectroscopy (FTIR) and thermogravimetry coupled to Fourier-transformed infrared spectroscopy (TG-FTIR) were used to characterize these compounds. The results provided information concerning the chemical composition, dehydration, coordination modes of the ligands, crystallinity of the samples, thermal behavior and thermal decomposition of the compounds. The theoretical and experimental spectroscopic studies suggest that ibuprofen coordinates through the carboxylate group as a chelating ligand.

  11. Thermal and spectroscopic studies on solid ibuprofen complexes of lighter trivalent lanthanides

    International Nuclear Information System (INIS)

    Gálico, D.A.; Holanda, B.B.C.; Guerra, R.B.; Legendre, A.O.; Rinaldo, D.; Treu-Filho, O.; Bannach, G.

    2014-01-01

    Highlights: • Lighter trivalent lanthanide complexes of ibuprofen have been synthesized. • The TG-FTIR allowed the identification of propane as the gas evolved during the thermal decomposition of the neodymium compound. • The thermal analysis provided information about the composition, dehydration, thermal behavior and thermal decomposition of the samples. • The theoretical and experimental spectroscopic studies suggest that the carboxylate group of ibuprofen is coordinated to the metals by a bidentate bond. - Abstract: Solid-state compounds of general formula Ln(L) 3 , in which L is ibuprofen and Ln stands for trivalent La, Ce, Pr, Nd, Sm and Eu, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), X-ray powder diffractometry (DRX), complexometry, Fourier-transformed infrared spectroscopy (FTIR) and thermogravimetry coupled to Fourier-transformed infrared spectroscopy (TG-FTIR) were used to characterize these compounds. The results provided information concerning the chemical composition, dehydration, coordination modes of the ligands, crystallinity of the samples, thermal behavior and thermal decomposition of the compounds. The theoretical and experimental spectroscopic studies suggest that ibuprofen coordinates through the carboxylate group as a chelating ligand

  12. Theoretical studies on CH+ ion molecule using configuration interaction method and its spectroscopic properties

    International Nuclear Information System (INIS)

    Machado, F.B.C.

    1985-01-01

    The use of the configuration (CI) method for the calculation of very accurate potential energy curves and dipole moment functions, and then their use in the comprehension of spectroscopic properties of diatomic molecules is presented. The spectroscopic properties of CH + and CD + such as: vibrational levels, spectroscopic constants, averaged dipole moments for all vibrational levels, radiative transition probabilities for emission and absorption, and radiative lifetimes are verificated. (M.J.C.) [pt

  13. Spectroscopic study of honey from Apis mellifera from different regions in Mexico

    Science.gov (United States)

    Frausto-Reyes, C.; Casillas-Peñuelas, R.; Quintanar-Stephano, JL; Macías-López, E.; Bujdud-Pérez, JM; Medina-Ramírez, I.

    2017-05-01

    The objective of this study was to analyze by Raman and UV-Vis-NIR Spectroscopic techniques, Mexican honey from Apis Mellífera, using representative samples with different botanic origins (unifloral and multifloral) and diverse climates. Using Raman spectroscopy together with principal components analysis, the results obtained represent the possibility to use them for determination of floral origin of honey, independently of the region of sampling. For this, the effect of heat up the honey was analyzed in relation that it was possible to greatly reduce the fluorescence background in Raman spectra, which allowed the visualization of fructose and glucose peaks. Using UV-Vis-NIR, spectroscopy, a characteristic spectrum profile of transmittance was obtained for each honey type. In addition, to have an objective characterization of color, a CIE Yxy and CIE L*a*b* colorimetric register was realized for each honey type. Applying the principal component analysis and their correlation with chromaticity coordinates allowed classifying the honey samples in one plot as: cutoff wavelength, maximum transmittance, tones and lightness. The results show that it is possible to obtain a spectroscopic record of honeys with specific characteristics by reducing the effects of fluorescence.

  14. In vitro drug interaction of levocetirizine and diclofenac: Theoretical and spectroscopic studies

    Science.gov (United States)

    Abo Dena, Ahmed S.; Abdel Gaber, Sara A.

    2017-06-01

    Levocetirizine dihydrochloride is known to interact with some anti-inflammatory drugs. We report here a comprehensive integrated theoretical and experimental study for the in vitro drug interaction between levocetirizine dihydrochloride (LEV) and diclofenac sodium (DIC). The interaction of the two drugs was confirmed by the molecular ion peak obtained from the mass spectrum of the product. Moreover, FTIR and 1HNMR spectra of the individual drugs and their interaction product were inspected to allocate the possible sites of interaction. In addition, quantum mechanical DFT calculations were performed to search for the interaction sites and to verify the types of interactions deduced from the spectroscopic studies such as charge-transfer and non-bonding π-π interactions. It was found that the studied drugs interact with each other in aqueous solution via four types of interactions, namely, ion-pair formation, three weak hydrogen bonds, non-bonding π-π interactions and charge-transfer from DIC to LEV.

  15. Swiss bare mice: a suitable model for transcutaneous in vivo Raman spectroscopic studies of breast cancer.

    Science.gov (United States)

    Bhattacharjee, T; Kumar, Piyush; Maru, G; Ingle, A; Krishna, C Murali

    2014-01-01

    Breast cancer is the most common cancer affecting females worldwide. As early detection results in better prognosis, screening tools for breast cancer are being explored. Raman spectroscopy, a rapid, objective, and noninvasive tool, has shown promising results in the diagnosis of several cancers including breast cancer. For development as a screening tool, a study of spectral signatures associated with breast cancer progression is imperative. However, such studies are not possible in human subjects. Hence, there is a need for a suitable animal model, which is conducive to transcutaneous in vivo Raman spectroscopic measurements of breast with minimal interference from skin and hair and has contribution from functional mammary epithelium of breast. In this study, rodent models like C57, Swiss albino, Swiss bare, agouti mice, and Sprague-Dawley rats were evaluated. Among these models, transcutaneous breast spectra of hairless Swiss bare mice have the best signal-to-noise ratio and were closest to reported ex vivo as well as intraoperative in vivo human breast spectra. Principal component-linear discriminant analysis of several anatomical sites confirms minimal skin interference and suggests contribution from functional mammary epithelium of breast. Moreover, transcutaneous spectra from normal breast and breast tumors of Swiss bare mice could be classified with 99% efficiency, which is better than the previous reports. Thus, Swiss bare mice model may be better suited for transcutaneous in vivo Raman spectroscopic studies of breast physiology and pathology, especially breast cancer. Prospectively, in addition to cancer progression, breast-to-bone metastasis can also be studied, since these anatomical sites can be uniquely classified.

  16. Complexation of enalapril maleate with {beta}-cyclodextrin: NMR spectroscopic study in solution

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Syed Mashhood; Maheshwari, Arti; Asmat, Fahmeena [Aligarh Muslim University, Aligarh (India). Dept. of Chemistry]. E-mail: smashhoodali@yahoo.com; Koketsu, Mamoru [Gifu University, Gifu (Japan). Div. of Instrumental Analysis

    2006-07-15

    A detailed NMR ({sup 1}H , COSY, ROESY) spectroscopic study of complexation of enalapril maleate with {beta}-cyclodextrin was carried out. The {sup 1}H NMR spectrum of enalapril maleate confirmed the existence of cis-trans equilibrium in solution, possibly due to hindered rotation along the amide bond. The cis-trans ratio remained almost the same in the presence of {beta}-cyclodextrin but in one case it was found significantly different which suggests a catalytic role of {beta}-cyclodextrin in the isomerization. {sup 1}H NMR titration studies confirmed the formation of an enalapril-{beta}-cyclodextrin inclusion complex as evidenced by chemical shift variations in the proton resonances of both the host and the guest. The stoichiometry of the complex was determined to be 2:1 (guest: host). The mode of penetration of the guest into the {beta}-cyclodextrin cavity as well as the structure of the complex were established using ROESY spectroscopy. (author)

  17. Raman Spectroscopic Methods for Classification of Normal and Malignant Hypopharyngeal Tissues: An Exploratory Study

    Directory of Open Access Journals (Sweden)

    Parul Pujary

    2011-01-01

    Full Text Available Laryngeal cancer is more common in males. The present study is aimed at exploration of potential of conventional Raman spectroscopy in classifying normal from a malignant laryngopharyngeal tissue. We have recorded Raman spectra of twenty tissues (aryepiglottic fold using an in-house built Raman setup. The spectral features of mean malignant spectrum suggests abundance proteins whereas spectral features of mean normal spectrum indicate redundancy of lipids. PCA was employed as discriminating algorithm. Both, unsupervised and supervised modes of analysis as well as match/mismatch “limit test” methodology yielded clear classification among tissue types. The findings of this study demonstrate the efficacy of conventional Raman spectroscopy in classification of normal and malignant laryngopharyngeal tissues. A rigorous evaluation of the models with development of suitable fibreoptic probe may enable real-time Raman spectroscopic diagnosis of laryngopharyngeal cancers in future.

  18. Spectroscopic, structural, thermal and antimicrobial studies of 4,6-bis

    African Journals Online (AJOL)

    The isolated complexes were characterized by elemental analysis, magnetic properties, conductance measurements, mass, IR, UV-Vis and 1H NMR spectroscopic methods and thermal analyses. The thermogravimetric and infrared spectroscopic data confirmed the presence of water in the composition of the complexes ...

  19. 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

  20. Spectroscopic study of jet-cooled indole-3-carbinol by thermal evaporation

    International Nuclear Information System (INIS)

    Moon, Cheol Joo; Kim, Eun Bin; Min, Ahreum; Ahn, Ahreum; Seong, Yeon Guk; Choi, Myong Yong

    2016-01-01

    Cruciferous vegetables such as cabbage, kale, broccoli, and cauliflower have relatively high levels of indole-3-carbinol (I3C), which can be used as a possible cancer preventative agent particularly for breast, cervical, colorectal, and other hormone-related cancers. Thus, this naturally occurring substance, I3C, is now being used in dietary supplements. In conclusion, we have succeeded in obtaining the R2PI spectrum of a thermally unstable sample, I3C, by using a thermal buffer (herein, uracil) for the first time. Use of thermal evaporation method for thermally unstable biomolecules using thermal buffers will allow us to explore more gas phase spectroscopic studies for their intrinsic physiological properties in the near future

  1. Phosphorus-31 nuclear magnetic resonance spectroscopic study of the canine pancreas: applications to acute alcoholic pancreatitis

    Energy Technology Data Exchange (ETDEWEB)

    Janes, N.; Clemens, J.A.; Glickson, J.D.; Cameron, J.L.

    1988-01-01

    The first nuclear magnetic resonance spectroscopic study of the canine pancreas is described. Both in-vivo, ex-vivo protocols and NMR observables are discussed. The stability of the ex-vivo preparation based on the NMR observables is established for at least four hours. The spectra obtained from the in-vivo and ex-vivo preparations exhibited similar metabolite ratios, further validating the model. Metabolite levels were unchanged by a 50% increase in perfusion rate. Only trace amounts of phosphocreatine were observed either in the intact gland or in extracts. Acute alcoholic pancreatitis was mimicked by free fatty acid infusion. Injury resulted in hyperamylasemia, edema (weight gain), increased hematocrit and perfusion pressure, and depressed levels of high energy phosphates.

  2. Spectroscopic and theoretical study of the o-vanillin hydrazone of the mycobactericidal drug isoniazid

    Science.gov (United States)

    González-Baró, Ana C.; Pis-Diez, Reinaldo; Parajón-Costa, Beatriz S.; Rey, Nicolás A.

    2012-01-01

    A complete and detailed study of the hydrazone obtained from condensation of antituberculous isoniazid (hydrazide of the isonicotinic acid, INH) and o-vanillin (2-hydroxy-3-methoxybenzaldehyde, o-HVa) is performed. It includes structural and spectroscopic analyses, comparing experimental and theoretical results. The compound was obtained as a chloride of the pyridinic salt (INHOVA +Cl -) but it will be referred as INHOVA for the sake of simplicity. The conformational space was searched and optimized geometries were determined both in gas phase and including solvent effects. Vibrational (IR and Raman), electronic and NMR spectra were registered and assigned with the help of computational methods based on the Density Functional Theory. Isoniazid hydrazones are good candidates for therapeutic agents against tuberculosis with conserved efficiency and lower toxicity and resistance than parent INH.

  3. Spectroscopic study of jet-cooled indole-3-carbinol by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Cheol Joo; Kim, Eun Bin; Min, Ahreum; Ahn, Ahreum; Seong, Yeon Guk; Choi, Myong Yong [Gyeongsang National University, Jinju (Korea, Republic of)

    2016-10-15

    Cruciferous vegetables such as cabbage, kale, broccoli, and cauliflower have relatively high levels of indole-3-carbinol (I3C), which can be used as a possible cancer preventative agent particularly for breast, cervical, colorectal, and other hormone-related cancers. Thus, this naturally occurring substance, I3C, is now being used in dietary supplements. In conclusion, we have succeeded in obtaining the R2PI spectrum of a thermally unstable sample, I3C, by using a thermal buffer (herein, uracil) for the first time. Use of thermal evaporation method for thermally unstable biomolecules using thermal buffers will allow us to explore more gas phase spectroscopic studies for their intrinsic physiological properties in the near future.

  4. Spectroscopic and nonlinear optical studies of pure and Nd-doped lanthanum strontium borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Harde, G. B. [Department of Physics, Shri R. R. Lahoti Science College, Morshi, Maharashtra, India-444905 (India); Department of Physics, Sant Gadge Baba Amravati University, Amravati, Maharashtra, India-444602 (India); Muley, G. G., E-mail: gajananggm@yahoo.co.in [Department of Physics, Sant Gadge Baba Amravati University, Amravati, Maharashtra, India-444602 (India)

    2016-05-06

    Borate glasses of the system xNd{sub 2}O{sub 3}-(1-x) La{sub 2}O{sub 3}-SrCO{sub 3}-10H{sub 3}BO{sub 3} (with x = 0 and 0.05) were prepared by using a convectional melt quenching technique. The amorphous nature of the quenched glasses has been confirmed by powder X-ray diffraction analysis. In order to study the spectroscopic and nonlinear optical properties of fabricated glasses, ultraviolet-visible transmission spectroscopy and open aperture z-scan measurements have been employed. In Nd doped glasses, the transition {sup 4}I{sub 9/2} → {sup 4}G{sub 5/2} + {sup 2}G{sub 7/2} has found more prominent than the other transitions. Optical band gap energies of glasses have been determined and found less for Nd doped glass.

  5. Spectroscopic study; Estudio espectroscopico del PAA con iones de Eu{sup 3+} como material luminescente

    Energy Technology Data Exchange (ETDEWEB)

    Flores, M.; Rodriguez, R. [Departamento de Fisica, Universidad Autonoma Metropolitana Iztapalapa, Mexico D.F. (Mexico); Arroyo, R. [Departamento de Quimica, Universidad Autonoma Metropolitana Iztapalapa, A.P. 55-534, 09340 Mexico D.F. (Mexico)

    1999-07-01

    This work is focused about the spectroscopic properties of a polymer material which consists of Polyacrylic acid (Paa) doped at different concentrations of Europium ions (Eu{sup 3+}). They show that to stay chemically joined with the polymer by a study of Nuclear Magnetic Resonance (NMR) of {sup 1} H, {sup 13} C and Fourier Transform Infrared Spectroscopy (Ft-IR) they present changes in the intensity of signals, just as too when this material is irradiated at {lambda} = 394 nm. In according with the results obtained experimentally in this type of materials it can say that is possible to unify chemically the polymer with this type of cations, as well as, varying the concentration of them, since that these are distributed homogeneously inside the matrix maintaining its optical properties. These materials can be obtained more quickly and easy in solid or liquid phase and they have the best conditions for to make a quantitative analysis. (Author)

  6. Study of gamma detection capabilities of the REWARD mobile spectroscopic system

    Science.gov (United States)

    Balbuena, J. P.; Baptista, M.; Barros, S.; Dambacher, M.; Disch, C.; Fiederle, M.; Kuehn, S.; Parzefall, U.

    2017-07-01

    REWARD is a novel mobile spectroscopic radiation detector system for Homeland Security applications. The system integrates gamma and neutron detection equipped with wireless communication. A comprehensive simulation study on its gamma detection capabilities in different radioactive scenarios is presented in this work. The gamma detection unit consists of a precise energy resolution system based on two stacked (Cd,Zn)Te sensors working in coincidence sum mode. The volume of each of these CZT sensors is 1 cm3. The investigated energy windows used to determine the detection capabilities of the detector correspond to the gamma emissions from 137Cs and 60Co radioactive sources (662 keV and 1173/1333 keV respectively). Monte Carlo and Technology Computer-Aided Design (TCAD) simulations are combined to determine its sensing capabilities for different radiation sources and estimate the limits of detection of the sensing unit as a function of source activity for several shielding materials.

  7. Raman spectroscopic study on the excystation process in a single unicellular organism amoeba (Acanthamoeba polyphaga)

    Science.gov (United States)

    Lin, Yu-Chung; Perevedentseva, Elena; Cheng, Chia-Liang

    2015-05-01

    An in vivo Raman spectroscopic study of amoeba (Acanthamoeba polyphaga) is presented. The changes of the spectra during the amoeba cyst activation and excystation are analyzed. The spectra show the changes of the relative intensities of bands corresponding to protein, lipid, and carotenoid components during cyst activation. The presence of carotenoids in the amoeba is observed via characteristic Raman bands. These signals in the Raman spectra are intense in cysts but decrease in intensity with cyst activation and exhibit a correlation with the life cycle of amoeba. This work demonstrates the feasibility of using Raman spectroscopy for the detection of single amoeba microorganisms in vivo and for the analysis of the amoeba life activity. The information obtained may have implications for the estimation of epidemiological situations and for the diagnostics and prognosis of the development of amoebic inflammations.

  8. Spectroscopic studies of the physical origin of environmental aging effects on doped graphene

    International Nuclear Information System (INIS)

    Chang, J.-K.; Hsu, C.-C.; Liu, S.-Y.; Wu, C.-I.; Gharib, M.; Yeh, N.-C.

    2016-01-01

    The environmental aging effect of doped graphene is investigated as a function of the organic doping species, humidity, and the number of graphene layers adjacent to the dopant by studies of the Raman spectroscopy, x-ray and ultraviolet photoelectron spectroscopy, scanning electron microscopy, infrared spectroscopy, and electrical transport measurements. It is found that higher humidity and structural defects induce faster degradation in doped graphene. Detailed analysis of the spectroscopic data suggest that the physical origin of the aging effect is associated with the continuing reaction of H 2 O molecules with the hygroscopic organic dopants, which leads to formation of excess chemical bonds, reduction in the doped graphene carrier density, and proliferation of damages from the graphene grain boundaries. These environmental aging effects are further shown to be significantly mitigated by added graphene layers.

  9. Deficiency of standard effective-medium approximation for ellipsometry of layers of nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Bortchagovsky, E. G.; Dejneka, Alexandr; Jastrabík, Lubomír; Lozovski, V.Z.; Mishakova, T.O.

    2015-01-01

    Roč. 2015, Nov (2015), s. 602848 ISSN 1687-4110 Institutional support: RVO:68378271 Keywords : ellipsometry * layers of nanoparticles * Green function in ?-? representation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.758, year: 2015

  10. Transmission and reflection ellipsometry of thin films and multilayer systems.

    Science.gov (United States)

    Bader, G; Ashrit, P V; Truong, V V

    1998-03-01

    Ellipsometric studies are generally carried out in the reflection mode rather than in the transmission mode, requiring invariably opaque substrates or substrates in which the backreflection is minimized or suppressed by different methods. In the present research we used a transmission and reflection photoellipsometry method to study electrochromic materials and their multilayer systems deposited on thick substrates. The role of the substrate is examined carefully, and the contributions from multiple reflections in the substrate are taken into account in the theoretical treatment. This procedure not only allows the study of thin films deposited on quasi-transparent substrates, but when carried out in conjunction with reflection measurements it greatly improves the accuracy in the determination of the optical constants. Optical measurements are carried out on an automatic reflection transmission spectroscopic ellipsometer. Solid-state ionic materials used in electrochromic systems such as indium tin oxide, tungsten oxide, and their multilayer structures deposited on glass substrates are used as examples. A software based on the above theory, optikan, was developed to model and analyze such systems. It is demonstrated that the photoellipsometry method proposed is especially suited to analyzing electrochromic materials and transmitting devices in a nondestructive way.

  11. Application of spectroscopic techniques to the study of illuminated manuscripts: A survey

    Energy Technology Data Exchange (ETDEWEB)

    Pessanha, S.; Manso, M.; Carvalho, M.L., E-mail: luisa@cii.fc.ul.pt

    2012-05-15

    This work focused on the application of the most relevant spectroscopic techniques used for the characterization of illuminated manuscripts. The historical value of these unique and invaluable artworks, together with the increased awareness concerning the conservation of cultural heritage, prompted the application of analytical techniques to the study of these illuminations. This is essential for the understanding of the artist's working methods, which aids conservation-restoration. The characterization of the pigments may also help assign a probable date to the manuscript. For these purposes, the spectroscopic techniques used so far include those that provide information on the elemental content: X-ray fluorescence, total reflection X-ray fluorescence and scanning electron microscopy coupled with energy-dispersive spectroscopy and laser-induced breakdown spectroscopy. Complementary techniques, such as X-ray diffraction, Fourier transform infrared and Raman spectroscopy, reveal information regarding the compounds present in the samples. The techniques, suitability, technological evolution and development of high-performance detectors, as well as the possibility of microanalysis and the higher sensitivity of the equipment, will also be discussed. Furthermore, issues such as the necessity of sampling, the portability of the equipment and the overall advantages and disadvantages of different techniques will be analyzed. - Highlights: Black-Right-Pointing-Pointer The techniques used for studying illuminated manuscripts are described and compared. Black-Right-Pointing-Pointer For in situ, non-destructive analysis the most suitable technique is EDXRF. Black-Right-Pointing-Pointer For quantitative analysis TXRF is more appropriate. Black-Right-Pointing-Pointer Raman spectroscopy is mostly used for pigments identification. Black-Right-Pointing-Pointer FTIR was used for the characterization of binders and parchment.

  12. Application of spectroscopic techniques to the study of illuminated manuscripts: A survey

    International Nuclear Information System (INIS)

    Pessanha, S.; Manso, M.; Carvalho, M.L.

    2012-01-01

    This work focused on the application of the most relevant spectroscopic techniques used for the characterization of illuminated manuscripts. The historical value of these unique and invaluable artworks, together with the increased awareness concerning the conservation of cultural heritage, prompted the application of analytical techniques to the study of these illuminations. This is essential for the understanding of the artist's working methods, which aids conservation–restoration. The characterization of the pigments may also help assign a probable date to the manuscript. For these purposes, the spectroscopic techniques used so far include those that provide information on the elemental content: X-ray fluorescence, total reflection X-ray fluorescence and scanning electron microscopy coupled with energy-dispersive spectroscopy and laser-induced breakdown spectroscopy. Complementary techniques, such as X-ray diffraction, Fourier transform infrared and Raman spectroscopy, reveal information regarding the compounds present in the samples. The techniques, suitability, technological evolution and development of high-performance detectors, as well as the possibility of microanalysis and the higher sensitivity of the equipment, will also be discussed. Furthermore, issues such as the necessity of sampling, the portability of the equipment and the overall advantages and disadvantages of different techniques will be analyzed. - Highlights: ► The techniques used for studying illuminated manuscripts are described and compared. ► For in situ, non-destructive analysis the most suitable technique is EDXRF. ► For quantitative analysis TXRF is more appropriate. ► Raman spectroscopy is mostly used for pigments identification. ► FTIR was used for the characterization of binders and parchment.

  13. Spectroscopic Study of Plasma Polymerized a-C:H Films Deposited by a Dielectric Barrier Discharge.

    Science.gov (United States)

    Chandrashekaraiah, Thejaswini Halethimmanahally; Bogdanowicz, Robert; Rühl, Eckart; Danilov, Vladimir; Meichsner, Jürgen; Thierbach, Steffen; Hippler, Rainer

    2016-07-19

    Plasma polymerized a-C:H thin films have been deposited on Si (100) and aluminum coated glass substrates by a dielectric barrier discharge (DBD) operated at medium pressure using C₂H m /Ar ( m = 2, 4, 6) gas mixtures. The deposited films were characterized by Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS), Raman spectroscopy, and ellipsometry. FT-IRRAS revealed the presence of sp ³ and sp ² C-H stretching and C-H bending vibrations of bonds in the films. The presence of D and G bands was confirmed by Raman spectroscopy. Thin films obtained from C₂H₄/Ar and C₂H₆/Ar gas mixtures have I D /I G ratios of 0.45 and 0.3, respectively. The refractive indices were 2.8 and 3.1 for C₂H₄/Ar and C₂H₆/Ar films, respectively, at a photon energy of 2 eV.

  14. Biochemical activity of a fluorescent dye rhodamine 6G: Molecular modeling, electrochemical, spectroscopic and thermodynamic studies.

    Science.gov (United States)

    Al Masum, Abdulla; Chakraborty, Maharudra; Ghosh, Soumen; Laha, Dipranjan; Karmakar, Parimal; Islam, Md Maidul; Mukhopadhyay, Subrata

    2016-11-01

    Interaction of CT DNA with Rhodamine 6G (R6G) has been studied using molecular docking, electrochemical, spectroscopic and thermodynamic methods. From the study, it was illustrated that Rhodamine 6G binds to the minor groove of CT DNA. The binding was cooperative in nature. Circular voltametric study showed significant change in peak current and peak potential due to complexation. All the studies showed that the binding constant was in the order of 10 6 M -1 . Circular dichroic spectra showed significant conformational change on binding and DNA unwind during binding. Thermodynamic study showed that binding was favored by negative enthalpy and positive entropy change. From thermodynamic study it was also observed that several positive and negative free energies played significant role during binding and the unfavorable conformational free energy change was overcame by highly negative hydrophobic and salt dependent free energy changes. The experimental results were further validated using molecular docking study and the effect of structure on binding has been studied theoretically. From docking study it was found that the hydrophobic interaction and hydrogen bonds played a significant role during binding. The dye was absorbed by cell and this phenomenon was studied using fluorescent microscope. Cell survivability test showed that the dye active against Human Breast Cancer cells MDA-MB 468. ROS study showed that the activity is due to the production of reactive oxygen. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Studies of multiple stellar systems - IV. The triple-lined spectroscopic system Gliese 644

    Science.gov (United States)

    Mazeh, Tsevi; Latham, David W.; Goldberg, Elad; Torres, Guillermo; Stefanik, Robert P.; Henry, Todd J.; Zucker, Shay; Gnat, Orly; Ofek, Eran O.

    2001-07-01

    We present a radial velocity study of the triple-lined system Gliese 644 and derive spectroscopic elements for the inner and outer orbits with periods of 2.9655 and 627d. We also utilize old visual data, as well as modern speckle and adaptive optics observations, to derive a new astrometric solution for the outer orbit. These two orbits together allow us to derive masses for each of the three components in the system: MA=0.410+/-0.028 (6.9 per cent), MBa=0.336+/-0.016 (4.7 per cent), and MBb=0.304+/-0.014 (4.7 per cent)Msolar. We suggest that the relative inclination of the two orbits is very small. Our individual masses and spectroscopic light ratios for the three M stars in the Gliese 644 system provide three points for the mass-luminosity relation near the bottom of the main sequence, where the relation is poorly determined. These three points agree well with theoretical models for solar metallicity and an age of 5Gyr. Our radial velocities for Gliese 643 and vB 8, two common proper motion companions of Gliese 644, support the interpretation that all five M stars are moving together in a physically bound group. We discuss possible scenarios for the formation and evolution of this configuration, such as the formation of all five stars in a sequence of fragmentation events leading directly to the hierarchical configuration now observed, versus formation in a small N cluster with subsequent dynamical evolution into the present hierarchical configuration.

  16. Spectroscopic imaging studies of nanoscale polarity and mass transport phenomena in self-assembled organic nanotubes.

    Science.gov (United States)

    Xu, Hao; Nagasaka, Shinobu; Kameta, Naohiro; Masuda, Mitsutoshi; Ito, Takashi; Higgins, Daniel A

    2017-08-02

    Synthetic organic nanotubes self-assembled from bolaamphiphile surfactants are now being explored for use as drug delivery vehicles. In this work, several factors important to their implementation in drug delivery are explored. All experiments are performed with the nanotubes immersed in ethanol. First, Nile Red (NR) and a hydroxylated Nile Red derivative (NR-OH) are loaded into the nanotubes and spectroscopic fluorescence imaging methods are used to determine the apparent dielectric constant of their local environment. Both are found in relatively nonpolar environments, with the NR-OH molecules preferring regions of relatively higher dielectric constant compared to NR. Unique two-color imaging fluorescence correlation spectroscopy (imaging FCS) measurements are then used along with the spectroscopic imaging results to deduce the dielectric properties of the environments sensed by mobile and immobile populations of probe molecules. The results reveal that mobile NR molecules pass through less polar regions, likely within the nanotube walls, while immobile NR molecules are found in more polar regions, possibly near the nanotube surfaces. In contrast, mobile and immobile NR-OH molecules are found to locate in environments of similar polarity. The imaging FCS results also provide quantitative data on the apparent diffusion coefficient for each dye. The mean diffusion coefficient for the NR dye was approximately two-fold larger than that of NR-OH. Slower diffusion by the latter could result from its additional hydrogen bonding interactions with polar triglycine, amine, and glucose moieties near the nanotube surfaces. The knowledge gained in these studies will allow for the development of nanotubes that are better engineered for applications in the controlled transport and release of uncharged, dipolar drug molecules.

  17. Study on the interaction of catechins with human serum albumin using spectroscopic and electrophoretic techniques

    Science.gov (United States)

    Trnková, Lucie; Boušová, Iva; Staňková, Veronika; Dršata, Jaroslav

    2011-01-01

    The interaction between eight naturally occurring flavanols (catechin, epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, and epigallocatechin gallate) and human serum albumin (HSA) has been investigated by spectroscopic (fluorescence quenching and UV-Vis absorption) and electrophoretic (native and SDS PAGE) techniques under simulated physiological conditions (pH 7.40, 37 °C). The spectroscopic results confirmed the complex formation for the tested systems. The binding constants and the number of binding sites were obtained by analysis of fluorescence data. The strongest binding affinity to HSA was found for epicatechin gallate and decreased in the order epicatechin gallate ⩾ catechin gallate > epigallocatechin gallate > gallocatechin gallate ≫ epicatechin ⩾ catechin > gallocatechin ⩾ epigallocatechin. All free energy changes possessed negative sign indicating the spontaneity of catechin-HSA systems formation. The binding distances between the donor (HSA) and the acceptors (catechins) estimated by the Förster theory revealed that non-radiation energy transfer from HSA to catechins occurred with high possibility. According to results obtained by native PAGE, the galloylated catechins increased the electrophoretic mobility of HSA, which indicated the change in the molecular charge of HSA, whilst the non-galloylated catechins caused no changes. The ability of aggregation and cross-linking of tested catechins with HSA was not proved by SDS-PAGE. The relationship between the structure characteristics of all tested catechins (e.g. presence of the galloyl moiety on the C-ring, the number of hydroxyl groups on the B-ring, and the spatial arrangement of the substituents on the C-ring) and their binding properties to HSA is discussed. The presented study contributes to the current knowledge in the area of protein-ligand binding, particularly catechin-HSA interactions.

  18. The hippocampus in patients treated with electroconvulsive therapy: a proton magnetic resonance spectroscopic imaging study.

    Science.gov (United States)

    Ende, G; Braus, D F; Walter, S; Weber-Fahr, W; Henn, F A

    2000-10-01

    We monitored the effect of electroconvulsive therapy (ECT) on the nuclear magnetic resonance-detectable metabolites N-acetylaspartate, creatine and phosphocreatine, and choline-containing compounds in the hippocampus by means of hydrogen 1 magnetic resonance spectroscopic imaging. We hypothesized that if ECT-induced memory deterioration was associated with neuronal loss in the hippocampus, the N-acetylaspartate signal would decrease after ECT and any increased membrane turnover would result in an increase in the signal from choline-containing compounds. Seventeen patients received complete courses of ECT, during which repeated proton magnetic resonance spectroscopic imaging studies of the hippocampal region were performed. Individual changes during the course of ECT were compared with values obtained in 24 healthy control subjects and 6 patients remitted from major depression without ECT. No changes in the hippocampal N-acetylaspartate signals were detected after ECT. A significant mean increase of 16% of the signal from choline-containing compounds after 5 or more ECT treatments was observed. Despite the mostly unilateral ECT application (14 of 17 patients), the increase in the choline-containing compound signal was observed bilaterally. Lactate or elevated lipid signals were not detected. All patients showed clinical amelioration of depression after ECT. Electroconvulsive therapy is not likely to induce hippocampal atrophy or cell death, which would be reflected by a decrease in the N-acetylaspartate signal. Compared with an age-matched control group, the choline-containing compounds signal in patients with a major depressive episode was significantly lower than normal, before ECT and normalized during ECT.

  19. Combined study of biphasic and zero-order release formulations with dissolution tests and ATR-FTIR spectroscopic imaging.

    Science.gov (United States)

    Wray, Patrick; Li, Jing; Li, Ling Qiao; Kazarian, Sergei G

    2014-07-01

    In this study of multi-layer tablets, the dissolution of biphasic and zero-order release formulations has been studied primarily using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopic imaging as well as UV-Vis detection of dissolved drug in the effluent stream and USP dissolution testing. Bilayer tablets, containing the excipients microcrystalline cellulose (MCC) and glucose, were used for biphasic release with nicotinamide and buflomedil as model drugs. ATR-FTIR spectroscopic imaging showed the changing component distributions during dissolution. Further experiments studied monolithic and barrier-layered tablets containing hydroxypropyl methylcellulose, MCC and buflomedil dissolving in a USP I apparatus. These data were compared with UV-Vis dissolution profiles obtained online with the ATR flow-through cell. ATR-FTIR imaging data of the biphasic formulations demonstrated that the drug release was affected by excipient ratios and effects such as interference between tablet sections. Tablets placed in the ATR-FTIR flow-through cell exhibited zero-order UV-Vis dissolution profile data at high flow rates, similar to barrier-layered formulations studied using the USP I apparatus. ATR-FTIR spectroscopic imaging provided information regarding the dissolution mechanisms in multi-layer tablets which could assist formulation development. The ability to relate data from USP dissolution tests with that from the ATR-FTIR flow-through cell could help spectroscopic imaging complement dissolution methods used in the industry. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  20. Study of interaction of butyl p-hydroxybenzoate with human serum albumin by molecular modeling and multi-spectroscopic method

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qin, E-mail: wqing07@lzu.c [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Zhang Yaheng, E-mail: zhangyah04@lzu.c [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Sun Huijun, E-mail: sun.hui.jun-04@163.co [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen Hongli, E-mail: hlchen@lzu.edu.c [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen Xingguo, E-mail: chenxg@lzu.edu.c [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)

    2011-02-15

    Study of the interaction between butyl p-hydroxybenzoate (butoben) and human serum albumin (HSA) has been performed by molecular modeling and multi-spectroscopic method. The interaction mechanism was predicted through molecular modeling first, then the binding parameters were confirmed using a series of spectroscopic methods, including fluorescence spectroscopy, UV-visible absorbance spectroscopy, circular dichroism (CD) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. The thermodynamic parameters of the reaction, standard enthalpy {Delta}H{sup 0} and entropy {Delta}S{sup 0}, have been calculated to be -29.52 kJ mol{sup -1} and -24.23 J mol{sup -1} K{sup -1}, respectively, according to the Van't Hoff equation, which suggests the van der Waals force and hydrogen bonds are the predominant intermolecular forces in stabilizing the butoben-HSA complex. Results obtained by spectroscopic methods are consistent with that of the molecular modeling study. In addition, alteration of secondary structure of HSA in the presence of butoben was evaluated using the data obtained from UV-visible absorbance, CD and FT-IR spectroscopies. - Research highlights: The interaction between butyl p-hydroxybenzoate with HSA has been investigated for the first time. Molecular modeling study can provide theoretical direction for experimental design. Multi-spectroscopic method can provide the binding parameters and thermodynamic parameters. These results are important for food safety and human health when using parabens as a preservative.

  1. A spectroscopic study of absorption and emission features of interstellar dust components

    International Nuclear Information System (INIS)

    Zwet, G.P. van der.

    1986-01-01

    The spectroscopic properties of silicate interstellar dust grains are the subject of this thesis. The process of accretion and photolysis is simulated in the laboratory by condensing mixtures of gases onto a cold substrate (T ∼ 12 K) in a vacuum chamber and photolyzing these mixtures with a vacuum ultraviolet source. Alternatively, the gas mixtures may be passed through a microwave discharge first, before deposition. The spectroscopic properties of the ices are investigated using ultraviolet, visible and infrared spectroscopy. (Auth.)

  2. Structural and spectroscopic studies on Er3+ doped boro-tellurite glasses

    Science.gov (United States)

    Selvaraju, K.; Marimuthu, K.

    2012-04-01

    Er3+ doped boro-tellurite glasses with the chemical composition (69-x)B2O3-xTeO2-15MgO-15K2O-1Er2O3 (where x=0, 10, 20, 30 and 40 wt%) have been prepared and their structural and spectroscopic behavior were studied and reported. The varying tellurium dioxide content in the host matrix that results, changes in structural and spectroscopic behavior around Er3+ ions are explored through XRD, FTIR, UV-VIS-NIR and luminescence measurements. The XRD pattern confirms the amorphous nature of the prepared glasses and the FTIR spectra explore the fundamental groups and the local structural units in the prepared boro-tellurite glasses. The bonding parameters (βbar and δ) have been calculated from the observed band positions of the absorption spectra to claim the ionic/covalent nature of the prepared glasses. The Judd-Ofelt (JO) intensity parameters Ωλ (λ=2, 4 and 6) were determined through experimental and calculated oscillator strengths obtained from the absorption spectra and their results are studied and compared with reported literature. The variation in the JO parameters Ωλ (λ=2, 4 and 6) with the change in chemical composition have been discussed in detail. The JO parameters have also been used to derive the important radiative properties like transition probability (A), branching ratio (βR) and peak stimulated emission cross-section (σPE) for the excited state transitions 2H9/2→4I15/2 and 2H11/2 and 4S3/2→4I15/2 of the Er3+ ions and the results were studied and reported. Using Davis and Mott theory, optical band gap energy (Eopt) values for the direct and indirect allowed transitions have been calculated and discussed along with the Urbach energy values for the prepared Er3+ doped boro-tellurite glasses in the present study. The optical properties of the prepared glasses with the change in tellurium dioxide have been studied and compared with similar results.

  3. 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.

  4. RAMAN SPECTROSCOPIC STUDY ON PREDICTION OF TREATMENT RESPONSE IN CERVICAL CANCERS

    Directory of Open Access Journals (Sweden)

    S. RUBINA

    2013-04-01

    Full Text Available Concurrent chemoradiotherapy (CCRT is the choice of treatment for locally advanced cervical cancers; however, tumors exhibit diverse response to treatment. Early prediction of tumor response leads to individualizing treatment regimen. Response evaluation criteria in solid tumors (RECIST, the current modality of tumor response assessment, is often subjective and carried out at the first visit after treatment, which is about four months. Hence, there is a need for better predictive tool for radioresponse. Optical spectroscopic techniques, sensitive to molecular alteration, are being pursued as potential diagnostic tools. Present pilot study aims to explore the fiber-optic-based Raman spectroscopy approach in prediction of tumor response to CCRT, before taking up extensive in vivo studies. Ex vivo Raman spectra were acquired from biopsies collected from 11 normal (148 spectra, 16 tumor (201 spectra and 13 complete response (151 CR spectra, one partial response (8 PR spectra and one nonresponder (8 NR spectra subjects. Data was analyzed using principal component linear discriminant analysis (PC-LDA followed by leave-one-out cross-validation (LOO-CV. Findings suggest that normal tissues can be efficiently classified from both pre- and post-treated tumor biopsies, while there is an overlap between pre- and post-CCRT tumor tissues. Spectra of CR, PR and NR tissues were subjected to principal component analysis (PCA and a tendency of classification was observed, corroborating previous studies. Thus, this study further supports the feasibility of Raman spectroscopy in prediction of tumor radioresponse and prospective noninvasive in vivo applications.

  5. Spectroscopic studies on diamond like carbon films synthesized by pulsed laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Madhusmita; Krishnan, R., E-mail: krish@igcar.gov.in; Ravindran, T. R.; Das, Arindam; Mangamma, G.; Dash, S.; Tyagi, A. K. [Material Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603102, Tamil Nadu (India)

    2016-05-23

    Hydrogen free Diamond like Carbon (DLC) thin films enriched with C-C sp{sup 3} bonding were grown on Si (111) substrates at laser pulse energies varying from 100 to 400 mJ (DLC-100, DLC-200, DLC-300, DLC-400), by Pulsed Laser Ablation (PLA) utilizing an Nd:YAG laser operating at fundamental wavelength. Structural, optical and morphological evolutions as a function of laser pulse energy were studied by micro Raman, UV-Vis spectroscopic studies and Atomic Force Microscopy (AFM), respectively. Raman spectra analysis provided critical clues for the variation in sp{sup 3} content and optical energy gap. The sp{sup 3} content was estimated using the FWHM of the G peak and found to be in the range of 62-69%. The trend of evolution of sp{sup 3} content matches well with the evolution of I{sub D}/I{sub G} ratio with pulse energy. UV-Vis absorption study of DLC films revealed the variation of optical energy gap with laser pulse energy (1.88 – 2.23 eV), which matches well with the evolution of G-Peak position of the Raman spectra. AFM study revealed that roughness, size and density of particulate in DLC films increase with laser pulse energy.

  6. Activation of catalase by pioglitazone: Multiple spectroscopic methods combined with molecular docking studies.

    Science.gov (United States)

    Yekta, Reza; Dehghan, Gholamreza; Rashtbari, Samaneh; Sheibani, Nader; Moosavi-Movahedi, Ali Akbar

    2017-12-01

    Pioglitazone is an important prescription antidiabetic drug with positive roles in controlling high blood sugar in patients with type 2 diabetes. In the present study, we investigated the effects of pioglitazone on the structure and function of bovine liver catalase (BLC) using different spectroscopic and theoretical methods. UV-Vis absorption, fluorescence spectroscopy, synchronous fluorescence, and circular dichroism studies revealed conformational changes in the BLC structure and heme group in the presence of different concentrations of pioglitazone. Kinetic studies indicated that pioglitazone can increase BLC activity by approximately threefold compared with free enzyme. The fluorescence quenching data showed one binding site for pioglitazone, and the binding constants at 298, 304, and 310 K were calculated as 5.01 × 10 7  M -1 , 5.8 × 10 7  M -1 , and 6.6 × 10 7  M -1 , respectively. The static type of quenching mechanism was mainly involved in the quenching of intrinsic emission of the enzyme. Thermodynamic data suggested that hydrophobic interactions played a major role in the binding reaction of pioglitazone with BLC. The molecular docking studies indicated that pioglitazone interacts with the cavity in the middle of the β-barrel and wrapping domain of BLC. Thus, pioglitazone can increase catalase activity by changing the BLC structure. Copyright © 2017 John Wiley & Sons, Ltd.

  7. A spectroscopic and computational study of the singlet and triplet excited states of synthetic β-functionalized chlorins

    International Nuclear Information System (INIS)

    Brueckner, Christian; McCarthy, Jason R.; Daniell, Heather W.; Pendon, Zeus D.; Ilagan, Robielyn P.; Francis, Tasha M.; Ren Lei; Birge, Robert R.; Frank, Harry A.

    2003-01-01

    This paper presents a comparative investigation of the absorption, fluorescence, electron paramagnetic resonance (EPR), and transient triplet-triplet absorption spectroscopic properties and triplet state dynamics of two functionalized, synthetic, meso-phenylchlorins. The chromophores investigated are the novel 2-hydroxy-3-oxa-5,10,15,20-tetrakisphenylchlorin (3) and the known 2,3-dioxo-5,10,15,20-tetrakisphenylchlorin (4). In these chromophores, one peripheral -CH-CH- bond of the parent porphyrin meso-tetrakisphenylporphyrin (TPP, 1) was formally replaced by a -CH(OH)O- (lactol) or a β-diketone moiety. The spectroscopic data are compared with results from investigations on the parent porphyrin TPP studied here and the parent chlorin 5,10,15,20-tetrakisphenylchlorin (TPC, 2) from the literature. The spectroscopic observables are examined both qualitatively within the framework of the four orbital model and quantitatively using MNDO-PSDCI methods. The results delineate the role of β-lactol and β-dicarbonyl moieties in controlling the electronic and spectroscopic properties of these chromophores. This investigation serves as the foundation from which to derive a general understanding of the effects of β-functionalization on the electronic properties of chlorin-type chromophores. This knowledge is required for the design and understanding of long-wavelength absorbing and fluorescing chromophores to be used in light harvesting systems and photomedicine

  8. In vitro drug interaction of levocetirizine and diclofenac: Theoretical and spectroscopic studies.

    Science.gov (United States)

    Abo Dena, Ahmed S; Abdel Gaber, Sara A

    2017-06-15

    Levocetirizine dihydrochloride is known to interact with some anti-inflammatory drugs. We report here a comprehensive integrated theoretical and experimental study for the in vitro drug interaction between levocetirizine dihydrochloride (LEV) and diclofenac sodium (DIC). The interaction of the two drugs was confirmed by the molecular ion peak obtained from the mass spectrum of the product. Moreover, FTIR and 1 HNMR spectra of the individual drugs and their interaction product were inspected to allocate the possible sites of interaction. In addition, quantum mechanical DFT calculations were performed to search for the interaction sites and to verify the types of interactions deduced from the spectroscopic studies such as charge-transfer and non-bonding π-π interactions. It was found that the studied drugs interact with each other in aqueous solution via four types of interactions, namely, ion-pair formation, three weak hydrogen bonds, non-bonding π-π interactions and charge-transfer from DIC to LEV. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. An integrated spectroscopic approach for the non-invasive study of modern art materials and techniques

    Science.gov (United States)

    Rosi, F.; Miliani, C.; Clementi, C.; Kahrim, K.; Presciutti, F.; Vagnini, M.; Manuali, V.; Daveri, A.; Cartechini, L.; Brunetti, B. G.; Sgamellotti, A.

    2010-09-01

    A non-invasive study has been carried out on 18 paintings by Alberto Burri (1915-1995), one of Italy’s most important contemporary painters. The study aims to demonstrate the appropriate and suitable use of portable non-invasive instrumentation for the characterization of materials and techniques found in works dating from 1948 to 1975 belonging to the Albizzini Collection. Sampling of any kind has been forbidden, in order to maintain the integrity of the paintings. Furthermore, the material heterogeneity of each single artwork could potentially result in a poorly representative sampling campaign. Therefore, a non-invasive and in situ analytical approach has been deemed mandatory, notwithstanding the complexity of modern materials and challenging data interpretation. It is the non-invasive nature of the study that has allowed for the acquisition of vast spectral data (a total of about 650 spectra including XRF, mid and near FTIR, micro-Raman and UV-vis absorption and emission spectroscopies). In order to better handle and to extrapolate the most meaningful information from these data, a statistical multivariate analysis, namely principal component analysis (PCA), has been applied to the spectral results. In particular, the possibility of combining elemental and molecular information has been explored by uniting XRF and infrared spectra in one PCA dataset. The combination of complementary spectroscopic techniques has allowed for the characterization of both inorganic and organic pigments, extenders, fillers, and binders employed by Alberto Burri.

  10. Effective binding of perhalogenated closo-borates to serum albumins revealed by spectroscopic and ITC studies

    Science.gov (United States)

    Kuperman, Marina V.; Losytskyy, Mykhaylo Yu.; Bykov, Alexander Yu.; Yarmoluk, Sergiy M.; Zhizhin, Konstantin Yu.; Kuznetsov, Nikolay T.; Varzatskii, Oleg A.; Gumienna-Kontecka, Elzbieta; Kovalska, Vladyslava B.

    2017-08-01

    The interactions of boron cluster compounds closo-borates with biomolecules are widely studied due to their efficiency as agents for boron neutron capture therapy of cancer. In present work the binding abilities of anionic halogen closo-borates [B10Hal10]2- (Hal = Cl, Br, I) and [B12Hal12]2- (Hal = Cl, I) towards bovine and human serum albumins were investigated by spectroscopic and isothermal titration calorimetry (ITC) methods. The protein fluorescence quenching method and ITC studies confirmed the complex formation. The degree of protein fluorescence quenching increased from chlorine to iodine boron derivatives that is attributed to external heavy atom effect. The ITC data point on the existence in the protein structure of two types of binding sites: with higher and lower affinity to closo-borates. Albumin-closo-borate complex binding ratio, n (4-5 anions per protein molecule) is higher than for the parent hydrogen closo-borates (2 anions per protein molecule). Binding constants estimated by fluorescent and ITC methods indicate higher affinity of halogen closo-borates to albumins (K in the range of 104-106 M-1) comparing to that of the hydrogen closo-borate (K about 103 M-1). Due to their high affinity and high binding ratio to albumins halogen closo-borates are proposed for further studies as agents for boron neutron capture therapy.

  11. Hydrogeochemical and spectroscopic studies of radioactive materials in Ayrakan and Cheshmeh Shotori areas, northeastern Isfahan province

    Directory of Open Access Journals (Sweden)

    Mostafa Esmaeili Vardanjani

    2011-11-01

    Full Text Available Groundwaters hydrochemistry of Ayrakan and Cheshmeh Shotori areas and geochemistry of rare earth elements, indicate Ayrakan alkali granite as the origin of uranium and other dissolved elements in groundwaters of these areas. Geochemical and hydrogeochemical studies as well as the trend of uranium and thorium transition and mobility in aqueous environments of these areas indicate uranium adsorption by iron hydroxide (goethite as the deterrent agent against uranium transition and mobility from depth to surface. Gamma-ray spectroscopic study of sediments from Cheshmeh Shotori area by HPGe detector indicates the presence of 226Ra in high contents and as the radioactive nuclide that is the reason for high activity of these sediments. Production of 226Ra from 238U decay, shorter half-life of 226Ra compared to 238U, radium transition by groundwaters from depth to surface as well as hydrogeochemical evidences, all suggest the possibility of existence of hidden uranium deposit and uranium mineralization in depth and the distance between Ayrakan and Cheshmeh Shotori areas.

  12. Vibrational spectroscopic and DFT calculation studies of cobalt(II) complexes with 3-hydroxypicolinic acid.

    Science.gov (United States)

    Furić, Krešimir; Kodrin, Ivan; Kukovec, Boris-Marko; Mihalić, Zlatko; Popović, Zora

    2013-01-15

    Two cobalt(II) complexes with 3-hydroxypicolinic acid (3-hydroxypyridine-2-carboxylic acid, 3-OHpicH), trans-[Co(3-OHpic)2(py)2] (2) and cis-[Co(3-OHpic)2(4-pic)2] (3) (py=pyridine; 4-pic=4-picoline or 4-methylpyridine), previously synthesized and characterized by X-ray diffraction, are here studied by Raman and mid-infrared spectroscopy with the help from the corresponding DFT vibrational calculations using B3LYP/6-311G(d,p) computational model. Intramolecular O-H⋯O hydrogen bond appears in both complexes 2 and 3, while weak C-H⋯O hydrogen bonds assemble molecules of 2 or 3 into 3D architecture. A complete presentation of all Raman, infrared and theoretical results is given for complex 3. The measured spectra are shown, relative intensities and bandwidths are discussed and the assignment of vibrational bands is given on the basis of the DFT calculations. The calculated spectra agree very well with the presented experimental findings, thanks to the suitable grouping of modes. The same vibrational calculations also reveal insignificant influence of H→CH3 substitution for the spectroscopic characterization of the complex. A careful study of differences between calculated and observed wavenumbers suggests that modified single-factor scaling is actually better than the classic multi-factor scaling approach. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Synthesis, structural and spectroscopic studies of 2-oxoacenaphthylen-1(2H)-ylidene nicotinohydrazide.

    Science.gov (United States)

    Henriques, M S C; Del Amparo, R; Pérez-Álvarez, D; Nogueira, B A; Rodríguez-Argüelles, M C; Paixão, J A

    2017-02-05

    The synthesis of a new hydrazone, 2-oxoacenaphthylen-1(2H)-ylidene nicotinohydrazide, and its structural and spectroscopic characterization is reported. The obtained powder was recrystallized from DMSO and ethanol that afforded small crystals used for single-crystal X-ray diffraction studies. The compound was found to crystallize in two polymorphs, depending on the crystallization conditions. One of the polymorphs (form I) crystallizes in the centrosymmetric P2 1 /c monoclinic space group, the other (form II) crystallizes in the non-centrosymmetric, but achiral, orthorhombic space group P2 1 2 1 2 1 . Conformation of the molecules is similar in both polymorphs, but the network of weak intermolecular interactions determining the crystal packing is different. In form II an additional C-H⋯O bond connects molecules related by the screw-axis running parallel to the a-axis. Crystals of both polymorphs were also screened by FT-IR and Raman microscopy; a detailed analysis of the spectra and comparison with those of the isolated molecule calculated by ab-initio HF/MP2 and DFT/B3LYP methods using a correlation consistent cc-pVDZ basis set is presented. In addition, UV-vis and NMR studies were performed in solution. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. An Infrared Spectroscopic Study Toward the Formation of Alkylphosphonic Acids and Their Precursors in Extraterrestrial Environments

    Science.gov (United States)

    Turner, Andrew M.; Abplanalp, Matthew J.; Blair, Tyler J.; Dayuha, Remwilyn; Kaiser, Ralf I.

    2018-01-01

    The only known phosphorus-containing organic compounds of extraterrestrial origin, alkylphosphonic acids, were discovered in the Murchison meteorite and have accelerated the hypothesis that reduced oxidation states of phosphorus were delivered to early Earth and served as a prebiotic source of phosphorus. While previous studies looking into the formation of these alkylphosphonic acids have focused on the iron–nickel phosphide mineral schreibersite and phosphorous acid as a source of phosphorus, this work utilizes phosphine (PH3), which has been discovered in the circumstellar envelope of IRC +10216, in the atmosphere of Jupiter and Saturn, and believed to be the phosphorus carrier in comet 67P/Churyumov–Gerasimenko. Phosphine ices prepared with interstellar molecules such as carbon dioxide, water, and methane were subjected to electron irradiation, which simulates the secondary electrons produced from galactic cosmic rays penetrating the ice, and probed using infrared spectroscopy to understand the possible formation of alkylphosphonic acids and their precursors on interstellar icy grains that could become incorporated into meteorites such as Murchison. We present the first study and results on the possible synthesis of alkylphosphonic acids produced from phosphine-mixed ices under interstellar conditions. All functional groups of alkylphosphonic acids were detected through infrared spectroscopically, suggesting that this class of molecules can be formed in interstellar ices.

  15. Molecular spectroscopic studies on the interaction of ferulic acid with calf thymus DNA

    Science.gov (United States)

    Zhang, Shufang; Sun, Xuejun; Qu, Fengli; Kong, Rongmei

    2013-08-01

    The interaction between ferulic acid and calf thymus deoxyribonucleic acid (ctDNA) under physiological conditions (Tris-HCl buffer solutions, pH 7.4) was investigated by UV-Vis spectroscopy, fluorescence spectroscopy, DNA melting techniques, and viscosity measurements. Results indicated that a complex of ferulic acid with ctDNA was formed with a binding constant of K290K = 7.60 × 104 L mol-1 and K310K = 4.90 × 104 L mol-1. The thermodynamic parameters enthalpy change (ΔH°), entropy change (ΔS°) and Gibbs free energy (ΔG°) were calculated to be -1.69 × 104 J mol-1, 35.36 J K-1 mol-1 and -2.79 × 104 J mol-1 at 310 K, respectively. The acting forces between ferulic acid and DNA mainly included hydrophobic interaction and hydrogen bonds. Acridine orange displacement studies revealed that ferulic acid can substitute for AO probe in the AO-DNA complex which was indicative of intercalation binding. Thermal denaturation study suggested that the interaction of ferulic acid with DNA could result in the increase of the denaturation temperature, which indicated that the stabilization of the DNA helix was increased in the presence of ferulic acid. Spectroscopic techniques together with melting techniques and viscosity determination provided evidences of intercalation mode of binding for the interaction between ferulic acid and ctDNA.

  16. Theoretical spectroscopic study of the conjugate microcystin-LR-europium cryptate

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Julio G.; Dutra, Jose Diogo L.; Costa Junior, Nivan B. da; Freire, Ricardo O., E-mail: rfreire@ufs.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Departamento de Quimica; Alves Junior, Severino; Sa, Gilberto F. de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Quimica Fundamental

    2013-02-15

    In this work, theoretical tools were used to study spectroscopic properties of the conjugate microcystin-LR-europium cryptate. The Sparkle/AM1 model was applied to predict the geometry of the system and the INDO/S-CIS model was used to calculate the excited state energies. Based on the Judd-Ofelt theory, the intensity parameters were predicted and a theoretical model based on the theory of the 4f-4f transitions was applied to calculate energy transfer and backtransfer rates, radiative and non-radiative decay rates, quantum efficiency and quantum yield. A detailed study of the luminescent properties of the conjugate Microcystin-LR-europium cryptate was carried out. The results show that the theoretical quantum yield of luminescence of 23% is in good agreement with the experimental value published. This fact suggests that this theoretical protocol can be used to design new systems in order to improve their luminescence properties. The results suggest that this luminescent system may be a good conjugate for using in assay ELISA for detection by luminescence of the Microcystin-LR in water. (author)

  17. In vitro DNA binding studies of lenalidomide using spectroscopic in combination with molecular docking techniques

    Science.gov (United States)

    Xu, Liang; Hu, Yan-Xi; Li, Yan-Cheng; Zhang, Li; Ai, Hai-Xin; Liu, Yu-Feng; Liu, Hong-Sheng

    2018-02-01

    In the present work, the binding interaction between lenalidomide (LEN) and calf thymus DNA (ct-DNA) was systematically studied by using fluorescence, ultraviolet-visible (UV-vis) absorption, circular dichroism (CD) spectroscopies under imitated physiological conditions (pH = 7.4) coupled with molecular docking. It was found that LEN was bound to ct-DNA with high binding affinity (Ka = 2.308 × 105 M-1 at 283 K) through groove binding as evidenced by a slight decrease in the absorption intensity in combination with CD spectra. Thermodynamic parameters (ΔG 0 and ΔS interaction. Furthermore, competitive binding experiments with ethidium bromide and 4‧, 6-dia-midino-2-phenylindoleas probes showed that LEN could preferentially bind in the minor groove of double-stranded DNA. The average lifetime of LEN was calculated to be 7.645 ns. The φ of LEN was measured as 0.09 and non-radiation energy transfer between LEN and DNA had occurred. The results of the molecular docking were consistent with the experimental results. This study explored the potential applicability of the spectroscopic properties of LEN and also investigated its interactions with relevant biological targets. In addition, it will provide some theoretical references for the deep research of simultaneous administration of LEN with other drugs.

  18. Complexation of enalapril maleate with beta-cyclodextrin: NMR spectroscopic study in solution

    Directory of Open Access Journals (Sweden)

    Syed Mashhood Ali

    2006-07-01

    Full Text Available A detailed NMR (¹H , COSY, ROESY spectroscopic study of complexation of enalapril maleate with beta-cyclodextrin was carried out. The ¹H NMR spectrum of enalapril maleate confirmed the existence of cis-trans equilibrium in solution, possibly due to hindered rotation along the amide bond. The cis-trans ratio remained almost the same in the presence of beta-cyclodextrin but in one case it was found significantly different which suggests a catalytic role of beta-cyclodextrin in the isomerization. ¹H NMR titration studies confirmed the formation of an enalapril-beta-cyclodextrin inclusion complex as evidenced by chemical shift variations in the proton resonances of both the host and the guest. The stoichiometry of the complex was determined to be 2:1 (guest: host. The mode of penetration of the guest into the beta-cyclodextrin cavity as well as the structure of the complex were established using ROESY spectroscopy.

  19. LED phototherapy on midpalatal suture after rapid maxilla expansion: a Raman spectroscopic study

    Science.gov (United States)

    Rosa, Cristiane B.; Habib, Fernando Antonio L.; de Araújo, Telma M.; dos Santos, Jean N.; Cangussu, Maria Cristina T.; Barbosa, Artur Felipe S.; de Castro, Isabele Cardoso V.; Soares, Luiz Guilherme P.; Pinheiro, Antonio L. B.

    2015-03-01

    A quick bone formation after maxillary expansion would reduce treatment timeand the biomodulating effects of LED light could contribute for it. The aim of this study was to analyze the effect of LED phototherapy on the acceleration of bone formation at the midpalatal suture after maxilla expansion. Thirty rats divided into 6 groups were used on the study at 2 time points - 7 days: Control; Expansion; and Expansion + LED; and 14 days: Expansion; Expansion + LED in the first week; Expansion and LED in the first and second weeks. LED irradiation occurred at every 48 h during 2 weeks. Expansion was accomplished using a spatula and maintained with a triple helicoid of 0.020" stainless steel orthodontic wire. A LED light (λ850 ± 10nm, 150mW ± 10mW, spot of 0.5cm2, t=120 sec, SAEF of 18J/cm2) was applied in one point in the midpalatal suture immediately behind the upper incisors. Near infrared Raman spectroscopic analysis of the suture region was carried and data submitted to statistical analyzes (p≤0.05). Raman spectrum analysis demonstrated that irradiation increased hydroxyapatite in the midpalatal suture after expansion. The results of this indicate that LED irradiation; have a positive biomodulation contributing to the acceleration of bone formation in the midpalatal suture after expansion procedure.

  20. Scanning Tunnelling Spectroscopic Studies of Dirac Fermions in Graphene and Topological Insulators

    Directory of Open Access Journals (Sweden)

    wang K.-L.

    2012-03-01

    Full Text Available We report novel properties derived from scanning tunnelling spectroscopic (STS studies of Dirac fermions in graphene and the surface state (SS of a strong topological insulator (STI, Bi2Se3. For mono-layer graphene grown on Cu by chemical vapour deposition (CVD, strain-induced scalar and gauge potentials are manifested by the charging effects and the tunnelling conductance peaks at quantized energies, respectively. Additionally, spontaneous time-reversal symmetry breaking is evidenced by the alternating anti-localization and localization spectra associated with the zero-mode of two sublattices while global time-reversal symmetry is preserved under the presence of pseudo-magnetic fields. For Bi2Se3 epitaxial films grown on Si(111 by molecular beam epitaxy (MBE, spatially localized unitary impurity resonances with sensitive dependence on the energy difference between the Fermi level and the Dirac point are observed for samples thicker than 6 quintuple layers (QL. These findings are characteristic of the SS of a STI and are direct manifestation of strong topological protection against impurities. For samples thinner than 6-QL, STS studies reveal the openup of an energy gap in the SS due to overlaps of wave functions between the surface and interface layers. Additionally, spin-preserving quasiparticle interference wave-vectors are observed, which are consistent with the Rashba-like spin-orbit splitting.

  1. Spectroscopic and thermodynamic studies on ferulic acid - Alpha-2-macroglobulin interaction

    Science.gov (United States)

    Rehman, Ahmed Abdur; Sarwar, Tarique; Arif, Hussain; Ali, Syed Saqib; Ahsan, Haseeb; Tabish, Mohammad; Khan, Fahim Halim

    2017-09-01

    Ferulic acid is a major phenolic acid found in numerous plant species in conjugated form. It binds to enzymes and oligomeric proteins and modifies their structure and function. This study was designed to examine the interaction of ferulic acid, an active ingredient of some important medicines, with α2M, a key serum proteinase, under physiological conditions. The mechanism of interaction was studied by spectroscopic techniques such as, UV-visible absorption, fluorescence spectroscopy, circular dichroism along with isothermal titration calorimetry. Fluorescence quenching of α2M by ferulic acid demonstrated the formation of α2M-ferulic acid complex by static quenching mechanism. Binding parameters calculated by Stern-Volmer method showed that ferulic acid binds to α2M with moderate affinity of the order of ∼104 M-1. The thermodynamic signatures reveal that binding was enthalpy driven and hydrogen bonding played a major role in ferulic acid-α2M binding. CD spectra analysis suggests very little conformational changes in α2M on ferulic acid binding.

  2. Development of Conductive Boron-Doped Diamond Electrode: A microscopic, Spectroscopic, and Voltammetric Study

    Directory of Open Access Journals (Sweden)

    Kevin E. Bennet

    2013-12-01

    Full Text Available Building on diamond characteristics such as hardness, chemical inertness and low electron emission threshold voltage, the current microscopic, spectroscopic and voltammetric investigations are directed towards improving the properties of electrode coating materials for their future use in clinical studies of deep brain stimulation via fast-scan cyclic voltammetry (FSCV. In this study we combine the capabilities of confocal Raman mapping in providing detailed and accurate analysis of local distributions of material constituents in a series of boron-doped polycrystalline diamond films grown by chemical vapor deposition, with information from the more conventional techniques of scanning electron microscopy (SEM and infrared absorption spectroscopy. Although SEM images show a uniform distribution of film crystallites, they have the limitation of being unable to differentiate the distribution of boron in the diamond. Values of 1018–1021 atoms/cm3 of boron content have been estimated from the absorption coefficient of the 1290 cm−1 infrared absorption band and from the 500 cm−1 Raman vibration. The observed accumulation of boron atoms and carbon sp2 impurities at the grain boundaries suggests that very high doping levels do not necessarily contribute to improvement of the material’s conductivity, corroborating with voltammetric data. FSCV results also indicate an enhanced stability of analyte detection.

  3. Human hemoglobin structural and functional alterations and heme degradation upon interaction with benzene: A spectroscopic study.

    Science.gov (United States)

    Hosseinzadeh, Reza; Moosavi-Movahedi, Ali Akbar

    2016-03-15

    Here, the effect of benzene on hemoglobin structure, stability and heme prosthetic group integrity was studied by different methods. These included UV-vis absorption spectrophotometry, normal and synchronous fluorescence techniques, and differential scanning calorimetry (DSC). Our results indicated that benzene has high hemolytic potential even at low concentrations. The UV-vis spectroscopic results demonstrated that benzene altered both the globin chain and the heme prosthetic group of hemoglobin increasing met- and deoxy-Hb, while decreasing oxy-Hb. However, with increasing benzene the concentration of all species decreased due to heme destruction. The spectrophotometric results show that benzene has a high potential for penetrating the hydrophobic pocket of hemoglobin. These results were consistent with the molecular docking simulation results of benzene-hHb. Aggregation and thermal denaturation studies show that the increased benzene concentration induced hemoglobin aggregation with a decrease in stability, which is consistent with the DSC results. Conventional fluorescence spectroscopy revealed that the heme degradation species were produced in the presence of benzene. The results of constant wavelength synchronous fluorescence spectroscopy (CWSFS) indicated that at least five heme-degraded species were produced. Together, our results indicated that benzene has adverse effects on hemoglobin structure and function, and heme degradation. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Potentiometric and spectroscopic study of the interaction of 3d transition metal ions with inositol hexakisphosphate

    Science.gov (United States)

    Veiga, Nicolás; Macho, Israel; Gómez, Kerman; González, Gabriel; Kremer, Carlos; Torres, Julia

    2015-10-01

    Among myo-inositol phosphates, the most abundant in nature is the myo-inositol hexakisphosphate, InsP6. Although it is known to be vital to cell functioning, the biochemical research into its metabolism needs chemical and structural analysis of all the protonation, complexation and precipitation processes that it undergoes in the biological media. In view of its high negative charge at physiological level, our group has been leading a thorough research into the InsP6 chemical and structural behavior in the presence of the alkali and alkaline earth metal ions essential for life. The aim of this article is to extend these studies, dealing with the chemical and structural features of the InsP6 interaction with biologically relevant 3d transition metal ions (Fe(II), Fe(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)), in a non-interacting medium and under simulated physiological conditions. The metal-complex stability constants were determined by potentiometry, showing under ligand-excess conditions the formation of mononuclear species in different protonation states. Under metal ion excess, polymetallic species were detected for Fe(II), Fe(III), Zn(II) and Cu(II). Additionally, the 31P NMR and UV-vis spectroscopic studies provided interesting structural aspects of the strong metal ion-InsP6 interaction.

  5. Gamma spectroscopic studies of some neutron deficient even Te and Pb isotopes

    International Nuclear Information System (INIS)

    Ruyven, J.J. van.

    1982-01-01

    In this thesis the results of an extensive experimental study of the nuclei 118 120 Te and 196 Pb by means of in-beam gamma and electron spectroscopic methods are presented. In Chapter II a survey is given of the experimental methods applied to obtain information on properties of excited states of these nuclei. How nuclear structure studies on states accessible with these methods can benefit from the simultaneous measurement of the total energy of the γ-cascade connecting the entry point and the relevant excited state is discussed briefly in Chapter III. The design and the performance of the six detector NaI(Tl) sumspectrometer with which these measurements are carried out is described also in this chapter. Since the NaI(Tl) sumspectrometer is sensitive not only to gamma-rays but also to neutrons which are inevitably present in ( H.I.,xnγ) reactions, the author describes in Chapter IV the experimental determination of the response of large NaI(Tl) detectors to neutrons with energies 0.7 118 120 Te and 196 Pb, and a discussion of the experimental results in terms of nuclear models (IBA and broken pair model) are presented. (Auth.)

  6. A Spectroscopic Study of the Rich Supernova Remnant Population in M83

    Science.gov (United States)

    Winkler, P. Frank; Blair, William P.; Long, Knox S.

    2017-04-01

    We report the results from a spectrophotometric study sampling the ≳ 300 candidate supernova remnants (SNRs) in M83 identified through optical imaging with Magellan/IMACS and Hubble Space Telescope/WFC3. Of the 118 candidates identified based on a high [S II] λλ 6716, 6731 to Hα emission ratio, 117 show spectroscopic signatures of shock-heated gas, confirming them as SNRs—the largest uniform set of SNR spectra for any galaxy. Spectra of 22 objects with a high [O III] λ5007 to Hα emission ratio, selected in an attempt to identify young ejecta-dominated SNRs like Cas A, reveal only one (previously reported) object with the broad (≳ 1000 {km} {{{s}}}-1) emission lines characteristic of ejecta-dominated SNRs, beyond the known SN1957D remnant. The other 20 [O III]-selected candidates include planetary nebulae, compact H II regions, and one background QSO. Although our spectroscopic sample includes 22 SNRs smaller than 11 pc, none of the other objects show broad emission lines; instead their spectra stem from relatively slow (˜ 200 {km} {{{s}}}-1) radiative shocks propagating into the metal-rich interstellar medium of M83. With six SNe in the past century, one might expect more of M83's small-diameter SNRs to show evidence of ejecta; this appears not to be the case. We attribute their absence to several factors, including that SNRs expanding into a dense medium evolve quickly to the ISM-dominated phase, and that SNRs expanding into regions already evacuated by earlier SNe are probably very faint. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência, Tecnologia e Inovação (Brazil).

  7. Multiple-layered effective medium approximation approach to modeling environmental effects on alumina passivated highly porous silicon nanostructured thin films measured by in-situ Mueller matrix ellipsometry

    Science.gov (United States)

    Mock, Alyssa; Carlson, Timothy; VanDerslice, Jeremy; Mohrmann, Joel; Woollam, John A.; Schubert, Eva; Schubert, Mathias

    2017-11-01

    Optical changes in alumina passivated highly porous silicon slanted columnar thin films during controlled exposure to toluene vapor are reported. Electron-beam evaporation glancing angle deposition and subsequent atomic layer deposition are utilized to deposit alumina passivated nanostructured porous silicon thin films. In-situ Mueller matrix generalized spectroscopic ellipsometry in an environmental cell is then used to determine changes in optical properties of the nanostructured thin films by inspection of individual Mueller matrix elements, each of which exhibit sensitivity to adsorption. The use of a multiple-layered effective medium approximation model allows for accurate description of the inhomogeneous nature of toluene adsorption onto alumina passivated highly porous silicon slanted columnar thin films.

  8. Solvatochromism of 9,10-phenanthrenequinone: An electronic and resonance Raman spectroscopic study

    Science.gov (United States)

    Ravi Kumar, Venkatraman; Rajkumar, Nagappan; Umapathy, Siva

    2015-01-01

    Solvent effects play a vital role in various chemical, physical, and biological processes. To gain a fundamental understanding of the solute-solvent interactions and their implications on the energy level re-ordering and structure, UV-VIS absorption, resonance Raman spectroscopic, and density functional theory calculation studies on 9,10-phenanthrenequinone (PQ) in different solvents of diverse solvent polarity has been carried out. The solvatochromic analysis of the absorption spectra of PQ in protic dipolar solvents suggests that the longest (1n-π1*; S1 state) and the shorter (1π-π1*; S2 state) wavelength band undergoes a hypsochromic and bathochromic shift due to intermolecular hydrogen bond weakening and strengthening, respectively. It also indicates that hydrogen bonding plays a major role in the differential solvation of the S2 state relative to the ground state. Raman excitation profiles of PQ (400-1800 cm-1) in various solvents followed their corresponding absorption spectra therefore the enhancements on resonant excitation are from single-state rather than mixed states. The hyperchromism of the longer wavelength band is attributed to intensity borrowing from the nearby allowed electronic transition through vibronic coupling. Computational calculation with C2ν symmetry constraint on the S2 state resulted in an imaginary frequency along the low-frequency out-of-plane torsional modes involving the C=O site and therefore, we hypothesize that this mode could be involved in the vibronic coupling.

  9. Solvatochromism of 9,10-phenanthrenequinone: an electronic and resonance Raman spectroscopic study.

    Science.gov (United States)

    Ravi Kumar, Venkatraman; Rajkumar, Nagappan; Umapathy, Siva

    2015-01-14

    Solvent effects play a vital role in various chemical, physical, and biological processes. To gain a fundamental understanding of the solute-solvent interactions and their implications on the energy level re-ordering and structure, UV-VIS absorption, resonance Raman spectroscopic, and density functional theory calculation studies on 9,10-phenanthrenequinone (PQ) in different solvents of diverse solvent polarity has been carried out. The solvatochromic analysis of the absorption spectra of PQ in protic dipolar solvents suggests that the longest (1n-π(1)*; S1 state) and the shorter (1π-π(1)*; S2 state) wavelength band undergoes a hypsochromic and bathochromic shift due to intermolecular hydrogen bond weakening and strengthening, respectively. It also indicates that hydrogen bonding plays a major role in the differential solvation of the S2 state relative to the ground state. Raman excitation profiles of PQ (400-1800 cm(-1)) in various solvents followed their corresponding absorption spectra therefore the enhancements on resonant excitation are from single-state rather than mixed states. The hyperchromism of the longer wavelength band is attributed to intensity borrowing from the nearby allowed electronic transition through vibronic coupling. Computational calculation with C2ν symmetry constraint on the S2 state resulted in an imaginary frequency along the low-frequency out-of-plane torsional modes involving the C=O site and therefore, we hypothesize that this mode could be involved in the vibronic coupling.

  10. Spectroscopic Studies of Carotenoid-to-Bacteriochlorophyll Energy Transfer in LHRC Photosynthetic Complex from Roseiflexus castenholzii

    Energy Technology Data Exchange (ETDEWEB)

    Niedzwiedzki, Dariusz [Washington Univ., St. Louis, MO (United States); Collins, Aaron M. [Washington Univ., St. Louis, MO (United States); LaFountain, Amy M. [Univ. of Connecticut, Storrs, CT (United States); Enriquez, Miriam M. [Univ. of Connecticut, Storrs, CT (United States); Frank, Harry A. [Washington Univ., St. Louis, MO (United States); Blankenship, R. E. [Washington Univ., St. Louis, MO (United States)

    2010-06-14

    Carotenoids present in the photosynthetic light-harvesting reaction center (LHRC) complex from chlorosome lacking filamentous anoxygenic phototroph, Roseiflexus castenholzii were purified and characterized for their photochemical properties. The LHRC from anaerobically grown cells contains five different carotenoids, methoxy-keto-myxocoxanthin, γ-carotene, and its three derivatives, whereas the LHRC from aerobically grown cells contains only three carotenoid pigments with methoxy-keto-myxocoxanthin being the dominant one. The spectroscopic properties and dynamics of excited singlet states of the carotenoids were studied by steady-state absorption, fluorescence and ultrafast time-resolved optical spectroscopy in organic solvent and in the intact LHRC complex. Time-resolved transient absorption spectroscopy performed in the near-infrared (NIR) on purified carotenoids combined with steady-state absorption spectroscopy led to the precise determination of values of the energies of the S1(21Ag-) excited state. Global and single wavelength fitting of the ultrafast spectral and temporal data sets of the carotenoids in solvents and in the LHRC revealed the pathways of de-excitation of the carotenoid excited states.

  11. Spectroscopic studies on the interaction between chalcone and bovine serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Naik, Keerti M.; Nandibewoor, Sharanappa T., E-mail: stnandibewoor@yahoo.com

    2013-11-15

    The interaction between chalcone and bovine serum albumin (BSA) has been studied by spectroscopic techniques under physiological condition. By the analysis of fluorescence spectrum and fluorescence intensity, it was observed that the chalcone has a strong ability to quench the intrinsic fluorescence with BSA through a static quenching procedure and non-radiation energy transfer were the main reasons for the fluorescence quenching. The association constants of chalcone with BSA were determined at different temperatures based on fluorescence quenching results. The positive entropy change and enthalpy change indicated that the interaction of chalcone and BSA was driven mainly by hydrophobic forces. The process of binding was a spontaneous process in which Gibbs free energy change was negative. The distance, r, between donor (BSA) and acceptor (chalcone) was obtained according to the Forster's theory of non-radiation energy transfer. The UV–vis, CD, FT-IR, synchronous and 3-D spectral results revealed the changes in the secondary structure of BSA upon interaction with chalcone. The effects of some common metal ions on binding of BSA–chalcone complex were also investigated. -- Highlights: • We explored the interaction between chalcone and BSA by fluorescence spectroscopy. • The fluorescence quenching mechanism was static quenching. • The binding constants and thermodynamic parameters were calculated. • The interaction is driven mainly by hydrophobic force. • The binding of chalcone to BSA induced changes in the secondary structure of BSA.

  12. Spectroscopic study of atmospheric pressure 915 MHz microwave plasma at high argon flow rate

    International Nuclear Information System (INIS)

    Miotk, R; Hrycak, B; Jasinski, M; Mizeraczyk, J

    2012-01-01

    In this paper results of optical emission spectroscopic (OES) study of atmospheric pressure microwave 915 MHz argon plasma are presented. The plasma was generated in microwave plasma source (MPS) cavity-resonant type. The aim of research was determination of electron excitation temperature T exc gas temperature Tg and electron number density n e . All experimental tests were performed with a gas flow rate of 100 and 200 l/min and absorbed microwave power PA from 0.25 to 0.9 kW. The emission spectra at the range of 300 – 600 nm were recorded. Boltzmann plot method for argon 5p – 4s and 5d – 4p transition lines allowed to determine T exc at level of 7000 K. Gas temperature was determined by comparing the measured and simulated spectra using LIFBASE program and by analyzing intensities of two groups of unresolved rotational lines of the OH band. Gas temperature ranged 600 – 800 K. The electron number density was determined using the method based on the Stark broadening of hydrogen H β line. The measured n e rang ed 2 × 10 15 − 3.5×10 15 cm −3 , depending on the absorbed microwave power. The described MPS works very stable with various working gases at high flow rates, that makes it an attractive tool for different gas processing.

  13. GC-FID and NMR Spectroscopic Studies on Gamma Irradiated Walnut Lipids

    Directory of Open Access Journals (Sweden)

    Vassilia J. Sinanoglou

    2015-01-01

    Full Text Available Walnuts have an excellent fatty acid profile, beneficial for coronary heart diseases. A diet rich in walnuts has shown to decrease the total and LDL cholesterol levels as well as lipoprotein levels. In this study, the effects of different doses of γ-irradiation and different packaging conditions on proximate composition and fatty acid profile of walnuts (Juglans regia L. were investigated merging data from different spectroscopic techniques. Walnuts moisture, ash, fat, and protein content as well as fatty acid profile were evaluated immediately after irradiation. GC-FID results showed that SFA increased and MUFA and PUFA decreased with the increase of irradiation dose. Moreover, MUFA/SFA and PUFA/SFA ratios decreased P<0.05 compared to control samples. Furthermore, NMR spectroscopy was implemented to examine possible discrimination patterns based on irradiation dose and packaging. This approach revealed the role of PUFA decrease with the parallel increase of irradiation dose while indicating the protective role of vacuum and MAP compared to air packaging. In conclusion, at irradiation doses of up to 5 kGy, the walnuts retained the nutritional benefits of its fatty acids, in particular MUFA and PUFA. Concerning the different types of packaging, greater stability in the nuts was observed using MAP packaging.

  14. The structural, electronic and spectroscopic properties of 4FPBAPE molecule: Experimental and theoretical study

    Science.gov (United States)

    Tanış, Emine; Babur Sas, Emine; Kurban, Mustafa; Kurt, Mustafa

    2018-02-01

    The experimental and theoretical study of 4-Formyl Phenyl Boronic Acid Pinacol Ester (4FPBAPE) molecule were performed in this work. 1H, 13C NMR and UV-Vis spectra were tested in dimethyl sulfoxide (DMSO). The structural, spectroscopic properties and energies of 4FPBAPE were obtained for two potential conformers from density functional theory (DFT) with B3LYP/6-311G (d, p) and CAM-B3LYP/6-311G (d, p) basis sets. The optimal geometry of those structures was obtained according to the position of oxygen atom upon determining the scan coordinates for each conformation. The most stable conformer was found as the A2 form. The fundamental vibrations were determined based on optimized structure in terms of total energy distribution. Electronic properties such as oscillator strength, wavelength, excitation energy, HOMO, LUMO and molecular electrostatic potential and structural properties such as radial distribution functions (RDF) and probability density depending on coordination number are presented. Theoretical results of 4-FPBAPE spectra were found to be compatible with observed spectra.

  15. Application of spectroscopic techniques for the analysis of kidney stones: a pilot study

    Science.gov (United States)

    Shameem, K. M., Muhammed; Chawla, Arun; Bankapur, Aseefhali; Unnikrishnan, V. K.; Santhosh, C.

    2016-03-01

    Identification and characterization of kidney stone remains one of the important analytical tasks in the medical field. Kidney stone is a common health complication throughout the world, which may cause severe pain, obstruction and infection of urinary tract, and can lead to complete renal damage. It commonly occurs in both sexes regardless of age. Kidney stones have different composition, although each stones have a major single characteristic component. A complete understanding of a sample properties and their function can only be feasible by utilizing elemental and molecular information simultaneously. Two laser based analytical techniques; Laser Induced Breakdown spectroscopy (LIBS) and Raman spectroscopy have been used to study different types of kidney stones from different patients. LIBS and Raman spectroscopy are highly complementary spectroscopic techniques, which provide elemental and molecular information of a sample. Q-switched Nd:YAG laser at 355 nm laser having energy 17mJ per pulse at 10 Hz repetition rate was used for getting LIBS spectra. Raman measurements were carried out using a home assembled micro-Raman spectrometer. Using the recorded Raman spectra of kidney stones, we were able to differentiate different kinds of kidney stones. LIBS spectra of the same stones are showing the evidence of C, Ca, H, and O and also suggest the presence of certain pigments.

  16. Chiral alkylated-aniline as a noninvasive fluorescence sensor: Spectroscopic and molecular modeling studies

    Science.gov (United States)

    Sengupta, Bidisha; Mukherjee, Chirantan Sen; Chakraborty, Sandipan; Muhammad, Maria Jones; Gladney, William; Armstrong, George

    2017-12-01

    Aniline, heterocyclic aromatic amines, and arylamines are known carcinogens. Recently aniline mustard has come into prominence as a novel anticancer agent. In this project, microwave irradiation has been used to synthesize an optically active alkylated aniline namely 2,6-dimethyl-4-(1-(p-tolyl)ethyl)aniline (abbreviated DMPA). The presence of quartet and doublet peaks in NMR and a single chromatogram in HPLC verified that the final product DMPA, prepared from the synthesis reactions, had no major impurities. By using a Lux chiral column in HPLC, two peaks have been detected in the chromatogram, which correspond to two enantiomers of the chiral aniline derivative. Fluorescence spectroscopic measurements on DMPA indicated conspicuous dependence of its emission behavior on the polarity (in terms of the empirical polarity parameter ET(30)) of the homogeneous solvents used, a property important for an optical sensor. The nature of the emission profiles, along with the relevant parameter namely wavelength at emission maximum (λemmax) is used to infer the distribution, binding and microenvironment of the DMPA molecules in human serum albumin protein (HSA). DMPA is weakly fluorescent in aqueous buffer medium, with a dramatic enhancement in the fluorescence emission in the presence of HSA. Molecular modeling studies have been carried out on the two enantiomers (R and S) of DMPA with HSA. The implications of these findings are examined in relation to the potentialities of DMPA as a novel fluorescence sensor for biological systems.

  17. A theoretical benchmark study of the spectroscopic constants of the very heavy rare gas dimers.

    Science.gov (United States)

    Shee, Avijit; Knecht, Stefan; Saue, Trond

    2015-04-28

    Spectroscopic constants for the homonuclear dimers of the very heavy rare gases radon (Rn) and eka-radon (Uuo) are reported. A computational protocol using the eXact 2-Component molecular-mean field Hamiltonian has been established based on extensive calculations of the xenon dimer. We find that reliable results require CCSD(T) calculations at the extrapolated basis set limit. In this limit counterpoise corrected results are closer to experimentally derived values than uncorrected ones. Furthermore, in an attempt to reduce the computational cost while retaining very high accuracy, we studied the performance of range-separated density functional theory. Although we observe a somewhat more favorable basis set convergence and reduced importance of connected triples by range-separated methods compared to pure wave function theory, in practice we have to employ the same computational protocol for obtaining converged results. At the Dirac-Coulomb level we find an almost fourfold increase of binding energy when going from the radon to the eka-radon dimer, but the inclusion of spin-other orbit interaction reduces the dissociation energy of the heaviest dimer by about 40%.

  18. Structural, spectroscopic and DFT study of 4-methoxybenzohydrazide Schiff bases. A new series of polyfunctional ligands

    Science.gov (United States)

    Ferraresi-Curotto, Verónica; Echeverría, Gustavo A.; Piro, Oscar E.; Pis-Diez, Reinaldo; González-Baró, Ana C.

    2015-02-01

    Five Schiff bases obtained from condensation of 4-methoxybenzohydrazide with related aldehydes, namely o-vanillin, vanillin, 5-bromovanillin, 5-chlorosalicylaldehyde and 5-bromosalicylaldehyde were prepared. A detailed structural and spectroscopic study is reported. The crystal structures of four members of the family were determined and compared with one another. The hydrazones obtained from 5-chlorosalicylaldehyde and 5-bromosalicylaldehyde resulted to be isomorphic to each other. The solid-state structures are stabilized by intra-molecular Osbnd H⋯N interactions in salicylaldehyde derivatives between the Osbnd H moiety from the aldehyde and the hydrazone nitrogen atom. All crystals are further stabilized by inter-molecular H-bonds mediated by the crystallization water molecule. A comparative analysis between experimental and theoretical results is presented. The conformational space was searched and geometries were optimized both in gas phase and including solvent effects. The structure is predicted for the compound for which the crystal structure was not determined. Infrared and electronic spectra were measured and assigned with the help of data obtained from computational methods based on the Density Functional Theory.

  19. Spectroscopic studies on hydrogen/deuterium exchange equilibria and related phenomena in aqueous solution

    International Nuclear Information System (INIS)

    Taylor, C.E.

    1978-07-01

    This thesis describes spectroscopic studies on the aqueous phase hydroxide ion and acid dissociation of the 3-cyano pyridinium ion. Firstly, NMR spectroscopy was used, in the fast exchange mode, to measure the hydrogen isotope fractionation constants for the exchange sites in the hydroxide ion and its solvation shell. As part of the above analysis, values have been derived for the NMR chemical shifts of the hydroxide ion and solvation shell protons. Secondly, the NMR fast exchange method was used to assess the effect of temperature on the hydroxide ion fractionation constant. Thirdly, the NMR fast exchange method was used to assess the nature and structure of ion pairs of the type M + , OH - (H 2 O)sub(p) where M = Tl, Na, K, Li. Data necessary to these analyses were the Ion Chemical Shift of the thallous ion and the volume magnetic susceptibilities of some MOH solutions. These have been measured and are reported here, the latter being determined over a wide concentration range. Finally, U.V. - Visible spectroscopy was employed to measure the pKsub(H) of the 3-cyano pyridinium ion over a range of temperatures and the pKsub(D) at 298.5 K. The results are given and discussed. (U.K.)

  20. Combined spectroscopic, DFT, TD-DFT and MD study of newly synthesized thiourea derivative

    Science.gov (United States)

    Menon, Vidya V.; Sheena Mary, Y.; Shyma Mary, Y.; Panicker, C. Yohannan; Bielenica, Anna; Armaković, Stevan; Armaković, Sanja J.; Van Alsenoy, Christian

    2018-03-01

    A novel thiourea derivative, 1-(3-bromophenyl)-3-[3-(trifluoromethyl)phenyl]thiourea (ANF-22) is synthesized and characterized by FTIR, FT-Raman and NMR spectroscopy experimentally and theoretically. A detailed conformational analysis of the title molecule has been conducted in order to locate the lowest energy geometry, which was further subjected to the detailed investigation of spectroscopic, reactive, degradation and docking studies by density functional theory (DFT) calculations and molecular dynamics (MD) simulations. Time dependent DFT (TD-DFT) calculations have been used also in order to simulate UV spectra and investigate charge transfer within molecule. Natural bond orbital analysis has been performed analyzing the charge delocalization and using HOMO and LUMO energies the electronic properties are analyzed. Molecular electrostatic potential map is used for the quantitative measurement of active sites in the molecule. In order to determine the locations possibly prone to electrophilic attacks we have calculated average local ionization energies and mapped them to the electron density surface. Further insight into the local reactivity properties have been obtained by calculation of Fukui functions, also mapped to the electron density surface. Possible degradation properties by the autoxidation mechanism have been assessed by calculations of bond dissociation energies for hydrogen abstraction. Atoms of title molecule with significant interactions with water molecules have been determined by calculations of radial distribution functions. The title compound can be a lead compound for developing new analgesic drug.

  1. Spectroscopic studies and biological activity of some transition metal complexes of unusual Schiff base.

    Science.gov (United States)

    Abu Al-Nasr, Ahmad K; Ramadan, Ramadan M

    2013-03-15

    Unusual Schiff base ligand, 4-ethanimidoyl-6-[(1E)-N-(2-hydroxy-4-methylphenyl)ethanimidoyl]benzene-1,3-diol, L, was synthesized via catalytic process involving the interaction of some metal ions with a macrocyclic Schiff base (MSB). The transition metal derivatives [ML(H(2)O)(4)](NO(3))(3), M=Cr(III) and Fe(III), [NiL(H(2)O)(4)](NO(3))(2), [ML(H(2)O)(2)](NO(3))(2), M=Zn(II) and Cd(II), [Cl(2)Pd(μ-Cl)(2)PdL], [PtL(Cl)(2)] and [PtL(Cl)(4)] were also synthesized from the corresponding metal species with L. The Schiff bases and complexes were characterized by elemental analysis, mass spectrometry, IR and (1)H NMR spectroscopy. The crystal structure of L was determined by X-ray analysis. The spectroscopic studies revealed a variety of structure arrangements for the complexes. The biological activities of L and metal complexes against the Escherchia coli as Gram-negative bacteria and Staphylococcus aureus as Gram-positive bacteria, and the two fungus Aspergillus flavus and Candida albicans were screened. The cytotoxicity of [PtL(Cl)(2)] complex, a cis-platin analogous, was checked as an antitumor agent on two breast cancer cell lines (MCF7 and T47D) and human liver carcinoma cell line (HepG2). Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Spectroscopic studies and biological activity of some transition metal complexes of unusual Schiff base

    Science.gov (United States)

    Abu Al-Nasr, Ahmad K.; Ramadan, Ramadan M.

    2013-03-01

    Unusual Schiff base ligand, 4-ethanimidoyl-6-[(1E)-N-(2-hydroxy-4-methylphenyl)ethanimidoyl]benzene-1,3-diol, L, was synthesized via catalytic process involving the interaction of some metal ions with a macrocyclic Schiff base (MSB). The transition metal derivatives [ML(H2O)4](NO3)3, M = Cr(III) and Fe(III), [NiL(H2O)4](NO3)2, [ML(H2O)2](NO3)2, M = Zn(II) and Cd(II), [Cl2Pd(μ-Cl)2PdL], [PtL(Cl)2] and [PtL(Cl)4] were also synthesized from the corresponding metal species with L. The Schiff bases and complexes were characterized by elemental analysis, mass spectrometry, IR and 1H NMR spectroscopy. The crystal structure of L was determined by X-ray analysis. The spectroscopic studies revealed a variety of structure arrangements for the complexes. The biological activities of L and metal complexes against the Escherchia coli as Gram-negative bacteria and Staphylococcus aureus as Gram-positive bacteria, and the two fungus Aspergillus flavus and Candida albicans were screened. The cytotoxicity of [PtL(Cl)2] complex, a cis-platin analogous, was checked as an antitumor agent on two breast cancer cell lines (MCF7 and T47D) and human liver carcinoma cell line (HepG2).

  3. Synthesis, spectroscopic, DFT and in vitro biological studies of vanadium(III) complexes of aryldithiocarbonates

    Science.gov (United States)

    Andotra, Savit; Kumar, Sandeep; Kour, Mandeep; Vikas; Chayawan; Sharma, Vishal; Jaglan, Sundeep; Pandey, Sushil. K.

    2017-06-01

    Vanadium(III) tris(dithiocarbonates), [(ROCS2)3V] (R = o-, m-, p-CH3C6H4 and 4-Cl-3-CH3C6H3) and donor stabilized addition complexes [(ROCS2)2V(Cl)·L] [L = NC5H5 or P(C6H5)3] were synthesized and characterized by elemental analyses, IR, mass, TGA/DTA, SEM magnetic susceptibility and heteronuclear NMR (1H, 13C and 31P) spectroscopic studies. The cytotoxicity of the complexes was measured in vitro using the cultivated human cell lines. In addition, the antioxidant activities of the ligands and its vanadium complexes were also investigated through their scavenging effect on DPPH radicals. The antimicrobial activity of ligands and some complexes has been conducted against three bacterial strains and fungus. The density functional theory (DFT) calculations of ligands and vanadium complexes were performed by the DFT/B3LYP/LANL2DZ method to obtain the optimized molecular geometry, vibrational frequencies, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), thermodynamic properties and various other quantum-mechanical parameters.

  4. Spectroscopic characterization, antimicrobial activity, DFT computation and docking studies of sulfonamide Schiff bases

    Science.gov (United States)

    Mondal, Sudipa; Mandal, Santi M.; Mondal, Tapan Kumar; Sinha, Chittaranjan

    2017-01-01

    Schiff bases synthesised from the condensation of 2-(hydroxy)naphthaldehyde and sulfonamides (sufathiazole (STZ), sulfapyridine (SPY), sulfadiazine (SDZ), sulfamerazine (SMZ) and sulfaguanidine (SGN)) are characterized by different spectroscopic data (FTIR, UV-Vis, Mass, NMR) and two of them, (E)-4-(((2-hydroxynaphthalen-1-yl)methylene)amino)-N-(thiazol-2-yl)benzenesulfonamide (1a) and (E)-N-(diaminomethylene)-4-(((2-hydroxynaphthalen-1-yl)methylene)amino)benzenesulfonamide (1e) have been confirmed by single crystal X-ray structure determination. Antimicrobial activities of the Schiff bases have been evaluated against certified and resistant Gram positive (Staphylococcus aureus, Enterococcus facelis) and Gram negative (Streptococcus pyogenes, Salmonella typhi, Shigella dysenteriae, Shigella flexneri, Klebsiella pneumonia) pathogens. Performance of Schiff base against the resistant pathogens are better than standard stain and MIC data lie 32-128 μg/ml while parent sulfonamides are effectively inactive (MIC >512 μg/ml). The DFT optimized structures of the Schiff bases have been used to accomplish molecular docking studies with DHPS (dihydropteroate synthase) protein structure (downloaded from Protein Data Bank) to establish the most preferred mode of interaction. ADMET filtration, Cytotoxicity (MTT assay) and haemolysis assay have been examined for evaluation of druglike character.

  5. Study on the interaction between curcumin and CopC by spectroscopic and docking methods.

    Science.gov (United States)

    Song, Zhen; Yuan, Wen; Zhu, Ruitao; Wang, Song; Zhang, Caifeng; Yang, Binsheng

    2017-03-01

    Curcumin is a widely studied polyphenolic compound which has a variety of biological activity as anti-inflammatory and antitumor drugs. Recent research reported that copper chaperone binding with small molecular may relate to the treatment of cancer. In this work, the interaction between curcumin and CopC has been investigated in detail by means of UV-vis absorption, FTIR, CD, fluorescence spectroscopic and molecular docking methods The results showed that the CopC conformation was altered by curcumin with reduction of β-sheet and increase of random coil. Furthermore, curcumin can form a host-guest inclusion supramolecular complex with curcumin, and the forming constant had been calculated to be (2.85±0.21)×10 5 M -1 . In addition, the binding ability between Cu 2+ and curcumin was less than that between Cu 2+ and CopC. Moreover, the binding of curcumin with Cu 2+ has an effect on the binding ability between curcumin and CopC. The thermodynamic parameters ΔH and ΔS at different temperatures were obtained. The formation of CopC-curcumin complex depended on the hydrophobic force, and the binding average distance between CopC and curcumin was determined. What's more, the binding site of curcumin to CopC was shown vividly by an automated public domain software package ArgusLab 4.0.1. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Spectroscopic and kinetic studies of photochemical reaction of magnesium tetraphenylporphyrin with oxygen.

    Science.gov (United States)

    Zhang, Jianbin; Zhang, Pengyan; Zhang, Zhengfu; Wei, Xionghui

    2009-05-07

    Magnesium tetraphenylporphyrin (MgTPP) was synthesized from meso-tetraphenylporphyrin (H(2)TPP) in N,N-dimethylformamide (DMF). The photochemical properties of MgTPP in the presence of oxygen were investigated in dichloromethane (CH(2)Cl(2)) by conventional fluorescence, UV-vis, (1)H NMR, MALDI-TOF-MS, FTIR, and XPS spectroscopic techniques. Spectral analyses showed that under irradiation, MgTPP molecules reacted with O(2) molecules, and a stable 1:1 adduct was produced. During the photochemical reaction process, one oxygen molecule was bound to the pyrrolenine nitrogens in the MgTPP molecule, and the characteristic N-O bonds were identified using the FTIR and XPS techniques. The kinetics of the photochemical reaction of MgTPP with O(2) has been studied in an oxygen-saturated solution. Under irradiation conditions, the experimental rate follows a pseudo-first-order reaction for MgTPP, having a half-life from 40 to 130 min under various irradiation intensities. The kinetic rate constant of photochemical reaction of MgTPP with O(2) showed a linear dependence.

  7. Optical study of BST films combining ellipsometry and reflectivity

    Czech Academy of Sciences Publication Activity Database

    Železný, Vladimír; Chvostová, Dagmar; Pajasová, Libuše; Jelínek, Miroslav; Kocourek, Tomáš; Daniš, S.; Valvoda, V.

    2009-01-01

    Roč. 255, č. 10 (2009), s. 5280-5283 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z10100520 Keywords : BST thin films * optical properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.616, year: 2009

  8. Characterizing the structure of lipodisq nanoparticles for membrane protein spectroscopic studies.

    Science.gov (United States)

    Zhang, Rongfu; Sahu, Indra D; Liu, Lishan; Osatuke, Anna; Comer, Raven G; Dabney-Smith, Carole; Lorigan, Gary A

    2015-01-01

    Membrane protein spectroscopic studies are challenging due to the difficulty introduced in preparing homogenous and functional hydrophobic proteins incorporated into a lipid bilayer system. Traditional membrane mimics such as micelles or liposomes have proved to be powerful in solubilizing membrane proteins for biophysical studies, however, several drawbacks have limited their applications. Recently, a nanosized complex termed lipodisq nanoparticles was utilized as an alternative membrane mimic to overcome these caveats by providing a homogeneous lipid bilayer environment. Despite all the benefits that lipodisq nanoparticles could provide to enhance the biophysical studies of membrane proteins, structural characterization in different lipid compositions that closely mimic the native membrane environment is still lacking. In this study, the formation of lipodisq nanoparticles using different weight ratios of POPC/POPG lipids to SMA polymers was characterized via solid-state nuclear magnetic resonance (SSNMR) spectroscopy and dynamic light scattering (DLS). A critical weight ratio of (1/1.25) for the complete solubilization of POPC/POPG vesicles has been observed and POPC/POPG vesicles turned clear instantaneously upon the addition of the SMA polymer. The size of lipodisq nanoparticles formed from POPC/POPG lipids at this weight ratio of (1/1.25) was found to be about 30 nm in radius. We also showed that upon the complete solubilization of POPC/POPG vesicles by SMA polymers, the average size of the lipodisq nanoparticles is weight ratio dependent, when more SMA polymers were introduced, smaller lipodisq nanoparticles were obtained. The results of this study will be helpful for a variety of biophysical experiments when specific size of lipid disc is required. Further, this study will provide a proper path for researchers working on membrane proteins to obtain pertinent structure and dynamic information in a physiologically relevant membrane mimetic environment

  9. Spectroscopic Study of Plasma Polymerized a-C:H Films Deposited by a Dielectric Barrier Discharge

    Directory of Open Access Journals (Sweden)

    Thejaswini Halethimmanahally Chandrashekaraiah

    2016-07-01

    Full Text Available Plasma polymerized a-C:H thin films have been deposited on Si (100 and aluminum coated glass substrates by a dielectric barrier discharge (DBD operated at medium pressure using C2Hm/Ar (m = 2, 4, 6 gas mixtures. The deposited films were characterized by Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS, Raman spectroscopy, and ellipsometry. FT-IRRAS revealed the presence of sp3 and sp2 C–H stretching and C–H bending vibrations of bonds in the films. The presence of D and G bands was confirmed by Raman spectroscopy. Thin films obtained from C2H4/Ar and C2H6/Ar gas mixtures have ID/IG ratios of 0.45 and 0.3, respectively. The refractive indices were 2.8 and 3.1 for C2H4/Ar and C2H6/Ar films, respectively, at a photon energy of 2 eV.

  10. Chiral lactic hydrazone derivatives as potential bioactive antibacterial agents: Synthesis, spectroscopic, structural and molecular docking studies

    Science.gov (United States)

    Noshiranzadeh, Nader; Heidari, Azam; Haghi, Fakhri; Bikas, Rahman; Lis, Tadeusz

    2017-01-01

    A series of novel chiral lactic-hydrazone derivatives were synthesized by condensation of (S)-lactic acid hydrazide with salicylaldehyde derivatives and characterized by elemental analysis and spectroscopic studies (FT-IR, 1H NMR and 13C NMR spectroscopy). The structure of one compound was determined by single crystal X-ray analysis. Antibacterial activity of the synthesized compounds was studied against Staphylococcus aureus, Streptococcus pneumonia, Escherichia coli and Pseudomonas aeruginosa as bacterial cultures by broth microdilution method. All of the synthesized compounds showed good antibacterial activity with MIC range of 64-512 μg/mL. Compounds (S,E)-2-hydroxy-N-(2-hydroxy-5-nitrobenzylidene)propanehydrazide (5) and (S,E)-2-hydroxy-N-((3-hydroxy-5-(hydroxymethyl)-2-methylpyridin-4-yl)propanehydrazide (7) were the most effective antibacterial derivatives against S. aureus and E. coli respectively with a MIC value of 64 μg/mL. Bacterial biofilm formation assay showed that these compounds significantly inhibited biofilm formation of P. aeruginosa. Also, in silico molecular docking studies were performed to show lipoteichoic acid synthase (LtaS) inhibitory effect of lactic hydrazone derivatives. The association between electronic and structural effects of some substituents on the benzylidene moiety and the biological activity of these chiral compounds were studied. Structural studies show that compound with higher hydrogen bonding interactions show higher antibacterial activity. The results show chiral hydrazone derivatives based on lactic acid hydrazide could be used as potential lead compounds for developing novel antibacterial agents.

  11. Spectroscopic profiling and computational study of the binding of tschimgine: A natural monoterpene derivative, with calf thymus DNA

    Science.gov (United States)

    Khajeh, Masoumeh Ashrafi; Dehghan, Gholamreza; Dastmalchi, Siavoush; Shaghaghi, Masoomeh; Iranshahi, Mehrdad

    2018-03-01

    DNA is a major target for a number of anticancer substances. Interaction studies between small molecules and DNA are essential for rational drug designing to influence main biological processes and also introducing new probes for the assay of DNA. Tschimgine (TMG) is a monoterpene derivative with anticancer properties. In the present study we tried to elucidate the interaction of TMG with calf thymus DNA (CT-DNA) using different spectroscopic methods. UV-visible absorption spectrophotometry, fluorescence and circular dichroism (CD) spectroscopies as well as molecular docking study revealed formation of complex between TMG and CT-DNA. Binding constant (Kb) between TMG and DNA was 2.27 × 104 M- 1, that is comparable to groove binding agents. The fluorescence spectroscopic data revealed that the quenching mechanism of fluorescence of TMG by CT-DNA is static quenching. Thermodynamic parameters (ΔH analysis, viscosity measurements and molecular docking.

  12. Near-infrared spectroscopic studies of self-forming lipids and nanovesicles

    Science.gov (United States)

    Bista, Rajan K.; Bruch, Reinhard F.

    2009-02-01

    Lipids and liposomes have remained an active research topic for several decades due to their significance as membrane model. Several vibrational spectroscopic techniques have been developed and employed to study the properties of lipids and liposomes. In this study, near-infrared (NIR) spectroscopy has been used to analyze a suite of synthesized PEGylated lipids trademarked as QuSomesTM. The three amphiphiles used in this study, differ in their apolar hydrophobic chain length and contain various units of polar polyethylene glycol (PEG) head groups. In contrast to conventional phospholipids, this new kind of lipids forms liposomes spontaneously upon hydration, without the supply of external activation energy. Whilst the NIR spectra of QuSomesTM show a common pattern, differences in the spectra are observed which enable the lipids to be distinguished. NIR absorption spectra of these new artificial lipids have been recorded in the spectral range of 4800-9000 cm-1 (~2100-1100 nm) by using a new miniaturized spectrometer based on micro-optical-electro-mechanical systems (MOEMS) technology. In particular, we have established specific band structures as "molecular fingerprints" corresponding to overtones and combinations vibrational modes involving mainly C-H and O-H functional groups for sample analysis of QuSomesTM. Moreover, we have demonstrated that the nanovesicles formed by such lipids in polar solvents show high stability and obey Beer's law at low concentration. The results reported in this study may find applications in various field including the development of lipids based drug delivery systems.

  13. Line narrowing spectroscopic studies of DNA-carcinogen adducts and DNA-dye complexes

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Myungkoo [Iowa State Univ., Ames, IA (United States)

    1995-12-06

    Laser-induced fluorescence line narrowing and non-line narrowing spectroscopic methods were applied to conformational studies of stable DNA adducts of the 7β, 8α-dihydoxy-9α, l0α-epoxy-7,8,9, 10-tetrahydrobenzo[α]pyrene (anti-BPDE). Stereochemically distinct (+)-trans-, (-)-trans-, (+)-cis- and (-)-cis adducts of anti-BPDE bound to exocyclic amino group of the central guanine in an 11-mer oligonucleotide, exist in a mixture of conformations in frozen aqueous buffer matrices. The (+)-trans adduct adopts primarily an external conformation with a smaller fraction ( ~25 %) exists in a partially base-stacked conformation. Both cis adducts were found to be intercalated with significant π-π stacking interactions between the pyrenyl residues and the bases. Conformations of the trans-adduct of (+)-anti -BPDE in 11-mer oligonucleotides were studied as a function of flanking bases. In single stranded form the adduct at G2 or G3 (5 ft-flanking, base guanine) adopts a conformation with strong, interaction with the bases. In contrast, the adduct with a 5ft-flanking, thymine exists in a primarily helixexternal conformation. Similar differences were observed in the double stranded oligonucleotides. The nature of the 3ft-flanking base has little influence on the conformational equilibrium of the (+)-trans-anti BPDE-dG adduct. The formation and repair of BPDE-N2-dG in DNA isolated from the skin of mice treated topically with benzo[α]pyrene (BP) was studied. Low-temperature fluorescence spectroscopy of the intact DNA identified the major adduct as (+)-trans-anti-BPDE-N-dG, and the minor adduct fraction consisted mainly of (+)-cis-anti-BPDE-N2-dG.

  14. Line narrowing spectroscopic studies of DNA-carcinogen adducts and DNA-dye complexes

    International Nuclear Information System (INIS)

    Suh, Myungkoo.

    1995-01-01

    Laser-induced fluorescence line narrowing and non-line narrowing spectroscopic methods were applied to conformational studies of stable DNA adducts of the 7β, 8α-dihydoxy-9α, l0α-epoxy-7,8,9, 10-tetrahydrobenzo[α]pyrene (anti-BPDE). Stereochemically distinct (+)-trans-, (-)-trans-, (+)-cis- and (-)-cis adducts of anti-BPDE bound to exocyclic amino group of the central guanine in an 11-mer oligonucleotide, exist in a mixture of conformations in frozen aqueous buffer matrices. The (+)-trans adduct adopts primarily an external conformation with a smaller fraction ( ∼ 25 %) exists in a partially base-stacked conformation. Both cis adducts were found to be intercalated with significant π-π stacking interactions between the pyrenyl residues and the bases. Conformations of the trans-adduct of (+)-anti -BPDE in 11-mer oligonucleotides were studied as a function of flanking bases. In single stranded form the adduct at G 2 or G 3 (5 ft-flanking, base guanine) adopts a conformation with strong, interaction with the bases. In contrast, the adduct with a 5ft-flanking, thymine exists in a primarily helixexternal conformation. Similar differences were observed in the double stranded oligonucleotides. The nature of the 3ft-flanking base has little influence on the conformational equilibrium of the (+)-trans-anti BPDE-dG adduct. The formation and repair of BPDE-N 2 -dG in DNA isolated from the skin of mice treated topically with benzo[α]pyrene (BP) was studied. Low-temperature fluorescence spectroscopy of the intact DNA identified the major adduct as (+)-trans-anti-BPDE-N-dG, and the minor adduct fraction consisted mainly of (+)-cis-anti-BPDE-N 2 -dG

  15. Edge and Core Impurity Transport Study with Spectroscopic Instruments in LHD

    International Nuclear Information System (INIS)

    Morita, Shigeru; Goto, Motoshi; Kobayashi, Masahiro; Muto, Sadatsugu; Chowdhuri, Malay Bikas; Chunfeng, Dong; Hangyu, Zhou; Zhengying, Cui; Fujii, Keisuke; Hasuo, Masahiro; Iwamae, Atsushi; Furuzawa, Akihiro; Sakurai, Ikuya; Tawara, Yuzuru; Yinxian, Jie; Baonian, Wan; Zhenwei, Wu; Koubiti, Mohammed; Yamaguchi, Naohiro

    2009-01-01

    Impurity transport was investigated at both edge and core regions in large helical device (LHD) with developed spectroscopic instruments which can measure one- and two-dimensional distributions of impurities. The edge impurity behavior was studied recently using four carbon resonant transitions in different ionization stages of CIII (977A), CIV (1548A), CV (40.3A) and CVI (33.7A). When the line-averaged electron density, n e , is increased from 1 to 6 x 10 13 cm -3 , the ratio of (CIII+CIV)/n e increases while the ratio of (CV+CVI)/n e decreases. Here, CIII+CIV (CV+CVI) expresses the sum of CIII (CV) and CIV (CVI) intensities. The CIII+CIV indicates the carbon influx and the CV+CVI indicates the emissions through the transport in the ergodic layer. The result thus gives experimental evidence on the impurity screening by the ergodic layer in LHD, which is also supported by a three-dimensional edge particle simulation. The core impurity behavior is also studied in high-density discharges (n e ≤ 1x 10 15 cm -3 ) with multi H 2 -pellets injection. It is found that the ratio of V/D (V: convection velocity, D: diffusion coefficient) decreases after pellet injection and Z eff profile shows a flat one at values of 1.1-1.2. These results confirm no impurity accumulation occurs in high-density discharges. As a result, the iron density, n Fe , is analyzed to be 6 x 10 -7 ( = n Fe /n e ) of which the amount can be negligible as radiation source even in such high-density discharges. One- and two-dimensional impurity distributions from space-resolved VUV and EUV spectrometers newly developed for further impurity transport study are also presented with their preliminary results. (magnetically confined plasma)

  16. Raman spectroscopic study of alunite occurrences in the Sapes porphyry-epithermal deposit, NE Greece

    Science.gov (United States)

    Papazotos, Panagiotis; Perraki, Maria; Voudouris, Panagiotis; Skliros, Vasilios

    2017-04-01

    The Sapes area, Northeastern Greece, represent a deeply eroded Oligocene volcanic edifice built up of post-collisional intermediate-to-acidic intrusives and their volcanic equivalents. The area hosts a telescoped porphyry-epithermal system and associated high-sulfidation epithermal Au-Ag-Cu-Bi-Te mineralization within advanced argillic alteration lithocaps (Voudouris, 2014). Alunite is a common mineralogical constituent among the advanced argillic alteration assemblages and it is a hydrated aluminium potassium sulfate mineral with a general formula KAl3(SO4)2(OH)6. The objective of this work is to study the alunites samples in the Sapes porphyry-epithermal deposit by means of Raman spectroscopy, as it has been shown to be a useful tool in studying the alunite structure, either natural or synthetic (Frost et al., 2006; Maubec et al., 2012). Raman spectra were excited employing a 532 nm laser at a resolution of 2 cm-1 in the range of 100-4000 cm-1. Raman spectra exhibit distinguished bands at 162 cm-1, attributed to translational mode of cations and or librational and translational modes of SO42-, at 235 cm-1 suggesting framework deformations including the SO42- entities as a whole or attributed to OH/O hydrogen bond stretching mode, a weak band at 385 cm-1 may corresponding to Al-OH stretching vibrations, a moderate band at 564 cm-1 assigned to Al-O and OH deformation modes, bands at 484 and 653 cm-1 respectively due to v2(SO42-) and v4(SO42-) bending modes, a very strong vibration at 1025 cm-1 that is ascribed to the v1 stretching vibration of the SO42- bands located at 1080 and 1186 cm-1 due to v3(SO42-) stretching modes and finally two bands at 3480 cm-1 and 3502 cm-1 that are assigned to the OH stretching vibrations (Breitinger et al., 1997; Frost et al., 2006; Maubec et al., 2012 and references therein). A Raman and FTIR spectroscopic future work will focus on the comparative study among the alunites occurrences in Greece (Sapes, Limnos, Lesvos and Milos), so

  17. Velocity and abundance precisions for future high-resolution spectroscopic surveys : A study for 4MOST

    NARCIS (Netherlands)

    Caffau, E.; Koch, A.; Sbordone, L.; Sartoretti, P.; Hansen, C. J.; Royer, F.; Leclerc, N.; Bonifacio, P.; Christlieb, N.; Ludwig, H.-G.; Grebel, E. K.; de Jong, R. S.; Chiappini, C.; Walcher, J.; Mignot, S.; Feltzing, S.; Cohen, M.; Minchev, I.; Helmi, A.; Piffl, T.; Depagne, E.; Schnurr, O.

    In preparation for future, large-scale, multi-object, high-resolution spectroscopic surveys of the Galaxy, we present a series of tests of the precision in radial velocity and chemical abundances that any such project can achieve at a 4 m class telescope. We briefly discuss a number of science cases

  18. Dielectric and impedance spectroscopic studies of (Sr1–xPbx)TiO2 ...

    Indian Academy of Sciences (India)

    Administrator

    of 10,000 while the dielectric constant of undoped glass ceramic sample is of the order of 500. Complex impedance and modulus spectroscopic techniques were used to find out the contributions of polarization of crystallites and glass crystal interfaces to the resulting dielectric behaviour. Keywords. Perovskite lead strontium ...

  19. Calorimetric and spectroscopic studies on solvation energetics for H₂ storage in the CO₂/HCOOH system.

    Science.gov (United States)

    Fink, Cornel; Katsyuba, Sergey; Laurenczy, Gabor

    2016-04-28

    Solvents playing a crucial role in many chemical reactions and additives can be used to shift the reaction equilibrium. Herein we study the enthalpy of mixing for selected solvents (aqueous, organic) and basic additives (amines, aqueous KOH) when mixed with formic acid with the aim to optimize hydrogen storage/delivery in the CO2/HCOOH system. Formic acid, resulting from carbon dioxide hydrogenation, reaches highest yields when effectively "removed" from the reaction equilibrium. In terms of energy efficiency, any heat released during CO2 hydrogenation has to be reused in the reverse reaction, during the production of hydrogen. In any scenario, the usage of basic chemicals, non-innocent solvents, causes higher energy release in CO2 hydrogenation, which has to be reused in the hydrogen delivery process. Therefore, the enthalpy of mixing is a valuable parameter for designing hydrogen storage devices since it allows the estimation of energy balance for the CO2 hydrogenation/H2 liberation cycle. The highest formic acid concentrations in direct catalytic CO2 hydrogenation under acidic conditions were reached in DMSO. DMSO exhibits considerably stronger interactions with formic acid compared to water as was observed in calorimetric measurements. This difference can be ascribed, at least partly, to stronger hydrogen bonding of FA to DMSO than to water in the corresponding solutions, examined by a combination of IR spectroscopic and quantum chemical studies. Furthermore, the investigation of DMSO/FA- and water/FA systems by (1)H- and (13)C-NMR spectroscopy revealed that only 1 : 1 aggregates are formed in the DMSO solutions of FA in a broad concentration range, while the stoichiometry and the number of the FA-water aggregates essentially depend on the concentration of aqueous solutions.

  20. Spectroscopic and molecular docking techniques study of the interaction between oxymetholone and human serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Madrakian, Tayyebeh, E-mail: madrakian@basu.ac.ir; Bagheri, Habibollah; Afkhami, Abbas; Soleimani, Mohammad

    2014-11-15

    In this study, the binding of oxymetholone (OXM), a doping drug, to human serum albumin (HSA) was explored at pH 7.40 by spectroscopic methods including spectrofluorimetry, three dimensional excitation–emission matrix (3D EEM), UV–vis absorption, resonance rayleigh scattering (RRS) and molecular docking. The fluorescence results showed that there was a considerable quenching of the intrinsic fluorescence of HSA upon binding to OXM by static quenching mechanism. The Stern–Volmer quenching constants (K{sub SV}) between OXM and HSA at three different temperatures 295, 303, 308 K, were obtained as 4.63×10{sup 4}, 3.05×10{sup 4} and 1.49×10{sup 4} L mol{sup −1}, respectively. Furthermore this interaction was confirmed by UV–vis spectrophotometric and RRS techniques. The binding site number, n, apparent binding constant, K{sub b}, and corresponding thermodynamic parameters (ΔS, ΔH and ΔG) were measured at different temperatures. The Van der Waals and hydrogen-bond forces were found to stabilize OXM–HSA complex. The distance (r) between the donor and acceptor was obtained from Förster's theory of fluorescence resonance energy transfer (FRET) and found to be 1.67 nm. The 3D EEM showed that OXM slightly changes the secondary structure of HSA. Furthermore, the molecular docking was employed for identification of drug binding sites and interaction of OXM with amino acid residues. - Highlights: • The binding of OXM as a doping drug with HSA was studied by different techniques. • The binding constant of HSA–OXM was calculated. • The binding site of OXM on HSA was characterized with molecular docking. • The thermodynamic parameters were calculated according to fluorescence technique.

  1. Intra- und intermolecular hydrogen bonds. Spectroscopic, quantum chemical and molecular dynamics studies

    International Nuclear Information System (INIS)

    Simperler, A.

    1999-03-01

    Intra- and intermolecular H-bonds have been investigated with spectroscopic, quantum chemical, and molecular dynamics methods. The work is divided into the following three parts: 1. Intramolecular interactions in ortho-substituted phenols. Theoretical and experimental data that characterizes the intramolecular hydrogen bonds in 48 different o-substituted phenols are discussed. The study covers various kinds of O-H ... Y -type interactions (Y= N, O, S, F, Cl, Br, I, C=C, C=-C, and C-=N). The bond strength sequences for several series of systematically related compounds as obtained from IR spectroscopy data (i.e., v(OH) stretching frequencies) are discussed and reproduced with several theoretical methods (B3LYP/6-31G(d,p), B3LYP/6-311G(d,p), B3LYP/6-31++G(d,p), B3LYP/DZVP, MP2/6-31G(d,p), and MP2/6-31++G(d,p) levels of theory). The experimentally determined sequences are interpreted in terms of the intrinsic properties of the molecules: hydrogen bond distances, Mulliken partial charges, van der Waals radii, and electron densities of the Y-proton acceptors. 2. Competitive hydrogen bonds and conformational equilibria in 2,6-disubstituted phenols containing two different carbonyl substituents. The rotational isomers of ten unsymmetrical 2,6-disubstituted phenols as obtained by combinations of five different carbonyl substituents (COOH, COOCH 3 , CHO, COCH 3 , and CONH 2 ) have been theoretically investigated at the B3LYP/6-31G(d,p) level of theory. The relative stability of four to five conformers of each compound were determined by full geometry optimization for free molecules as well as for molecules in reaction fields with dielectric constants up to ε=37.5. A comparison with IR spectroscopic data of available compounds revealed excellent agreement with the theoretically predicted stability sequences and conformational equilibria. The stability of a conformer could be interpreted to be governed by the following two contributions: (i) an attractive hydrogen bond

  2. Synthetic, 119Sn NMR spectroscopic, electrochemical, and reactivity study of organotin A3 corrolates including chiral and ferrocenyl derivatives.

    Science.gov (United States)

    Tsay, Olga G; Kim, Byung-Kwon; Luu, Tuong Loan; Kwak, Juhyoun; Churchill, David G

    2013-02-18

    Various R/Ar-functionalized tin 5,10,15-tris(pentafluorophenyl)corrolate derivatives are reported herein including the first ferrocenyltin corrolate species. The isopropyl, sec-butyl-, 2-methyl-n-butyl-, phenyl-, 2-thienyl-, and ferrocenyltin species have been prepared and characterized through (1)H, (13)C, and (119)Sn HMQC NMR spectroscopy, mass spectrometry, UV-vis and photoluminescent spectroscopy, and cyclic voltammetry studies. J(C/H-Sn) NMR spectroscopic couplings and ring-current effects (upfield shifting) were determined for the R-Sn axial hydrogen and carbon atoms. This report adds to older conceptually similar reports, by, i.e., Janson et al. (J. Am. Chem. Soc. 1969, 91, 5210) and Walker et al. (J. Am. Chem. Soc.1983, 105, 6923-6929), as discussed herein. Such NMR spectroscopic aspects are discussed for these model systems. Compound Sn-Ph bond cleavage was achieved by treatment with I(2).

  3. Applications of synchrotron-based spectroscopic techniques in studying nucleic acids and nucleic acid-functionalized nanomaterials.

    Science.gov (United States)

    Wu, Peiwen; Yu, Yang; McGhee, Claire E; Tan, Li Huey; Lu, Yi

    2014-12-10

    In this review, we summarize recent progress in the application of synchrotron-based spectroscopic techniques for nucleic acid research that takes advantage of high-flux and high-brilliance electromagnetic radiation from synchrotron sources. The first section of the review focuses on the characterization of the structure and folding processes of nucleic acids using different types of synchrotron-based spectroscopies, such as X-ray absorption spectroscopy, X-ray emission spectroscopy, X-ray photoelectron spectroscopy, synchrotron radiation circular dichroism, X-ray footprinting and small-angle X-ray scattering. In the second section, the characterization of nucleic acid-based nanostructures, nucleic acid-functionalized nanomaterials and nucleic acid-lipid interactions using these spectroscopic techniques is summarized. Insights gained from these studies are described and future directions of this field are also discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. 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).

  5. Study on the interaction between amphiphilic drug and bovine serum albumin: A thermodynamic and spectroscopic description

    Energy Technology Data Exchange (ETDEWEB)

    Rub, Malik Abdul, E-mail: malikrub@gmail.com [Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah-21589 (Saudi Arabia); Khan, Javed Masood [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002 (India); Asiri, Abdullah M. [Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah-21589 (Saudi Arabia); Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah-21589 (Saudi Arabia); Khan, Rizwan Hasan, E-mail: rizwanhkhan1@gmail.com [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002 (India); Kabir-ud-Din [Department of Applied Chemistry, Aligarh Muslim University, Aligarh-202002 (India)

    2014-11-15

    Herein we report the interaction of amphiphilic drug clomipramine hydrochloride (CLP—a tricyclic antidepressant) with bovine serum albumin (BSA) studied by fluorescence, UV–vis, and circular dichroism (CD) spectroscopic techniques. Clomipramine hydrochloride is used to treat a variety of mental health problems. The quenching rate constant (k{sub q}) values, calculated according to the fluorescence data, decrease with increase in temperature indicating the static quenching procedure for the CLP–BSA interaction. The association binding constants (K{sub A}), evaluated at different conditions, and the thermodynamic parameters (free energy, enthalpy and entropy changes) indicate that the hydrophobic forces play a major role in the binding interaction of drug. The interaction of BSA with CLP was further confirmed by UV absorption spectra. Blue shift of position was detected due to the complex formation between the BSA–CLP. The molecular distance, r{sub 0}, between donor (BSA) and acceptor (CLP) was estimated by fluorescence resonance energy transfer (FRET) whose value (4.47 nm) suggests high probability of static quenching interaction. The CD results prove the conformational changes in the BSA on binding with the drug. Thus, the results supply qualitative and quantitative understanding of the binding of BSA to CLP, which is important in understanding their effect as therapeutic agents. - Highlights: • BSA can be considered as a good carrier for transportation of CLP in vivo. • The fluorescence results indicated the presence of static quenching mechanism in the binding process. • CD spectra showed the change in molecular conformation of BSA in the presence of CLP. • The results have applicability in model drug delivery.

  6. 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)

  7. Spectroscopic study of the light-harvesting protein C-phycocyanin associated with colorless linker peptides

    Energy Technology Data Exchange (ETDEWEB)

    Pizarro, Shelly Ann [Univ. of California, Berkeley, CA (United States)

    2000-05-01

    The phycobilisome (PBS) light-harvesting antenna is composed of chromophore-containing biliproteins and 'colorless' linker peptides and is structurally designed to support unidirectional transfer of excitation energy from the periphery of the PBS to its core. The linker peptides have a unique role in this transfer process by modulating the spectral properties of the associated biliprotein. There is only one three-dimensional structure of a biliprotein/linker complex available to date (APC/LC7.8) and the mechanism of interaction between these two proteins remains unknown. This study brings together a detailed spectroscopic characterization of C-Phycocyanin (PC)-linker complexes (isolated from Synechococcus sp. PCC 7002) with proteomic analysis of the linker amino acid sequences to produce a model for biliprotein/linker interaction. The amino acid sequences of the rod linkers [LR8.9, LR32.3 and LRC28.5] were examined to identify evolutionarily conserved regions important to either the structure or function of this protein family. Although there is not one common homologous site among all the linkers, there are strong trends across each separate subset (LC, LR and LRC) and the N-terminal segments of both LR32.3 and LRC28.5 display multiple regions of similarity with other linkers. Predictions of the secondary structure of LR32.3 and LRC28.5, and comparison to the crystal structure of LC7.8, further narrowed the candidates for interaction sites with the PC chromophores. Measurements of the absorption, fluorescence, CD and excitation anisotropy of PC trimer, PC/LR32.3, and PC/LRC28.5, document the spectroscopic effect of each linker peptide on the PC chromophores at a series of temperatures (298 to 77 K

  8. Study of the photodegradation of 2-bromophenol under UV and sunlight by spectroscopic, chromatographic and chemometric techniques.

    Science.gov (United States)

    Jayaraman, Anusha; Mas, Sílvia; Tauler, Romà; de Juan, Anna

    2012-12-01

    This work is focused on the study of the photodegradation of 2-bromophenol under the action of UV light and sunlight. The photodegradation process has been monitored using UV-Vis spectroscopy and High Performance Liquid Chromatography coupled to diode array and mass spectrometry detectors in tandem (HPLC-DAD-MS). Multivariate resolution methods, such as Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) and hybrid soft- and hard-modeling-Multivariate Curve Resolution (HS-MCR), have been applied to the experimental data to obtain the information about the kinetic evolution and identification of the compounds involved in the photodegradation process. From the analysis of HPLC-DAD results, the complexity of the photodegradation process has been confirmed. Ten components were found to be involved in parallel, second- or higher-order reactions, which could not be ascertained from the spectroscopic results. The HPLC-MS results allowed postulating the identity of some of the compounds (such as hydroxyderivatives and bromophenol homologs) which resulted from the reactions of photohydrolysis, debromination and bromine transfer to different position of the phenol ring. The effect of the UV light and sunlight on the photodegradation process was found to affect mainly the rate of the reaction, but not the identity of the photoproducts formed. The advantages and limitations of the spectroscopic and chromatographic analysis were also discussed. The potential of combining spectroscopic and chromatographic data in a single multiset structure was also shown. This strategy, uses the advantage of the good definition of the process time axis from the spectroscopic experiment and the capability to distinguish among compounds, linked to the use of chromatographic information. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. The biocompatibility of carbon hydroxyapatite/β-glucan composite for bone tissue engineering studied with Raman and FTIR spectroscopic imaging.

    Science.gov (United States)

    Sroka-Bartnicka, Anna; Kimber, James A; Borkowski, Leszek; Pawlowska, Marta; Polkowska, Izabela; Kalisz, Grzegorz; Belcarz, Anna; Jozwiak, Krzysztof; Ginalska, Grazyna; Kazarian, Sergei G

    2015-10-01

    The spectroscopic approaches of FTIR imaging and Raman mapping were applied to the characterisation of a new carbon hydroxyapatite/β-glucan composite developed for bone tissue engineering. The composite is an artificial bone material with an apatite-forming ability for the bone repair process. Rabbit bone samples were tested with an implanted bioactive material for a period of several months. Using spectroscopic and chemometric methods, we were able to determine the presence of amides and phosphates and the distribution of lipid-rich domains in the bone tissue, providing an assessment of the composite's bioactivity. Samples were also imaged in transmission using an infrared microscope combined with a focal plane array detector. CaF2 lenses were also used on the infrared microscope to improve spectral quality by reducing scattering artefacts, improving chemometric analysis. The presence of collagen and lipids at the bone/composite interface confirmed biocompatibility and demonstrate the suitability of FTIR microscopic imaging with lenses in studying these samples. It confirmed that the composite is a very good background for collagen growth and increases collagen maturity with the time of the bone growth process. The results indicate the bioactive and biocompatible properties of this composite and demonstrate how Raman and FTIR spectroscopic imaging have been used as an effective tool for tissue characterisation.

  10. Femtosecond electron diffraction and spectroscopic studies of a solid state organic chemical reaction

    Science.gov (United States)

    Jean-Ruel, Hubert

    Photochromic diarylethene molecules are excellent model systems for studying electrocyclic reactions, in addition to having important technological applications in optoelectronics. The photoinduced ring-closing reaction in a crystalline photochromic diarylethene derivative was fully resolved using the complementary techniques of transient absorption spectroscopy and femtosecond electron crystallography. These studies are detailed in this thesis, together with the associated technical developments which enabled them. Importantly, the time-resolved crystallographic investigation reported here represents a highly significant proof-of-principle experiment. It constitutes the first study directly probing the molecular structural changes associated with an organic chemical reaction with sub-picosecond temporal and atomic spatial resolution---to follow the primary motions directing chemistry. In terms of technological development, the most important advance reported is the implementation of a radio frequency rebunching system capable of producing femtosecond electron pulses of exceptional brightness. The temporal resolution of this newly developed electron source was fully characterized using laser ponderomotive scattering, confirming a 435 +/- 75 fs instrument response time with 0.20 pC bunches. The ultrafast spectroscopic and crystallographic measurements were both achieved by exploiting the photoreversibility of diarylethene. The transient absorption study was first performed, after developing a novel robust acquisition scheme for thermally irreversible reactions in the solid state. It revealed the formation of an open-ring excited state intermediate, following photoexcitation of the open-ring isomer with an ultraviolet laser pulse, with a time constant of approximately 200 fs. The actual ring closing was found to occur from this intermediate with a time constant of 5.3 +/- 0.3 ps. The femtosecond diffraction measurements were then performed using multiple crystal

  11. Electrochemical and spectroscopic studies of tungstencarbonyl complexes containing nitrogen and phosphorous ligands

    Directory of Open Access Journals (Sweden)

    Haddad Paula S.

    2000-01-01

    Full Text Available The present work deals with the synthesis, spectroscopic investigation and electrochemical behaviour of the compounds [W(CO4(bipy] (1, [W(CO3(bipy(dppm] (2 and [W(CO3(bipy(dppf] (3, bipy = 2,2'-bipyridine; dppm = bis(diphenylphosphinomethane; dppf = 1,1'-bis(diphenylphosphinoferrocene. The IR and 31P{¹H} NMR spectroscopic data have shown an octahedral coordination geometry for the tungsten atom with the diphosphines acting as monodentate ligands. The electrochemical behaviour of the complexes was investigated by cyclic voltammetry and controlled potential coulometry. Cyclic voltammograms have indicated that the compounds containing diphosphines ligands are more stable towards oxidation than compound (1.

  12. Hydrate formation during wet granulation studied by spectroscopic methods and multivariate analysis

    DEFF Research Database (Denmark)

    Jørgensen, Anna; Rantanen, Jukka; Karjalainen, Milja

    2002-01-01

    PURPOSE: The aim was to follow hydrate formation of two structurally related drugs, theophylline and caffeine, during wet granulation using fast and nondestructive spectroscopic methods. METHODS: Anhydrous theophylline and caffeine were granulated with purified water. Charge-coupled device (CCD......) Raman spectroscopy was compared with near-infrared spectroscopy (NIR) in following hydrate formation of drugs during wet granulation (off-line). To perform an at-line process analysis, the effect of water addition was monitored by NIR spectroscopy and principal components analysis (PCA). The changes...... in the crystal arrangements were verified by using X-ray powder diffraction (XRPD). RESULTS: Hydrate formation of theophylline and caffeine could be followed by CCD Raman spectroscopy. The NIR and Raman spectroscopic results were consistent with each other. NIR revealed the state of water, and Raman spectroscopy...

  13. Study on Biological Effects of La(3+) on Rat Liver Mitochondria by Microcalorimetric and Spectroscopic Methods.

    Science.gov (United States)

    Wu, Man; Gao, Jia-Ling; Feng, Zhi-Jiang; Liu, Wen; Zhang, Ye-Zhong; Liu, Yi; Dai, Jie

    2015-09-01

    The effects of lanthanum on heat production of mitochondria isolated from Wistar rat liver were investigated with microcalorimetry; simultaneously, the effects on mitochondrial swelling and membrane potential (Δψ) were determined by spectroscopic methods. La(3+) showed only inhibitory action on mitochondrial energy turnover with IC50 being 55.8 μmol L(-1). In the spectroscopic experiments, La(3+), like Ca(2+), induced rat liver mitochondrial swelling and decreased membrane potential (Δψ), which was inhibited by the specific permeability transition inhibitor, cyclosporine A (CsA). The induction ability of La(3+) was stronger than that of Ca(2+). These results demonstrated that La(3+) had some biotoxicity effect on mitochondria; the effects of La(3+) and Ca(2+) on rat liver mitochondrial membrane permeability transition (MPT) are different, and La represents toxic action rather than Ca analogy.

  14. Spectroscopic study of Alzheimer's amyloid fibrils using terahertz time domain spectroscopy

    International Nuclear Information System (INIS)

    Jung, Euna; Kim, Jeonghoi; Han, Younho; Moon, Kiwon; Lim, Meehyun; Han, Haewook; Park, Joonhyuck; Kim, Sungjee

    2008-01-01

    Alzheimer's disease, one of the most common neurodegenerative diseases, is characterized by extensive amyloid deposition. Amyloid deposits contain the abundant fibrils formed by amyloid β protein (Aβ). Because amyloid fibrils are associated with amyloid diseases, including Alzheimer's disease, type 2 diabetes, prion disease, Parkinson's disease, senile systemic amyloidosis and Huntington's disease, there has been considerable interest within the biomedical and biochemical research communities. In transmission electron microscopic (TEM)images, amyloid firils are 0.1∼10μm long and approximately 10nm wide. Amyloid fibrils commonly exhibit self assembled filaments, often described as twisted or parallel assemblies of finer protofilaments. They are formed by the spontaneous aggregation of a wide variety of peptides and proteins. Structural studies of amyloid fibrils have revealed that the common structural motif of virtually all amyloid fibrils consists of cross β sheets in which the peptide strands are arranged perpendicular to the long axis of the fiber. But little was known until recently about the molecular level structures of amyloid fibils. Therefore, spectroscopic investigation of both amyloid fibrils and Aβ at the molecular level can provide the significant evidence for the molecular understanding of amyloidogenesis and for the development of innovative therapeutic and diagnostic approaches. We used terahertz time domain spectroscopy (THz TDS)to investigate both Aβ and amyloid fibril. THz TDS, developed over the last two decades, is a powerful tool to extract the properties of biomaterials and provides unique spectral signatures of biomolecules within 0.1∼10THz, which exists between microwave and infrared frequency range. Current interest in THz radiation arises from its capability of probing the delocalized collective vibrational modes in proteins. Studying the collective modes of proteins in THz frequency range can play an

  15. Spectroscopic study of Alzheimer's amyloid fibrils using terahertz time domain spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Euna; Kim, Jeonghoi; Han, Younho; Moon, Kiwon; Lim, Meehyun; Han, Haewook; Park, Joonhyuck; Kim, Sungjee [POSTECH, Pohang (Korea, Republic of)

    2008-11-15

    Alzheimer's disease, one of the most common neurodegenerative diseases, is characterized by extensive amyloid deposition. Amyloid deposits contain the abundant fibrils formed by amyloid β protein (Aβ). Because amyloid fibrils are associated with amyloid diseases, including Alzheimer's disease, type 2 diabetes, prion disease, Parkinson's disease, senile systemic amyloidosis and Huntington's disease, there has been considerable interest within the biomedical and biochemical research communities. In transmission electron microscopic (TEM)images, amyloid firils are 0.1∼10μm long and approximately 10nm wide. Amyloid fibrils commonly exhibit self assembled filaments, often described as twisted or parallel assemblies of finer protofilaments. They are formed by the spontaneous aggregation of a wide variety of peptides and proteins. Structural studies of amyloid fibrils have revealed that the common structural motif of virtually all amyloid fibrils consists of cross β sheets in which the peptide strands are arranged perpendicular to the long axis of the fiber. But little was known until recently about the molecular level structures of amyloid fibils. Therefore, spectroscopic investigation of both amyloid fibrils and Aβ at the molecular level can provide the significant evidence for the molecular understanding of amyloidogenesis and for the development of innovative therapeutic and diagnostic approaches. We used terahertz time domain spectroscopy (THz TDS)to investigate both Aβ and amyloid fibril. THz TDS, developed over the last two decades, is a powerful tool to extract the properties of biomaterials and provides unique spectral signatures of biomolecules within 0.1∼10THz, which exists between microwave and infrared frequency range. Current interest in THz radiation arises from its capability of probing the delocalized collective vibrational modes in proteins. Studying the collective modes of proteins in THz frequency range can play an

  16. Fourier transform infrared spectroscopic study of intact cells of the nitrogen-fixing bacterium Azospirillum brasilense

    Science.gov (United States)

    Kamnev, A. A.; Ristić, M.; Antonyuk, L. P.; Chernyshev, A. V.; Ignatov, V. V.

    1997-06-01

    The data of Fourier transform infrared (FTIR) spectroscopic measurements performed on intact cells of the soil nitrogen-fixing bacterium Azospirillum brasilense grown in a standard medium and under the conditions of an increased metal uptake are compared and discussed. The structural FTIR information obtained is considered together with atomic absorption spectrometry (AAS) data on the content of metal cations in the bacterial cells. Some methodological aspects concerning preparation of bacterial cell samples for FTIR measurements are also discussed.

  17. Structure-dependent reactivity of Criegee intermediates studied with spectroscopic methods.

    Science.gov (United States)

    Jr-Min Lin, Jim; Chao, Wen

    2017-12-11

    Criegee intermediates are very reactive carbonyl oxides that are formed in reactions of unsaturated hydrocarbons with ozone (ozonolysis). Recently, Criegee intermediates have gained significant attention since a new preparation method has been reported in 2012, which employs the reaction of iodoalkyl radical with molecular oxygen: for instance, CH 2 I + O 2 → CH 2 OO + I. This new synthesis route can produce Criegee intermediates with a high number density, which allows direct detection of the Criegee intermediate via various spectroscopic tools, including vacuum UV photoionization mass spectrometry, absorption and action spectroscopy in the UV and IR regions, and microwave spectroscopy. Criegee intermediates have been thought to play important roles in atmospheric chemistry, such as in OH radical formation as well as oxidation of atmospheric gases such as SO 2 , NO 2 , volatile organic compounds, organic and inorganic acids, and even water. These reactions are relevant to acid rain and aerosol formation. Kinetics data including rate coefficients, product yields and their temperature and pressure dependences are important for understanding and modeling relevant atmospheric chemistry. In fundamental physical chemistry, Criegee intermediates have unique and interesting features, which have been partially revealed through spectroscopic, kinetic, and dynamic investigations. Although previous review articles have discussed Criegee intermediates, new data and knowledge on Criegee intermediates are still being accumulated. In this tutorial review, we have focused on structure-dependent reactivity of Criegee intermediates and various spectroscopic tools that have been utilized to probe the kinetics of Criegee intermediates.

  18. Physical and spectroscopic studies of Cr{sup 3+} doped mixed alkaline earth oxide borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Samdani, E-mail: samdanimohd82@gmail.com [Department of Engineering, Salalah College of Technology, Salalah (Oman); Ramadevudu, G. [Department of Physics, Vasavi College of Engineering, Ibrahimbagh, Hyderabad 500031, Telangana (India); Chary, M. Narasimha; Shareefuddin, Md. [Department of Physics, Osmania University, Hyderabad 500007, Telangana (India)

    2017-01-15

    A series of mixed alkaline earth oxide glasses xMgO-(30-x)BaO-69.8B{sub 2}O{sub 3}-0.2Cr{sub 2}O{sub 3} were prepared and studied using electron paramagnetic resonance (EPR), optical absorption, Raman spectroscopy and photoluminescence experimental techniques. The optical absorption spectra revealed the characteristic octahedral symmetry of Cr{sup 3+}ions through three broad band transitions {sup 4}A{sub 2g}(F)→ {sup 4}T{sub 2g}(F), {sup 4}A{sub 2g}(F)→ {sup 4}T{sub 1g}(F), and {sup 4}A{sub 2g}(F)→ {sup 2}T{sub 1g}(P). The crystal field (Dq) and Racah parameters (B and C), the optical band gap and Urbach energies of the glass samples were also reported along with the physical properties like density and molar volume. In the EPR spectra three resonance signals corresponding to Cr3+ ions were observed. A broad signal with g = 5.110 was observed which belongs to the isolated Cr3+ centers localized in the strongly distorted octahedral (rhombic) sites of the glass network, a narrow signal (g = 1.960) corresponding to the Cr{sup 3+} centers in the weekly distorted (cubic) sites of the glass network, and a third very broad signal (g = 2.210) was also observed corresponding to Cr{sup 3+}- Cr{sup 3+} paired centers coupled by magnetic dipolar interaction. Another resonance signal with effective value g ≈ 4.220 was attributed to Fe{sup 3+} ions impurity. The number of spins (N) participating in the resonance and susceptibility (χ) values at room temperature were reported and their values varied in a non-linear manner with the composition exhibiting mixed oxide effect. The estimated molecular bonding coefficients (α) values indicated stronger ionic contribution. The Raman spectral investigations were carried out. The Photoluminescence spectra bands near 690 and 750 nm correspond to the Cr{sup 3+} centers in high and low field sites respectively. - Highlights: • Spectroscopic studies were made on alkaline earth borate glasses. • Three resonance signals

  19. Time resolved spectroscopic investigation of SiD2 + D2: kinetic study

    Directory of Open Access Journals (Sweden)

    Al-Rubaiey Najem A.

    2017-01-01

    Full Text Available Silylenes (silanediyls have made an important impact on organosilicon chemistry even if it is of more recent foundation than carbenes in organic chemistry and much less complete. These species are highly reactive intermediates. They play a central role in the chemical vapour deposition (CVD of various silicon-containing thin films which have a technological importance in microelectronics as well as in the dry etching processes of silicon wafers. Spectroscopic methods have been developed to observe these species, a necessary pre-requisite to their direct monitoring. In this work, deuterated phenylsilane precursor, PhSiD3 was chosen for SiD2 because its analogue phenylsilane, PhSiH3 proved to be a good precursor for SiH2 and the high quality decay signals observed revealed that SiD2 be readily detected from PhSiD3 and that if other decomposition pathways (e.g. PhSiD + D2 are occurring, they do not effect measurements of the rate constants for SiD2. The absorption spectrum of SiD2 formed from the flash photolysis of a mixture of PhSiD3 and SF6 at 193nm were found in the region 17384-17391 cm-1 with strong band at 17387.07 cm-1. This single rotational line of pQ1 was chosen to monitor SiD2 removal. Time-resolved studies of SiD2 have been carried out to obtain rate constants for its bimolecular reactions with D2. The reactions were studied over the pressure range 5-100 Torr (in SF6 bath gas at four temperatures in the range 298-498K. Single decay from 10 photolysis laser shots were averaged and found to give reasonable first-order kinetics fits. Second order kinetics were obtained by pressure dependence of the pseudo first order decay constants and substance D2 pressures within experimental error. The reaction was found to be weakly pressure dependent at all temperatures, consistent with a third-body mediated association process. In addition, SiH2+ H2 reaction is approximately ca. 60% faster than SiD2+D2 reaction. Theoretical extrapolations (using

  20. Spectroscopic characterization, antimicrobial activity and molecular docking study of novel azo-imine functionalized sulphamethoxazoles

    Science.gov (United States)

    Sahu, Nilima; Mondal, Sudipa; Naskar, Kaushik; Mahapatra, Ananya Das; Gupta, Suvroma; Slawin, Alexandra M. Z.; Chattopadhyay, Debprasad; Sinha, Chittaranjan

    2018-03-01

    [SMXsbnd Ndbnd Nsbnd C6H3sbnd (p-OH)(msbnd CHO)] (1) reacts with ArNH2 to synthesize Schiff bases, [SMXsbnd Ndbnd Nsbnd C6H3sbnd (psbnd OH)(msbnd HCdbnd Nsbnd Ar)] (Ar = sbnd C6H5 (2a), sbnd C6H4sbnd psbnd CH3 (2b), sbnd C6H4sbnd psbnd OCH3 (2c), sbnd C6H4sbnd psbnd Cl (2d), sbnd C6H4sbnd psbnd NO2 (2e), sbnd C10H7 (2f)) and the products have been assessed for antibacterial properties against Gram positive bacteria, B. subtillis: IC50 (μg/ml): 39.2 (1), 60.1 (2a), 64.0 (2b), 85.6 (2c), 55.1 (2d), 88.4 (2e) and 65.1 (2f); and Gram negative bacteria, E. coli: IC50 (μg/ml): 159.0 (1), 151.4 (2a), 155.3 (2b), 140 (2c), 156.0 (2d), 153.5 (2e) and 157 (2f). The cell line toxicity (Vero cells) has also been evaluated with these compounds and EC50 (μg/ml) values are 129.9 (1), 74.2 (2a) and 93.0 (2b), 191.9 (2c), 99.1 (2d), 93.2 (2e) and 62.0 (2f). The anti-viral efficiency against harpies virus (HSVsbnd 1F ATCC-733) infection demonstrates that the compound 1 has highest selectivity index (CC50/EC50), 5.06 than the compounds 2a-f (CC50/EC50: 1.18 (2a), 1.42 (2b), 3.50 (2c), 1.45 (2d), 1.58 (2e), 1.29 (2f)). The compounds have been spectroscopically characterized and the structural confirmation has been established in one case by single crystal X-ray diffraction studies of 2c. In silico Molecular Docking study has been done using optimized geometries of the compounds to search the most favored binding mode of these drugs and hence useful to explain their competitive drug efficiency.

  1. Ellipsometry as a Nondestructive Depth Profiling Tool for Roll-to-Roll Manufactured Flexible Solar Cells

    DEFF Research Database (Denmark)

    Vesterager Madsen, Morten; Sylvester-Hvid, Kristian O.; Dastmalchi, Babak

    2011-01-01

    samples prepared by the spin coating technique. The solar cell device geometry was Kapton/Al/Cr/P3HT:PCBM/PEDOT:PSS/Ag. Variable angle ellipsometry was used to determine the optical dispersions of the pure phases of P3HT and PCBM allowing an effective medium approximation model to be employed...

  2. Spectroscopic studies of molecular iodine emitted into the gas phase by seaweed

    Directory of Open Access Journals (Sweden)

    S. M. Ball

    2010-07-01

    Full Text Available Time profiles of molecular iodine emissions from seven species of seaweed have been measured at high time resolution (7.5 s by direct spectroscopic quantification of the gas phase I2 using broadband cavity enhanced absorption spectroscopy. Substantial differences were found between species, both in the amounts of I2 emitted when the plants were exposed to air and in the shapes of their emission time profiles. Two species of kelp, Laminaria digitata and Laminaria hyperborea, were found to be the most potent emitters, producing an intense burst of I2 when first exposed to air. I2 was also observed from Saccharina latissima and Ascophyllum nodosum but in lower amounts and with broader time profiles. I2 mixing ratios from two Fucus species and Dictyopteris membranacea were at or below the detection limit of the present instrument (25 pptv. A further set of experiments investigated the time dependence of I2 emissions and aerosol particle formation when fragments of L. digitata were exposed to desiccation in air, to ozone and to oligoguluronate stress factors. Particle formation occurred in all L. digitata stress experiments where ozone and light were present, subject to the I2 mixing ratios being above certain threshold amounts. Moreover, the particle number concentrations closely tracked variations in the I2 mixing ratios, confirming the results of previous studies that the condensable particle-forming gases derive from the photochemical oxidation of the plant's I2 emissions. This work also supports the theory that particle nucleation in the coastal atmosphere occurs in "hot-spot" regions of locally elevated concentrations of condensable gases: the greatest atmospheric concentrations of I2 and hence of condensable iodine oxides are likely to be above plants of the most efficiently

  3. Enzymatic synthesis of tRNA-peptide conjugates and spectroscopic studies of fluorine-modified RNA

    International Nuclear Information System (INIS)

    Graber, D.

    2010-01-01

    possess the naturally occurring nucleoside modifications. Hence, an alternative process for access to 5'-fragments containing these modifications was needed. Starting from wild-type tRNA, a DNA-enzyme mediated position-specific cleavage at the desired cleavage site was elaborated. For quantitative cleavage, the introduction of repeated temperature cycles was inevitable. Dephosphorylation of the so obtained 2',3'-cyclophosphate cleavage products had to be performed prior to ligating the wild-type 5'-fragment by T4 RNA ligase to the chimeric 3'-fragment yielding the fully modified tRNA-peptide conjugate. The broad applicability of that approach was demonstrated by successful ligation of various tRNA, and tRNA from different species. In the second part of this thesis fluorinated nucleic acids were applied to 19F NMR spectroscopic investigations. One subproject concerned fluorinated nucleic acids for probing secondary structures. For that reason, a 2,4-difluorotoluyl-ribofuranose phosphoramidite was synthesized and site-specifically incorporated into oligonucleotides. As a proof of principle, the differentiation between monomolecular and bimolecular melting transitions was demonstrated by monitoring the temperature dependent alterations in the chemical shift signatures. It was also shown that oligonucleotides of self-complementary sequences - which simultaneously adopt different secondary structures - can be analyzed in terms of quantification of the coexisting populations. Moreover, melting temperatures determined by 19F NMR spectroscopy were in excellent accordance with those found using traditional UV-techniques. In another subproject, the interaction of tRNA pseudouridine synthase (TruB) with its TΨC loop tRNA substrate was studied using 19F NMR spectroscopy. So far, published contributions have focused on 5-fluorouridine substrate/enzyme reactions which were expected to result in a stable covalently linked RNA-enzyme complex. However, the enzyme was capable of

  4. 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...

  5. Towards Measurement of Polarization Properties of Skin using the Ellipsometry Technique

    Directory of Open Access Journals (Sweden)

    Pejhman Ghassemi

    2009-03-01

    Full Text Available Introduction: The human skin is an active medium from the optical point of view. Therefore, the diagnostic and therapeutic techniques employing light are increasing. Current optical techniques are based on the measurement of the intensity of reflected absorbed or backscattered light from or within skin. Studies have shown that biological tissues, and in particular skin, demonstrate polarization properties. Scattering of light from the surface of skin or the layers within it is a function of incident polarization. Therefore, by changing the polarization of the incident light and measuring the backscattered light, we can study those skin properties which affect the state of polarization. Material and methods: We have implemented a scattering ellipsometry system in order to investigate the polarization properties of a phantom representing skin. Using the Stocks vector defining the state of polarization and measuring the elements of the Mueller matrix representing the phantom under study, we have shown that by changing the reflection and scattering properties of the sample, polarization characteristics of the backscattered light will be affected. Results: The results of this investigation showed that some elements of the Mueller matrix of the phantom under study were affected by the polarization state of the incident light and the scattering component within the phantom. Therefore, these elements have the potential of being used as polarization markers of the biological tissue. Discussion and conclusion: Upon interaction of polarized light with the skin tissue, the backscattered light will contain optical and polarization information about the skin. Using a simple laboratory-made phantom, we have shown that by analyzing the polarization information within the backscattered light we can study the cause, and possibly the disease, which affected the polarization characteristics of the skin.

  6. IR spectroscopic study of the effect of ionizing radiation on the structure of polyacrylonitrile

    International Nuclear Information System (INIS)

    Platonova, N.V.; Klimenko, I.B.; Majburov, S.P.

    1993-01-01

    Based on an IR spectroscopic analysis, it is shown that the treatment of polyacrylonitrile films and fibers by gamma-irradiation leads to the cleavage of polymer chains, forming carbonyl-containing functional groups. The composition of these groups is found to depend on the treatment conditions. The presence of terminal methyl groups in the treated polymer is detected in its IR spectra only in the presence of residual basic solvent. The behaviour of the absorption bands in the range 1350-1380 cm -1 and at 970 cm -1 points to the occurrence of conformational changes in the polymer

  7. Spectroscopic study of the B[e] supergiant LHA 120-S 35

    Czech Academy of Sciences Publication Activity Database

    Torres, A.F.; Oksala, Mary E.; Cidale, L.S.; Kraus, Michaela; Borges Fernandes, M.; Barba, R.

    2012-01-01

    Roč. 55, č. 1 (2012), s. 155-158 E-ISSN 1669-9521. [Asociación Argentina de Astronomía : Reunion Anual. Mar del Plata, 17.09.2012-21.09.2012] R&D Projects: GA ČR(CZ) GAP209/11/1198; GA MŠk 7AMB12AR021 Institutional support: RVO:67985815 Keywords : LHA 120-S 35 * spectroscopic description Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics http://www.astronomiaargentina.org.ar/b55/boletin_55.pdf

  8. Hydrate formation during wet granulation studied by spectroscopic methods and multivariate analysis

    DEFF Research Database (Denmark)

    Jørgensen, Anna; Rantanen, Jukka; Karjalainen, Milja

    2002-01-01

    PURPOSE: The aim was to follow hydrate formation of two structurally related drugs, theophylline and caffeine, during wet granulation using fast and nondestructive spectroscopic methods. METHODS: Anhydrous theophylline and caffeine were granulated with purified water. Charge-coupled device (CCD......) Raman spectroscopy was compared with near-infrared spectroscopy (NIR) in following hydrate formation of drugs during wet granulation (off-line). To perform an at-line process analysis, the effect of water addition was monitored by NIR spectroscopy and principal components analysis (PCA). The changes...

  9. Multi-modal spectroscopic imaging with synchrotron light to study mechanisms of brain disease

    Science.gov (United States)

    Summers, Kelly L.; Fimognari, Nicholas; Hollings, Ashley; Kiernan, Mitchell; Lam, Virginie; Tidy, Rebecca J.; Takechi, Ryu; George, Graham N.; Pickering, Ingrid J.; Mamo, John C.; Harris, Hugh H.; Hackett, Mark J.

    2017-04-01

    The international health care costs associated with Alzheimer's disease (AD) and dementia have been predicted to reach $2 trillion USD by 2030. As such, there is urgent need to develop new treatments and diagnostic methods to stem an international health crisis. A major limitation to therapy and diagnostic development is the lack of complete understanding about the disease mechanisms. Spectroscopic methods at synchrotron light sources, such as FTIR, XRF, and XAS, offer a "multi-modal imaging platform" to reveal a wealth of important biochemical information in situ within ex vivo tissue sections, to increase our understanding of disease mechanisms.

  10. Application of spectroscopic methods to the study of ionizing radiation effects in polymers

    International Nuclear Information System (INIS)

    Jimenez P, G.

    1995-01-01

    In general the interaction of ionizing radiation with polymers generates physic-chemical changes. Aiming to quantity these changes, three spectroscopic analytical techniques were used (UV, IR and EPR) and the chemical corrosion technique was used for three DSTN (CR39, Lexan and Makrofol) which were exposed to two radiation types: electrons and gammas. The effects of radiation are compared. Also a correlation between the UV and Vg results in function of dose is presented. The possible causes of the increase in chemical corrosion are discussed. (Author)

  11. Multiple spectroscopic studies of the structural conformational changes of human serum albumin—Essential oil based nanoemulsions conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Sekar, Gajalakshmi; Sugumar, Saranya; Mukherjee, Amitava; Chandrasekaran, Natarajan, E-mail: nchandra40@hotmail.com

    2015-05-15

    Nanoemulsions have numerous biomedical applications. For the first time, we have investigated the effects of orange and eucalyptus essential oil based nanoemulsions towards the structural aspect of human serum albumin (HSA). Quenching effect of nanoemulsion against the intrinsic fluorescence potential of tryptophan and tyrosine residues were evidenced from the fluorescence spectroscopic analysis. Static quenching mechanism was found to lead the binding of HSA–nanoemulsion systems. Synchronous and three dimensional spectroscopic studies have revealed the possible changes to the aromatic environment of HSA by the nanoemulsion. UV–Visible spectroscopic studies have confirmed the existence of the ground state complex formation between HSA and the surface of nanoemulsions by exhibiting the hyper-chromic effect in a concentration dependant manner. FTIR spectroscopy revealed the slight alteration in the Amide I, II and III bands of HSA after interaction. FT-Raman spectroscopy showed the decrease in the Raman intensity of the aromatic amino acid residues and shift in the amide bands of HSA upon binding with the nanoemulsion. Dichoric band obtained from the far UV-CD spectra at 208 and 222 nm of HSA showed the corresponding decrease in the alpha-helical contents upon interaction with nanoemulsions. Near UV-CD spectra also showed the prominent changes in the aromatic positions of the amino acid residues of HSA on binding with nanoemulsions. The above study has extrapolated the side effect analysis of the nanoemulsions in pharmaceutical applications in vitro in reference to their interaction with serum proteins. - Highlights: • Orange and eucalyptus oil based nanoemulsions were formulated and characterized. • UV–Visible spectroscopy confirmed the ground state complex formation. • Fluorescence spectroscopy confirmed the molecular conformational changes. • FTIR spectroscopy deep-rooted the alteration in the amide bands of HSA. • FT-Raman spectroscopy established

  12. A flexible experimental setup for femtosecond time-resolved broad-band ellipsometry and magneto-optics

    Energy Technology Data Exchange (ETDEWEB)

    Boschini, F.; Hedayat, H.; Piovera, C.; Dallera, C. [Dipartimento di Fisica, Politecnico di Milano, p.zza Leonardo da Vinci 32, 20133 Milano (Italy); Gupta, A. [Department of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487 (United States); Carpene, E., E-mail: ettore.carpene@polimi.it [CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, p.zza Leonardo da Vinci 32, 20133 Milano (Italy)

    2015-01-15

    A versatile experimental setup for femtosecond time-resolved ellipsometry and magneto-optical Kerr effect measurements in the visible light range is described. The apparatus is based on the pump-probe technique and combines a broad-band probing beam with an intense near-infrared pump. According to Fresnel scattering matrix formalism, the analysis of the reflected beam at different polarization states of the incident probe light allows one to determine the diagonal and the off-diagonal elements of the dielectric tensor in the investigated sample. Moreover, the pump-probe method permits to study the dynamics of the dielectric response after a short and intense optical excitation. The performance of the experimental apparatus is tested on CrO{sub 2} single crystals as a benchmark.

  13. Using electrochemistry - total internal refection imaging ellipsometry to monitor biochemical oxygen demand on the surface tethered polyelectrolyte modified electrode

    Science.gov (United States)

    Liu, Wei; Li, Meng; Lv, Bei'er; Chen, YanYan; Ma, Hongwei; Jin, Gang

    2015-03-01

    Our previous work has proposed an electrochemistry - total internal reflection imaging ellipsometry (EC-TIRIE) technique to observe the dissolved oxygen (DO) reduction on Clark electrode since high interface sensitivity makes TIRIE a useful tool to study redox reactions on the electrode surface. To amplify the optical signal noise ratio (OSNR), a surface tethered weak polyelectrolyte, carboxylated poly(oligo(ethylene glycol) methacrylate-random- 2-hydroxyethylmethacrylate) (abbreviated as carboxylated poly(OEGMA-r-HEMA)), has been introduced on the electrode surface. Since Clark electrode is widely used in biochemical oxygen demand (BOD) detection, we use this technique to measure BOD in the sample. The dynamic range of the system is from 0 ˜ 25 mg/L. Two samples have been measured. Compared with the conventional method, the deviation of both optical and electrical signals are less than 10%.

  14. Detecting outliers and learning complex structures with large spectroscopic surveys - a case study with APOGEE stars

    Science.gov (United States)

    Reis, Itamar; Poznanski, Dovi; Baron, Dalya; Zasowski, Gail; Shahaf, Sahar

    2018-02-01

    In this work we apply and expand on a recently introduced outlier detection algorithm that is based on an unsupervised random forest. We use the algorithm to calculate a similarity measure for stellar spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). We show that the similarity measure traces non-trivial physical properties and contains information about complex structures in the data. We use it for visualization and clustering of the dataset, and discuss its ability to find groups of highly similar objects, including spectroscopic twins. Using the similarity matrix to search the dataset for objects allows us to find objects that are impossible to find using their best fitting model parameters. This includes extreme objects for which the models fail, and rare objects that are outside the scope of the model. We use the similarity measure to detect outliers in the dataset, and find a number of previously unknown Be-type stars, spectroscopic binaries, carbon rich stars, young stars, and a few that we cannot interpret. Our work further demonstrates the potential for scientific discovery when combining machine learning methods with modern survey data.

  15. FTIR and Raman spectroscopic studies of selenium nanoparticles synthesised by the bacterium Azospirillum thiophilum

    Science.gov (United States)

    Tugarova, Anna V.; Mamchenkova, Polina V.; Dyatlova, Yulia A.; Kamnev, Alexander A.

    2018-03-01

    Vibrational (Fourier transform infrared (FTIR) and Raman) spectroscopic techniques can provide unique molecular-level information on the structural and compositional characteristics of complicated biological objects. Thus, their applications in microbiology and related fields are steadily increasing. In this communication, biogenic selenium nanoparticles (Se NPs) were obtained via selenite (SeO32-) reduction by the bacterium Azospirillum thiophilum (strain VKM B-2513) for the first time, using an original methodology for obtaining extracellular NPs. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) showed the Se NPs to have average diameters within 160-250 nm; their zeta potential was measured to be minus 18.5 mV. Transmission FTIR spectra of the Se NPs separated from bacterial cells showed typical proteinacious, polysaccharide and lipid-related bands, in line with TEM data showing a thin layer covering the Se NPs surface. Raman spectra of dried Se NPs layer in the low-frequency region (under 500 cm-1 down to 150 cm-1) showed a single very strong band with a maximum at 250 cm-1 which, in line with its increased width (ca. 30 cm-1 at half intensity), can be attributed to amorphous elementary Se. Thus, a combination of FTIR and Raman spectroscopic approaches is highly informative in non-destructive analysis of structural and compositional properties of biogenic Se NPs.

  16. Applications of structural and spectroscopic techniques to the experimental and theoretical study of new luminescent materials

    CERN Document Server

    Navarro Ahumada, G A

    2001-01-01

    momentum:DELTA J = 6 is observed for this system. A declining cascade that can reasonably explain the unsuspected related spectral intensity, in the order of 10-9, is presented and suggested although a value was predicted for the electric dipolar force of lesser than 4 orders of magnitude what was observed. This problem is discussed and a mechanism is proposed for spectral intensities associated with two emissions characterized by DELTA J = 4 (electric hexadecapole) and DELTA J = 2 (electric cuadrupole). The laboratory tests made, include synthesis by solid state reactions of Dy sup 3 sup + and Ho sup 3 sup + , type elpasolites, structural characterization using the x-ray diffraction, neutron diffraction and diffuse neutron scattering techniques, and Raman and electronic spectroscopic characterization. Results are presented for cubic systems with Cr sup 3 sup + (3d sup 3 ) and Mo sup 3 sup + (4d sup 3 ) ions, since these are privileged from a spectroscopic point of view and except for the hexacyano ion of Cr(...

  17. Detecting outliers and learning complex structures with large spectroscopic surveys - a case study with APOGEE stars

    Science.gov (United States)

    Reis, Itamar; Poznanski, Dovi; Baron, Dalya; Zasowski, Gail; Shahaf, Sahar

    2018-05-01

    In this work, we apply and expand on a recently introduced outlier detection algorithm that is based on an unsupervised random forest. We use the algorithm to calculate a similarity measure for stellar spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). We show that the similarity measure traces non-trivial physical properties and contains information about complex structures in the data. We use it for visualization and clustering of the data set, and discuss its ability to find groups of highly similar objects, including spectroscopic twins. Using the similarity matrix to search the data set for objects allows us to find objects that are impossible to find using their best-fitting model parameters. This includes extreme objects for which the models fail, and rare objects that are outside the scope of the model. We use the similarity measure to detect outliers in the data set, and find a number of previously unknown Be-type stars, spectroscopic binaries, carbon rich stars, young stars, and a few that we cannot interpret. Our work further demonstrates the potential for scientific discovery when combining machine learning methods with modern survey data.

  18. Recent advances in biosynthetic modeling of nitric oxide reductases and insights gained from nuclear resonance vibrational and other spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Saumen; Reed, Julian; Sage, Timothy; Branagan, Nicole C.; Petrik, Igor D.; Miner, Kyle D.; Hu, Michael Y.; Zhao, Jiyong; Alp, E. Ercan; Lu, Yi

    2015-10-05

    This Forum Article focuses on recent advances in structural and spectroscopic studies of biosynthetic models of nitric oxide reductases (NORs). NORs are complex metalloenzymes found in the denitrification pathway of Earth's nitrogen cycle where they catalyze the proton-dependent twoelectron reduction of nitric oxide (NO) to nitrous oxide (N2O). While much progress has been made in biochemical and biophysical studies of native NORs and their variants, a. clear mechanistic understanding of this important metalloenzyme related to its function is still elusive. We report herein UV vis and nuclear resonance vibrational spectroscopy (NRVS) studies of mononitrosylated intermediates of the NOR reaction of a biosynthetic model. The ability to selectively substitute metals at either heme or nonheme metal sites allows the introduction of independent 57Fe probe atoms at either site, as well as allowing the preparation of analogues of stable reaction intermediates by replacing either metal with a redox inactive metal. Together with previous structural and spectroscopic results, we summarize insights gained from studying these biosynthetic models toward understanding structural features responsible for the NOR activity and its mechanism. As a result, the outlook on NOR modeling is also discussed, with an emphasis on the design of models capable of catalytic turnovers designed based on close mimics of the secondary coordination sphere of native NORs.

  19. Ellipsometry and energy characterization of the electron impact polymerization in the range 0–20 eV

    International Nuclear Information System (INIS)

    Zyn, V.I.

    2016-01-01

    The electron impact polymerization of adsorbed vapors of a hydrocarbon vacuum oil with molecular mass 450 Da (C 32 H 66 ) has been studied in-situ in the range 0–20 eV using ellipsometry and a servo system with the Kelvin's vibrating probe. This allowed registering at the same time the two energy-dependent characteristics (spectra) of the process: the film growth rate and the electrical potential of the irradiated surface. The first spectrum has two resonance maxima near 2.5 and 9.5 eV while the surface potential has only one weak extremum near 9.5 eV. The first growth rate peak at 2.5 eV was connected with a creation of radicals through a resonant process of the dissociative electron attachment and beginning polymerization. The peaks at 9.5 eV in both the spectra mean accelerating polymerization and decreasing surface charge owing to simultaneous birth of highly active radicals and free electrons. The single resonant process controlling both the processes simultaneously is the dissociative attachment of an electron to an anti-bonding molecular orbital, almost the same as at the 2.5 eV but differing by deeper decomposition of the transient anion, among the products of which are now not the radicals only but also free electrons. The kinetic curves obtained in pulsed regimes of the electron bombardment were qualitatively identical for different precursors and were used for calculations of cross sections of these processes. - Highlights: • Obtaining spectra of activated polymerization using ellipsometry and Kelvin probe. • Identified: two resonant and one non-resonant mechanisms of the activation. • The resonances are due to the action of the dissociative electron attachment. • Kinetics of transient processes in adsorbed layer under 20 eV pulsed electron beam.

  20. SPECTROSCOPIC ANALYSIS OF FIVE PHYLOGENETICALLY DISTANT FUNGI (DIVISION: ASCOMYCETE FROM VELLAR ESTUARY, SOUTHEAST COAST OF INDIA – A PILOT STUDY

    Directory of Open Access Journals (Sweden)

    Jayachandran Subburaj

    2013-04-01

    Full Text Available Fungal taxonomy is dynamically driven towards controversial discipline that consequently requires changes in nomenclature. Scarcity of microbiological expertise particularly for marine fungi is another major setback for these taxonomical differences. Here, five different species pharmacologically important marine fungi under Division Ascomycete were studied for their spectral variation. This work verified the practical applicability of FT-IR microspectroscopy technique for early and rapid identification of these species based on the spectral data showed striking difference with their major biomolecules such as lipids, proteins and nucleic acids produced by them. Spectra of all the species showed striking differences while individual peaks of each spectrum are parallel to each other in their respective spectral regions. Aspergillus oryzae have intense peaks in the lipid and nucleic acid spectral region and moderate bands in the amide spectrum. Phoma herbarum and Trichoderma piluliferum showed intense peaks in the protein spectral region but moderate peaks in the lipid and nucleic acid regions. Hypocrea lixii and Meyerozyma guilliermandii have less intense peaks in all the five spectral regions. This unique spectral representation is concordant with the cluster analysis dendrogram by minimum variance statistical method where low spectroscopic distance was found between H. lixii and M. guilliermondii whereas a higher spectroscopic distance was found between P. herbarum and T. piluliferum. FTIR spectroscopy delivers a combined advantage for efficient fungal classification as well as simultaneous visualization of chemical composition of samples as evident from this study.

  1. Fourier transform infrared spectroscopic study of gamma irradiated SiO2 nanoparticles

    Science.gov (United States)

    Huseynov, Elchin; Garibov, Adil; Mehdiyeva, Ravan; Huseynova, Efsane

    2018-03-01

    In the present work, nano SiO2 particles are investigated before and after gamma irradiation (25, 50, 75, 100 and 200 kGy) using Fourier transform infrared (FTIR) spectroscopy method for the wavenumber between 400-4000 cm-1. It is found that as a result of spectroscopic analysis, five new peaks have appeared after gamma radiation. Two of new obtained peaks (which are located at 687 cm-1 and 2357 cm-1 of wavenumber) were formed as a result of gamma radiation interaction with Si-O bonds. Another three new peaks (peaks appropriate to 941, 2052 and 2357 cm-1 values of wavenumber) appear as a result of interaction of water with nano SiO2 particles after gamma irradiation. It has been defined as asymmetrical bending vibration, symmetrical bending vibration, symmetrical stretching vibration and asymmetrical stretching vibration of Si-O bonds appropriate to peaks.

  2. Synthesis, structure, spectroscopic investigations, and computational studies of optically pure β-ketoamide

    Energy Technology Data Exchange (ETDEWEB)

    Mtat, D.; Touati, R. [Université de Monastir, Laboratoire de Synthèse Organique Asymétrique et Catalyse Homogène (UR11ES56), Faculté des Sciences (Tunisia); Guerfel, T., E-mail: taha-guerfel@yahoo.fr [Université de Kairouan, Laboratoire d’Electrochimie, Matériaux et Environnement (Tunisia); Walha, K. [Université de Sfax, M.E.S.Lab. Faculté des Sciences de Sfax (Tunisia); Ben Hassine, B. [Université de Monastir, Laboratoire de Synthèse Organique Asymétrique et Catalyse Homogène (UR11ES56), Faculté des Sciences (Tunisia)

    2016-12-15

    Chemical preparation, X-ray single crystal diffraction, IR and NMR spectroscopic investigations of a novel nonlinear optical organic compound (C{sub 17}H{sub 22}NO{sub 2}Cl) are described. The compound crystallizes in the orthorhombic system with the non-centrosymmetric sp. gr. P2{sub 1}2{sub 1}2{sub 1}. In the crystal structure, molecules are interconnected by N–H…O hydrogen bonds forming infinite chains along a axis. The Hirshfeld surface and associated fingerprint plots of the compound are presented to explore the nature of intermolecular interactions and their relative contributions in building the solid-state architecture. The molecular HOMO–LUMO compositions and their respective energy gaps are also drawn to explain the activity of the compound. The first hyperpolarizability β{sub tot} of the title compound is determined using DFT calculations. The optical properties are also investigated by UV–Vis absorption spectrum.

  3. A Spectroscopic Study of Impurity Behavior in Neutral-beam and Ohmically Heated TFTR Discharges

    Science.gov (United States)

    Stratton, B. C.; Ramsey, A. T.; Boody, F. P.; Bush, C. E.; Fonck, R. J.; Groenbner, R. J.; Hulse, R. A.; Richards, R. K.; Schivell, J.

    1987-02-01

    Quantitative spectroscopic measurements of Z{sub eff}, impurity densities, and radiated power losses have been made for ohmic- and neutral-beam-heated TFTR discharges at a plasma current of 2.2 MA and toroidal field of 4.7 T. Variations in these quantities with line-average plasma density (anti n{sub e}) and beam power up to 5.6 MW are presented for discharges on a graphite movable limiter. A detailed discussion of the use of an impurity transport model to infer absolute impurity densities and radiative losses from line intensity and visible continuum measurements is given. These discharges were dominated by low-Z impurities with carbon having a considerably higher density than oxygen, except in high-anti n{sub e} ohmic discharges, where the densities of carbon and oxygen were comparable. Metallic impurity concentrations and radiative losses were small, resulting in hollow radiated power profiles and fractions of the input power radiated being 30 to 50% for ohmic heating and 30% or less with beam heating. Spectroscopic estimates of the radiated power were in good agreement with bolometrically measured values. Due to an increase in the carbon density, Z{sub eff} rose from 2.0 to 2.8 as the beam power increased from 0 to 5.6 MW, pointing to a potentially serious dilution of the neutron-producing plasma ions as the beam power increased. Both the low-Z and metallic impurity concentrations were approximately constant with minor radius, indicating no central impurity accumulation in these discharges.

  4. Thermal stability and hot-stage Raman spectroscopic study of Ca-montmorillonite modified with different surfactants: A comparative study

    International Nuclear Information System (INIS)

    Sun, Zhiming; Park, Yuri; Zheng, Shuilin; Ayoko, Godwin A.; Frost, Ray L.

    2013-01-01

    Highlights: • A typical Ca-montmorillonite was modified with three surfactants through ion exchange. • The organoclays were characterized by XRD, TG and hot stage Raman. • The structural geometry and thermal properties of organoclays were analyzed. • The prepared organoclays show potential prospects in the environmental remediation. - Abstract: Three long chain cationic surfactants were intercalated into Ca-montmorillonite through ion exchange and the obtained organoclays were characterized by X-ray diffraction (XRD), high resolution thermogravimetric analysis (TG) and Raman spectroscopy. The intercalation of surfactants not only changes the surface properties of clay from hydrophilic to hydrophobic but also greatly increases the basal spacing of the interlayers based on XRD analysis. The thermal stability of organoclays intercalated with three surfactants (TTAB, DTAB and CTAB) and the different arrangements of the surfactant molecules intercalated into Ca-montmorillonite were determined by TG-DTG analysis. A Raman spectroscopic study on the Ca-montmorillonite modified by three surfactants prepared at different concentrations provided the detailed conformational ordering of different intercalated long-chain surfactants under different conditions. The wavenumber of the antisymmetric stretching mode is more sensitive than that of the symmetric stretching mode to the mobility of the tail of the amine chain. At room temperature, the conformational ordering is more easily affected by the packing density in the lateral model. With the increase of the temperature, the positions of both the antisymmetric and symmetric stretching bands shift to higher wavenumbers, which indicates a decrease of conformational ordering. This study offers new insights into the structure and properties of Ca-montmorillonite modified with different long chain surfactants. Moreover, the experimental results confirm the potential applications of organic Ca-montmorillonites for the removal

  5. X-Ray Beam Studies of Charge Sharing in Small Pixel, Spectroscopic, CdZnTe Detectors

    Science.gov (United States)

    Allwork, Christopher; Kitou, Dimitris; Chaudhuri, Sandeep; Sellin, Paul J.; Seller, Paul; Veale, Matthew C.; Tartoni, Nicola; Veeramani, Perumal

    2012-08-01

    Recent advances in the growth of CdZnTe material have allowed the development of small pixel, spectroscopic, X-ray imaging detectors. These detectors have applications in a diverse range of fields such as medical, security and industrial sectors. As the size of the pixels decreases relative to the detector thickness, the probability that charge is shared between multiple pixels increases due to the non zero width of the charge clouds drifting through the detector. These charge sharing events will result in a degradation of the spectroscopic performance of detectors and must be considered when analyzing the detector response. In this paper charge sharing and charge loss in a 250 μm pitch CdZnTe pixel detector has been investigated using a mono-chromatic X-ray beam at the Diamond Light Source, U.K. Using a 20 μm beam diameter the detector response has been mapped for X-ray energies both above (40 keV) and below (26 keV) the material K-shell absorption energies to study charge sharing and the role of fluorescence X-rays in these events.

  6. Spectroscopic and molecular docking studies on the interaction of human serum albumin with copper(II) complexes

    Science.gov (United States)

    Guhathakurta, Bhargab; Pradhan, Ankur Bikash; Das, Suman; Bandyopadhyay, Nirmalya; Lu, Liping; Zhu, Miaoli; Naskar, Jnan Prakash

    2017-02-01

    Two osazone based ligands, butane-2,3-dione bis(2‧-pyridylhydrazone) (BDBPH) and hexane-3,4-dione bis(2‧-pyridylhydrazone) (HDBPH), were synthesized out of the 2:1 M Schiff base condensation of 2-hydrazino pyridine respectively with 2,3-butanedione and 3,4-hexanedione. The X-ray crystal structures of both the ligands have been determined. The copper(II) complex of HDBPH has also been synthesized and structurally characterized. HDBPH and its copper(II) complex have thoroughly been characterized through various spectroscopic and analytical techniques. The X-ray crystal structure of the copper complex of HDBPH shows that it is a monomeric Cu(II) complex having 'N4O2' co-ordination chromophore. Interaction of human serum albumin (HSA) with these ligands and their monomeric copper(II) complexes have been studied by various spectroscopic means. The experimental findings show that the ligands as well as their copper complexes are good HSA binders. Molecular docking investigations have also been done to unravel the mode of binding of the species with HSA.

  7. UDP-GlcNAc Analogs as Inhibitors of O-GlcNAc Transferase (OGT): Spectroscopic, Computational and Biological Studies.

    Science.gov (United States)

    Merino, Pedro; Ghirardello, Mattia; Perrone, Daniela; Chinaglia, Nicola; Sadaba, David; Delso, Ignacio; Tejero, Tomas; Marchesi, Elena; Fogagnolo, Marco; Rafie, Karim; van Aalten, Daan M F

    2018-03-07

    A series of glycomimetics of UDP-GlcNAc in which the β-phosphate has been replaced by either an alkyl chain or a triazolyl ring and the sugar moiety has been replaced by a pyrrolidine ring have been synthesized by using different click-chemistry procedures. Their affinity for human O-GlcNAc transferase (hOGT) has been evaluated and both spectroscopically and computationally studied. The binding epitopes of the best ligands have been determined in solution using saturation transfer difference (STD) NMR spectroscopy. Experimental, spectroscopic and computational results are in agreement, pointing out the essential role for binding of the β-phosphate. We have found that the loss of interactions from the -phosphate can be counterbalanced by the presence of hydrophobic groups at a pyrroline ring acting as a surrogate of the carbohydrate unit. Two of the glycomimetics prepared reach inhibition in the micromolar scale. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Note: Grazing incidence small and wide angle x-ray scattering combined with imaging ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Koerstgens, V.; Meier, R.; Ruderer, M. A.; Guo, S.; Chiang, H.-Y.; Mueller-Buschbaum, P. [Technische Universitaet Muenchen, Physik-Department, Lehrstuhl fuer Funktionelle Materialien, James-Franck-Str. 1, 85748 Garching (Germany); Perlich, J.; Roth, S. V.; Gehrke, R. [HASYLAB, DESY, Notkestr. 85, 22607, Hamburg (Germany)

    2012-07-15

    The combination of grazing incidence small angle x-ray scattering (GISAXS) and grazing incidence wide angle x-ray scattering (GIWAXS) with optical imaging ellipsometry is presented as an upgrade of the available measurement techniques at the wiggler beamline BW4 of the Hamburger Synchrotronstrahlungslabor. The instrument is introduced with the description of the alignment procedure to assure the measurement of imaging ellipsometry and GISAXS/GIWAXS on the same sample spot. To demonstrate the possibilities of the new instrument examples of morphological investigation on films made of poly(3-hexylthiophene) and [6,6]-phenyl-C{sub 61} butyric acid methyl ester as well as textured poly(9,9-dioctylfluorene-alt-benzo-thia-diazole) are shown.

  9. Single shot ultrafast dynamic ellipsometry (UDE) of laser-driven shocks in single crystal explosives

    Energy Technology Data Exchange (ETDEWEB)

    Whitley, Von H [Los Alamos National Laboratory; Mcgrane, Shawn D [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory; Eakins, Dan E [Los Alamos National Laboratory; Bolme, Cindy A [Los Alamos National Laboratory

    2009-01-01

    We report on the first experiments to measure states in shocked energetic single crystals with dynamic ellipsometry. We demonstrate that these ellipsometric techniques can produce reasonable Hugoniot values using small amounts of crystalline RDX and PETN. Pressures, particle velocities and shock velocities obtained using shocked ellipsometry are comparable to those found using gas-gun flyer plates and molecular dynamics calculations. The adaptation of the technique from uniform thin films of polymers to thick non-perfect crystalline materials was a significant achievement. Correct sample preparation proved to be a crucial component. Through trial and error, we were able to resolve polishing issues, sample quality problems, birefringence effects and mounting difficulties that were not encountered using thin polymer films.

  10. Synthesis, spectroscopic and molecular docking studies of imidazolium and pyridinium based ionic liquids with HSA as potential antimicrobial agents

    Science.gov (United States)

    Trush, Maria M.; Semenyuta, Ivan V.; Vdovenko, Sergey I.; Rogalsky, Sergiy P.; Lobko, Evgeniya O.; Metelytsia, Larisa O.

    2017-06-01

    The interaction between human serum albumin (HSA) and synthesized imidazolium and pyridinium based ionic liquids (ILs), as good potential microbial growth inhibitors, was investigated by spectroscopic techniques combined with molecular docking analysis. All compounds were significant active against the tested bacterial and fungal strains. FT-IR spectroscopy indicated that the interaction of HSA with ILs generates considerable changes in protein secondary structure. The results of the molecular docking study showed that the studied ILs are able to firmly bind in the subdomain IIA of HSA with almost equal binding affinity (about -6.23 kcal/mol). Investigated HSA-ILs complex binds through hydrogen bonding or/and cation-π interactions. This study provides a better understanding of the binding of imidazolium and pyridinium based ILs to HSA and opens the way for their further biological and pharmaceutical investigations as candidates with antimicrobial properties.

  11. Ellipsometry and electronic microscopy of ashes swept of the Popocatepetl volcano; Elipsometria y microscopia electronica de barrido de las cenizas del volcan Popocatepetl

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Aaron; Munoz, Rafel; Falcon, Nelson [Universidad de Carabobo, Valencia (Venezuela); Chavira, Enrique [Instituto Nacional de Astrofisica Optica y Electronica, Puebla (Mexico)

    2001-12-01

    The ellipsometry and the scanning electronic microscopy is applied to the study of the optic properties of Popocatepetl volcano ash in connection with the form, ruggedness and elemental chemical composition of the microparticles, also to argue about the relation with atmospheric conditions. [Spanish] Se aplica la eliposometria y la microscopia electronica de barrido al estudio de las propiedades opticas de las cenizas de volcan Popocatepetl en relacion con la forma, rugosidad y composicion quimica elemental de las microparticulas, destacandose su vinculacion con las condiciones de visibilidad.

  12. Investigation of the binding mechanism and inhibition of bovine liver catalase by quercetin: Multi-spectroscopic and computational study.

    Science.gov (United States)

    Rashtbari, Samaneh; Dehghan, Gholamreza; Yekta, Reza; Jouyban, Abolghasem

    2017-01-01

    Introduction: The study on the side effects of various drugs and compounds on enzymes is a main issue for monitoring the conformational and functional changes of them. Quercetin (3,5,7,3',4'-pentahydroxyflavone, QUE), a polyphenolic flavonoid, widely found in fruits, vegetables and it is used as an ingredient in foods and beverages. The interaction of bovine liver catalase (BLC) with QUE has been studied in this research by using different spectroscopic methods. Methods: In this work, the interaction of QUE with BLC was investigated using different spectroscopic methods including ultraviolet-visible (UV-vis) absorption, circular dichroism (CD) and fluorescence spectroscopy and molecular docking studies. Results: Fluorescence data at different temperatures, synchronous fluorescence and CD studies revealed conformational changes in the BLC structure in the presence of different concentration of QUE. Also, the fluorescence quenching data showed that QUE can form a non-fluorescent complex with BLC and quench its intrinsic emission by a static process. The binding constant (Ka) for the interaction was 104, and the number of binding site was obtained ~1. The ∆H, ∆S and ∆G changes were obtained, indicating that hydrophobic interactions play a main role in the complex formation. In vitro kinetic studies revealed that QUE can inhibit BLC activity through non-competitive manner. Molecular docking study results were in good agreement with experimental data, confirming only one binding site on BLC for QUE at a cavity among the wrapping domain, threating arm and β-barrel. Conclusion: Inhibition of BLC activity upon interaction with QUE demonstrated that in addition to their beneficial effects, they should not be overlooked for their side effects.

  13. Spectroscopic and theoretical studies of Ga(III)protoporphyrin-IX and its reactions with myoglobin.

    Science.gov (United States)

    Pinter, Tyler B J; Dodd, Erin L; Bohle, D Scott; Stillman, Martin J

    2012-03-19

    Ga(III)protoporphyrin-IX (Ga-PP) has been proposed as a model for the key interporphyrin interactions in malaria pigment. Unlike the paramagnetic parent iron heme derivatives, Ga-PP is readily soluble in methanol (MeOH). We report optical, mass spectroscopic, and theoretical results for Ga-PP as well as its reactions with myoglobin. UV-visible absorption and MCD spectroscopy show that Ga-PP exhibits a typical spectrum for a main group metal: a Q-band at 539 nm and a B band at 406 nm when dissolved in MeOH. We also report optical data for Zn(II)protoporphyrin IX (Zn-PP) dissolved in MeOH, which exhibits a Q-band at 545 nm and a B band at 415 nm. ESI mass spectral data for Ga-PP dissolved in MeOH show the presence of predominantly monomers, with smaller fractions of dimers [(Ga-PP)(2)] and trimers. UV-visible and MCD absorption spectroscopy and ESI mass spectral data demonstrate the successful insertion of monomeric Ga-PP into apo-Mb. Ga-PP-Mb exhibits a B band at 417 nm and Q bands at 545 and 584 nm, which are all red-shifted from the free Ga-PP values. The calculated electronic structures and frontier molecular orbitals of Ga-PP, (Ga-PP)(2) and Zn-PP fit the previously reported trends in band energies and oscillator strengths as a function of molecular orbital energies. These new data can be applied to explain the experimentally observed optical spectroscopy. The observed Q-band energies are accounted for by calculated (HOMO-LUMO) gap of the frontier MOs, while the split in the two top occupied MOs accounts for the magnitude of the Q-band oscillator strength as well as the experimentally observed Q to B band energy separation. Although Ga-PP shares more spectroscopic properties with Zn-PP than it does with Fe(III)PPIX, the trivalent oxidation state allows this molecule to be used as a model for ferric hemes in heme proteins. © 2012 American Chemical Society

  14. Measurement of the surface susceptibility and the surface conductivity of atomically thin MoS2 by spectroscopic ellipsometry

    KAUST Repository

    Jayaswal, Gaurav

    2018-02-06

    We show how to correctly extract from the ellipsometric data the surface susceptibility and the surface conductivity that describe the optical properties of monolayer MoS. Theoretically, these parameters stem from modelling a single-layer two-dimensional crystal as a surface current, a truly two-dimensional model. Current experimental practice is to consider this model equivalent to a homogeneous slab with an effective thickness given by the interlayer spacing of the exfoliating bulk material. We prove that the error in the evaluation of the surface susceptibility of monolayer MoS, owing to the use of the slab model, is at least 10% or greater, a significant discrepancy in the determination of the optical properties of this material.

  15. Probing the inhibitory potency of epigallocatechin gallate against human γB-crystallin aggregation: Spectroscopic, microscopic and simulation studies

    Science.gov (United States)

    Chaudhury, Susmitnarayan; Dutta, Anirudha; Bag, Sudipta; Biswas, Pranandita; Das, Amit Kumar; Dasgupta, Swagata

    2018-03-01

    Aggregation of human ocular lens proteins, the crystallins is believed to be one of the key reasons for age-onset cataract. Previous studies have shown that human γD-crystallin forms amyloid like fibres under conditions of low pH and elevated temperature. In this article, we have investigated the aggregation propensity of human γB-crystallin in absence and presence of epigallocatechin gallate (EGCG), in vitro, when exposed to stressful conditions. We have used different spectroscopic and microscopic techniques to elucidate the inhibitory effect of EGCG towards aggregation. The experimental results have been substantiated by molecular dynamics simulation studies. We have shown that EGCG possesses inhibitory potency against the aggregation of human γB-crystallin at low pH and elevated temperature.

  16. Spectroscopic studies of Eu(III) Keggin's and Dawson's polyoxotungstates substituted by acetato and oxalato ligands

    International Nuclear Information System (INIS)

    But, Slawomir; Lis, Stefan

    2008-01-01

    Eu(III) Keggin's and Dawson's type of polyoxometalates (POM) complexes were synthesized and spectroscopically characterized. This work presents results obtained for chosen hybrids of acetato K 12 [{Eu(SiMo x W 11-x O 39 )(H 2 O)} 2 (CH 3 COO) 2 ].nH 2 O, K 16 [{Eu(CH 3 COO)(H 2 O) 2 (P 2 W 17 O 61 )} 2 ].nH 2 O and oxalato (NH 4 ) 29 K 5 [{Eu(P 2 W 17 O 61 )} 4 (C 2 O 4 ) 3 (H 2 O) 4 ].nH 2 O, where x = 0, 1. The solid state compositions of the hybrids were characterized by using elemental and ICP-AES analysis, derivatography and FTIR spectroscopy. Luminescence characteristics (intensity, quantum yields, luminescence lifetimes and excitation spectra in the range of the 5 D 0 7 F 0 transition) of the synthesized Eu(III) acetato and oxalato complexes were determined in the solid phase and in solution, and they were compared to their parent Eu(III):POM complexes of 1:1 stoichiometry (ML)

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

    Science.gov (United States)

    Liu, Wen-xin; Coveney, R M; Tang, Hong-xiao

    2003-07-01

    FT-IR, Raman microscopy, XRD, 29Si and 27Al MAS NMR, were used to investigate changes in surface properties of a natural illite sample 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 with acid, then increased after hydroxide back titration. The varied ratio of signal intensity between (IV)Al and (VI)Al species in 27Al MAS NMR spectra, together with the stable BET surface area after acidimetric titration, suggested that edge faces and basal planes in the layer structure of illite participated in dissolution of structural components. The combined spectroscopic evidence demonstrated that the reactions between illite surfaces and acid-leaching silicic acid and aluminum ions should be considered in the model description of surface acid-base properties of the aqueous illite.

  18. Infrared Spectroscopic Study For Structural Investigation Of Lithium Lead Silicate Glasses

    International Nuclear Information System (INIS)

    Ahlawat, Navneet; Aghamkar, Praveen; Ahlawat, Neetu; Agarwal, Ashish; Monica

    2011-01-01

    Lithium lead silicate glasses with composition 30Li 2 O·(70-x)PbO·xSiO 2 (where, x = 10, 20, 30, 40, 50 mol %)(LPS glasses) were prepared by normal melt quench technique at 1373 K for half an hour in air to understand their structure. Compositional dependence of density, molar volume and glass transition temperature of these glasses indicates more compactness of the glass structure with increasing SiO 2 content. Fourier transform infrared (FTIR) spectroscopic data obtained for these glasses was used to investigate the changes induced in the local structure of samples as the ratio between PbO and SiO 2 content changes from 6.0 to 0.4. The observed absorption band around 450-510 cm -1 in IR spectra of these glasses indicates the presence of network forming PbO 4 tetrahedral units in glass structure. The increase in intensity with increasing SiO 2 content (upto x = 30 mol %) suggests superposition of Pb-O and Si-O bond vibrations in absorption band around 450-510 cm -1 . The values of optical basicity in these glasses were found to be dependent directly on PbO/SiO 2 ratio.

  19. Combined FT-Raman spectroscopic and mass spectrometric study of ancient Egyptian sarcophagal fragments.

    Science.gov (United States)

    Edwards, Howell G M; Stern, Ben; Villar, Susana E Jorge; David, A Rosalie

    2007-02-01

    The application of combined Raman spectroscopic and GC-MS analytical techniques for the characterisation of organic varnish residues from Egyptian Dynastic funerary sarcophagal and cartonnage fragments from the Graeco-Roman period, ca. 2200 BP, is described. The nondestructive use of Raman spectroscopy was initially employed to derive information about the specific location of organic material on the specimens, which were then targeted in specific areas using minimal sampling for GC-MS analysis. In the case of the sarcophagal fragment, a degraded yellow-brown surface treatment was identified as a Pistacia spp. resin; this provides additional evidence for the use of this resin, which has previously been identified in Canaanite transport amphorae, varnishes and "incense" bowls in an Egyptian Late Bronze Age archaeological context. The cartonnage fragment also contained an organic coating for which the Raman spectrum indicated a degradation that was too severe to facilitate identification, but the GC-MS data revealed that it was composed of a complex mixture of fatty acid residues. The combined use of GC-MS and Raman spectroscopy for the characterisation of organic materials in an archaeological context is advocated for minimisation of sampling and restriction to specifically identified targets for museum archival specimens.

  20. A COMBINED SPECTROSCOPIC AND PHOTOMETRIC STELLAR ACTIVITY STUDY OF EPSILON ERIDANI

    Energy Technology Data Exchange (ETDEWEB)

    Giguere, Matthew J.; Fischer, Debra A. [Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States); Zhang, Cyril X. Y. [Department of Computer Science, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States); Matthews, Jaymie M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Cameron, Chris [Department of Mathematics, Physics and Geology, Cape Breton University, 1250 Grand Lake Road, Sydney, NS B1P 6L2 (Canada); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, Nashville, TN 37203 (United States)

    2016-06-20

    We present simultaneous ground-based radial velocity (RV) measurements and space-based photometric measurements of the young and active K dwarf Epsilon Eridani. These measurements provide a data set for exploring methods of identifying and ultimately distinguishing stellar photospheric velocities from Keplerian motion. We compare three methods we have used in exploring this data set: Dalmatian, an MCMC spot modeling code that fits photometric and RV measurements simultaneously; the FF′ method, which uses photometric measurements to predict the stellar activity signal in simultaneous RV measurements; and H α analysis. We show that our H α measurements are strongly correlated with the Microvariability and Oscillations of STars telescope ( MOST ) photometry, which led to a promising new method based solely on the spectroscopic observations. This new method, which we refer to as the HH′ method, uses H α measurements as input into the FF′ model. While the Dalmatian spot modeling analysis and the FF′ method with MOST space-based photometry are currently more robust, the HH′ method only makes use of one of the thousands of stellar lines in the visible spectrum. By leveraging additional spectral activity indicators, we believe the HH′ method may prove quite useful in disentangling stellar signals.

  1. Synthesis, characterization, spectroscopic properties and DFT study of a new pyridazinone family

    Science.gov (United States)

    Arrue, Lily; Rey, Marina; Rubilar-Hernandez, Carlos; Correa, Sebastian; Molins, Elies; Norambuena, Lorena; Zarate, Ximena; Schott, Eduardo

    2017-11-01

    Nitrogen compounds are widely investigated due to their pharmacological properties such as antihypertensive, antinociceptive, antibacterial, antifungal, analgesic, anticancer and inhibition activities and lately even as pesticide. In this context, we present the synthesis of new compounds: (E)-6-(3,4-dimethoxyphenyl)-3-(3-(3,4-dimethoxyphenyl)acryloyl)-1-(4-R-phenyl)- 5,6-dihydropyridazin-4(1H)-one (with R = sbnd H(1), -Cl(2), -Br(3), sbnd I(4) and sbnd COOH(5)) that was carried out by reaction of (1E, 6E)-1,7-bis(3,4-dimethoxyphenyl)hepta-1,6-diene-3,5-dione with a substituted phenylamine with general formula p-R-C6H4sbnd NH2 (R = sbnd H (1), sbnd Cl (2), -Br(3), sbnd I(4) and sbnd COOH(5)). This is the first synthesis report of a pyridazinone using as precursors a curcuminoid derivative and a diazonium salt formed in situ. All compounds were characterized by EA, FT-IR, UV-Vis, Emission,1H- and13C-NMR spectroscopy and the crystalline and molecular structure of 4 was solved by X-rays diffraction method. DFT and TD-DFT quantum chemical calculations were also employed to characterize the compounds and provide a rational explanation to the spectroscopic properties. To assess the biological activity of the systems, we focused on pesticide tests on compound 2, which showed an inhibitory effect in plant growth of Agrostis tenuis Higland.

  2. Spectroscopic and radiative properties study of Nd3+ doped cadmium-phosphate glasses

    International Nuclear Information System (INIS)

    Mahmoud, K.H.

    2010-01-01

    A spectroscopic investigation is performed on Nd 3+ doped cadmium-phosphate glasses. The Judd-Ofelt analysis is applied to the glass system in order to evaluate their potential as both glass laser and amplifier materials. The phenomenological Judd-Ofelt parameters Ω (2) , Ω (4) , and Ω (6) are determined, their values are 4.80x10 -20 , 6.18x10 -20 , and 7.14x10 -20 cm -2 , respectively. The quality factor for glass system is 0.86. Predicted radiative decay rates and branching ratios of transitions from Nd 3+4 F 3/2 state to the 4 I J manifolds are determined and analyzed. The calculated lifetime of the 4 F 3/2 metastable state of Nd 3+ is 31 μs. The results showed that 4 F 3/2 to 4 I 11/2 transition, with fluorescence at 1056 nm, has the most potential for laser application. Photoluminescence up-conversion under excitation at 488 nm laser light exhibits three emission bands of Nd 3+ ions at 541 (green), 601 (orange), and 677 nm (red). These emission bands are assigned to 4 G 7/2 → 4 I 9/2 , 4 G 7/2 → 4 I 11/2 , and 4 G 7/2 → 4 I 13/2 transitions, respectively. Analysis of luminescence spectra enhances the use of glass system in optical displays, lasers, and optical memory devices.

  3. Spectroscopic Studies on Organic Matter from Triassic Reptile Bones, Upper Silesia, Poland

    Science.gov (United States)

    Surmik, Dawid; Boczarowski, Andrzej; Balin, Katarzyna; Dulski, Mateusz; Szade, Jacek; Kremer, Barbara; Pawlicki, Roman

    2016-01-01

    Fossil biomolecules from an endogenous source were previously identified in Cretaceous to Pleistocene fossilized bones, the evidence coming from molecular analyses. These findings, however, were called into question and an alternative hypothesis of the invasion of the bone by bacterial biofilm was proposed. Herewith we report a new finding of morphologically preserved blood-vessel-like structures enclosing organic molecules preserved in iron-oxide-mineralized vessel walls from the cortical region of nothosaurid and tanystropheid (aquatic and terrestrial diapsid reptiles) bones. These findings are from the Early/Middle Triassic boundary (Upper Roetian/Lowermost Muschelkalk) strata of Upper Silesia, Poland. Multiple spectroscopic analyses (FTIR, ToF-SIMS, and XPS) of the extracted "blood vessels" showed the presence of organic compounds, including fragments of various amino acids such as hydroxyproline and hydroxylysine as well as amides, that may suggest the presence of collagen protein residues. Because these amino acids are absent from most proteins other than collagen, we infer that the proteinaceous molecules may originate from endogenous collagen. The preservation of molecular signals of proteins within the "blood vessels" was most likely made possible through the process of early diagenetic iron oxide mineralization. This discovery provides the oldest evidence of in situ preservation of complex organic molecules in vertebrate remains in a marine environment. PMID:26977600

  4. Spectroscopic Studies on Organic Matter from Triassic Reptile Bones, Upper Silesia, Poland.

    Directory of Open Access Journals (Sweden)

    Dawid Surmik

    Full Text Available Fossil biomolecules from an endogenous source were previously identified in Cretaceous to Pleistocene fossilized bones, the evidence coming from molecular analyses. These findings, however, were called into question and an alternative hypothesis of the invasion of the bone by bacterial biofilm was proposed. Herewith we report a new finding of morphologically preserved blood-vessel-like structures enclosing organic molecules preserved in iron-oxide-mineralized vessel walls from the cortical region of nothosaurid and tanystropheid (aquatic and terrestrial diapsid reptiles bones. These findings are from the Early/Middle Triassic boundary (Upper Roetian/Lowermost Muschelkalk strata of Upper Silesia, Poland. Multiple spectroscopic analyses (FTIR, ToF-SIMS, and XPS of the extracted "blood vessels" showed the presence of organic compounds, including fragments of various amino acids such as hydroxyproline and hydroxylysine as well as amides, that may suggest the presence of collagen protein residues. Because these amino acids are absent from most proteins other than collagen, we infer that the proteinaceous molecules may originate from endogenous collagen. The preservation of molecular signals of proteins within the "blood vessels" was most likely made possible through the process of early diagenetic iron oxide mineralization. This discovery provides the oldest evidence of in situ preservation of complex organic molecules in vertebrate remains in a marine environment.

  5. Spectroscopic and calorimetric studies of interaction of methimazole with human serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Afrin, Sadaf [Department of Chemistry, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh (India); Riyazuddeen, E-mail: rz1@rediffmail.com [Department of Chemistry, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh (India); Rabbani, Gulam; Khan, Rizwan Hasan [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh (India)

    2014-07-01

    The interaction of the anti-thyroid drug, 2-mercapto 1-methylimidazole (methimazole) with human serum albumin (HSA) has been examined by fluorescence and isothermal titration calorimetry (ITC) techniques. Fluorescence results indicate that in case of HSA–drug complex the quenching of fluorescence intensity is at 340 nm. The methimazole has an ability to quench the intrinsic fluorescence of HSA tryptophan through a static quenching procedure. The binding constant has been determined using Stern–Volmer modified equation and energy transfer mechanisms of quenching are discussed. The ΔG°, ΔH°, and ΔS° values are also calculated by ITC measurements. The experimental spectroscopic and thermodynamic parameters have been used for understanding the binding mechanism of anti-thyroid drug with HSA. - Highlights: • The binding of methimazole to HSA quenches the intrinsic fluorescence of tryptophan. • The negative ΔG° value suggests the binding of methimazole with HSA is spontaneous. • The main contribution to ΔG° arises from the ΔS° rather than from ΔH°, so hydrophobic forces most likely play a major role in the binding of methimazole to HSA.

  6. Electrochemical and Spectroscopic Study of Mononuclear Ruthenium Water Oxidation Catalysts: A Combined Experimental and Theoretical Investigation

    KAUST Repository

    de Ruiter, J. M.

    2016-09-20

    One of the key challenges in designing light-driven artificial photosynthesis devices is the optimization of the catalytic water oxidation process. For this optimization it is crucial to establish the catalytic mechanism and the intermediates of the catalytic cycle, yet a full description is often difficult to obtain using only experimental data. Here we consider a series of mononuclear ruthenium water oxidation catalysts of the form [Ru(cy)(L)(H2O)](2+) (cy = p-cymene, L = 2,2\\'-bipyridine and its derivatives). The proposed catalytic cycle and intermediates are examined using density functional theory (DFT), radiation chemistry, spectroscopic techniques, and electrochemistry to establish the water oxidation mechanism. The stability of the catalyst is investigated using online electrochemical mass spectrometry (OLEMS). The comparison between the calculated absorption spectra of the proposed intermediates with experimental spectra, as well as free energy calculations with electrochemical data, provides strong evidence for the proposed pathway: a water oxidation catalytic cycle involving four proton-coupled electron transfer (PCET) steps. The thermodynamic bottleneck is identified as the third PCET step, which involves O-O bond formation. The good agreement between the optical and thermodynamic data and DFT predictions further confirms the general applicability of this methodology as a powerful tool in the characterization of water oxidation catalysts and for the interpretation of experimental observables.

  7. Understanding reactivity of two newly synthetized imidazole derivatives by spectroscopic characterization and computational study

    Science.gov (United States)

    Hossain, Mossaraf; Thomas, Renjith; Mary, Y. Sheena; Resmi, K. S.; Armaković, Stevan; Armaković, Sanja J.; Nanda, Ashis Kumar; Vijayakumar, G.; Van Alsenoy, C.

    2018-04-01

    Two newly synthetized imidazole derivatives (1-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazole-2-yl acetate (MPDIA) and 1-(4-bromophenyl)-4,5-dimethyl-1H-imidazole-2-yl acetate (BPDIA)) have been prepared by solvent-free synthesis pathway and their specific spectroscopic and reactive properties have been discussed based on combined experimental and computational approaches. Aside of synthesis, experimental part of this work included measurements of IR, FT-Raman and NMR spectra. All of the aforementioned spectra were also obtained computationally, within the framework of density functional theory (DFT) approach. Additionally, DFT calculations have been used in order to investigate local reactivity properties based on molecular orbital theory, molecular electrostatic potential (MEP), average local ionization energy (ALIE), Fukui functions and bond dissociation energy (BDE). Molecular dynamics (MD) simulations have been used in order to obtain radial distribution functions (RDF), which were used for identification of the atoms with pronounced interactions with water molecules. MEP showed negative regions are mainly localized over N28, O29, O35 atoms, it is represent with red colour in rainbow color scheme for MPDIA and BPDIA (which are most reactive sites for electrophilic attack). The first order hyperpolarizabilities of MPDIA and BPDIA are 20.15 and 6.10 times that of the standard NLO material urea. Potential interaction with antihypertensive protein hydrolase.

  8. Spectroscopic Studies of Starburst Galaxies; the Dynamical Structure of Blue Compact Dwarf Galaxy Haro 6

    Directory of Open Access Journals (Sweden)

    Mun-Suk Chun

    1995-06-01

    Full Text Available We carried out photometric and spectroscopic observations of the blue compact dwarf galaxy Haro 6 in the Virgo Cluster of Galaxies. The long-slit spectroscopy was employed at three position angles, ϕ = 0°, ϕ = 30°, and ϕ = 120° CCD camera mounted on the Cassegrain Spectrograph. Based on the mean intrinsic axial ratio q0=0.3, we derived inclination i of the system as 44° our composite V-band CCD image. Careful analysis on the velocity field of the system chows an asymptotically flat rotation curve with the maximum rotational velocity V(rmax reaches about 12 km/sec. The calculation of the dynamical mass of Haro 6 with a simple mass model is briefly discussed with emphasis on the mass to luminosity ratio. From the IRAS Point Source Catalogue, we derived dust-to-gas ratio which indicates relatively low dust content, thus tempting us to conjecture the youth of the system.

  9. Spectroscopic and electrochemical study of the polynuclear clusters of ruthenium acetate

    International Nuclear Information System (INIS)

    Cipriano, C.

    1989-01-01

    The chemistry of the trinuclear clusters (Ru 3 O (C H 3 CO 2 ) 4 L 3 ) where L = imidazole, pyridine or pyrazine type of ligands, was investigated based on spectroscopic and electrochemical techniques. These complexes are of great interest from the point of view of their electronic and redox properties, providing multi site species for electron transfer processes. They were isolated in solid state, and characterized by means of elementary analyses and infrared spectra. The electrochemical behaviour in acetonitrile solution was typically reversible; the cyclic voltamograms exhibited a series of four or five mono electronic waves ascribed to the successive Ru I V Ru I I I Ru I I I / Ru I I I Ru I I I Ru I I I / ... Ru I I Ru I I Ru I I redox couples. The differences between the successive redox potentials were about 1 V, indicating strong metal-metal interaction in the trinuclear Ru 3 O centre. The E values were strongly sensitive to the nature of the N-heterocyclic ligand, increasing with the pi-acceptor properties of the pyridine and pyrazine derivatives, but in a much less pronounced way in the case of the imidazole derivatives. (author)

  10. Study of a sample of faint Be stars in the exofield of CoRoT. I. Spectroscopic characterization

    Science.gov (United States)

    Semaan, T.; Hubert, A. M.; Zorec, J.; Martayan, C.; Frémat, Y.; Gutiérrez-Soto, J.; Fabregat, J.

    2013-03-01

    Context. Be stars are probably the most rapid rotators among stars in the main sequence (MS) and, as such, are excellent candidates to study the incidence of the rotation on the characteristics of their non-radial pulsations, as well as on their internal structure. Pulsations are also thought to be possible mechanisms that help the mass ejection needed to build up the circumstellar disks of Be stars. Aims: The purpose of this paper is to identify a number of faint Be stars observed with the CoRoT satellite and to determine their fundamental parameters, which will enable us to study their pulsation properties as a function of the location in the HR diagram and to search for correlations with the light outbursts, which are possibly produced by discrete mass ejections. Methods: We identified those objects in the exofields of CoRoT presenting the Be phenomenon using Hα surveys, as well as automated methods based on pulsation properties that we finally confirmed with FLAMES/GIRAFFE and X-shooter spectroscopic observations at VLT/ESO, and with near-IR photometry. The spectra were 1) corrected for the veiling effect, 2) treated with the GIRFIT code to determine apparent fundamental parameters, and 3) corrected with the FASTROT code for effects induced by the rapid rotation. Results: A list of 41 Be star candidates were found from photometric and spectroscopic criteria. The spectral coverage useful for determining the fundamental parameters was obtained for only about half of them. We then spectroscopically identified 21 Be stars, two probable Be stars, and two B stars contaminated by the Sh 2-284 nebulosity. A short description of the spectral characteristics of each star is given. The fundamental parameters and, in particular, the rotation frequency νr (cycles per day) were all corrected for rotational effects at rotation rates ranging from Ω/Ωc = 0.8 to 1.0. We have determined the positions of Be stars in the HR diagram and find two of them located beyond the MS

  11. Synthesis, spectroscopic characterization, crystallographic studies and antibacterial assays of new copper(II) complexes with sulfathiazole and nimesulide

    Science.gov (United States)

    Nunes, Julia Helena Bormio; de Paiva, Raphael Enoque Ferraz; Cuin, Alexandre; da Costa Ferreira, Ana Maria; Lustri, Wilton Rogério; Corbi, Pedro Paulo

    2016-05-01

    New ternary copper(II) complexes of sulfathiazole (SFT, C9H8N3O2S2) or nimesulide (NMS, C13H11N2O5S) and 2,2‧-bipyridine (bipy) were synthesized, and characterized by chemical and spectroscopic techniques. Elemental analyses indicated a 2:1:1 sulfonamide/copper/bipy composition for both complexes. Mass spectrometric measurements permitted identifying the molecular ions [Cu(SFT)2(bipy)+H]+ and [Cu(NMS)2(bipy)+H]+ at m/z 728 and 835, respectively, confirming the proposed compositions. Crystal structure of the [Cu(SFT)2(bipy)] complex was solved by powder X-ray diffraction analysis (PXRD), attesting that the Cu(II) ion is hexacoordinated in a distorted octahedral geometry. Each SFT molecule coordinates to the metal ion by the nitrogen atoms of the SO2-N group and of the heterocyclic ring. The coordination sphere is completed by a bipyridine. Electronic paramagnetic resonance (EPR) studies were carried out for the [Cu(NMS)2(bipy)] complex, indicating a tetragonal environment around the metal ion. It was suggested that NMS coordinates to Cu(II) by the nitrogen and oxygen atoms of the SO2-N group, which was confirmed by infrared spectroscopic studies. Biological studies showed the antibacterial activity of both Cu-SFT and Cu-NMS complexes, with the minimum inhibitory concentration (MIC) values ranging from 0.10 to 0.84 mmol L-1 against Gram-negative bacteria for [Cu(SFT)2(bipy)], and from 1.50 to 3.00 mmol L-1 against Gram-positive and -negative bacteria for [Cu(NMS)2(bipy)].

  12. Vibrational spectroscopic and quantum theoretical study of host-guest interactions in clathrates: I. Hofmann type clathrates

    Directory of Open Access Journals (Sweden)

    VLADIMIR M. PETRUSEVSKI

    2000-06-01

    Full Text Available Hofmann type clatharates are host-guest compounds with the general formula M(NH32M'(CN4·2G, in which M(NH32M'(CN4 is the host lattice and G is benzene, the guest molecule. In previous studies, host-guest interactions have been investigated by analyzing the RT and LNT vibrational (infrared, far infrared and Raman spectra of these clathrates. All the observed changes in the vibrational spectra of these clathrates are referred to a host-guest interaction originating from weak hydrogen bonding between the ammonia hydrogen atoms from the host lattice and the p electron cloud of the guest (benzene molecules. In order to obtain an insight into the relative importance of the local crystalline field vs. the anharmonicity effects on the spectroscopic properties of the guest species upon enclathration, as well as to explain the observed band shifts and splittings, several quantum theoretical approaches are proposed.

  13. A comparative spectroscopic study of thiourea effect on the photophysical and molecular association behavior of various phenothiazine dyes

    Science.gov (United States)

    Ghanadzadeh Gilani, A.; Dezhampanah, H.; Poormohammadi-Ahandani, Z.

    2017-05-01

    This paper describes the role of a structure breaking additive (thiourea) on the photophysical and molecular association of a series of phenothiazine dyes in aqueous media using the absorption and fluorescence spectroscopic methods for the first time. The studied dyes were thionine, azure A, azure B, toluidine blue, and methylene blue. The spectral data were analyzed using DECOM program. Relevant spectral parameters in the dye solutions were estimated and discussed based on the chemical structure of the additive and excitonic treatment. The observation of spectral changes in the spectral data of the (water-additive-dye) system indicates the possible structure formation between the dye and additive molecules. However, it is found that in the high concentrations of thiourea the dimer geometries (H- and J-type dimers) are influenced by the dye-additive interactions. As a result, a competition between the dye-additive and dye-dye interactions was also observed.

  14. Spectroscopic studies on the binding interaction of phenothiazinium dyes, azure A and azure B to double stranded RNA polynucleotides

    Science.gov (United States)

    Khan, Asma Yasmeen; Suresh Kumar, Gopinatha

    2016-01-01

    This manuscript presents spectroscopic characterization of the interaction of two phenothiazinium dyes, azure A and azure B with double stranded (ds) ribonucleic acids, poly(A).poly(U), poly(C).poly(G) and poly(I).poly(C). Absorbance and fluorescence studies revealed that these dyes bind to the RNAs with binding affinities of the order 106 M-1 to poly(A).poly(U), and 105 M-1 to poly(C).poly(G) and poly(I).poly(C), respectively. Fluorescence quenching and viscosity data gave conclusive evidence for the intercalation of the dyes to these RNA duplexes. Circular dichroism results suggested that the conformation of the RNAs was perturbed on interaction and the dyes acquired strong induced optical activity on binding. Azure B bound to all the three RNAs stronger than azure A and the binding affinity varied as poly(A).poly(U) > poly(C).poly(G) > poly(I).poly(C) for both dyes.

  15. Spectroscopic and theoretical studies on cobalt(II) complex of maleonitriledithiolate and 5-nitro-1,10-phenanthroline

    Science.gov (United States)

    Liu, Yangmei; Peng, Zhenghe; Li, Daocong; Zhou, Yunhong

    2008-02-01

    The molecular structure, electronic and infrared spectroscopic properties for the title complex Co(mnt)(5-NO 2-phen) (mnt 2- = maleonitriledithiolate, 5-NO 2-phen = 5-nitro-1,10-phenanthroline) were studied in this paper. With semi-empirical PM3 and non-empirical density functional theory (DFT) methods, the gaseous molecular geometry of the complex was optimized and corresponding vibrational spectra was obtained. The calculated results of structure and frequency from DFT were more reasonable than those from PM3, and the two methods were both agreed with the experimental values. A complete assignment to the IR spectra of such a complicated molecule has been exhibited. An electronic spectra was calculated by ZINDOS/S method. The results showed that the calculated values agreed with the observed ones.

  16. Improvement of the inlet system for the spray-jet technique for use in spectroscopic studies and molecular deposition

    International Nuclear Information System (INIS)

    Yamada, Toshiki; Shinohara, Hidenori; Mashiko, Shinro

    2006-01-01

    We previously developed a molecular beam apparatus with a spray-jet technique in order to produce a molecular beam of non-volatile molecules in vacuum from the sprayed mist of a sample solution. The apparatus is for use in spectroscopic studies or a means of molecular deposition. The spray-jet inlet system consisted of an ultrasonic nebulizer, an inlet chamber and a pulsed nozzle. In the present paper, further improvements to the spray-jet inlet system are reported. The main improvement is the introduction of a pneumatic nebulizer to replace the previous ultrasonic nebulizer. The efficiency of molecular beam generation was evaluated on the basis of the signal intensity of the resonantly enhanced multiphoton ionization time-of-flight mass (REMPI-TOFMS) spectra for a Rhodamine B/methanol solution and the amount of sample consumed. The introduction of the pneumatic nebulizer increased the efficiency by a factor of 20

  17. Resonance Raman and EPR spectroscopic studies on heme-heme oxygenase complexes.

    Science.gov (United States)

    Sun, J; Wilks, A; Ortiz de Montellano, P R; Loehr, T M

    1993-12-28

    The binding of ferrous and ferric hemes and manganese(II)- and manganese(III)-substituted hemes to heme oxygenase has been investigated by optical absorption, resonance Raman, and EPR spectroscopy. The results are consistent with the presence of a six-coordinate heme moiety ligated to an essential histidine ligand and a water molecule. The latter ionizes with a pKa approximately 8.0 to give a mixture of high-spin and low-spin six-coordinate hydroxo adducts. Addition of excess cyanide converts the heme to a hexacoordinate low-spin species. The resonance Raman spectrum of the ferrous heme-heme oxygenase complex and that of the Mn(II)protoporphyrin-heme oxygenase complex shows bands at 216 and 212 cm-1, respectively, that are assigned to the metal-histidine stretching mode. The EPR spectrum of the oxidized heme-heme oxygenase complex has a strongly axial signal with g parallel of approximately 6 and g perpendicular approximately 2. 14NO and 15NO adducts of ferrous heme-heme oxygenase exhibit EPR hyperfine splittings of approximately 20 and approximately 25 Gauss, respectively. In addition, both nitrosyl complexes show additional superhyperfine splittings of approximately 7 Gauss from spin-spin interaction with the proximal histidine nitrogen. The heme environment in the heme-heme oxygenase enzyme-substrate complex has spectroscopic properties similar to those of the heme in myoglobin. Hence, there is neither a strongly electron-donating fifth (proximal) ligand nor an electron-withdrawing network on the distal side of the heme moiety comparable to that for cytochromes P-450 and peroxidases. This observation has profound implications about the nature of the oxygen-activating process in the heme-->biliverdin reaction that are discussed in this paper.

  18. Spectroscopic study on the interaction of Bacillus subtilis {alpha}-amylase with cetyltrimethylammonium bromide

    Energy Technology Data Exchange (ETDEWEB)

    Omidyan, R., E-mail: r.omidyan@sci.ui.ac.i [Department of Chemistry, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Kazemi, S.H. [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Bordbar, A.K. [Department of Chemistry, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Zaynalpour, S. [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of)

    2011-06-15

    The interaction between {alpha}-amylase from Bacillus subtilis and cetyltrimethylammonium bromide (CTAB) has been investigated at various temperature conditions using fluorescence and circular dichroism (CD) spectroscopic methods. Fluorescence data revealed that the fluorescence quenching of {alpha}-amylase by CTAB is the result of complex formation between CTAB and {alpha}-amylase. The thermodynamic analysis on the binding interaction data shows that the interactions are strongly exothermic ({Delta}H{sup o}=-17.92 kJ mol{sup -1}) accompanied with increase in entropy ({Delta}S{sup o} between 109 to 135 J mol{sup -1} K{sup -1}). Thus the binding of CTAB to {alpha}-amylase is both enthalpic and entropic driven, which represent the predominate role of both electrostatic and hydrophobic interactions in complex formation process. The values of 2.17x10{sup -3} M{sup -1} and 1.30 have been obtained from associative binding constant (K{sub a}) and stoichiometry of binding number (n), from analysis of fluorescence data, respectively. Circular dichroism spectra showed the substantial conformational changes in secondary structure of {alpha}-amylase due to binding of CTAB, which represents the complete destruction of both secondary and tertiary structure of {alpha}-amylase by CTAB. - Research highlights: {yields} The Fluorescence quenching effect of {alpha}-amylase by CTAB is a consequence of formation {alpha}-amylase-CTAB complex. {yields} The {alpha}-helical analyzing from the CD spectra in the various concentration of CTAB shows strongly deformation of {alpha}-amylase. {yields} Thermodynamic analysis of quenching verify that the interactions are both enthalpy and entropic driven.

  19. Spectroscopic, thermal and X-ray structural study of the antiparasitic and antiviral drug nitazoxanide

    Science.gov (United States)

    Bruno, Flavia P.; Caira, Mino R.; Monti, Gustavo A.; Kassuha, Diego E.; Sperandeo, Norma R.

    2010-12-01

    Nitazoxanide [2-(acetyloxy)- N-(5-nitro-2-thiazolyl)benzamide, NTZ] is a potent antiparasitic and antiviral agent recently approved. The anti-protozoal activity of NTZ is believed to be due to interference with the pyruvate:ferredoxin oxidoreductase (PFOR) enzyme dependent electron transfer reaction. As drug-enzyme interactions are governed by the three-dimensional stereochemistry of both participants, the crystal structure of NTZ was determined for the first time to identify the conformational preferences that may be related to biological activity. NTZ crystallizes as the carboxamide tautomer in the orthorhombic system, space group Pna2 1 with the following parameters at 100(2) K: a = 14.302(2) Å, b = 5.2800(8) Å, c = 33.183(5) Å, V = 2505.8(6) Å 3, Z = 8, D x = 1.629 g cm -3, R = 0.0319, wR2 = 0.0799 for 5121 reflections. In addition, the spectroscopic and thermal properties were determined and related to the molecular structure. The 13C CPMAS NMR spectra showed resolved signals for each carbon of NTZ, some signals being broad due to residual dipolar interaction with quadrupolar 14N nuclei. In particular, the resonance at about 127 ppm showed multiplicity, indicating more than one molecule in the asymmetric unit and this is consistent with the crystallographic data. The DSC and TG data revealed that NTZ shows a single DSC melting peak with extrapolated onset at 201 °C which is accompanied by a TG weight loss, indicating that NTZ melts with decomposition.

  20. Spectroscopic, DFT, and XRD Studies of Hydrogen Bonds in N-Unsubstituted 2-Aminobenzamides

    Directory of Open Access Journals (Sweden)

    Malose Jack Mphahlele

    2017-01-01

    Full Text Available The structures of the mono- and the dihalogenated N-unsubstituted 2-aminobenzamides were characterized by means of the spectroscopic (1H-NMR, UV-Vis, FT-IR, and FT-Raman and X-ray crystallographic techniques complemented with a density functional theory (DFT method. The hindered rotation of the C(O–NH2 single bond resulted in non-equivalence of the amide protons and therefore two distinct resonances of different chemical shift values in the 1H-NMR spectra of these compounds were observed. 2-Amino-5-bromobenzamide (ABB as a model confirmed the presence of strong intramolecular hydrogen bonds between oxygen and the amine hydrogen. However, intramolecular hydrogen bonding between the carbonyl oxygen and the amine protons was not observed in the solution phase due to a rapid exchange of these two protons with the solvent and fast rotation of the Ar–NH2 single bond. XRD also revealed the ability of the amide unit of these compounds to function as a hydrogen bond donor and acceptor simultaneously to form strong intermolecular hydrogen bonding between oxygen of one molecule and the NH moiety of the amine or amide group of the other molecule and between the amine nitrogen and the amide hydrogen of different molecules. DFT calculations using the B3LYP/6-311++G(d,p basis set revealed that the conformer (A with oxygen and 2-amine on the same side predominates possibly due to the formation of a six-membered intramolecular ring, which is assisted by hydrogen bonding as observed in the single crystal XRD structure.

  1. Spectroscopic study of the final protective corrosion product on weathering steel

    International Nuclear Information System (INIS)

    Yamashita, M.; Misawa, T.

    1998-01-01

    Recent progress in understanding the structure and properties of final protective rust layer on weathering steel and its application for structural steels is shown based on the data obtained mainly by spectroscopic characterization. The main constituent of the weathering steel rust layer is changed with exposure period from γ- FeOOH (less than a few years) via, amorphous substance (several years), to α-FeOOH goethite phase (decades). The corrosion rate of the weathering steel decreased with this phase transformation. The final protective rust layer possesses the structure of α- (Fe 1 - X p Cr x)O OH, Cr substitute goethite; the crystal size decreases with its Cr-content. It is shown that the Cr content in the Cr-substituted goethite increases gradiently with reaching the rust/steel interface. This increase in the Cr content and resultant aggregation of fine crystals lead a densely packed Cr-substituted goethite rust layers which provides higher protective ability for atmospheric corrosives. It is found that the Cr-substituted goethite possesses the cation selective ability at the vicinity of the rust/steel interface where the Cr content can be estimated approximately 5-10 mass %. Thus, the final protective rust layer of the Cr-substituted goethite impedes the penetration of aggressive corrosive anions such as Cl - and SO 4 2- , besides the physically prevention effect of its densely aggregated structure for corrosive penetration. It is found that Cr 2 (SO 4 ) 3 is effective for obtaining the final protective rust layer in a short period. SO 4 2 accelerates rust formation and Cr 3- substitutes goethite crystal lattice point at the initial stage of corrosion; resultantly the rust layer formed suppresses dissolution of the steel even in the severe environment. (Author)

  2. Spectroscopic and electrochemical characterization of nanostructured optically transparent carbon electrodes.

    Science.gov (United States)

    Benavidez, Tomás E; Garcia, Carlos D

    2013-07-01

    The present paper describes the results related to the optical and electrochemical characterization of thin carbon films fabricated by spin coating and pyrolysis of AZ P4330-RS photoresist. The goal of this paper is to provide comprehensive information allowing for the rational selection of the conditions to fabricate optically transparent carbon electrodes (OTCE) with specific electrooptical properties. According to our results, these electrodes could be appropriate choices as electrochemical transducers to monitor electrophoretic separations. At the core of this manuscript is the development and critical evaluation of a new optical model to calculate the thickness of the OTCE by variable angle spectroscopic ellipsometry. Such data were complemented with topography and roughness (obtained by atomic force microscopy), electrochemical properties (obtained by cyclic voltammetry), electrical properties (obtained by electrochemical impedance spectroscopy), and structural composition (obtained by Raman spectroscopy). Although the described OTCE were used as substrates to investigate the effect of electrode potential on the real-time adsorption of proteins by ellipsometry, these results could enable the development of other biosensors that can be then integrated into various CE platforms. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Resolution and Determination of the Absolute Configuration of a Twisted Bis-Lactam Analogue of Troger's Base: A Comparative Spectroscopic and Computational Study

    DEFF Research Database (Denmark)

    Rúnarsson, Ögmundur Vidar; Benkhäuser, Christian; Christensen, Niels Johan

    2015-01-01

    unambiguously confirming the results from the spectroscopic studies. We conclude that, for the Troger's base (TB) analogue (2), we may rank the reliability of the individual methods for AC determination as AXRD >> VCD > ECD, while the synergy of all three methods provides very strong confidence in the assigned...

  4. Variable angle spectroscopic ellipsometric characterization of HfO2 thin film

    Science.gov (United States)

    Kumar, M.; Kumari, N.; Karar, V.; Sharma, A. L.

    2018-02-01

    Hafnium Oxide film was deposited on BK7 glass substrate using reactive oxygenated E-Beam deposition technique. The film was deposited using in-situ quartz crystal thickness monitoring to control the film thickness and rate of evaporation. The thin film was grown with a rate of deposition of 0.3 nm/s. The coated substrate was optically characterized using spectrophotometer to determine its transmission spectra. The optical constants as well as film thickness of the hafnia film were extracted by variable angle spectroscopic ellipsometry with Cauchy fitting at incidence angles of 65˚, 70˚ and 75˚.

  5. Optical characteristics of H{sub 2}O-based and O{sub 3}-based HfO{sub 2} films deposited by ALD using spectroscopy ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xiaojiao; Liu, Hongxia; Zhong, Bo; Fei, Chenxi; Wang, Xing; Wang, Qianqiong [Xidian University, School of Microelectronics, Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xi' an (China)

    2015-06-15

    Optical properties of thin atomic layer-deposited HfO{sub 2} films grown by H{sub 2}O and O{sub 3} are analyzed by variable angle spectroscopic ellipsometry. By investigating the dielectric constant, it is found that a higher real part of the dielectric constant (ε {sub 1}) value is observed for H{sub 2}O-based film due to less silicate component in the film. Careful examination of the log scale of imaginary part of the dielectric constant (ε {sub 2}) leads to the conclusion that the absorption features in the energy range of 3.2-5.35 eV originate from the interface layer between the silicon substrate and the native oxide. In particular, O{sub 3}-based gate stacks have less sub-band gap defect states besides the silicon's critical features. Moreover, a larger high-frequency dielectric constant, direct and indirect band gap values are obtained for O{sub 3}-based film. Meanwhile, suitable valence band offsets (3.38 and 3.55 eV) and conduction band offsets (1.58 and 1.47 eV) are obtained for H{sub 2}O- and O{sub 3}-based HfO{sub 2} gate stacks, respectively, indicating both type of dielectric films can provide sufficient tunneling barriers for both electrons and holes. (orig.)

  6. Theoretical study of H2/+/ spectroscopic properties. II, III. [2p and 3d excited electronic states

    Science.gov (United States)

    Beckel, C. L.; Shafi, M.; Peek, J. M.

    1973-01-01

    Description of the theoretical spectroscopic properties of the 2p pi/sub u/ and 3d sigma/sub g/ excited states of the H2/+/ hydrogen molecular ion. Numerical integration of the Schrodinger equation is used to determine vibration-rotation eigenvalues. Dunham power series expansions are used to determine the equilibrium separation, potential coefficients, and spectroscopic constants. The eigenvalues are used to determine delta-G, Bv, Dv, and Hv.

  7. Dielectric constant extraction of graphene nanostructured on SiC substrates from spectroscopy ellipsometry measurement using Gauss–Newton inversion method

    International Nuclear Information System (INIS)

    Maulina, Hervin; Santoso, Iman; Subama, Emmistasega; Nurwantoro, Pekik; Abraha, Kamsul; Rusydi, Andrivo

    2016-01-01

    The extraction of the dielectric constant of nanostructured graphene on SiC substrates from spectroscopy ellipsometry measurement using the Gauss-Newton inversion (GNI) method has been done. This study aims to calculate the dielectric constant and refractive index of graphene by extracting the value of ψ and Δ from the spectroscopy ellipsometry measurement using GNI method and comparing them with previous result which was extracted using Drude-Lorentz (DL) model. The results show that GNI method can be used to calculate the dielectric constant and refractive index of nanostructured graphene on SiC substratesmore faster as compared to DL model. Moreover, the imaginary part of the dielectric constant values and coefficient of extinction drastically increases at 4.5 eV similar to that of extracted using known DL fitting. The increase is known due to the process of interband transition and the interaction between the electrons and electron-hole at M-points in the Brillouin zone of graphene.

  8. Molecular spectroscopic and thermodynamic studies on the interaction of anti-platelet drug ticlopidine with calf thymus DNA

    Science.gov (United States)

    Afrin, Shumaila; Rahman, Yusra; Sarwar, Tarique; Husain, Mohammed Amir; Ali, Abad; Shamsuzzaman; Tabish, Mohammad

    2017-11-01

    Ticlopidine is an anti-platelet drug which belongs to the thienopyridine structural family and exerts its effect by functioning as an ADP receptor inhibitor. Ticlopidine inhibits the expression of TarO gene in S. aureus and may provide protection against MRSA. Groove binding agents are known to disrupt the transcription factor DNA complex and consequently inhibit gene expression. Understanding the mechanism of interaction of ticlopidine with DNA can prove useful in the development of a rational drug designing system. At present, there is no such study on the interaction of anti-platelet drugs with nucleic acids. A series of biophysical experiments were performed to ascertain the binding mode between ticlopidine and calf thymus DNA. UV-visible and fluorescence spectroscopic experiments confirmed the formation of a complex between ticlopidine and calf thymus DNA. Moreover, the values of binding constant were found to be in the range of 103 M- 1, which is indicative of groove binding between ticlopidine and calf thymus DNA. These results were further confirmed by studying the effect of denaturation on double stranded DNA, iodide quenching, viscometric studies, thermal melting profile as well as CD spectral analysis. The thermodynamic profile of the interaction was also determined using isothermal titration calorimetric studies. The reaction was found to be endothermic and the parameters obtained were found to be consistent with those of known groove binders. In silico molecular docking studies further corroborated well with the experimental results.

  9. Ionization of covalent immobilized poly(4-vinylphenol) monolayers measured by ellipsometry, QCM and SPR

    Energy Technology Data Exchange (ETDEWEB)

    Uppalapati, Suji [Department of Chemistry, University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854 (United States); Kong, Na; Norberg, Oscar [KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm (Sweden); Ramström, Olof, E-mail: ramstrom@kth.se [KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm (Sweden); Yan, Mingdi, E-mail: Mingdi_Yan@uml.edu [Department of Chemistry, University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854 (United States); KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm (Sweden)

    2015-07-15

    Covalently immobilized poly(4-vinylphenol) (PVP) monolayer films were fabricated by spin coating PVP on perfluorophenyl azide (PFPA)-functionalized surfaces followed by UV irradiation. The pH-responsive behavior of these PVP ultrathin films was evaluated by ellipsometry, quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). By monitoring the responses of these films to pH in situ, the ionization constant of the monolayer thin films was obtained. The apparent pK{sub a} value of these covalently immobilized PVP monolayers, 13.4 by SPR, was 3 units higher than that of the free polymer in aqueous solution.

  10. Spectroscopic studies on the binding interaction of phenothiazinium dyes toluidine blue O, azure A and azure B to DNA

    Science.gov (United States)

    Paul, Puja; Suresh Kumar, Gopinatha

    2013-04-01

    In this study a detailed characterization of the binding aspects of three phenothiazinium dyes, toluidine blue O (TBO), azure A and azure B with herring testes DNA is presented employing spectroscopic techniques. The absorbance and fluorescence properties of these dyes have been remarkably modified upon binding with DNA and the interaction is manifested through noncooperative binding as revealed form non-linear Scatchard plots with negative slopes at all binding ratios. The binding clearly revealed the high preference of TBO to DNA followed by the other two dyes azure A and azure B. The affinity of TBO was higher by about two times than that of the azures. From the series of studies using absorption, steady-state emission, the effect of ferrocyanide ion-induced steady-state fluorescence quenching, fluorescence polarization anisotropy, circular dichroism, the mode of binding of these dyes to the DNA double helix has been substantiated to be principally intercalative in nature. The stoichiometry of the association of these dyes to DNA was determined by the continuous variation analysis of Job from fluorescence data. The conformational aspects of the interaction was delineated from circular dichroism studies wherein higher perturbation was observed with TBO. Hydrodynamic study using viscosity measurements of linear rod like DNA confirmed that the binding was intercalative and strongest for TBO and weaker for azure A and azure B. The utility of the present work lies in exploring the potential binding applicability of these dyes to DNA for their development as effective therapeutic agents.

  11. Spectroscopic studies of europium-tetracyclines complexes and their applications in detection of hydrogen peroxide and urea peroxide

    International Nuclear Information System (INIS)

    Grasso, Andrea Nastri

    2010-01-01

    In this work were studied the spectroscopic properties of trivalent europium ion complexed with components of tetracycline family, chlorotetracycline, oxytetracycline and metacycline, in the presence of hydrogen peroxide and urea peroxide. Optical parameters were obtained such as absorption, emission, lifetime and calibration curves were constructed for luminescence spectra. Experiments were carried out with both inorganic compounds and europium-tetracyclines complexes in order to verify possible interferences. Studies for glucose determination were also described using europium-tetracyclines complexes as biosensors. Results show that europium tetracyclines complexes emit a narrow band in the visible region and, in the presence of hydrogen peroxide or urea peroxide there is a greater enhancement in their luminescence and lifetime. Thus, europium-tetracyclines complexes studied can be used as biosensors for hydrogen and urea peroxides determination as a low cost and room temperature method. An indirect method for glucose determination was studied by adding glucose oxidase enzyme in europium-tetracyclines complex in the presence of glucose promoting as product hydrogen peroxide. (author)

  12. Multi-spectroscopic and molecular docking studies on the interaction of darunavir, a HIV protease inhibitor with calf thymus DNA

    Science.gov (United States)

    Shi, Jie-Hua; Zhou, Kai-Li; Lou, Yan-Yue; Pan, Dong-Qi

    2018-03-01

    Molecular interaction of darunavir (DRV), a HIV protease inhibitor with calf thymus deoxyribonucleic acid (ct-DNA) was studied in physiological buffer (pH 7.4) by multi-spectroscopic approaches hand in hand with viscosity measurements and molecular docking technique. The UV absorption and fluorescence results together revealed the formation of a DRV-ct-DNA complex having binding affinities of the order of 103 M- 1, which was more in keeping with the groove binding. The results that DRV bound to ct-DNA via groove binding mode was further evidenced by KI quenching studies, viscosity measurements, competitive binding investigations with EB and Rhodamine B and CD spectral analysis. The effect of ionic strength indicated the negligible involvement of electrostatic interaction between DRV and ct-DNA. The thermodynamic parameters regarding the binding interaction of DRV with ct-DNA in terms of enthalpy change (ΔH0) and entropy change (ΔS0) were - 63.19 kJ mol- 1 and - 141.92 J mol- 1 K- 1, indicating that hydrogen bonds and van der Waals forces played a predominant role in the binding process. Furthermore, molecular simulation studies suggested that DRV molecule was prone to bind in the A-T rich region of the minor groove of DNA.

  13. Structural and spectroscopic characterization of DMF complexes with nitrogen, carbon dioxide, ammonia and water. Infrared matrix isolation and theoretical studies

    Science.gov (United States)

    Sałdyka, Magdalena; Mielke, Zofia; Haupa, Karolina

    2018-02-01

    An infrared spectroscopic and MP2/6-311++G(2d,2p) study of the complexes between N,N-dimethylformamide (DMF) and nitrogen, carbon dioxide, water, ammonia trapped in solid argon matrices is reported. The 1:1 molecular complexes have been identified in the DMF/B/Ar matrices (B = N2, CO, H2O, NH3); their structures were determined by comparison of the spectra with the results of calculations. The analysis of the experimental and theoretical data indicate that the DMF-N2, CO complexes present in the matrices are stabilized by (C=)O⋯N and (C=)O⋯C van der Waals interactions. In turn, in the DMF-H2O, NH3 complexes the (C=)O⋯H(OH) and (C=)O⋯H(NH2) hydrogen bonding is present in which the carbonyl group of DMF acts as a proton acceptor. In all systems studied the C-H⋯X (X = N, C, O) bonding is a second intermolecular force stabilizing the planar complexes. Some spectral features indicate that for DMF-H2O, DMF-NH3 systems the nonplanar structures with the C=O⋯H interaction are also present. The study demonstrated the strong sensitivity of the CH stretching wavenumber to an involvement of the C-H and/or C=O groups of DMF in an intermolecular interaction.

  14. Spectroscopic approaches to study DNA damage induced in genome exposed to ionizing radiation and its enzymatic repair

    International Nuclear Information System (INIS)

    Yokoya, Akinari; Fujii, Kentaro; Oka, Toshitaka; Watanabe, Ritsuko

    2012-01-01

    Recent progress on spectroscopic study on physicochemical process of DNA damage induction will be reported. It has been predicted by computer track simulation studies that complex DNA damage, so called clustered DNA damage sites, is produced along the tack particularly of high Linear Energy Transfer (LET) ions. The clustered DNA damage, consisting of two or more isolated lesions such as single strand breaks or nucleobase lesions, is thought to compromise DNA repair enzymes. We have revealed that the nucleobase lesions produced by He 2+ ion impact to simple model DNA (plasmid) are hardly processed by base excision repair enzymes (E. coli DNA glycosylases). Using the third generation synchrotron radiation facility (SPring-8), we have studied unpaired electron species or desorbed ions as intermediates of DNA damage using an EPR apparatus or mass spectrometer installed in the soft X-ray beamline in SPring-8. These aspects are compared with the yields of final products of single- and double-strand breaks and base lesions revealed biochemical techniques. Models of complex DNA damage induction will be proposed considering various modification factors of the damage induction, ionization of valence and inner-shell electrons, OH radicals, hydration layer and the impact of secondary electrons. (author)

  15. Syntheses, spectroscopic properties and molecular structure of silver phytate complexes - IR, UV-VIS studies and DFT calculations

    Science.gov (United States)

    Zając, A.; Dymińska, L.; Lorenc, J.; Ptak, M.; Hanuza, J.

    2018-03-01

    Silver phytate IP6, IP6Ag, IP6Ag2 and IP6Ag3 complexes in the solid state have been synthesized changing the phosphate to metal mole ratio. The obtained products have been characterized by means of chemical and spectroscopic studies. Attenuated total reflection Fourier transform infrared technique and Raman microscope were used in the measurements. These results were discussed in terms of DFT (Density Functional Theory) quantum chemical calculations using the B3LYP/6-31G(d,p) approach. The molecular structures of these compounds have been proposed on the basis of group theory and geometry optimization taking into account the shape and the number of the observed bands corresponding to the stretching and bending vibrations of the phosphate group and metal-oxygen polyhedron. The role of inter- and intra-hydrogen bonds in stabilization of the structure has been discussed. It was found that three types of hydrogen bonds appear in the studied compounds: terminal, and those engaged in the inter- and intra-molecular interactions. The Fermi resonance as a result of the strong intra-molecular Osbnd H⋯O hydrogen bonds was discovered. Electron absorption spectra have been measured to characterize the electron properties of the studied complexes and their local symmetry.

  16. Effect of substituents on redox, spectroscopic and structural properties of conjugated diaryltetrazines--a combined experimental and theoretical study.

    Science.gov (United States)

    Kurach, Ewa; Djurado, David; Rimarčik, Jan; Kornet, Aleksandra; Wlostowski, Marek; Lukeš, Vladimir; Pécaut, Jacques; Zagorska, Malgorzata; Pron, Adam

    2011-02-21

    Two series of new soluble conjugated compounds containing tetrazine central ring have been synthesized. The three-ring compounds have been synthesized by the reaction of aryl cyanide (where aryl = thienyl, alkylthienyl, phenyl or pyridyl) with hydrazine followed by oxidation of the intermediate product with diethyl azodicarboxylate. The five-ring compounds have been prepared using two pathways: (i) reaction of 5-cyano-2,2'-bithiophene (or its alkyl derivative) with hydrazine; (ii) via Suzuki or Stille coupling of 3,6-bis(5-bromo-2-thienyl)-1,2,4,5-tetrazine with a stannyl or boronate derivative of alkylthiophene. UV-vis spectroscopic properties of the synthesized compounds are strongly dependent on the nature of the aryl group, the position of the solubilizing substituent and the length of the molecule, showing the highest bathochromic shift (λ(max) > 440 nm) for five-ring compounds with alkyl groups attached to C(α) carbon in the terminal thienyl ring. An excellent linear correlation has been found for spectroscopically determined and theoretically calculated (TD-B3LYP/6-31G*) excitation energies. With the exception of dipyridyl derivative, the calculated lowest unoccupied molecular orbital (LUMO) level of the investigated molecules changes within a narrow range (from -2.63 to -2.41 eV), in line with the electrochemical data, which show a reversible reduction process with the redox potential varying from -1.23 V to -1.33 V (vs. Fc/Fc(+)). The electrochemically determined positions of the LUMO levels are consistently lower by 0.9 to 1.2 eV with respect to the calculated ones. All molecules readily crystallize. Single crystal studies of 3,6-bis(2,2'-bithien-5-yl)-1,2,4,5-tetrazine show that it crystallizes in a P2(1)/c space group whose structural arrangement is not very favorable to the charge carriers flow within the crystal. Powder diffraction studies of other derivatives have shown that their structural organization is sensitive to the position of the

  17. Jarosite occurrence in the Deccan Volcanic Province of Kachchh, western India: Spectroscopic studies on a Martian analog locality

    Science.gov (United States)

    Bhattacharya, Satadru; Mitra, Souvik; Gupta, Saibal; Jain, Nirmala; Chauhan, Prakash; Parthasarathy, G.; Ajai

    2016-03-01

    The sulfate mineral jarosite is considered a key indicator of hydrous, acidic, and oxidizing conditions on the surface of early Mars. Here we report an analog terrestrial locality hosting jarosite from Matanumadh, Kachchh, western India, using detailed spectroscopic studies on weathered basalts of the Deccan Volcanic Province and overlying tuffaceous shales and sandstones of the Matanumadh Formation. Hyperspectral data in the visible/near-infrared (350-2500 nm) to midinfrared (4000-400 cm-1) region of the electromagnetic spectrum and X-ray diffraction patterns have been acquired on samples collected from the field to detect and characterize the hydrous sulfate and phyllosilicate phases present at the studied site. Hydrous sulfates occur in association with Al-rich phyllosilicates (kaolinite) that overlie a zone of Fe/Mg smectites in altered basalts. Jarosite is found within both saprolitic clay horizons altered from the basalt and within variegated sandstone and shale/clay units overlying the saprolite; it mostly occurs as secondary veins with or without gypsum. Jarosite is also seen as coatings on kaolinite clasts of varying shapes and sizes within the tuffaceous variegated sandstone unit. We argue that the overall geological setting of the Matanumadh area, with this unusual mineral assemblage developing within altered basalts and in the overlying sedimentary sequence, mimics the geological environment of many of the identified jarosite localities on Mars and can be considered as a Martian analog from this perspective.

  18. Phytochemical, spectroscopic and density functional theory study of Diospyrin, and non-bonding interactions of Diospyrin with atmospheric gases

    Science.gov (United States)

    Fazl-i-Sattar; Ullah, Zakir; Ata-ur-Rahman; Rauf, Abdur; Tariq, Muhammad; Tahir, Asif Ali; Ayub, Khurshid; Ullah, Habib

    2015-04-01

    Density functional theory (DFT) and phytochemical study of a natural product, Diospyrin (DO) have been carried out. A suitable level of theory was developed, based on correlating the experimental and theoretical data. Hybrid DFT method at B3LYP/6-31G (d,p) level of theory is employed for obtaining the electronic, spectroscopic, inter-molecular interaction and thermodynamic properties of DO. The exact structure of DO is confirmed from the nice validation of the theory and experiment. Non-covalent interactions of DO with different atmospheric gases such as NH3, CO2, CO, and H2O were studied to find out its electroactive nature. The experimental and predicted geometrical parameters, IR and UV-vis spectra (B3LYP/6-31+G (d,p) level of theory) show excellent correlation. Inter-molecular non-bonding interaction of DO with atmospheric gases is investigated through geometrical parameters, electronic properties, charge analysis, and thermodynamic parameters. Electronic properties include, ionization potential (I.P.), electron affinities (E.A.), electrostatic potential (ESP), density of states (DOS), HOMO, LUMO, and band gap. All these characterizations have corroborated each other and confirmed the presence of non-covalent nature in DO with the mentioned gases.

  19. Spectroscopic studies of lutetium pyro-silicates Lu2Si2O7 doped with bismuth and europium

    International Nuclear Information System (INIS)

    Bretheau-Raynal, Francoise

    1981-01-01

    Single crystals of thortveitite structure pyro-silicates were grown by a floating zone technique associated with an arc image furnace. The samples were systematically characterized by X-Ray diffraction and microprobe analysis. Thanks to oriented single crystals of Lu 2 Si 2 O 7 , Yb 2 Si 2 O 7 and Sc 2 Si 2 O 7 , the recorded infrared and Raman spectra allow complete attribution of internal and external vibration modes, in good agreement with group theory predictions for C 2h factor group. Spectroscopic studies of Eu 3+ doping ion in Lu 2 Si 2 O 7 confirm C 2 point symmetry for the cationic site. Oscillator strengths and Judd-Ofelt parameters for Eu 3+ were calculated. A three level scheme ( 1 S 0 , 3 P 0 , 3 P 1 ) of Bi 3+ ion is used to explain radiative and non radiative mechanisms in Lu 2 Si 2 O 7 doped with bismuth. Finally, the mechanisms of low temperature (T =9 K) energy transfer between Bi 3+ and Eu 3+ in lutetium pyro-silicate was studied. The transfer occurs by non radiative process, without any diffusion of the excitation energy within the donor system and is due to dipole-dipole interactions between Bi 3+ and Eu 3+ ions. (author) [fr

  20. Modification of benzoxazole derivative by bromine-spectroscopic, antibacterial and reactivity study using experimental and theoretical procedures

    Science.gov (United States)

    Aswathy, V. V.; Alper-Hayta, Sabiha; Yalcin, Gözde; Mary, Y. Sheena; Panicker, C. Yohannan; Jojo, P. J.; Kaynak-Onurdag, Fatma; Armaković, Stevan; Armaković, Sanja J.; Yildiz, Ilkay; Van Alsenoy, C.

    2017-08-01

    N-[2-(2-bromophenyl)-1,3-benzoxazol-5-yl]-2-phenylacetamide (NBBPA) was synthesized in this study as an original compound in order to evaluate its antibacterial activity against representative Gram-negative and Gram-positive bacteria, with their drug-resistant clinical isolate. Microbiological results showed that this compound had moderate antibacterial activity. Study also encompassed detailed FT-IR, FT-Raman and NMR experimental and theoretical spectroscopic characterization and assignation of the ring breathing modes of the mono-, ortho- and tri-substituted phenyl rings is in agreement with the literature data. DFT calculations were also used to identify specific reactivity properties of NBBPA molecule based on the molecular orbital, charge distribution and electron density analysis, which indicated the reactive importance of carbonyl and NH2 groups, together with bromine atom. DFT calculations were also used for investigation of sensitivity of the NBBPA molecules towards the autoxidation mechanism, while molecular dynamics (MD) simulations were used to investigate the influence of water. The molecular docking results suggest that the compound might exhibit inhibitory activity against GyrB complex.