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Sample records for anti-stokes raman spectroscopic

  1. A versatile setup using femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yujie, E-mail: styojm@physics.tamu.edu [Texas A& M University, College Station, Texas 77843 (United States); Voronine, Dmitri V.; Sokolov, Alexei V. [Texas A& M University, College Station, Texas 77843 (United States); Baylor University, Waco, Texas 76798 (United States); Scully, Marlan O. [Texas A& M University, College Station, Texas 77843 (United States); Baylor University, Waco, Texas 76798 (United States); Princeton University, Princeton, New Jersey 08544 (United States)

    2015-08-15

    We report a versatile setup based on the femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering. The setup uses a femtosecond Ti:Sapphire oscillator source and a folded 4f pulse shaper, in which the pulse shaping is carried out through conventional optical elements and does not require a spatial light modulator. Our setup is simple in alignment, and can be easily switched between the collinear single-beam and the noncollinear two-beam configurations. We demonstrate the capability for investigating both transparent and highly scattering samples by detecting transmitted and reflected signals, respectively.

  2. Coherent anti-Stokes Raman spectroscopy: Understanding the essentials

    Science.gov (United States)

    Ariunbold, Gombojav O.; Altangerel, Narangerel

    2016-12-01

    This paper is a brief overview to coherent anti- Stokes Raman spectroscopic technique and introduces the strengths and barriers to its use all based on the interpretation of simple theoretical formulae. The use of the Gaussian ultrashort pulses is highlighted as a practical elucidatory reconstruction tool of coherent Raman spectra. The paper presents the integral formulae for coherent anti-Stokes and Stokes Raman scattering, and discusses the closed-form solutions, its complex error function, and the delay time formula for enhancement of the inferred pure coherent Raman spectra. As an example, the timeresolved coherent Stokes Raman scattering experimental observations are quantitatively elucidated.Understanding the essentials of coherent Raman spectroscopy, therefore, promotes the importance of a number of experiments including the ones utilizing a broadband excitation with a narrowband delayed probing for successful background suppression.

  3. Coherent Anti-Stokes Raman Scattering Heterodyne Interferometry

    CERN Document Server

    Bredfeldt, J S; Vinegoni, C; Hambir, S; Boppart, S A

    2003-01-01

    A new interferometric technique is demonstrated for measuring Coherent Anti-Stokes Raman Scattering (CARS) signals. Two forward-directed CARS signals are generated, one in each arm of an interferometer. The deterministic nature of the CARS process allows for these two signals, when spatially and temporally overlapped, to interfere with one another. Heterodyne detection can therefore be employed to increase the sensitivity in CARS signal detection. In addition, nonlinear CARS interferometry will facilitate the use of this spectroscopic technique for molecular contrast in Optical Coherence Tomography (OCT).

  4. Raman and coherent anti-Stokes Raman scattering microspectroscopy for biomedical applications

    Science.gov (United States)

    Krafft, Christoph; Dietzek, Benjamin; Schmitt, Michael; Popp, Jürgen

    2012-04-01

    A tutorial article is presented for the use of linear and nonlinear Raman microspectroscopies in biomedical diagnostics. Coherent anti-Stokes Raman scattering (CARS) is the most frequently applied nonlinear variant of Raman spectroscopy. The basic concepts of Raman and CARS are introduced first, and subsequent biomedical applications of Raman and CARS are described. Raman microspectroscopy is applied to both in-vivo and in-vitro tissue diagnostics, and the characterization and identification of individual mammalian cells. These applications benefit from the fact that Raman spectra provide specific information on the chemical composition and molecular structure in a label-free and nondestructive manner. Combining the chemical specificity of Raman spectroscopy with the spatial resolution of an optical microscope allows recording hyperspectral images with molecular contrast. We also elaborate on interfacing Raman spectroscopic tools with other technologies such as optical tweezing, microfluidics and fiber optic probes. Thereby, we aim at presenting a guide into one exciting branch of modern biophotonics research.

  5. Collinear and noncollinear emission of anti-stokes and second order stokes Raman radiation

    Science.gov (United States)

    Aussenegg, F. R.; Lippitsch, M. E.; Brandmüller, J.; Nitsch, W.

    1981-04-01

    Generating higher order stimulated Raman scattering in benzene, apart from phase-matched anti-Stokes radiation a collinear anti-Stokes emission is observed, which is explained by parametric four-photon processes under mismatch condition.

  6. Imaging properties of coherent anti-Stokes Raman scattering microscope

    Institute of Scientific and Technical Information of China (English)

    Yuan Jing-He; Xiao Fan-Rong; Wang Gui-Ying; Xu Zhi-Zhan

    2005-01-01

    The coherent anti-Stokes Raman scattering (CARS) microscope with the combination of confocal and CARS techniques is a remarkable alternative for imaging chemical or biological specimens that neither fluoresce nor tolerate labelling. CARS is a nonlinear optical process, the imaging properties of CARS microscopy will be very different from the conventional confocal microscope. In this paper, the intensity distribution and the polarization property of the optical field near the focus was calculated. By using the Green function, the precise analytic solution to the wave equation of a Hertzian dipole source was obtained. We found that the intensity distributions vary considerably with the different experimental configurations and the different specimen shapes. So the conventional description of microscope (e.g. the point spread function) will fail to describe the imaging properties of the CARS microscope.

  7. Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds.

    Science.gov (United States)

    Pope, Iestyn; Payne, Lukas; Zoriniants, George; Thomas, Evan; Williams, Oliver; Watson, Peter; Langbein, Wolfgang; Borri, Paola

    2014-11-01

    Nanoparticles have attracted enormous attention for biomedical applications as optical labels, drug-delivery vehicles and contrast agents in vivo. In the quest for superior photostability and biocompatibility, nanodiamonds are considered one of the best choices due to their unique structural, chemical, mechanical and optical properties. So far, mainly fluorescent nanodiamonds have been utilized for cell imaging. However, their use is limited by the efficiency and costs in reliably producing fluorescent defect centres with stable optical properties. Here, we show that single non-fluorescing nanodiamonds exhibit strong coherent anti-Stokes Raman scattering (CARS) at the sp(3) vibrational resonance of diamond. Using correlative light and electron microscopy, the relationship between CARS signal strength and nanodiamond size is quantified. The calibrated CARS signal in turn enables the analysis of the number and size of nanodiamonds internalized in living cells in situ, which opens the exciting prospect of following complex cellular trafficking pathways quantitatively.

  8. Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds

    Science.gov (United States)

    Pope, Iestyn; Payne, Lukas; Zoriniants, George; Thomas, Evan; Williams, Oliver; Watson, Peter; Langbein, Wolfgang; Borri, Paola

    2014-11-01

    Nanoparticles have attracted enormous attention for biomedical applications as optical labels, drug-delivery vehicles and contrast agents in vivo. In the quest for superior photostability and biocompatibility, nanodiamonds are considered one of the best choices due to their unique structural, chemical, mechanical and optical properties. So far, mainly fluorescent nanodiamonds have been utilized for cell imaging. However, their use is limited by the efficiency and costs in reliably producing fluorescent defect centres with stable optical properties. Here, we show that single non-fluorescing nanodiamonds exhibit strong coherent anti-Stokes Raman scattering (CARS) at the sp3 vibrational resonance of diamond. Using correlative light and electron microscopy, the relationship between CARS signal strength and nanodiamond size is quantified. The calibrated CARS signal in turn enables the analysis of the number and size of nanodiamonds internalized in living cells in situ, which opens the exciting prospect of following complex cellular trafficking pathways quantitatively.

  9. Quantitative coherent anti-Stokes Raman scattering (CARS) microscopy.

    Science.gov (United States)

    Day, James P R; Domke, Katrin F; Rago, Gianluca; Kano, Hideaki; Hamaguchi, Hiro-o; Vartiainen, Erik M; Bonn, Mischa

    2011-06-23

    The ability to observe samples qualitatively at the microscopic scale has greatly enhanced our understanding of the physical and biological world throughout the 400 year history of microscopic imaging, but there are relatively few techniques that can truly claim the ability to quantify the local concentration and composition of a sample. We review coherent anti-Stokes Raman scattering (CARS) as a quantitative, chemically specific, and label-free microscopy. We discuss the complicating influence of the nonresonant response on the CARS signal and the various experimental and mathematical approaches that can be adopted to extract quantitative information from CARS. We also review the uses to which CARS has been employed as a quantitative microscopy to solve challenges in material and biological science.

  10. Coherent anti-Stokes Raman scattering under electric field stimulation

    Science.gov (United States)

    Capitaine, Erwan; Ould Moussa, Nawel; Louot, Christophe; Lefort, Claire; Pagnoux, Dominique; Duclère, Jean-René; Kaneyasu, Junya F.; Kano, Hideaki; Duponchel, Ludovic; Couderc, Vincent; Leproux, Philippe

    2016-12-01

    We introduce an experiment using electro-CARS, an electro-optical method based on the combination of ultrabroadband multiplex coherent anti-Stokes Raman scattering (M-CARS) spectroscopy and electric field stimulation. We demonstrate that this method can effectively discriminate the resonant CARS signal from the nonresonant background owing to a phenomenon of molecular orientation in the sample medium. Such molecular orientation is intrinsically related to the induction of an electric dipole moment by the applied static electric field. Evidence of the electro-CARS effect is obtained with a solution of n -alkanes (CnH2 n +2 , 15 ≤n ≤40 ), for which an enhancement of the CARS signal-to-noise ratio is achieved in the case of CH2 and CH3 symmetric/asymmetric stretching vibrations. Additionally, an electric-field-induced second-harmonic generation experiment is performed in order to corroborate the orientational organization of molecules due to the electric field excitation. Finally, we use a simple mathematical approach to compare the vibrational information extracted from electro-CARS measurements with spontaneous Raman data and to highlight the impact of electric stimulation on the vibrational signal.

  11. Quantitative, Comparable Coherent Anti-Stokes Raman Scattering (CARS) Spectroscopy: Correcting Errors in Phase Retrieval

    CERN Document Server

    Camp, Charles H; Cicerone, Marcus T

    2015-01-01

    Coherent anti-Stokes Raman scattering (CARS) microspectroscopy has demonstrated significant potential for biological and materials imaging. To date, however, the primary mechanism of disseminating CARS spectroscopic information is through pseudocolor imagery, which explicitly neglects a vast majority of the hyperspectral data. Furthermore, current paradigms in CARS spectral processing do not lend themselves to quantitative sample-to-sample comparability. The primary limitation stems from the need to accurately measure the so-called nonresonant background (NRB) that is used to extract the chemically-sensitive Raman information from the raw spectra. Measurement of the NRB on a pixel-by-pixel basis is a nontrivial task; thus, reference NRB from glass or water are typically utilized, resulting in error between the actual and estimated amplitude and phase. In this manuscript, we present a new methodology for extracting the Raman spectral features that significantly suppresses these errors through phase detrending ...

  12. Coherent anti-Stokes Raman scattering microscopy with a photonic crystal fiber based light source

    DEFF Research Database (Denmark)

    Paulsen, H.N.; Hilligsøe, Karen Marie; Thøgersen, J.;

    2003-01-01

    A coherent anti-Stokes Raman scattering microscope based on a Ti:sapphire femtosecond oscillator and a photonic crystal fiber is demonstrated. The nonlinear response of the fiber is used to generate the additional wavelength needed in the Raman process. The applicability of the setup...

  13. Single-pulse coherent anti-Stokes Raman spectroscopy via fiber Bragg grating

    Science.gov (United States)

    Oh, Seung Ryeol; Park, Joo Hyun; Kwon, Won Sik; Kim, Jin Hwan; Kim, Kyung-Soo; Lee, Jae Yong; Kim, Soohyun

    2016-03-01

    Fiber Bragg grating is used in a variety of applications. In this study, we suggest compact, cost-effective coherent anti- Stokes Raman spectroscopy which is based on the pulse shaping methods via commercialized fiber Bragg grating. The experiment is performed incorporating a commercialized femtosecond pulse laser system (MICRA, Coherent) with a 100 mm length of 780-HP fiber which is inscribed 50 mm of Bragg grating. The pump laser for coherent anti-Stokes Raman spectroscopy has a bandwidth of 90 nm and central wavelength of 815 nm with a notch shaped at 785 nm. The positive chirped pulse is compensated by chirped mirror set. We compensate almost 14000 fs2 of positive group delay dispersion for the transform-limited pulse at the sample position. The pulse duration was 15 fs with average power of 50 mW, and showed an adequate notch shape. Finally, coherent anti-Stokes Raman signals are observed using a spectrometer (Jobin Yvon Triax320 and TE-cooled Andor Newton EMCCD). We obtained coherent anti-Stokes Raman signal of acetone sample which have Raman peak at the spectral finger-print region. In conclusion, the proposed method is more simple and cost-effective than the methods of previous research which use grating pairs and resonant photonic crystal slab. Furthermore, the proposed method can be used as endoscope application.

  14. Broadband multiplex coherent anti-Stokes Raman scattering microscopy employing photonic-crystal fibers

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn; Paulsen, Henrik Nørgaard; Birkedal, Victoria;

    2006-01-01

    We demonstrate spectral multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy and microscopy based on a single Ti:sapphire oscillator and a nonlinear photonic-crystal fiber (PCF). The Stokes pulse is generated by spectral conversion of the laser pulse in a PCF. The pump pulse...

  15. Coherent anti-Stokes Raman scattering microscopy for pharmaceutics: a shift in the right direction

    NARCIS (Netherlands)

    Fussell, Andrew Luke

    2014-01-01

    This dissertation demonstrates coherent anti-Stokes Raman scattering (CARS) microscopy as a tool in pharmaceutical solid state development. CARS microscopy is a nonlinear optical imaging technique that uses inelastic scattering of light to provide chemically specific imaging. CARS microscopy is suit

  16. Combustion Diagnostics by Pure Rotational Coherent Anti-Stokes Raman Scattering

    Science.gov (United States)

    Leipertz, Alfred; Seeger, Thomas

    Since its first use in Richard Chang's laboratory in 1982 in a comparative study with vibrational coherent anti-Stokes Raman scattering (VCARS) in a flame, pure rotational coherent anti-Stokes Raman scattering (RCARS) has gained tremendous importance for gas temperature and relative species concentration measurements in combustion diagnostics. The field of application covers basic studies on diagnostics development and on flame research as well as its use in technical combustion systems, e.g., for the determination of the gas-phase temperature in the vaporizing spray of a gasoline direct injection (GDI) injector or for the simultaneous measurement of gas temperature and exhaust-gas-recirculation rate (EGR rate) in a homogeneous charge compression ignition (HCCI) engine. An overview is given on the fundamentals of the technique and on its most important technical applications.

  17. Design of supercontinuum source for coherent anti-Stokes Raman scattering microscopy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui; CHANG Sheng-jiang; ZHANG Yan-xin; ZHAO Xiang-ting

    2008-01-01

    A new method to obtain supemontinuum(SC)source for multiplex coherent anti-stokes Raman scattering(CARS)micros-copy is proposed.The nonlinear propagation in photonic-crystal fibers(PCF)of femtosecond pulse laser with central wavelength at 800.9 nm is studied with scalar wave theory.Based on the incident laser power and dispersion of PCF,super broadband source for multiplex CARS microscopy is designed.

  18. Polarized multiplex coherent anti-Stokes Raman scattering using a picosecond laser and a fiber supercontinuum.

    Science.gov (United States)

    Michel, Sébastien; Courjaud, Antoine; Mottay, Eric; Finot, Christophe; Dudley, John; Rigneault, Hervé

    2011-02-01

    We perform multiplex coherent anti-Stokes Raman scattering (CARS) micro-spectroscopy with a picosecond pulsed laser and a broadband supercontinuum (SC) generated in photonic crystal fiber. CARS signal stability is achieved using an active fiber coupler that avoids thermal and mechanical drifts. We obtain multiplex CARS spectra for test liquids in the 600-2000 cm(-1) spectral range. In addition we investigate the polarization dependence of the CARS spectra when rotating the pump beam linear polarization state relative to the linearly polarized broad stokes SC. From these polarization measurements we deduce the Raman depolarization ratio, the resonant versus nonresonant contribution, the Raman resonance frequency, and the linewidth.

  19. Quantitative interpretation of time-resolved coherent anti-Stokes Raman spectroscopy with all Gaussian pulses

    CERN Document Server

    Ariunbold, Gombojav O

    2016-01-01

    Coherent Raman scattering spectroscopy is studied purposely, with the Gaussian ultrashort pulses as a hands-on elucidatory extraction tool of the clean coherent Raman resonant spectra from the overall measured data contaminated with the non-resonant four wave mixing background. The integral formulae for both the coherent anti-Stokes and Stokes Raman scattering are given in the semiclassical picture, and the closed-form solutions in terms of a complex error function are obtained. An analytic form of maximum enhancement of pure coherent Raman spectra at threshold time delay depending on bandwidth of probe pulse is also obtained. The observed experimental data for pyridine in liquid-phase are quantitatively elucidated and the inferred time-resolved coherent Raman resonant results are reconstructed with a new insight.

  20. Supercontinuum generation for coherent anti- Stokes Raman scattering microscopy with photonic crystal fibers

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Isomäki, Antti; Hansen, Kim P.

    2011-01-01

    Photonic crystal fiber (PCF) designs with two zero-dispersion wavelengths (ZDWs) are experimentally investigated in order to suggest a novel PCF for coherent anti-Stokes Raman scattering (CARS) microscopy. From our investigation, we select the optimum PCF design and demonstrate a tailored spectrum...... with power concentrated around the relevant wavelengths for lipid imaging (648 nm and 1027 nm). This new PCF is characterized by varying the fiber length, the average power, and the pulse width of the fs pump pulses. It was found that the selected PCF design gave a significantly improved spectral...

  1. Spectral model of time-domain coherent anti-Stokes Raman scattering

    CERN Document Server

    Marrocco, Michele

    2014-01-01

    We show that the increasingly popular nonlinear optical technique of time-domain coherent anti-Stokes Raman scattering (CARS), which is usually understood in terms of the semiclassical time-dependent third-order polarization, can be equally explained in terms of the time-delayed version of the Yuratich equation so popular in traditional frequency-domain CARS. The method brings out the strong dependence of CARS time traces and time-delayed CARS lineshapes on the spectral envelope of the probe laser electric field. Examples are analytically shown for experimental results that are otherwise treated by means of numerical methods only.

  2. Experimental Investigation on Selective Excitation of Two-Pulse Coherent Anti-Stokes Raman Scattering

    Institute of Scientific and Technical Information of China (English)

    LI Xia; ZHANG Hui; ZHANG Xiang-Yun; ZHANG Shi-An; WANG Zu-Geng; SUN Zhen-Rong

    2008-01-01

    Selective excitation of coherent anti-Stokes Raman scattering from the benzene solution is achieved by adaptive pulse shaping based on genetic algorithm, and second harmonic generation frequency-resolved optical gating (SHG-FROG) technique is adopted to characterize the original and optimal laser pulses. The mechanism for two-pulse coherent mode-selective excitation of Raman scattering is experimentally investigated by modulating the pump pulse in the frequency domain, and it is indicated that two-pulse coherent mode-selective excitation of Raman scattering mainly depends on the effective frequency components of the pump pulse related to specific vibrational mode. The experimental results suggest that two-pulse CARS has good signal-to-background ratio and high sensitivity, and it has attractive potential applications in the complicated molecular system.

  3. Broadband coherent anti-Stokes Raman scattering light generation in BBO crystal by using two crossing femtosecond laser pulses.

    Science.gov (United States)

    Liu, Jun; Zhang, Jun; Kobayashi, Takayoshi

    2008-07-01

    As broad as 12000 cm(-1) coherent anti-Stokes Raman scattering (CARS) light from ultraviolet to infrared was generated in a BBO crystal by using two crossing femtosecond laser pulses with 30% conversion efficiency. More than fifteenth-order anti-Stokes and second-order Stokes Raman sidebands were observed with nice Gaussian spatial mode. The effect of the crossing angle between two input beams on the spectrum and emitting angle of the Raman sidebands was studied in detail. Calculation shows that the phase-matching condition determines the frequencies and angles of the sidebands.

  4. Revealing silent vibration modes of nanomaterials by detecting anti-Stokes hyper-Raman scattering with femtosecond laser pulses

    Science.gov (United States)

    Zeng, Jianhua; Chen, Lei; Dai, Qiaofeng; Lan, Sheng; Tie, Shaolong

    2016-01-01

    We proposed a scheme in which normal Raman scattering is coupled with hyper-Raman scattering for generating a strong anti-Stokes hyper-Raman scattering in nanomaterials by using femtosecond laser pulses. The proposal was experimentally demonstrated by using a single-layer MoS2 on a SiO2/Si substrate, a 17 nm-thick MoS2 on an Au/SiO2 substrate and a 9 nm-thick MoS2 on a SiO2-SnO2/Ag/SiO2 substrate which were confirmed to be highly efficient for second harmonic generation. A strong anti-Stokes hyper-Raman scattering was also observed in other nanomaterials possessing large second-order susceptibilities, such as silicon quantum dots self-assembled into ``coffee'' rings and tubular Cu-doped ZnO nanorods. In all the cases, many Raman inactive vibration modes were clearly revealed in the anti-Stokes hyper-Raman scattering. Apart from the strong anti-Stokes hyper-Raman scattering, Stokes hyper-Raman scattering with small Raman shifts was detected during the ablation process of thick MoS2 layers. It was also observed by slightly defocusing the excitation light. The detection of anti-Stokes hyper-Raman scattering may serve as a new technique for studying the Raman inactive vibration modes in nanomaterials.We proposed a scheme in which normal Raman scattering is coupled with hyper-Raman scattering for generating a strong anti-Stokes hyper-Raman scattering in nanomaterials by using femtosecond laser pulses. The proposal was experimentally demonstrated by using a single-layer MoS2 on a SiO2/Si substrate, a 17 nm-thick MoS2 on an Au/SiO2 substrate and a 9 nm-thick MoS2 on a SiO2-SnO2/Ag/SiO2 substrate which were confirmed to be highly efficient for second harmonic generation. A strong anti-Stokes hyper-Raman scattering was also observed in other nanomaterials possessing large second-order susceptibilities, such as silicon quantum dots self-assembled into ``coffee'' rings and tubular Cu-doped ZnO nanorods. In all the cases, many Raman inactive vibration modes were clearly

  5. Stimulated-emission pumping enabling sub-diffraction-limited spatial resolution in coherent anti-Stokes Raman scattering microscopy

    NARCIS (Netherlands)

    Cleff, C.; Gross, P.; Fallnich, C.; Offerhaus, H.L.; Herek, J.L.; Kruse, K.; Beeker, W.P.; Lee, C.J.; Boller, K-J.

    2013-01-01

    We present a theoretical investigation of stimulated emission pumping to achieve sub-diffraction-limited spatial resolution in coherent anti-Stokes Raman scattering (CARS) microscopy. A pair of control light fields is used to prepopulate the Raman state involved in the CARS process prior to the CARS

  6. Low-concentration chemical sensing using surface-enhanced coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Hua, Xia; Sinyukov, Alexander; Traverso, Andrew; Veronine, Dmitri; Wang, Kai; Xia, Hui; Yang, Wenlong; Yuan, Luqi; Sokolov, Alexei; Scully, Marlan

    2010-10-01

    Measurements of surface enhanced coherent anti-Stokes Raman spectra (CARS) of cyclohexane are carried out. Random aggregates of gold nanoparticles for field enhancement were deposited on a glass substrate and were characterized using atomic force microscopy (AFM). Surface enhancement of the CARS signal by gold nanoparticles is observed. This technique can be used to detect low amounts of chemicals with a higher sensitivity compared to the conventional surface-enhanced Raman spectroscopy (SERS). The lowest detected concentration of cyclohexane in a thin film of methanol was 1%. However, it was not possible to detect any signal from the same sample of cyclohexane without gold nanoparticles using conventional CARS technique. Therefore, surface enhancement is necessary to achieve higher spectroscopy sensitivity. Further studies of nanostructure-enhanced electrical fields are required to quantitatively understand the observed effects and will be performed in the future.

  7. Automated identification of subcellular organelles by coherent anti-stokes Raman scattering.

    Science.gov (United States)

    El-Mashtoly, Samir F; Niedieker, Daniel; Petersen, Dennis; Krauss, Sascha D; Freier, Erik; Maghnouj, Abdelouahid; Mosig, Axel; Hahn, Stephan; Kötting, Carsten; Gerwert, Klaus

    2014-05-06

    Coherent anti-Stokes Raman scattering (CARS) is an emerging tool for label-free characterization of living cells. Here, unsupervised multivariate analysis of CARS datasets was used to visualize the subcellular compartments. In addition, a supervised learning algorithm based on the "random forest" ensemble learning method as a classifier, was trained with CARS spectra using immunofluorescence images as a reference. The supervised classifier was then used, to our knowledge for the first time, to automatically identify lipid droplets, nucleus, nucleoli, and endoplasmic reticulum in datasets that are not used for training. These four subcellular components were simultaneously and label-free monitored instead of using several fluorescent labels. These results open new avenues for label-free time-resolved investigation of subcellular components in different cells, especially cancer cells.

  8. Delivery of picosecond lasers in multimode fibers for coherent anti-Stokes Raman scattering imaging.

    Science.gov (United States)

    Wang, Zhiyong; Yang, Yaliang; Luo, Pengfei; Gao, Liang; Wong, Kelvin K; Wong, Stephen T C

    2010-06-07

    We investigated the possibility of using standard commercial multimode fibers (MMF), Corning SMF28 fibers, to deliver picosecond excitation lasers for coherent anti-Stokes Raman scattering (CARS) imaging. We theoretically and/or experimentally analyzed issues associated with the fiber delivery, such as dispersion length, walk-off length, nonlinear length, average threshold power for self-phase modulations, and four-wave mixing (FWM). These analyses can also be applied to other types of fibers. We found that FWM signals are generated in MMF, but they can be filtered out using a long-pass filter for CARS imaging. Finally, we demonstrated that MMF can be used for delivery of picosecond excitation lasers in the CARS imaging system without any degradation of image quality.

  9. Shaping femtosecond coherent anti-Stokes Raman spectra using optimal control theory.

    Science.gov (United States)

    Pezeshki, Soroosh; Schreiber, Michael; Kleinekathöfer, Ulrich

    2008-04-21

    Optimal control theory is used to tailor laser pulses which enhance a femtosecond time-resolved coherent anti-Stokes Raman scattering (fs-CARS) spectrum in a certain frequency range. For this aim the optimal control theory has to be applied to a target state distributed in time. Explicit control mechanisms are given for shaping either the Stokes or the probe pulse in the four-wave mixing process. A simple molecule for which highly accurate potential energy surfaces are available, namely molecular iodine, is used to test the procedure. This approach of controlling vibrational motion and delivering higher intensities to certain frequency ranges might also be important for the improvement of CARS microscopy.

  10. Fast spectral coherent anti-Stokes Raman scattering microscopy with high-speed tunable picosecond laser.

    Science.gov (United States)

    Cahyadi, Harsono; Iwatsuka, Junichi; Minamikawa, Takeo; Niioka, Hirohiko; Araki, Tsutomu; Hashimoto, Mamoru

    2013-09-01

    We develop a coherent anti-Stokes Raman scattering (CARS) microscopy system equipped with a tunable picosecond laser for high-speed wavelength scanning. An acousto-optic tunable filter (AOTF) is integrated in the laser cavity to enable wavelength scanning by varying the radio frequency waves applied to the AOTF crystal. An end mirror attached on a piezoelectric actuator and a pair of parallel plates driven by galvanometer motors are also introduced into the cavity to compensate for changes in the cavity length during wavelength scanning to allow synchronization with another picosecond laser. We demonstrate fast spectral imaging of 3T3-L1 adipocytes every 5  cm-1 in the Raman spectral region around 2850  cm-1 with an image acquisition time of 120 ms. We also demonstrate fast switching of Raman shifts between 2100 and 2850  cm-1, corresponding to CD2 symmetric stretching and CH2 symmetric stretching vibrations, respectively. The fast-switching CARS images reveal different locations of recrystallized deuterated and nondeuterated stearic acid.

  11. Molecular Orientation in Dry and Hydrated Cellulose Fibers: A Coherent Anti-Stokes Raman Scattering Microscopy Study

    OpenAIRE

    Zimmerley, Maxwell; Younger, Rebecca; Valenton, Tiffany; Oertel, David C.; Ward, Jimmie L.; Potma, Eric O.

    2010-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is combined with spontaneous Raman scattering microspectroscopy and second harmonic generation (SHG) microscopy to interrogate the molecular alignment in dry and hydrated cellulose fibers. Two types of cellulose were investigated: natural cellulose I in cotton fibers and regenerated cellulose II in rayon fibers. On the basis of the orientation of the methylene symmetric stretching vibration, the molecular alignment of cellulose microfibr...

  12. Coherent anti-Stokes Raman scattering microscopy of human smooth muscle cells in bioengineered tissue scaffolds

    Science.gov (United States)

    Brackmann, Christian; Esguerra, Maricris; Olausson, Daniel; Delbro, Dick; Krettek, Alexandra; Gatenholm, Paul; Enejder, Annika

    2011-02-01

    The integration of living, human smooth muscle cells in biosynthesized cellulose scaffolds was monitored by nonlinear microscopy toward contractile artificial blood vessels. Combined coherent anti-Stokes Raman scattering (CARS) and second harmonic generation (SHG) microscopy was applied for studies of the cell interaction with the biopolymer network. CARS microscopy probing CH2-groups at 2845 cm-1 permitted three-dimensional imaging of the cells with high contrast for lipid-rich intracellular structures. SHG microscopy visualized the fibers of the cellulose scaffold, together with a small signal obtained from the cytoplasmic myosin of the muscle cells. From the overlay images we conclude a close interaction between cells and cellulose fibers. We followed the cell migration into the three-dimensional structure, illustrating that while the cells submerge into the scaffold they extrude filopodia on top of the surface. A comparison between compact and porous scaffolds reveals a migration depth of <10 μm for the former, whereas the porous type shows cells further submerged into the cellulose. Thus, the scaffold architecture determines the degree of cell integration. We conclude that the unique ability of nonlinear microscopy to visualize the three-dimensional composition of living, soft matter makes it an ideal instrument within tissue engineering.

  13. Label-free imaging of human breast tissues using coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Yang, Yaliang; Gao, Liang; Wang, Zhiyong; Thrall, Michael J.; Luo, Pengfei; Wong, Kelvin K.; Wong, Stephen T.

    2011-03-01

    Breast cancer is a common disease in women. Current imaging and diagnostic methods for breast cancer confront several limitations, like time-consuming, invasive and with a high cost. Alternative strategies are in high demand to alleviate patients' trauma and lower medical expenses. Coherent anti-Stokes Raman scattering (CARS) imaging technique offers many advantages, including label-free, sub-wavelength spatial resolution and video-rate imaging speed. Therefore, it has been demonstrated as a powerful tool for various biomedical applications. In this study, we present a label-free fast imaging method to identify breast cancer and its subtypes using CARS microscopy. Human breast tissues, including normal, benign and invasive carcinomas, were imaged ex vivo using a custom-built CARS microscope. Compared with results from corresponding hematoxylin and eosin (H&E) stains, the CARS technique has demonstrated its capability in identifying morphological features in a similar way as in H&E stain. These features can be used to distinguish breast cancer from normal and benign tissues, and further separate cancer subtypes from each other. Our pilot study suggests that CARS microscopy could be used as a routine examination tool to characterize breast cancer ex vivo. Moreover, its label-free and fast imaging properties render this technique as a promising approach for in vivo and real-time imaging and diagnosis of breast cancer.

  14. Femtosecond Coherent Anti-Stokes Raman Scattering Gas Phase Thermometry at 5 kHz

    Science.gov (United States)

    Fineman, Claresta; Lucht, Robert

    2014-05-01

    Understanding the thermal instabilities occurring in turbulent combustion, such as in modern gas turbine combustors, is critical for more reliable and fuel-efficient operation. Non-intrusive laser based spectroscopy methods have been documented as the techniques of choice for turbulent combustion diagnostics. Specifically, femtosecond coherent anti-Stokes Raman scattering (fs-CARS) thermometry has been established for temporal resolution of turbulent fluctuations in flame structure and provides accurate measurements across a wide range of temperatures. Experiments performed to date include 5 kHz pure vibrational N2 chirped probe-pulse fs-CARS thermometry on non-premixed hydrogen jet diffusion flames, methane jet diffusion flames, and the DLR gas turbine model combustor (GTMC). The fs-CARS signal generation process requires precise spatial and temporal overlap of tightly focused pulsed laser beams of less than 100 fs pulse duration. Here, signal loss due to beam steering, pressure fluctuations, or shear layer density gradients can become a problem. The effect of such interferences has been investigated using high velocity flow of compressed nitrogen gas from a converging-diverging nozzle. Resulting changes in fs-CARS spectra have been studied. Funding for this work was provided by the U.S. Department of Energy, Division of Chemical Sciences, Geosciences and Biosciences.

  15. Investigation of porous media combustion by coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Weikl, M. C.; Tedder, S. A.; Seeger, T.; Leipertz, A.

    2010-10-01

    High efficiency, marginal pollutant emissions and low fuel consumption are desirable standards for modern combustion devices. The porous burner technology is a modern type of energy conversion with a strong potential to achieve these standards. However, due to the solid ceramic framework investigation of the thermodynamic properties of combustion, for example temperature, is difficult. The combustion process inside the ceramic structure of a porous burner was experimentally investigated by coherent anti-Stokes Raman spectroscopy (CARS). In this work, we present measurements using dual-pump dual-broadband CARS (DP-DBB-CARS) of temperature and species concentrations inside the reaction and flue gas zone of a porous media burner. Improvements to the setup and data evaluation procedure in contrast to previous measurements are discussed in detail. The results at varied thermal power and stoichiometry are presented. In addition, measurements at a range of radial positions inside a pore are conducted and correlated with the solid structure of the porous foam, which was determined by X-ray computer tomography.

  16. Effect of Scatterering on Coherent Anti-Stokes Raman Scattering (CARS) signals

    CERN Document Server

    Ranasinghesagara, Janaka C; Piazza, Vincenzo; Potma, Eric O; Venugopalan, Vasan

    2016-01-01

    We develop a computational framework to examine the factors responsible for scattering-induced distortions of coherent anti-Stokes Raman scattering (CARS) signals in turbid samples. We use the Huygens-Fresnel Wave-based Electric Field Superposition (HF-WEFS) method combined with the radiating dipole approximation to compute the effects of scattering-induced distortions of focal excitation fields on the far-field CARS signal. We analyze the effect of spherical scatterers, placed in the vicinity of the focal volume, on the CARS signal emitted by different objects (2{\\mu}m diameter solid sphere, 2{\\mu}m diameter myelin cylinder and 2{\\mu}m diameter myelin tube). We find that distortions in the CARS signals arise not only from attenuation of the focal field but also from scattering-induced changes in the spatial phase that modifies the angular distribution of the CARS emission. Our simulations further show that CARS signal attenuation can be minimized by using a high numerical aperture condenser. Moreover, unlike...

  17. Investigation of lipid homeostasis in living Drosophila by coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Chien, Cheng-Hao; Chen, Wei-Wen; Wu, June-Tai; Chang, Ta-Chau

    2012-12-01

    To improve our understanding of lipid metabolism, Drosophila is used as a model animal, and its lipid homeostasis is monitored by coherent anti-Stokes Raman scattering microscopy. We are able to achieve in vivo imaging of larval fat body (analogous to adipose tissue in mammals) and oenocytes (analogous to hepatocytes) in Drosophila larvae at subcellular level without any labeling. By overexpressing two lipid regulatory proteins-Brummer lipase (Bmm) and lipid storage droplet-2 (Lsd-2)-we found different phenotypes and responses under fed and starved conditions. Comparing with the control larva, we observed more lipid droplet accumulation by ˜twofold in oenocytes of fat-body-Bmm-overexpressing (FB-Bmm-overexpressing) mutant under fed condition, and less lipid by ˜fourfold in oenocytes of fat-body-Lsd-2-overexpressing (FB-Lsd-2-overexpressing) mutant under starved condition. Moreover, together with reduced size of lipid droplets, the lipid content in the fat body of FB-Bmm-overexpressing mutant decreases much faster than that of the control and FB-Lsd-2-overexpressing mutant during starvation. From long-term starvation assay, we found FB-Bmm-overexpressing mutant has a shorter lifespan, which can be attributed to faster consumption of lipid in its fat body. Our results demonstrate in vivo observations of direct influences of Bmm and Lsd-2 on lipid homeostasis in Drosophila larvae.

  18. Diagnosing lung cancer using coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Gao, Liang; Yang, Yaliang; Xing, Jiong; Thrall, Michael J.; Wang, Zhiyong; Li, Fuhai; Luo, Pengfei; Wong, Kelvin K.; Zhao, Hong; Wong, Stephen T. C.

    2011-03-01

    Lung carcinoma is the most prevalent type of cancer in the world, and it is responsible for more deaths than other types of cancer. During diagnosis, a pathologist primarily aims to differentiate small cell carcinoma from non-small cell carcinoma on biopsy and cytology specimens, which is time consuming due to the time required for tissue processing and staining. To speed up the diagnostic process, we investigated the feasibility of using coherent anti-Stokes Raman scattering (CARS) microscopy as a label-free strategy to image lung lesions and differentiate subtypes of lung cancers. Different mouse lung cancer models were developed by injecting human lung cancer cell lines, including adenocarcinoma, squamous cell carcinoma, and small cell carcinoma, into lungs of the nude mice. CARS images were acquired from normal lung tissues and different subtypes of cancer lesions ex vivo using intrinsic contrasts from symmetric CH2 bonds. These images showed good correlation with the hematoxylin and eosin (H&E) stained sections from the same tissue samples with regard to cell size, density, and cell-cell distance. These features are routinely used in diagnosing lung lesions. Our results showed that the CARS technique is capable of providing a visualizable platform to differentiate different kinds of lung cancers using the same pathological features without histological staining and thus has the potential to serve as a more efficient examination tool for diagnostic pathology. In addition, incorporating with suitable fiber-optic probes would render the CARS technique as a promising approach for in vivo diagnosis of lung cancer.

  19. Compact fibre-based coherent anti-Stokes Raman scattering spectroscopy and interferometric coherent anti-Stokes Raman scattering from a single femtosecond fibre-laser oscillator

    Indian Academy of Sciences (India)

    Vikas Kumar; Alessio Gambetta; Cristian Manzoni; Roberta Ramponi; Giulio Cerullo; Marco Marangoni

    2010-12-01

    We demonstrate a new approach to CARS spectroscopy by efficiently synthesizing synchronized narrow-bandwidth (less than 10 cm-1) pump and Stokes pulses (frequency difference continuously tunable upto ∼ 3000 cm-1) based on spectral compression together with second harmonic generation (in periodically-poled nonlinear crystals) of femtosecond pulses emitted by a single compact Er-fibre oscillator. For a far better signal to non-resonant background contrast, interferometric CARS (I-CARS) is demonstrated and CARS signal enhancement upto three orders of magnitude is achieved by constructive interference with an auxiliary local oscillator at anti-Stokes field, also synthesized by spectral compression of pulses emitted from the same fibre oscillator.

  20. The application of Raman and anti-stokes Raman spectroscopy for in situ monitoring of structural changes in laser irradiated titanium dioxide materials

    Energy Technology Data Exchange (ETDEWEB)

    Rigby, Stephanie J. [Centre for Research in Energy and Environment, School of Engineering, Robert Gordon University, Aberdeen AB10 1FR (United Kingdom); Al-Obaidi, Ala H.R. [Smart Light Devices, Unit 13, Tyseal Base, Craigshaw Crescent Aberdeen, West Tullos Industrial Estate, Aberdeen AB12 3AW (United Kingdom); Lee, Soo-Keun [School of Environmental Science and Engineering, POSTECH, San 31 Hyoja Dong Nam-Gu, Pohang, Kyungpook 790-784 (Korea, Republic of); McStay, Daniel [Discovery Technologies Ltd., Redshank House, Alness Point Business Park, Alness IV17 0IJ (United Kingdom); Robertson, Peter K.J. [Centre for Research in Energy and Environment, School of Engineering, The Robert Gordon University, Aberdeen AB10 1FR (United Kingdom)]. E-mail: peter.robertson@rgu.ac.uk

    2006-09-15

    The use of Raman and anti-stokes Raman spectroscopy to investigate the effect of exposure to high power laser radiation on the crystalline phases of TiO{sub 2} has been investigated. Measurement of the changes, over several time integrals, in the Raman and anti-stokes Raman of TiO{sub 2} spectra with exposure to laser radiation is reported. Raman and anti-stokes Raman provide detail on both the structure and the kinetic process of changes in crystalline phases in the titania material. The effect of laser exposure resulted in the generation of increasing amounts of the rutile crystalline phase from the anatase crystalline phase during exposure. The Raman spectra displayed bands at 144 cm{sup -1} (A1g), 197 cm{sup -1} (Eg), 398 cm{sup -1} (B1g), 515 cm{sup -1} (A1g), and 640 cm{sup -1} (Eg) assigned to anatase which were replaced by bands at 143 cm{sup -1} (B1g), 235 cm{sup -1} (2 phonon process), 448 cm{sup -1} (Eg) and 612 cm{sup -1} (A1g) which were assigned to rutile. This indicated that laser irradiation of TiO{sub 2} changes the crystalline phase from anatase to rutile. Raman and anti-stokes Raman are highly sensitive to the crystalline forms of TiO{sub 2} and allow characterisation of the effect of laser irradiation upon TiO{sub 2}. This technique would also be applicable as an in situ method for monitoring changes during the laser irradiation process.

  1. Investigation of fiber Bragg grating as a spectral notch shaper for single-pulse coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Oh, Seung Ryeol; Park, Joo Hyun; Kim, Kyung-Soo; Lee, Eun Seong; Lee, Jae Yong; Kim, Soohyun

    2017-01-01

    We experimentally demonstrate compact and efficient single-pulse coherent anti-Stokes Raman spectroscopy (CARS) via spectral notch shaping implemented with a fiber Bragg grating. We show that a fiber Bragg grating can serve as a narrowband notch filtering component on a 90 nm broadband femtosecond pulsed laser without spectral distortion. Finally, we obtain CARS spectra of various samples in the fingerprint region of molecular vibrations. This scheme has potential for compact implementations of all-fiber single-pulse multiplex CARS due to its compatibility with fiber optics.

  2. Longitudinal in vivo coherent anti-Stokes Raman scattering imaging of demyelination and remyelination in injured spinal cord

    Science.gov (United States)

    Shi, Yunzhou; Zhang, Delong; Huff, Terry B.; Wang, Xiaofei; Shi, Riyi; Xu, Xiao-Ming; Cheng, Ji-Xin

    2011-10-01

    In vivo imaging of white matter is important for the mechanistic understanding of demyelination and evaluation of remyelination therapies. Although white matter can be visualized by a strong coherent anti-Stokes Raman scattering (CARS) signal from axonal myelin, in vivo repetitive CARS imaging of the spinal cord remains a challenge due to complexities induced by the laminectomy surgery. We present a careful experimental design that enabled longitudinal CARS imaging of de- and remyelination at single axon level in live rats. In vivo CARS imaging of secretory phospholipase A2 induced myelin vesiculation, macrophage uptake of myelin debris, and spontaneous remyelination by Schwann cells are sequentially monitored over a 3 week period. Longitudinal visualization of de- and remyelination at a single axon level provides a novel platform for rational design of therapies aimed at promoting myelin plasticity and repair.

  3. Background-free coherent anti-stokes Raman spectroscopy and microscopy by dual-soliton pulse generation

    CERN Document Server

    Chen, Kun; Wei, Haoyun; Li, Yan

    2016-01-01

    We propose an all-fiber-generated dual-soliton pulses based scheme for the background-free detection of coherent anti-Stokes Raman spectroscopy under the spectral focusing mechanism. Due to the strong birefringence and high nonlinearity of a polarization-maintaining photonic crystal fiber (PM-PCF), two redshifted soliton pulses can be simultaneously generated relying on high-order dispersion and nonlinear effects along two eigenpolarization axes in the anomalous dispersion regime, while allowing feasible tunability of the frequency distance and temporal interval between them. This proposed scheme, termed as DS-CARS, exploits a unique combination of slight frequency-shift and advisable temporal walk-off of this two soliton pulses to achieve robust and efficient suppression of nonresonant background with compact all-fiber coherent excitation source. Capability of the DS-CARS is experimentally demonstrated by the background-free CARS spectroscopy and unambiguous CARS microscopy of polymer beads in the fingerprin...

  4. Detection of chemical interfaces in coherent anti-Stokes Raman scattering microscopy: Dk-CARS. I. Axial interfaces.

    Science.gov (United States)

    Gachet, David; Rigneault, Hervé

    2011-12-01

    We develop a full vectorial theoretical investigation of the chemical interface detection in conventional coherent anti-Stokes Raman scattering (CARS) microscopy. In Part I, we focus on the detection of axial interfaces (i.e., parallel to the optical axis) following a recent experimental demonstration of the concept [Phys. Rev. Lett. 104, 213905 (2010)]. By revisiting the Young's double slit experiment, we show that background-free microscopy and spectroscopy is achievable through the angular analysis of the CARS far-field radiation pattern. This differential CARS in k space (Dk-CARS) technique is interesting for fast detection of interfaces between molecularly different media. It may be adapted to other coherent and resonant scattering processes.

  5. Selective excitation of molecular mode in a mixture by femtosecond resonance-enhanced coherent anti-Stokes Raman scattering spectroscopy

    Institute of Scientific and Technical Information of China (English)

    He Ping; Li Si-Ning; Fan Rong-Wei; Li Xiao-Hui; Xia Yuan-Qin; Yu Xin; Chen De-Ying

    2012-01-01

    Femtosecond time-resolved coherent anti-Stokes Raman scattering (CARS) spectroscopy is used to investigate gaseous molecular dynamics.Due to the spectrally broad laser pulses,usually poorly resolved spectra result from this broad spectroscopy.However,it can be demonstrated that by the electronic resonance enhancement optimization control a selective excitation of specific vibrational mode is possible.Using an electronically resonance-enhanced effect,iodine molecule specific CARS spectroscopy can be obtained from a mixture of iodine-air at room temperature and a pressure of 1 atm (corresponding to a saturation iodine vapour as low as about 35 Pa).The dynamics on either the electronically excited state or the ground state of iodine molecules obtained is consistent with previous studies (vacuum,heated and pure iodine) in the femtosecond time resolved CARS spectroscopy,showing that an effective method of suppressing the non-resonant CARS background and other interferences is demonstrated.

  6. Investigation of protein distribution in solid lipid particles and its impact on protein release using coherent anti-Stokes Raman scattering microscopy

    DEFF Research Database (Denmark)

    Christophersen, Philip C.; Birch, Ditlev; Saarinen, Jukka

    2015-01-01

    The aim of this study was to gain new insights into protein distribution in solid lipid microparticles (SLMs) and subsequent release mechanisms using a novel label-free chemical imaging method, coherent anti-Stokes Raman scattering (CARS) microscopy. Lysozyme-loaded SLMs were prepared using diffe...

  7. Polyglutamine aggregate structure in vitro and in vivo; new avenues for coherent anti-Stokes Raman scattering microscopy.

    Directory of Open Access Journals (Sweden)

    Nicolas M Perney

    Full Text Available Coherent anti-Stokes Raman scattering (CARS microscopy is applied for the first time for the evaluation of the protein secondary structure of polyglutamine (polyQ aggregates in vivo. Our approach demonstrates the potential for translating information about protein structure that has been obtained in vitro by X-ray diffraction into a microscopy technique that allows the same protein structure to be detected in vivo. For these studies, fibres of polyQ containing peptides (D(2Q(15K(2 were assembled in vitro and examined by electron microscopy and X-ray diffraction methods; the fibril structure was shown to be cross β-sheet. The same polyQ fibres were evaluated by Raman spectroscopy and this further confirmed the β-sheet structure, but indicated that the structure is highly rigid, as indicated by the strong Amide I signal at 1659 cm(-1. CARS spectra were simulated using the Raman spectrum taking into account potential non-resonant contributions, providing evidence that the Amide I signal remains strong, but slightly shifted to lower wavenumbers. Combined CARS (1657 cm(-1 and multi-photon fluorescence microscopy of chimeric fusions of yellow fluorescent protein (YFP with polyQ (Q40 expressed in the body wall muscle cells of Caenorhabditis elegans nematodes (1 day old adult hermaphrodites revealed diffuse and foci patterns of Q40-YFP that were both fluorescent and exhibited stronger CARS (1657 cm(-1 signals than in surrounding tissues at the resonance for the cross β-sheet polyQ in vitro.

  8. Dual/differential coherent anti-Stokes Raman scattering module for multiphoton microscopes with a femtosecond Ti:sapphire oscillator

    Science.gov (United States)

    Li, Bei; Borri, Paola; Langbein, Wolfgang

    2013-06-01

    In the last decade, coherent anti-Stokes Raman scattering (CARS) microscopy has emerged as a powerful multiphoton imaging technique offering label-free chemical sensitivity and high three-dimensional resolution. However, its widespread application in the life sciences has been hampered by the use of costly pulsed lasers, the existence of a nonresonant background requiring involved technical solutions for its efficient suppression, and the limited acquisition speed of multiplex techniques addressing several vibrational resonances, if improved chemical specificity is needed. We have recently reported a differential CARS technique (D-CARS), which simultaneously measures two vibrational frequencies, enhancing the chemical selectivity and sensitivity without introducing costly hardware, while maintaining fast acquisition. In this study, we demonstrate a compact, fully automated, cost-effective module, which integrates on hardware and software level with a commercial multiphoton microscope based on a single 100 fs Ti:Sapphire oscillator and enables D-CARS microscopy in a user-friendly format for applications in the life sciences.

  9. Anti-Stokes resonant x-ray Raman scattering for atom specific and excited state selective dynamics

    Science.gov (United States)

    Kunnus, Kristjan; Josefsson, Ida; Rajkovic, Ivan; Schreck, Simon; Quevedo, Wilson; Beye, Martin; Grübel, Sebastian; Scholz, Mirko; Nordlund, Dennis; Zhang, Wenkai; Hartsock, Robert W.; Gaffney, Kelly J.; Schlotter, William F.; Turner, Joshua J.; Kennedy, Brian; Hennies, Franz; Techert, Simone; Wernet, Philippe; Odelius, Michael; Föhlisch, Alexander

    2016-10-01

    Ultrafast electronic and structural dynamics of matter govern rate and selectivity of chemical reactions, as well as phase transitions and efficient switching in functional materials. Since x-rays determine electronic and structural properties with elemental, chemical, orbital and magnetic selectivity, short pulse x-ray sources have become central enablers of ultrafast science. Despite of these strengths, ultrafast x-rays have been poor at picking up excited state moieties from the unexcited ones. With time-resolved anti-Stokes resonant x-ray Raman scattering (AS-RXRS) performed at the LCLS, and ab initio theory we establish background free excited state selectivity in addition to the elemental, chemical, orbital and magnetic selectivity of x-rays. This unparalleled selectivity extracts low concentration excited state species along the pathway of photo induced ligand exchange of Fe(CO)5 in ethanol. Conceptually a full theoretical treatment of all accessible insights to excited state dynamics with AS-RXRS with transform-limited x-ray pulses is given—which will be covered experimentally by upcoming transform-limited x-ray sources.

  10. High-order Stokes and anti-Stokes Raman generation in monoisotopic CVD {sup 12}C-diamond

    Energy Technology Data Exchange (ETDEWEB)

    Kaminskii, Alexander A. [Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation); Lux, Oliver; Rhee, Hanjo; Eichler, Hans J. [Institute of Optics and Atomic Physics, Technische Universitaet Berlin (Germany); Ralchenko, Victor G.; Bolshakov, Andrey P. [General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Shirakawa, Akira; Yoneda, Hitoki [Institute for Laser Science, University of Electro-Communications, Tokyo (Japan)

    2016-06-15

    We determined, for the first time, the room temperature phonon energy related to the F{sub 2g} vibration mode (ω{sub SRS(12C)} ∝ 1333.2 cm{sup -1}) in a mono-crystalline single-isotope CVD {sup 12}C-diamond crystal by means of stimulated Raman scattering (SRS) spectroscopy. Picosecond one-micron excitation using a Nd{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}-laser generates a nearly two-octave spanning SRS frequency comb (∝12000 cm{sup -1}) consisting of higher-order Stokes and anti-Stokes components. The spacing of the spectral lines was found to differ by Δω{sub SRS} ∝ 0.9 cm{sup -1} from the comb spacing (ω{sub SRS(natC)} ∝ 1332.3 cm{sup -1}) when pumping a conventional CVD diamond crystal with a natural composition of the two stable carbon isotopes {sup 12}C (98.93%) and {sup 13}C (1.07%). (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Assessment of liver steatosis and fibrosis in rats using integrated coherent anti-Stokes Raman scattering and multiphoton imaging technique

    Science.gov (United States)

    Lin, Jian; Lu, Fake; Zheng, Wei; Xu, Shuoyu; Tai, Dean; Yu, Hanry; Huang, Zhiwei

    2011-11-01

    We report the implementation of a unique integrated coherent anti-Stokes Raman scattering (CARS), second-harmonic generation (SHG), and two-photon excitation fluorescence (TPEF) microscopy imaging technique developed for label-free monitoring of the progression of liver steatosis and fibrosis generated in a bile duct ligation (BDL) rat model. Among the 21 adult rats used in this study, 18 rats were performed with BDL surgery and sacrificed each week from weeks 1 to 6 (n = 3 per week), respectively; whereas 3 rats as control were sacrificed at week 0. Colocalized imaging of the aggregated hepatic fats, collagen fibrils, and hepatocyte morphologies in liver tissue is realized by using the integrated CARS, SHG, and TPEF technique. The results show that there are significant accumulations of hepatic lipid droplets and collagen fibrils associated with severe hepatocyte necrosis in BDL rat liver as compared to a normal liver tissue. The volume of normal hepatocytes keeps decreasing and the fiber collagen content in BDL rat liver follows a growing trend until week 6; whereas the hepatic fat content reaches a maximum in week 4 and then appears to stop growing in week 6, indicating that liver steatosis and fibrosis induced in a BDL rat liver model may develop at different rates. This work demonstrates that the integrated CARS and multiphoton microscopy imaging technique has the potential to provide an effective means for early diagnosis and detection of liver steatosis and fibrosis without labeling.

  12. Detecting polymeric nanoparticles with coherent anti-stokes Raman scattering microscopy in tissues exhibiting fixative-induced autofluorescence

    Science.gov (United States)

    Garrett, N. L.; Godfrey, L.; Lalatsa, A.; Serrano, D. R.; Uchegbu, I. F.; Schatzlein, A.; Moger, J.

    2015-03-01

    Recent advances in pharmaceutical nanotechnology have enabled the development of nano-particulate medicines with enhanced drug performance. Although the fate of these nano-particles can be macroscopically tracked in the body (e.g. using radio-labeling techniques), there is little information about the sub-cellular scale mechanistic processes underlying the particle-tissue interactions, or how these interactions may correlate with pharmaceutical efficacy. To rationally engineer these nano-particles and thus optimize their performance, these mechanistic interactions must be fully understood. Coherent Anti-Stokes Raman scattering (CARS) microscopy provides a label-free means for visualizing biological samples, but can suffer from a strong non-resonant background in samples that are prepared using aldehyde-based fixatives. We demonstrate how formalin fixative affects the detection of polymeric nanoparticles within kidneys following oral administration using CARS microscopy, compared with samples that were snap-frozen. These findings have implications for clinical applications of CARS for probing nanoparticle distribution in tissue biopsies.

  13. Detection of Lipid-Rich Prostate Circulating Tumour Cells with Coherent Anti-Stokes Raman Scattering Microscopy

    Directory of Open Access Journals (Sweden)

    Mitra Ranjana

    2012-11-01

    Full Text Available Abstract Background Circulating tumour cells (CTC are an important indicator of metastasis and associated with a poor prognosis. Detection sensitivity and specificity of CTC in the peripheral blood of metastatic cancer patient remain a technical challenge. Methods Coherent anti-Stokes Raman scattering (CARS microscopy was employed to examine the lipid content of CTC isolated from the peripheral blood of metastatic prostate cancer patients. CARS microscopy was also employed to evaluate lipid uptake and mobilization kinetics of a metastatic human prostate cancer cell line. Results One hundred CTC from eight metastatic prostate cancer patients exhibited strong CARS signal which arose from intracellular lipid. In contrast, leukocytes exhibited weak CARS signal which arose mostly from cellular membrane. On average, CARS signal intensity of prostate CTC was 7-fold higher than that of leukocytes (P Conclusions Intracellular lipid could serve as a biomarker for prostate CTC which could be sensitively detected with CARS microscopy in a label-free manner. Strong affinity for lipid by metastatic prostate cancer cells could be used to improve detection sensitivity and therapeutic targeting of prostate CTC.

  14. Simultaneous temperature and exhaust-gas recirculation-measurements in a homogeneous charge-compression ignition engine by use of pure rotational coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Weikl, Markus C.; Beyrau, Frank; Leipertz, Alfred

    2006-05-01

    Pure rotational coherent anti-Stokes Raman spectroscopy was used for the simultaneous determination of temperature and exhaust-gas recirculation in a homogeneous charge-compression ignition engine. Measurements were performed in a production-line four-cylinder gasoline engine operated with standard gasoline fuel through small optical line-of-sight accesses. The homogenization process of fresh intake air with recirculated exhaust gas was observed during the compression stroke, and the effect of charge temperature on combustion timing is shown. Single-pulse coherent anti-Stokes Raman spectroscopy spectra could not only be taken in the compression stroke but also during the gas-exchange cycle and after combustion. Consequently, the used method has been shown to be suitable for the investigation of two of the key parameters for self-ignition, namely temperature and charge composition.

  15. Coherent Anti-Stokes Raman Scattering Spectroscopy of Single Molecules in Solution

    Energy Technology Data Exchange (ETDEWEB)

    Sunney Xie, Wei Min, Chris Freudiger, Sijia Lu

    2012-01-18

    During this funding period, we have developed two breakthrough techniques. The first is stimulated Raman scattering microscopy, providing label-free chemical contrast for chemical and biomedical imaging based on vibrational spectroscopy. Spontaneous Raman microscopy provides specific vibrational signatures of chemical bonds, but is often hindered by low sensitivity. We developed a three-dimensional multiphoton vibrational imaging technique based on stimulated Raman scattering (SRS). The sensitivity of SRS imaging is significantly greater than that of spontaneous Raman microscopy, which is achieved by implementing high-frequency (megahertz) phase-sensitive detection. SRS microscopy has a major advantage over previous coherent Raman techniques in that it offers background-free and readily interpretable chemical contrast. We demonstrated a variety of biomedical applications, such as differentiating distributions of omega-3 fatty acids and saturated lipids in living cells, imaging of brain and skin tissues based on intrinsic lipid contrast, and monitoring drug delivery through the epidermis. This technology offers exciting prospect for medical imaging. The second technology we developed is stimulated emission microscopy. Many chromophores, such as haemoglobin and cytochromes, absorb but have undetectable fluorescence because the spontaneous emission is dominated by their fast non-radiative decay. Yet the detection of their absorption is difficult under a microscope. We use stimulated emission, which competes effectively with the nonradiative decay, to make the chromophores detectable, as a new contrast mechanism for optical microscopy. We demonstrate a variety of applications of stimulated emission microscopy, such as visualizing chromoproteins, non-fluorescent variants of the green fluorescent protein, monitoring lacZ gene expression with a chromogenic reporter, mapping transdermal drug distribu- tions without histological sectioning, and label-free microvascular

  16. In vivo lipid saturation study of C. elegans using quantitative broadband coherent anti-Stokes Raman imaging (Conference Presentation)

    Science.gov (United States)

    Littleton, Bradley; Kavanagh, Thomas; Nie, Yu; Abbate, Vincenzo; Hylands, Peter; Sturzenbaum, Stephen; Richards, David

    2016-03-01

    In vivo lipid saturation maps of microscopic nematodes (Caenorhabditis elegans) have been produced using our novel Spectral Interferometric Polarisation Coherent anti-Stokes Raman Scattering (SIP-CARS) imaging technique. This technique employs simple passive polarisation optics and a balanced homodyne detection scheme to exploit symmetries in the CARS polarisation response resulting in the complete cancellation of the non-resonant background (NRB) and real component of the CARS signal (with no prior or post assumptions as regards to their form). The remaining imaginary component of the CARS response is linear with analyte concentration and directly relatable to the spontaneous Raman spectrum [1]. Furthermore, the resonant CARS signal is interferometrically amplified by the non-resonant response, a necessity for rapid imaging at biologically relevant powers [2]. This technique permits acquisition of a broad NRB-free spectrum, in excess of 1800cm-1, in a single exposure at each pixel. This allows simultaneous determination of lipid droplet saturation, from the fingerprint region, and lipid order, from the C-H stretch region from which maps can be readily constructed. Additionally exploiting the dispersive nature of our signal collection two-photon autofluorescence can be isolated and images subsequently produced. We have successfully applied this technique to identify differences in lipid saturation distributions in selective C. elegans mutants and demonstrated that the technique is sufficiently sensitive to detect the effects of lipid metabolism altering drugs on wild type C. elegans. [1] Littleton et al, Phys Rev Lett, 111, 103902 (2013) [2] Parekh et al, Biophys J, 99, 2695-2704 (2010)

  17. Experimental demonstration of mode-selective phonon excitation of 6H-SiC by a mid-infrared laser with anti-Stokes Raman scattering spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Kyohei; Hachiya, Kan; Okumura, Kensuke; Mishima, Kenta; Inukai, Motoharu; Torgasin, Konstantin; Omer, Mohamed [Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Sonobe, Taro [Kyoto University Research Administration Office, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Zen, Heishun; Negm, Hani; Kii, Toshiteru; Masuda, Kai; Ohgaki, Hideaki [Institute of Advanced Energy, Kyoto University, Gokasyo, Uji, Kyoto 611-0011 (Japan)

    2013-10-28

    Mode-selective phonon excitation by a mid-infrared laser (MIR-FEL) is demonstrated via anti-Stokes Raman scattering measurements of 6H-silicon carbide (SiC). Irradiation of SiC with MIR-FEL and a Nd-YAG laser at 14 K produced a peak where the Raman shift corresponds to a photon energy of 119 meV (10.4 μm). This phenomenon is induced by mode-selective phonon excitation through the irradiation of MIR-FEL, whose photon energy corresponds to the photon-absorption of a particular phonon mode.

  18. Anti-Stokes Resonance Raman of Ir Illuminated Dendrimer Iron (III)-Porphyrins%红外辐照下树枝状铁(iii)卟啉的反斯托克斯共振拉曼

    Institute of Scientific and Technical Information of China (English)

    MO Yu-jun; D.L.Jiang; M.Uymura; T.Aida; T.Kitagawa

    2005-01-01

    The benzene dendrimers of Fe(Ⅲ) tetraphenyl porphyrin chloride[LnFe(Ⅲ)TPPCl] with n = 3, 4, and 5 (n: number of layers) have been synthesized and the IR illumination effects at benzene bands were examined with anti- Stokes resonance Raman speetroseopy for their dioxane solutions.Boltzman temperatures were determined from the Stokes to anti - Stokes intensity ratio for the speetra excited at 413.1 nm in the presence and absence of IR illumination.

  19. Ab initio study of coherent anti-Stokes Raman scattering (CARS) of the 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) explosive

    Science.gov (United States)

    Mohammed, Abdelsalam; Ågren, Hans; Thorvaldsen, Andreas J.; Ruud, Kenneth

    2010-01-01

    Coherent anti-Stokes Raman scattering (CARS) of the 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) C 3H 6N 6O 6 molecule is studied by ab initio methods. The results are compared to available experimental observations and against calculations and experimental observations of the conventional non-resonant Raman spectrum for RDX. It is found that all intense bands in the observed CARS spectrum and all Raman differential cross sections are well reproduced by the calculations. The features of the resonant CARS signal vary strongly from the corresponding Raman signal, and are obtained with a considerably larger cross section, a fact that could further facilitate the use of CARS spectroscopy in applications of stand-off detection of gaseous samples at ultra-low concentrations.

  20. Three-pulse multiplex coherent anti-Stokes/Stokes Raman scattering (CARS/CSRS) microspectroscopy using a white-light laser source

    Science.gov (United States)

    Bito, Kotatsu; Okuno, Masanari; Kano, Hideaki; Leproux, Philippe; Couderc, Vincent; Hamaguchi, Hiro-o.

    2013-06-01

    We have developed a three-pulse non-degenerate multiplex coherent Raman microspectroscopic system using a white-light laser source. The fundamental output (1064 nm) of a Nd:YAG laser is used for the pump radiation with the white-light laser output (1100-1700 nm) for the Stokes radiation to achieve broadband multiplex excitations of vibrational coherences. The second harmonic (532 nm) of the same Nd:YAG laser is used for the probe radiation. Thanks to the large wavelength difference between the pump and probe radiations, coherent anti-Stokes Raman scattering (CARS) and coherent Stokes Raman scattering (CSRS) can be detected simultaneously. Simultaneous detection of CARS and CSRS enables us to obtain information on the electronic resonance effect that affects differently the CARS and CSRS signals. Simultaneous analysis of the CARS and CSRS signals provides us the imaginary part of χ(3) without introducing any arbitrary parameter in the maximum entropy method (MEM).

  1. The manipulation of massive ro-vibronic superpositions using time-frequency-resolved coherent anti-Stokes Raman scattering (TFRCARS) from quantum control to quantum computing

    CERN Document Server

    Zadoyan, R; Lidar, D A; Apkarian, V A

    2001-01-01

    Molecular ro-vibronic coherences, joint energy-time distributions of quantum amplitudes, are selectively prepared, manipulated, and imaged in Time-Frequency-Resolved Coherent Anti-Stokes Raman Scattering (TFRCARS) measurements using femtosecond laser pulses. The studies are implemented in iodine vapor, with its thermally occupied statistical ro-vibrational density serving as initial state. The evolution of the massive ro-vibronic superpositions, consisting of 1000 eigenstates, is followed through two-dimensional images. The first- and second-order coherences are captured using time-integrated frequency-resolved CARS, while the third-order coherence is captured using time-gated frequency-resolved CARS. The Fourier filtering provided by time integrated detection projects out single ro-vibronic transitions, while time-gated detection allows the projection of arbitrary ro-vibronic superpositions from the coherent third-order polarization. Beside the control and imaging of chemistry, the controlled manipulation of...

  2. Hyperspectral imaging and characterization of live cells by broadband coherent anti-Stokes Raman scattering (CARS) microscopy with singular value decomposition (SVD) analysis.

    Science.gov (United States)

    Khmaladze, Alexander; Jasensky, Joshua; Price, Erika; Zhang, Chi; Boughton, Andrew; Han, Xiaofeng; Seeley, Emily; Liu, Xinran; Banaszak Holl, Mark M; Chen, Zhan

    2014-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy can be used as a powerful imaging technique to identify chemical compositions of complex samples in biology, biophysics, medicine, and materials science. In this work we developed a CARS microscopic system capable of hyperspectral imaging. By employing an ultrafast laser source, a photonic crystal fiber, and a scanning laser microscope together with spectral detection by a highly sensitive back-illuminated cooled charge-coupled device (CCD) camera, we were able to rapidly acquire and process hyperspectral images of live cells with chemical selectivity. We discuss various aspects of hyperspectral CARS image analysis and demonstrate the use of singular value decomposition methods to characterize the cellular lipid content.

  3. In planta imaging of Δ⁹-tetrahydrocannabinolic acid in Cannabis sativa L. with hyperspectral coherent anti-Stokes Raman scattering microscopy.

    Science.gov (United States)

    Garbacik, Erik T; Korai, Roza P; Frater, Eric H; Korterik, Jeroen P; Otto, Cees; Offerhaus, Herman L

    2013-04-01

    Nature has developed many pathways to produce medicinal products of extraordinary potency and specificity with significantly higher efficiencies than current synthetic methods can achieve. Identification of these mechanisms and their precise locations within plants could substantially increase the yield of a number of natural pharmaceutics. We report label-free imaging of Δ⁹-tetrahydrocannabinolic acid (THCa) in Cannabis sativa L. using coherent anti-Stokes Raman scattering microscopy. In line with previous observations we find high concentrations of THCa in pistillate flowering bodies and relatively low amounts within flowering bracts. Surprisingly, we find differences in the local morphologies of the THCa-containing bodies: organelles within bracts are large, diffuse, and spheroidal, whereas in pistillate flowers they are generally compact, dense, and have heterogeneous structures. We have also identified two distinct vibrational signatures associated with THCa, both in pure crystalline form and within Cannabis plants; at present the exact natures of these spectra remain an open question.

  4. In planta imaging of Δ9-tetrahydrocannabinolic acid in Cannabis sativa L. with hyperspectral coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Garbacik, Erik T.; Korai, Roza P.; Frater, Eric H.; Korterik, Jeroen P.; Otto, Cees; Offerhaus, Herman L.

    2013-04-01

    Nature has developed many pathways to produce medicinal products of extraordinary potency and specificity with significantly higher efficiencies than current synthetic methods can achieve. Identification of these mechanisms and their precise locations within plants could substantially increase the yield of a number of natural pharmaceutics. We report label-free imaging of Δ9-tetrahydrocannabinolic acid (THCa) in Cannabis sativa L. using coherent anti-Stokes Raman scattering microscopy. In line with previous observations we find high concentrations of THCa in pistillate flowering bodies and relatively low amounts within flowering bracts. Surprisingly, we find differences in the local morphologies of the THCa-containing bodies: organelles within bracts are large, diffuse, and spheroidal, whereas in pistillate flowers they are generally compact, dense, and have heterogeneous structures. We have also identified two distinct vibrational signatures associated with THCa, both in pure crystalline form and within Cannabis plants; at present the exact natures of these spectra remain an open question.

  5. Protein expression guided chemical profiling of living cells by the simultaneous observation of Raman scattering and anti-Stokes fluorescence emission

    Science.gov (United States)

    Chiu, Liang-da; Ichimura, Taro; Sekiya, Takumasa; Machiyama, Hiroaki; Watanabe, Tomonobu; Fujita, Hideaki; Ozawa, Takeaki; Fujita, Katsumasa

    2017-01-01

    Our current understanding of molecular biology provides a clear picture of how the genome, transcriptome and proteome regulate each other, but how the chemical environment of the cell plays a role in cellular regulation remains much to be studied. Here we show an imaging method using hybrid fluorescence-Raman microscopy that measures the chemical micro-environment associated with protein expression patterns in a living cell. Simultaneous detection of fluorescence and Raman signals, realised by spectrally separating the two modes through the single photon anti-Stokes fluorescence emission of fluorescent proteins, enables the accurate correlation of the chemical fingerprint of a specimen to its physiological state. Subsequent experiments revealed the slight chemical differences that enabled the chemical profiling of mouse embryonic stem cells with and without Oct4 expression. Furthermore, using the fluorescent probe as localisation guide, we successfully analysed the detailed chemical content of cell nucleus and Golgi body. The technique can be further applied to a wide range of biomedical studies for the better understanding of chemical events during biological processes. PMID:28272392

  6. Lipid droplet pattern and nondroplet-like structure in two fat mutants of Caenorhabditis elegans revealed by coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Yi, Yung-Hsiang; Chien, Cheng-Hao; Chen, Wei-Wen; Ma, Tian-Hsiang; Liu, Kuan-Yu; Chang, Yu-Sun; Chang, Ta-Chau; Lo, Szecheng J.

    2014-01-01

    Lipid is an important energy source and essential component for plasma and organelle membranes in all kinds of cells. Coherent anti-Stokes Raman scattering (CARS) microscopy is a label-free and nonlinear optical technique that can be used to monitor the lipid distribution in live organisms. Here, we utilize CARS microscopy to investigate the pattern of lipid droplets in two live Caenorhabditis elegans mutants (fat-2 and fat-3). The CARS images showed a striking decrease in the size, number, and content of lipid droplets in the fat-2 mutant but a slight difference in the fat-3 mutant as compared with the wild-type worm. Moreover, a nondroplet-like structure with enhanced CARS signal was detected for the first time in the uterus of fat-2 and fat-3 mutants. In addition, transgenic fat-2 mutant expressing a GFP fusion protein of vitellogenin-2 (a yolk lipoprotein) revealed that the enhanced CARS signal colocalized with the GFP signal, which suggests that the nondroplet-like structure is primarily due to the accumulation of yolk lipoproteins. Together, this study implies that CARS microscopy is a potential tool to study the distribution of yolk lipoproteins, in addition to lipid droplets, in live animals.

  7. What are the intensities and line-shapes of the twenty four polarization terms in coherent anti-Stokes Raman spectroscopy?

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Kai [School of Science, Tianjin University of Technology and Education, Tianjin, 300222 (China); Lee, Soo-Y., E-mail: sooying@ntu.edu.sg [Division of Physics & Applied Physics, and Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)

    2015-12-15

    Coherent anti-Stokes Raman spectroscopy (CARS) is conventionally described by just one diagram/term where the three electric field interactions act on the ket side in a Feynman dual time-line diagram in a specific time order of pump, Stokes and probe pulses. In theory, however, any third-order nonlinear spectroscopy with three different electric fields interacting with a molecule can be described by forty eight diagrams/terms. They reduce to just 24 diagrams/terms if we treat the time ordering of the electric field interactions on the ket independently of those on the bra, i.e. the ket and bra wave packets evolve independently. The twenty four polarization terms can be calculated in the multidimensional, separable harmonic oscillator model to obtain the intensities and line-shapes. It is shown that in fs/ps CARS, for the two cases of off-resonance CARS in toluene and resonance CARS in rhodamine 6G, where we use a fs pump pulse, a fs Stokes pulse and a ps probe pulse, we obtain sharp vibrational lines in four of the polarization terms where the pump and Stokes pulses can create a vibrational coherence on the ground electronic state, while the spectral line-shapes of the other twenty terms are broad and featureless. The conventional CARS term with sharp vibrational lines is the dominant term, with intensity at least one order of magnitude larger than the other terms.

  8. Measurement of vibrationally excited N2(v) in an atmospheric-pressure air pulsed corona discharge using coherent anti-Stokes Raman scattering

    Science.gov (United States)

    Teramoto, Yoshiyuki; Ono, Ryo

    2014-08-01

    Vibrationally excited N2(v = 1, 2) in an atmospheric-pressure air pulsed corona discharge was measured using coherent anti-Stokes Raman scattering (CARS). In a dry air discharge, the vibrational temperature determined from the ratio N2(v = 2)/N2(v = 0), Tv2, was approximately 500 K higher than that determined from N2(v = 1)/N2(v = 0), Tv1, immediately after the discharge pulse. Both vibrational temperatures reached equilibrium within 100 μs after the discharge pulse by the vibration-to-vibration (V-V) process of N2-N2. The translational temperature was also measured using CARS. The rise in the translational temperature due to vibration-to-translation (V-T) energy transfer was not observed for a postdischarge time of 5 μs-1 ms in the dry-air discharge. However, when the air was humidified, a significant V-T energy transfer was observed. It was due to an extremely rapid V-T process of H2O-H2O following the V-V process of N2-H2O. Measurements showed that the humidification of the ambient air accelerated the decrease in the N2 vibrational temperature and increased the translational temperature. N2(v) was generated mostly in the secondary streamer, not in the primary one, according to estimation from the measured N2(v) density.

  9. Multimodal coherent anti-Stokes Raman scattering microscopy reveals microglia-associated myelin and axonal dysfunction in multiple sclerosis-like lesions in mice

    Science.gov (United States)

    Imitola, Jaime; Côté, Daniel; Rasmussen, Stine; Xie, X. Sunney; Liu, Yingru; Chitnis, Tanuja; Sidman, Richard L.; Lin, Charles. P.; Khoury, Samia J.

    2011-02-01

    Myelin loss and axonal degeneration predominate in many neurological disorders; however, methods to visualize them simultaneously in live tissue are unavailable. We describe a new imaging strategy combining video rate reflectance and fluorescence confocal imaging with coherent anti-Stokes Raman scattering (CARS) microscopy tuned to CH2 vibration of myelin lipids, applied in live tissue of animals with chronic experimental autoimmune encephalomyelitis (EAE). Our method allows monitoring over time of demyelination and neurodegeneration in brain slices with high spatial resolution and signal-to-noise ratio. Local areas of severe loss of lipid signal indicative of demyelination and loss of the reflectance signal from axons were seen in the corpus callosum and spinal cord of EAE animals. Even in myelinated areas of EAE mice, the intensity of myelin lipid signals is significantly reduced. Using heterozygous knock-in mice in which green fluorescent protein replaces the CX3CR1 coding sequence that labels central nervous system microglia, we find areas of activated microglia colocalized with areas of altered reflectance and CARS signals reflecting axonal injury and demyelination. Our data demonstrate the use of multimodal CARS microscopy for characterization of demyelinating and neurodegenerative pathology in a mouse model of multiple sclerosis, and further confirm the critical role of microglia in chronic inflammatory neurodegeneration.

  10. Longitudinal, 3D in vivo imaging of sebaceous glands by coherent anti-Stokes Raman scattering microscopy –normal function and response to cryotherapy

    Science.gov (United States)

    Jung, Yookyung; Tam, Joshua; Jalian, H. Ray; Anderson, R. Rox; Evans, Conor L.

    2014-01-01

    Sebaceous glands perform complex functions, and are centrally involved in the pathogenesis of acne vulgaris. Current techniques for studying sebaceous glands are mostly static in nature, whereas the gland’s main function – excretion of sebum via the holocrine mechanism – can only be evaluated over time. We present a longitudinal, real-time alternative – the in vivo, label-free imaging of sebaceous glands using Coherent Anti-Stokes Raman Scattering (CARS) microscopy, which is used to selectively visualize lipids. In mouse ears, CARS microscopy revealed dynamic changes in sebaceous glands during the holocrine secretion process, as well as in response to damage to the glands caused by cooling. Detailed gland structure, plus the active migration of individual sebocytes and cohorts of sebocytes were measured. Cooling produced characteristic changes in sebocyte structure and migration. This study demonstrates that CARS microscopy is a promising tool for studying the sebaceous gland and its associated disorders in three-dimensions in vivo. PMID:25026458

  11. Label-free assessment of adipose-derived stem cell differentiation using coherent anti-Stokes Raman scattering and multiphoton microscopy

    Science.gov (United States)

    Mouras, Rabah; Bagnaninchi, Pierre O.; Downes, Andrew R.; Elfick, Alistair P. D.

    2012-11-01

    Adult stem cells (SCs) hold great potential as likely candidates for disease therapy but also as sources of differentiated human cells in vitro models of disease. In both cases, the label-free assessment of SC differentiation state is highly desirable, either as a quality-control technology ensuring cells to be used clinically are of the desired lineage or to facilitate in vitro time-course studies of cell differentiation. We investigate the potential of nonlinear optical microscopy as a minimally invasive technology to monitor the differentiation of adipose-derived stem cells (ADSCs) into adipocytes and osteoblasts. The induction of ADSCs toward these two different cell lineages was monitored simultaneously using coherent anti-Stokes Raman scattering, two photon excitation fluorescence (TPEF), and second harmonic generation at different time points. Changes in the cell's morphology, together with the appearance of biochemical markers of cell maturity were observed, such as lipid droplet accumulation for adipo-induced cells and the formation of extra-cellular matrix for osteo-induced cells. In addition, TPEF of flavoproteins was identified as a proxy for changes in cell metabolism that occurred throughout ADSC differentiation toward both osteoblasts and adipocytes. These results indicate that multimodal microscopy has significant potential as an enabling technology for the label-free investigation of SC differentiation.

  12. What are the intensities and line-shapes of the twenty four polarization terms in coherent anti-Stokes Raman spectroscopy?

    Directory of Open Access Journals (Sweden)

    Kai Niu

    2015-12-01

    Full Text Available Coherent anti-Stokes Raman spectroscopy (CARS is conventionally described by just one diagram/term where the three electric field interactions act on the ket side in a Feynman dual time-line diagram in a specific time order of pump, Stokes and probe pulses. In theory, however, any third-order nonlinear spectroscopy with three different electric fields interacting with a molecule can be described by forty eight diagrams/terms. They reduce to just 24 diagrams/terms if we treat the time ordering of the electric field interactions on the ket independently of those on the bra, i.e. the ket and bra wave packets evolve independently. The twenty four polarization terms can be calculated in the multidimensional, separable harmonic oscillator model to obtain the intensities and line-shapes. It is shown that in fs/ps CARS, for the two cases of off-resonance CARS in toluene and resonance CARS in rhodamine 6G, where we use a fs pump pulse, a fs Stokes pulse and a ps probe pulse, we obtain sharp vibrational lines in four of the polarization terms where the pump and Stokes pulses can create a vibrational coherence on the ground electronic state, while the spectral line-shapes of the other twenty terms are broad and featureless. The conventional CARS term with sharp vibrational lines is the dominant term, with intensity at least one order of magnitude larger than the other terms.

  13. Picosecond anti-Stokes generation in a photonic-crystal fiber for interferometric CARS microscopy.

    Science.gov (United States)

    Andresen, Esben Ravn; Keiding, Søren Rud; Potma, Eric Olaf

    2006-08-07

    We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration, we employ the generated anti-Stokes pulses as reference pulses in an interferometric coherent anti-Stokes Raman scattering imaging experiment showing that interpulse coherence among the pump, Stokes and anti-Stokes beams is retained.

  14. Three-pulse multiplex coherent anti-Stokes/Stokes Raman scattering (CARS/CSRS) microspectroscopy using a white-light laser source

    OpenAIRE

    Bito, Kotatsu; Okuno, Masanari; Kano, Hideaki; LEPROUX, Philippe; Couderc, Vincent; Hamaguchi, Hiro-o

    2013-01-01

    We have developed a three-pulse non-degenerate multiplex coherent Raman microspectroscopic system using a white-light laser source. The fundamental output (1064 nm) of a Nd:YAG laser is used for the pump radiation with the white-light laser output (1100–1700 nm) for the Stokes radiation to achieve broadband multiplex excitations of vibrational coherences. The second harmonic (532 nm) of the same Nd:YAG laser is used for the probe radiation. Thanks to the large wavelength difference between th...

  15. 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....

  16. Observation of anomalous Stokes versus anti-Stokes ratio in MoTe2 atomic layers

    Science.gov (United States)

    Goldstein, Thomas; Chen, Shao-Yu; Xiao, Di; Ramasubramaniam, Ashwin; Yan, Jun

    We grow hexagonal molybdenum ditelluride (MoTe2), a prototypical transition metal dichalcogenide (TMDC) semiconductor, with chemical vapor transport methods and investigate its atomic layers with Stokes and anti-Stokes Raman scattering. We report observation of all six types of zone center optical phonons. Quite remarkably, the anti-Stokes Raman intensity of the low energy layer-breathing mode becomes more intense than the Stokes peak under certain experimental conditions, creating an illusion of 'negative temperature'. This effect is tunable, and can be switched from anti-Stokes enhancement to suppression by varying the excitation wavelength. We interpret this observation to be a result of resonance effects arising from the C excitons in the vicinity of the Brillouin zone center, which are robust even for multiple layers of MoTe2. The intense anti-Stokes Raman scattering provides a cooling channel for the crystal and opens up opportunities for laser cooling of atomically thin TMDC semiconductor devices. Supported by the University of Massachusetts Amherst, the National Science Foundation Center for Hierarchical Manufacturing (CMMI-1025020) and Office of Emerging Frontiers in Research and Innovation (EFRI-1433496).

  17. Raman and surface enhanced Raman spectroscopic investigation on Lamiaceae plants

    Science.gov (United States)

    Rösch, P.; Popp, J.; Kiefer, W.

    1999-05-01

    The essential oils of Thymus vulgaris and Origanum vulgaris are studied by means of micro-Raman spectroscopy. The containing monoterpenes can be identified by their Raman spectra. Further the essential oils are investigated in their natural environment, the so-called oil cells of these Lamiaceae plants, with surface enhanced Raman spectroscopy (SERS). This method has the advantage to enhance Raman signals and furthermore the SERS effect leads to fluorescence quenching.

  18. Coherent anti-Stokes Raman scattering microscopy of single nanodiamonds

    OpenAIRE

    Pope, Iestyn; Payne, Lukas; Zoriniants, George; Thomas, Evan L. H.; Williams, Oliver Aneurin; Watson, Peter Duncan; Langbein, Wolfgang Werner; Borri, Paola

    2014-01-01

    Nanoparticles have attracted enormous attention for biomedical applications as optical labels, drug-delivery vehicles and contrast agents in vivo. In the quest for superior photostability and biocompatibility, nanodiamonds are considered one of the best choices due to their unique structural, chemical, mechanical and optical properties. So far, mainly fluorescent nanodiamonds have been utilized for cell imaging. However, their use is limited by the efficiency and costs in reliably producing f...

  19. FAST CARS Developing a Laser Spectroscopic Technique for Rapid Identification of Bacterial Spores

    CERN Document Server

    Scully, M O; Lucht, R P; Opatrny, T; Pilloff, H; Rebane, A; Sokolov, A V; Zubairy, M S

    2002-01-01

    Airborne contaminants, e.g., bacterial spores, are usually analyzed by time consuming microscopic, chemical and biological assays. Current research into real time laser spectroscopic detectors of such contaminants is based on e.g. resonant Raman spectroscopy. The present approach derives from recent experiments in which atoms and molecules are prepared by one (or more) coherent laser(s) and probed by another set of lasers. The connection with previous studies based on "Coherent Anti-Stokes Raman Spectroscopy" (CARS) is to be noted. However generating and utilizing maximally coherent oscillation in macromolecules having an enormous number of degrees of freedom is much more challenging. This extension of the CARS technique is called FAST CARS (Femtosecond Adaptive Spectroscopic Techniques for Coherent Anti-Stokes Raman Spectroscopy), and the present paper proposes and analyses ways in which it could be used to rapidly identify pre-selected molecules in real time.

  20. 在Na2(A1∑_u+)与H2碰撞中的相干反斯托克斯拉曼谱研究%Coherent Anti-Stokes Raman Spectroscopy Study in the Na2(A1∑_u~+)-H2 Collision

    Institute of Scientific and Technical Information of China (English)

    蔡勤; 张利平; 栾楠楠; 程玉锋; 戴康; 沈异凡

    2011-01-01

    Coherent anti-Stokes Raman spectroscopy (CARS) has been used to analyze the internal state distribution of H2 after energy transfer with Na2 (A1 S,f ). The scanned CARS reveals that during energy transfer processes H2 molecules are produced at the V=l, 2 and 3 vibrational levels. Two possible populations ratios (w,/ra2) are obtained from scanned CARS peaks. The actual population ratio Hi/n2 is determined to be 1. 82 through shape simulations of the time resolved CARS profiles under a kinetic model. The n,/n2 ratio indicates that the H2 molecules produced by the energy transfer process are 0.53 populated at the V=l level, 0.30 at V=2 and 0.17 at V=3. The relative fraction (, ) of average energy disposal is derived as 0.51, 0.46, 0.03, which has a major energy releases in vibrational and translational. This consequence supports the col linear collision geometry in ratio Na2-H2 energy transfer.%利用相干反斯托克斯拉曼谱(CARS)分析了H:在与Na2(A1∑_u~+)碰撞后的振转态布居数分布.扫描CARS表明了在能量转移过程中H:在V=1,2,3振动能级上得到布居.由扫描CARS的峰值得到2个可能的布居数比值,通过解速率方程组及时间分辨CARS轮廓模拟,确定实际的布居数比n1//n2为1.82,得到了在能量转移中H2在V=1,2,3振动能级上的布居数之比为0.53:0.30:0.17.平均转移能量分配的相对值,,分别为0.51,0.46,0.03,能量主要配置在振动和平动上,支持Na2-H2的直线式碰撞传能机制.

  1. Raman spectroscopic studies on p-terphenyl under high pressure

    Science.gov (United States)

    Liu, Tianyuan; Xu, Shengnan; Sun, Chenglin; Zhou, Mi

    2014-11-01

    High-pressure Raman scattering studies are performed on p-terphenyl up to 5 GPa. The Raman activities of different symmetric molecules were analyzed by means of group theory methods. A phase transition was detected at 1.3 GPa from changes in the slope on plots of frequency versus pressure. The diminishing of internal modes indicated that the molecule symmetry transformed from C2 to D2h. This is an effective method for detecting planar molecular structure of p-terphenyl by ring-ring stretching vibration mode, which can provide a new spectroscopic evidence of planar conjugated polyphenyl molecular conformation.

  2. Laser induced broad band anti-Stokes white emission from LiYbF4 nanocrystals

    Institute of Scientific and Technical Information of China (English)

    L. Marciniak; R. Tomala; M. Stefanski; D. Hreniak; W. Strek

    2016-01-01

    Spectroscopic properties of tetragonal LiYbF4 nanocrystals under high dense NIR excitation at vacuum condition were in-vestigated. White, broad band emission covering whole visible part of the spectrum from LiYbF4 nanocrystals was observed. Its in-tensity strongly depended on the excitation power, excitation wavelength and ambient pressure. Temperature of the nanocrystals un-der 975 nm excitation was determined as a function of excitation power. Strong photo-induced current was observed from LiYbF4 pallet. The emission kinetic was analyzed. The mechanism of the anti-Stokes white emission was discussed in terms of the la-ser-induced charge transfer emission from Yb2+ states.

  3. Surface enhanced Raman scattering spectroscopic waveguide

    Science.gov (United States)

    Lascola, Robert J; McWhorter, Christopher S; Murph, Simona H

    2015-04-14

    A waveguide for use with surface-enhanced Raman spectroscopy is provided that includes a base structure with an inner surface that defines a cavity and that has an axis. Multiple molecules of an analyte are capable of being located within the cavity at the same time. A base layer is located on the inner surface of the base structure. The base layer extends in an axial direction along an axial length of an excitation section. Nanoparticles are carried by the base layer and may be uniformly distributed along the entire axial length of the excitation section. A flow cell for introducing analyte and excitation light into the waveguide and a method of applying nanoparticles may also be provided.

  4. 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.

  5. 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.

  6. Spectroscopic characterization of biological agents using FTIR, normal Raman and surface-enhanced Raman spectroscopies

    Science.gov (United States)

    Luna-Pineda, Tatiana; Soto-Feliciano, Kristina; De La Cruz-Montoya, Edwin; Pacheco Londoño, Leonardo C.; Ríos-Velázquez, Carlos; Hernández-Rivera, Samuel P.

    2007-04-01

    FTIR, Raman spectroscopy and Surface Enhanced Raman Scattering (SERS) requires a minimum of sample allows fast identification of microorganisms. The use of this technique for characterizing the spectroscopic signatures of these agents and their stimulants has recently gained considerable attention due to the fact that these techniques can be easily adapted for standoff detection from considerable distances. The techniques also show high sensitivity and selectivity and offer near real time detection duty cycles. This research focuses in laying the grounds for the spectroscopic differentiation of Staphylococcus spp., Pseudomonas spp., Bacillus spp., Salmonella spp., Enterobacter aerogenes, Proteus mirabilis, Klebsiella pneumoniae, and E. coli, together with identification of their subspecies. In order to achieve the proponed objective, protocols to handle, cultivate and analyze the strains have been developed. Spectroscopic similarities and marked differences have been found for Spontaneous or Normal Raman spectra and for SERS using silver nanoparticles have been found. The use of principal component analysis (PCA), discriminate factor analysis (DFA) and a cluster analysis were used to evaluate the efficacy of identifying potential threat bacterial from their spectra collected on single bacteria. The DFA from the bacteria Raman spectra show a little discrimination between the diverse bacterial species however the results obtained from the SERS demonstrate to be high discrimination technique. The spectroscopic study will be extended to examine the spores produced by selected strains since these are more prone to be used as Biological Warfare Agents due to their increased mobility and possibility of airborne transport. Micro infrared spectroscopy as well as fiber coupled FTIR will also be used as possible sensors of target compounds.

  7. Picosecond anti-Stokes generation in a photonic-crystal fiber for interferometric CARS microscopy

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn

    2006-01-01

    We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration...

  8. Raman spectroscopic analysis of a `noli me tangere' painting

    Science.gov (United States)

    Hibberts, Stephen; Edwards, Howell G. M.; Abdel-Ghani, Mona; Vandenabeele, Peter

    2016-12-01

    The discovery of an oil painting in seriously damaged condition with an important historical and a heterodox detail with possible origins in the late fifteenth century has afforded the opportunity for Raman microscopic analysis prior to its restoration being undertaken. The painting depicts a risen Christ following His crucifixion in a `noli me tangere' pose with three women in an Italian terrace garden with a stone balustrade overlooking a rural landscape and an undoubted view of late-medieval Florence. The picture has suffered much abuse and is in very poor condition, which is possibly attributable to its controversial portrayal of a polydactylic Christ with six toes on His right foot. By the late sixteenth century, after the Council of Trent, this portrayal would almost certainly have been frowned upon by the Church authorities or more controversially as a depiction of the holy. Raman spectroscopic analysis of the pigments places the painting as being consistent chronologically with the Renaissance period following the identification of cinnabar, haematite, red lead, lead white, goethite, verdigris, caput mortuum and azurite with no evidence of more modern synthetic pigments or of modern restoration having been carried out. An interesting pigment mixture found here is that of the organic dye carmine and cinnabar to produce a particular bright red pigment coloration. Stratigraphic examination of the paint fragments has demonstrated the presence of an orange resin layer immediately on top of the canvas substrate, effectively rendering the pigment as a sandwich between this substratal resin and the overlying varnish. The Raman spectroscopic evidence clearly indicates that an attribution of the artwork to the Renaissance is consistent with the scientific analysis of the pigment composition. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

  9. Tip-enhanced Raman spectroscopic imaging of patterned thiol monolayers

    Directory of Open Access Journals (Sweden)

    Johannes Stadler

    2011-08-01

    Full Text Available Full spectroscopic imaging by means of tip-enhanced Raman spectroscopy (TERS was used to measure the distribution of two isomeric thiols (2-mercaptopyridine (2-PySH and 4-mercaptopyridine (4-PySH in a self-assembled monolayer (SAM on a gold surface. From a patterned sample created by microcontact printing, an image with full spectral information in every pixel was acquired. The spectroscopic data is in good agreement with the expected molecular distribution on the sample surface due to the microcontact printing process. Using specific marker bands at 1000 cm−1 for 2-PySH and 1100 cm−1 for 4-PySH, both isomers could be localized on the surface and semi-quantitative information was deduced from the band intensities. Even though nanometer size resolution information was not required, the large signal enhancement of TERS was employed here to detect a monolayer coverage of weakly scattering analytes that were not detectable with normal Raman spectroscopy, emphasizing the usefulness of TERS.

  10. On-Line Multichannel Raman Spectroscopic Detection System For Capillary Zone Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An on-line multichannel Raman spectroscopic detection system for capillary electrophoresis was established by using an Ar+ laser and a cryogenically cooled ICCD. Resonant excitation Raman spectra of methyl red and methyl orange were employed to test the system. The result shows that it could yield on-line electrophoretogram and time series of Raman spectra.

  11. Raman spectroscopic characterisations and analytical discrimination between caffeine and demethylated analogues of pharmaceutical relevance

    Science.gov (United States)

    Edwards, H. G. M.; Munshi, T.; Anstis, M.

    2005-05-01

    The FT Raman spectrum of caffeine was analysed along with that of its demethylated analogues, theobromine and theophylline. The similar but not identical structures of these three compounds allowed a more detailed assignment of the Raman bands. Noticeable differences in the Raman spectra of these compounds were apparent and key marker bands have been identified for the spectroscopic identification of these three compounds.

  12. Ionization penalty in nonlinear Raman neuroimaging.

    Science.gov (United States)

    Voronin, Aleksandr A; Fedotov, Ilya V; Doronina-Amitonova, Lyubov V; Ivashkina, Olga I; Zots, Marina A; Fedotov, Andrei B; Anokhin, Konstantin V; Zheltikov, Aleksei M

    2011-02-15

    Light-assisted ionization accompanying coherent anti-Stokes Raman scattering (CARS) of ultrashort laser pulses in brain tissue is shown to manifest itself in a detectable blueshift of the anti-Stokes signal. This blueshift can serve as an indicator of ionization processes in CARS-based neuroimaging.

  13. Competition between two types of anti-Stokes emission in Ho(3+)-activated ZBLAN glass.

    Science.gov (United States)

    Koepke, Cz; Wisniewski, K; Piatkowski, D; Malinowski, M

    2009-01-21

    A competition between two anti-Stokes emissions has been observed and interpreted in ZBLAN glass activated by Ho(3+) ions. The first anti-Stokes emission intensity was seen to increase with temperature, whereas another, upconverted emission, was seen to decrease under the same conditions. Both observed tendencies are believed to be caused by the same effect: the multiphonon anti-Stokes excitation of the state responsible for the first emission. Analysis of the kinetics and fits of the theoretical model to experimental data are presented.

  14. Competition between two types of anti-Stokes emission in Ho3+-activated ZBLAN glass

    Science.gov (United States)

    Koepke, Cz; Wisniewski, K.; Piatkowski, D.; Malinowski, M.

    2009-01-01

    A competition between two anti-Stokes emissions has been observed and interpreted in ZBLAN glass activated by Ho3+ ions. The first anti-Stokes emission intensity was seen to increase with temperature, whereas another, upconverted emission, was seen to decrease under the same conditions. Both observed tendencies are believed to be caused by the same effect: the multiphonon anti-Stokes excitation of the state responsible for the first emission. Analysis of the kinetics and fits of the theoretical model to experimental data are presented.

  15. Infrared and Raman spectroscopic features of plant cuticles: a review

    Science.gov (United States)

    Heredia-Guerrero, José A.; Benítez, José J.; Domínguez, Eva; Bayer, Ilker S.; Cingolani, Roberto; Athanassiou, Athanassia; Heredia, Antonio

    2014-01-01

    The cuticle is one of the most important plant barriers. It is an external and continuous lipid membrane that covers the surface of epidermal cells and whose main function is to prevent the massive loss of water. The spectroscopic characterization of the plant cuticle and its components (cutin, cutan, waxes, polysaccharides and phenolics) by infrared and Raman spectroscopies has provided significant advances in the knowledge of the functional groups present in the cuticular matrix and on their structural role, interaction and macromolecular arrangement. Additionally, these spectroscopies have been used in the study of cuticle interaction with exogenous molecules, degradation, distribution of components within the cuticle matrix, changes during growth and development and characterization of fossil plants. PMID:25009549

  16. Analytical Raman spectroscopic discrimination between yellow pigments of the Renaissance

    Science.gov (United States)

    Edwards, Howell G. M.

    2011-10-01

    The Renaissance represented a major advance in painting techniques, subject matter, artistic style and the use of pigments and pigment mixtures. However, most pigments in general use were still mineral-based as most organic dyes were believed to be fugitive; the historical study of artists' palettes and recipes has assumed importance for the attribution of art works to the Renaissance period. Although the application of diagnostic elemental and molecular spectroscopic techniques play vital and complementary roles in the analysis of art works, elemental techniques alone cannot definitively provide the data needed for pigment identification. The advantages and limitations of Raman spectroscopy for the definitive diagnostic characterisation of yellow pigments that were in use during the Renaissance is demonstrated here in consideration of heavy metal oxides and sulphides; these data will be compared with those obtained from analyses of synthetic yellow pigments that were available during the eighteenth and nineteenth Centuries which could have been used in unrecorded restorations of Renaissance paintings.

  17. Analytical Raman spectroscopic discrimination between yellow pigments of the Renaissance.

    Science.gov (United States)

    Edwards, Howell G M

    2011-10-01

    The Renaissance represented a major advance in painting techniques, subject matter, artistic style and the use of pigments and pigment mixtures. However, most pigments in general use were still mineral-based as most organic dyes were believed to be fugitive; the historical study of artists' palettes and recipes has assumed importance for the attribution of art works to the Renaissance period. Although the application of diagnostic elemental and molecular spectroscopic techniques play vital and complementary roles in the analysis of art works, elemental techniques alone cannot definitively provide the data needed for pigment identification. The advantages and limitations of Raman spectroscopy for the definitive diagnostic characterisation of yellow pigments that were in use during the Renaissance is demonstrated here in consideration of heavy metal oxides and sulphides; these data will be compared with those obtained from analyses of synthetic yellow pigments that were available during the eighteenth and nineteenth Centuries which could have been used in unrecorded restorations of Renaissance paintings.

  18. INFRARED AND RAMAN SPECTROSCOPIC FEATURES OF PLANT CUTICLES: A REVIEW

    Directory of Open Access Journals (Sweden)

    José Alejandro Heredia-Guerrero

    2014-06-01

    Full Text Available The cuticle is one of the most important plant barriers. It is an external and continuous lipid membrane that covers the surface of epidermal cells and whose main function is to prevent the massive loss of water. The spectroscopic characterization of the plant cuticle and its components (cutin, cutan, waxes, polysaccharides and phenolics by infrared and Raman spectroscopies has provided significant advances in the knowledge of the functional groups present in the cuticular matrix and on their structural role, interaction and macromolecular arrangement. Additionally, these spectroscopies have been used in the study of cuticle interaction with exogenous molecules, degradation, distribution of components within the cuticle matrix, changes during growth and development and characterization of fossil plants.

  19. Generation of Anti-Stokes Line in Fundamental Mode of Photonic Crystal Fibre

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; HOU Lan-Tian; LIU Zhao-Lun; ZHOU Gui-Yao

    2008-01-01

    A photonic crystal fibre (PCF) with zero-dispersion wavelength around 800 nm is designed and fabricated. Simulated results show that the zero-dispersion wavelength of fundamental mode for this PCF is at 826 nm, and phase-matched four-wave mixing can be achieved in fundamental mode. Using 20Ofs Ti:sapphire laser with central wavelength at 810nm as pump, the anti-Stokes line around 610nm is generated efficiently. The output signal has a Gaussian-like profile, which indicates that the anti-Stokes signal is in the fundamental mode of the PCF. The energy of anti-Stokes signal is higher than that of residual pump laser and the maximum ratio of the anti-Stokes signal to the pump component in the output spectrum is estimated to be 1.2.

  20. An induction heating diamond anvil cell for high pressure and temperature micro-Raman spectroscopic measurements.

    Science.gov (United States)

    Shinoda, Keiji; Noguchi, Naoki

    2008-01-01

    A new external heating configuration is presented for high-temperature diamond anvil cell instruments. The supporting rockers are thermally excited by induction from an externally mounted copper coil passing a 30 kHz alternating current. The inductive heating configuration therefore avoids the use of breakable wires, yet is capable of cell temperatures of 1100 K or higher. The diamond anvil cell has no resistive heaters, but uses a single-turn induction coil for elevating the temperature. The induction coil is placed near the diamonds and directly heats the tungsten carbide rockers that support the diamond. The temperature in the cell is determined from a temperature-power curve calibrated by the ratio between the intensities of the Stokes and anti-Stokes Raman lines of silicon. The high-pressure transformation of quartz to coesite is successfully observed by micro-Raman spectroscopy using this apparatus. The induction heating diamond anvil cell is thus a useful alternative to resistively heated diamond anvil cells.

  1. Early dental caries detection using a fibre-optic coupled polarization-resolved Raman spectroscopic system.

    Science.gov (United States)

    Ko, Alex C-T; Hewko, Mark; Sowa, Michael G; Dong, Cecilia C S; Cleghorn, Blaine; Choo-Smith, Lin-P'ing

    2008-04-28

    A new fibre-optic coupled polarization-resolved Raman spectroscopic system was developed for simultaneous collection of orthogonally polarized Raman spectra in a single measurement. An application of detecting incipient dental caries based on changes observed in Raman polarization anisotropy was also demonstrated using the developed fibre-optic Raman spectroscopic system. The predicted reduction of polarization anisotropy in the Raman spectra of caries lesions was observed and the results were consistent with those reported previously with Raman microspectroscopy. The capability of simultaneous collection of parallel- and cross-polarized Raman spectra of tooth enamel in a single measurement and the improved laser excitation delivery through fibre-optics demonstrated in this new design illustrates its future clinical potential.

  2. Spectroscopic ellipsometric and Raman spectroscopic investigations of pulsed laser treated glassy carbon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Csontos, J., E-mail: jcsontos@titan.physx.u-szeged.hu [University of Szeged, Department of Optics and Quantum Electronics, Dóm tér 9, H-6720 Szeged (Hungary); Pápa, Z.; Gárdián, A. [University of Szeged, Department of Optics and Quantum Electronics, Dóm tér 9, H-6720 Szeged (Hungary); Füle, M. [University of Szeged, Department of Experimental Physics, Dóm tér 9, H-6720 Szeged (Hungary); Budai, J. [University of Szeged, Department of Optics and Quantum Electronics, Dóm tér 9, H-6720 Szeged (Hungary); Toth, Z. [University of Szeged, Department of Optics and Quantum Electronics, Dóm tér 9, H-6720 Szeged (Hungary); University of Szeged, Department of Oral Biology and Experimental Dental Research, Tisza Lajos krt. 64, H-6720 Szeged (Hungary)

    2015-05-01

    Highlights: • Laser treatment modifies the top layer of glassy carbon as shown by ellipsometry. • Raman signal is composed from signals of the layer and the glassy carbon substrate. • Using volumetric fluence allows to compare the effects of different lasers. • Melting effects of glassy carbon was observed in case of Nd:YAG laser treatment. - Abstract: In this study spectroscopic ellipsometry (SE) and Raman spectroscopy are applied to study structural modification of glassy carbon, due to high intensity laser ablation. Two KrF lasers with different pulse durations (480 fs and 18 ns), an ArF (20 ns), and a frequency doubled Nd:YAG laser (8 ns) were applied to irradiate the surface of glassy carbon targets. The main characteristics of the different laser treatments are compared by introducing the volumetric fluence which takes into account the different absorption values at different wavelengths. SE showed the appearance of a modified layer on the ablated surfaces. In the case of the ns lasers the thickness of this layer was in the range of 10–60 nm, while in the case of fs laser it was less than 20 nm. In all cases the average refractive index (n) of the modified layers slightly decreased compared to the refractive index of glassy carbon. Increase in extinction coefficient (k) was observed in the cases of ArF and fs KrF laser treatment, while the k values decreased significantly in the cases of nanosecond pulse duration KrF and Nd:YAG laser treatments. In the Raman spectra of the ablated areas the characteristic D and G peaks were widened due to appearance of an amorphous phase. Both Raman spectroscopy and SE indicate that the irradiated areas show carbon nanoparticle formation in all cases.

  3. Raman spectroscopic analysis of a belltower commemorative wall decoration

    Science.gov (United States)

    Fernandes, R. F.; de Oliveira, L. F. C.; Edwards, H. G. M.; Brooke, C. J.; Pepper, M.

    2017-02-01

    The Raman spectroscopic analysis of a rare wall decoration in a church belltower, depicting the initials of couples married there in circular roundels over some 230 years, since 1777, has been undertaken prior to their impending restoration. The spectral data indicate that the red pigment is exclusively haematite which has been applied to plaster which exhibits the signatures variously of calcite, gypsum, anhydrite, calcium phosphate and dolomitic limestone; evidence of amorphous carbon is attributed to the deposition of soot from candle illumination, which has been recorded in historical documentation. The presence of biosignatures attributed to carotenoids in several samples is evidence of biological colonisation and potential deterioration which requires special treatment in the restoration strategies. The blackened areas near the upper edges of the wall decoration indicate carbon deposition and organic contamination. The latest addition to the decoration accomplished in 2008 shows that haematite has been used over a calcite ground. In earlier dated specimens, the presence of limewash is evident, which has only been partially converted into calcite by aerial attack from carbon dioxide in moist conditions.

  4. Raman spectroscopic imaging of the whole Ciona intestinalis embryo during development.

    Directory of Open Access Journals (Sweden)

    Mitsuru J Nakamura

    Full Text Available Intracellular composition and the distribution of bio-molecules play central roles in the specification of cell fates and morphogenesis during embryogenesis. Consequently, investigation of changes in the expression and distribution of bio-molecules, especially mRNAs and proteins, is an important challenge in developmental biology. Raman spectroscopic imaging, a non-invasive and label-free technique, allows simultaneous imaging of the intracellular composition and distribution of multiple bio-molecules. In this study, we explored the application of Raman spectroscopic imaging in the whole Ciona intestinalis embryo during development. Analysis of Raman spectra scattered from C. intestinalis embryos revealed a number of localized patterns of high Raman intensity within the embryo. Based on the observed distribution of bio-molecules, we succeeded in identifying the location and structure of differentiated muscle and endoderm within the whole embryo, up to the tailbud stage, in a label-free manner. Furthermore, during cell differentiation, we detected significant differences in cell state between muscle/endoderm daughter cells and daughter cells with other fates that had divided from the same mother cells; this was achieved by focusing on the Raman intensity of single Raman bands at 1002 or 1526 cm(-1, respectively. This study reports the first application of Raman spectroscopic imaging to the study of identifying and characterizing differentiating tissues in a whole chordate embryo. Our results suggest that Raman spectroscopic imaging is a feasible label-free technique for investigating the developmental process of the whole embryo of C. intestinalis.

  5. Clinical cancer diagnosis using optical fiber-delivered coherent anti-stokes ramon scattering microscopy

    Science.gov (United States)

    Gao, Liang

    This thesis describes the development of a combined label-free imaging and analytical strategy for intraoperative characterization of cancer lesions using the coherent anti-Stokes Raman scattering imaging (CARS) technique. A cell morphology-based analytical platform is developed to characterize CARS images and, hence, provide diagnostic information using disease-related pathology features. This strategy is validated for three different applications, including margin detection for radical prostatectomy, differential diagnosis of lung cancer, as well as detection and differentiation of breast cancer subtypes for in situ analysis of margin status during lumpectomy. As the major contribution of this thesis, the developed analytical strategy shows high accuracy and specificity for all three diseases and thus has introduced the CARS imaging technique into the field of human cancer diagnosis, which holds substantial potential for clinical translations. In addition, I have contributed a project aimed at miniaturizing the CARS imaging device into a microendoscope setup through a fiber-delivery strategy. A four-wave-mixing (FWM) background signal, which is caused by simultaneous delivery of the two CARS-generating excitation laser beams, is initially identified. A polarization-based strategy is then introduced and tested for suppression of this FWM noise. The approach shows effective suppression of the FWM signal, both on microscopic and prototype endoscopic setups, indicating the potential of developing a novel microendoscope with a compatible size for clinical use. These positive results show promise for the development of an all-fiber-based, label-free imaging and analytical platform for minimally invasive detection and diagnosis of cancers during surgery or surgical-biopsy, thus improving surgical outcomes and reducing patients' suffering.

  6. Raman spectroscopic investigation of thorium dioxide-uranium dioxide (ThO₂-UO₂) fuel materials.

    Science.gov (United States)

    Rao, Rekha; Bhagat, R K; Salke, Nilesh P; Kumar, Arun

    2014-01-01

    Raman spectroscopic investigations were carried out on proposed nuclear fuel thorium dioxide-uranium dioxide (ThO2-UO2) solid solutions and simulated fuels based on ThO2-UO2. Raman spectra of ThO2-UO2 solid solutions exhibited two-mode behavior in the entire composition range. Variations in mode frequencies and relative intensities of Raman modes enabled estimation of composition, defects, and oxygen stoichiometry in these compounds that are essential for their application. The present study shows that Raman spectroscopy is a simple, promising analytical tool for nondestructive characterization of this important class of nuclear fuel materials.

  7. Raman spectroscopic identification of normal and malignant hepatocytes

    Institute of Scientific and Technical Information of China (English)

    Jianyu Guo; Bing Du; Min Qian; Weiying Cai; Zugeng Wang; Zhenrong Sun

    2009-01-01

    Raman spectroscopy has strong potential for providing non-invasion diagnosis of cancers. In this paper, micro-Raman spectroscopy is used to diagnose one most common liver cancer, hepatocellular carcinoma (HCC). The statistical analyzes, including i-test, principal component analysis (PCA), and linear discrim inant analysis (LDA), are performed on the Raman spectra of malignant and normal hepatocytes. The t-test-LDA results show that the 786- and 1004-cm-1 bands of the malignant and normal hepatocytes are significantly different, and PCA-LDA results show an overall accuracy of 100% for the Raman spectro scopic identification of normal and malignant hepatocytes in our experiment.

  8. Raman spectroscopic investigation of blood and related materials

    Science.gov (United States)

    Gnyba, M.; Jedrzejewska-Szczerska, M.; Wróbel, M. S.

    2015-03-01

    This paper reports preliminary studies on use of Raman spectroscopy for investigation of blood. High quality blood spectra were recorded in-vitro with excitation wavelengths of 830 nm. Because of complex composition of the blood as well as by light attenuation and scattering in the tissues, spectra set up from wide, low-intensive Raman bands and intensive optical background. To get information about origin of bands in Raman spectra it is necessary to create phantom, which would show influence of this parameter and can be used to calibrate the Raman measurement system. Spectra of phantoms of selected blood components were acquired and discussed.

  9. Stokes and anti-stokes stimulated Mie scattering on nanoparticle suspensions of latex

    Science.gov (United States)

    Burkhanov, I. S.; Krivokhizha, S. V.; Chaikov, L. L.

    2016-12-01

    Stokes and anti-Stokes shifts of stimulated concentration light scattering (SCLS, stimulated Mie scattering) in suspensions of various-sized latex nanoparticles in water were measured by the light guide scheme, under conditions of backscattering in the presence of convection.

  10. The pH dependent Raman spectroscopic study of caffeine

    Science.gov (United States)

    Kang, Jian; Gu, Huaimin; Zhong, Liang; Hu, Yongjun; Liu, Fang

    2011-02-01

    First of all the surface enhanced Raman spectroscopy (SERS) and normal Raman spectra of caffeine aqueous solution were obtained at different pH values. In order to obtain the detailed vibrational assignments of the Raman spectroscopy, the geometry of caffeine molecule was optimized by density functional theory (DFT) calculation. By comparing the SERS of caffeine with its normal spectra at different pH values; it is concluded that pH value can dramatically affect the SERS of caffeine, but barely affect the normal Raman spectrum of caffeine aqueous solution. It can essentially affect the reorientation of caffeine molecule to the Ag colloid surface, but cannot impact the vibration of functional groups and chemical bonds in caffeine molecule.

  11. Raman spectroscopic identification of normal and malignant human stomach cells

    Institute of Scientific and Technical Information of China (English)

    Jipeng Yang; Jianyu Guo; Liangping Wu; Zhenrong Sun; Weiying Cai; Zugeng Wang

    2005-01-01

    @@ Micro-Raman spectroscopy is employed to identify the normal and malignant human stomach cells. For the cancer cell, the reduced intensity of the Raman peak at 1250 cm-1 indicates that the protein secondary structure transforms from β-sheet or disordered structures to α-helical, while the increased intensity of the symmetric PO2 stretching vibration mode at 1094 cm-1 shows the increased DNA content.

  12. 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.

  13. Raman spectroscopic analysis of Mexican natural artists' materials

    Science.gov (United States)

    Vandenabeele, Peter; Ortega-Avilès, Mayahuel; Castilleros, Dolores Tenorio; Moens, Luc

    2007-12-01

    This work represents the Raman spectra of 15 natural artists' materials that were obtained from local market in Mexico. Some of these products are not endemic to the region, but are often used in local conservation practice. Other materials are of local origin and have been used for centuries by local craftsmen. The Raman spectra that are reported here are: Chia oil, linseed oil, Campeche wax, beeswax, white copal, dammar, colophony, mastic, pixoy, chapopote, chucum, aje gum, gutta gum, peach gum and gum Arabic. The sample of pixoy was mixed with TiO 2, although it was not clear whether this was done intentionally or not. The Raman spectrum of chapopote, the local name for bitumen, contained features of carbonaceous and terpenoid matter. The Raman spectra of chapopote and chucum suffered severely from fluorescence, resulting in noisy Raman spectra. Aje gum and gutta gum are not gums, since they are resinous (terpenoid) in nature. Aje is a rare animal resin originating from Coccus axin.

  14. 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.

  15. Raman spectroscopic studies of lithium manganates with spinel structure

    CERN Document Server

    Julien, C M

    2003-01-01

    Raman scattering spectra of a set of lithium manganospinels Li sub 1 sub - sub x sub + sub z Mn sub 2 sub - sub z O sub 4 with 0 sup<= x sup<= 1 and 0 sup<= z sup<= 0.33 are reported and analysed. Structural changes have been investigated following the evolution of Raman spectra with the concentration of lithium cations. The local structure was characterized as a function of the mean oxidation state of manganese cations. The trigonal distortion of MnO sub 6 octahedra is evidenced by insertion of lithium ions into the [B sub 2]O sub 4 spinel framework. A comparison with tetragonal Mn sub 3 O sub 4 and Fe sub 3 O sub 4 spinels shows the influence of the Jahn-Teller effect on the Raman features for this class of materials.

  16. Raman spectroscopic determination of norbixin and tartrazine in sugar.

    Science.gov (United States)

    Uhlemann, Ute; Strelau, Katharina K; Weber, Karina; Da Costa Filho, Paulo Augusto; Rösch, Petra; Popp, Jürgen

    2012-08-01

    In this paper, a method for the detection of norbixin and tartrazine in sugar by means of resonance Raman spectroscopy is presented. The extraction was done in four steps using methanol and the measurements were performed in aqueous solution. The excitation wavelength was 514 nm for norbixin and 488 nm for tartrazine samples. The characteristic resonance Raman signals of the dyes were fitted by different functions. Depending on the R² values of the different fits, each spectrum was classified as positive or negative response. A detection limit of 250 ng g⁻¹ for norbixin and 989 ng g⁻¹ for tartrazine in solid sugar samples could be reached by logistic regression.

  17. Competition between two types of anti-Stokes emission in Ho{sup 3+}-activated ZBLAN glass

    Energy Technology Data Exchange (ETDEWEB)

    Koepke, Cz; Wisniewski, K; Piatkowski, D [Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Malinowski, M [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland)], E-mail: koepke@fizyka.umk.pl

    2009-01-21

    A competition between two anti-Stokes emissions has been observed and interpreted in ZBLAN glass activated by Ho{sup 3+} ions. The first anti-Stokes emission intensity was seen to increase with temperature, whereas another, upconverted emission, was seen to decrease under the same conditions. Both observed tendencies are believed to be caused by the same effect: the multiphonon anti-Stokes excitation of the state responsible for the first emission. Analysis of the kinetics and fits of the theoretical model to experimental data are presented.

  18. Method and system to measure temperature of gases using coherent anti-stokes doppler spectroscopy

    Science.gov (United States)

    Rhodes, Mark

    2013-12-17

    A method of measuring a temperature of a noble gas in a chamber includes providing the noble gas in the chamber. The noble gas is characterized by a pressure and a temperature. The method also includes directing a first laser beam into the chamber and directing a second laser beam into the chamber. The first laser beam is characterized by a first frequency and the second laser beam is characterized by a second frequency. The method further includes converting at least a portion of the first laser beam and the second laser beam into a coherent anti-Stokes beam, measuring a Doppler broadening of the coherent anti-Stokes beam, and computing the temperature using the Doppler broadening.

  19. Raman spectroscopic study of ancient South African domestic clay pottery

    Science.gov (United States)

    Legodi, M. A.; de Waal, D.

    2007-01-01

    The technique of Raman spectroscopy was used to examine the composition of ancient African domestic clay pottery of South African origin. One sample from each of four archaeological sites including Rooiwal, Lydenburg, Makahane and Graskop was studied. Normal dispersive Raman spectroscopy was found to be the most effective analytical technique in this study. XRF, XRD and FT-IR spectroscopy were used as complementary techniques. All representative samples contained common features, which were characterised by kaolin (Al 2Si 2O 5(OH) 5), illite (KAl 4(Si 7AlO 20)(OH) 4), feldspar (K- and NaAlSi 3O 8), quartz (α-SiO 2), hematite (α-Fe 2O 3), montmorillonite (Mg 3(Si,Al) 4(OH) 2·4.5H 2O[Mg] 0.35), and calcium silicate (CaSiO 3). Gypsum (CaSO 4·2H 2O) and calcium carbonates (most likely calcite, CaCO 3) were detected by Raman spectroscopy in Lydenburg, Makahane and Graskop shards. Amorphous carbon (with accompanying phosphates) was observed in the Raman spectra of Lydenburg, Rooiwal and Makahane shards, while rutile (TiO 2) appeared only in Makahane shard. The Raman spectra of Lydenburg and Rooiwal shards further showed the presence of anhydrite (CaSO 4). The results showed that South African potters used a mixture of clays as raw materials. The firing temperature for most samples did not exceed 800 °C, which suggests the use of open fire. The reddish brown and grayish black colours were likely due to hematite and amorphous carbon, respectively.

  20. Characteristics of intermediate state related to anti-Stokes luminescence of ZnO single crystals

    Science.gov (United States)

    Fujii, Katsushi; Goto, Takenari; Yao, Takafumi

    2014-06-01

    Anti-Stokes luminescence from ZnO is supposed to be a two-step two-photon absorption process with an intermediate state. The intermediate state is assumed to be a localized state with two different excited and relaxed states. One of the localized states is believed to be the well-known 2.4 eV green luminescence; the other is difficult to observe experimentally. We found an interesting 2.25 eV deep luminescence from ZnO, which has been shown to relate to anti-Stokes luminescence. The 2.25 eV yellow luminescence was observable only below the band gap excitation and through a time-resolved observation after the excitation light was turned off. The intermediate states were found to be a photo-excited donor-acceptor pair and its lattice relaxation state. The characteristics and the role of the intermediate state of ZnO related to the anti-Stokes luminescence are discussed.

  1. [Raman spectroscopic investigation of hydrogen storage in nitrogen gas hydrates].

    Science.gov (United States)

    Meng, Qing-guo; Liu, Chang-ling; Ye, Yu-guang; Li, Cheng-feng

    2012-08-01

    Recently, hydrogen storage using clathrate hydrate as a medium has become a hotspot of hydrogen storage research In the present paper, the laser Raman spectroscopy was used to study the hydrogen storage in nitrogen hydrate. The synthetic nitrogen hydrate was reacted with hydrogen gas under relatively mild conditions (e.g., 15 MPa, -18 degrees C). The Raman spectra of the reaction products show that the hydrogen molecules have enclathrated the cavities of the nitrogen hydrate, with multiple hydrogen cage occupancies in the clathrate cavities. The reaction time is an important factor affecting the hydrogen storage in nitrogen hydrate. The experimental results suggest that nitrogen hydrates are expected to be an effective media for hydrogen storage.

  2. 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.

  3. 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.

  4. Raman spectroscopic measurements of beta-carotene and lycopene in human skin

    Science.gov (United States)

    Darvin, M. E.; Gerzonde, I.; Ey, S.; Brandt, Nikolai N.; Albrecht, Hansjoerg; Gonchukov, Sergei A.; Sterry, Wolfram; Lademann, Juergen

    2004-08-01

    The antioxidant β-carotene and lycopene substances were detected non-invasively, in vivo in human skin using resonance Raman spectroscopy. Both substances were detected simultaneously. To distinguish between the substances, the Raman signals were excited at 488 nm and 514,5 nm simultaneously using a multilane Ar+ laser. The application of a fiber based optical imaging system allowed the detection of β-carotene and lycopene on any skin area. The disturbance of the measurements because of non-homogeneous skin pigmentation was avoided by using a measuring area of 28 mm2. The minimum power density for registration of the Raman signals and their optimum relation was determined. The Raman spectroscopic method is well suited for the evaluation of the efficacy of topically or systematically applied amounts of β-carotene and lycopene.

  5. Raman spectroscopic differentiation of planktonic bacteria and biofilms.

    Science.gov (United States)

    Kusić, Dragana; Kampe, Bernd; Ramoji, Anuradha; Neugebauer, Ute; Rösch, Petra; Popp, Jürgen

    2015-09-01

    Both biofilm formations as well as planktonic cells of water bacteria such as diverse species of the Legionella genus as well as Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli were examined in detail by Raman microspectroscopy. Production of various molecules involved in biofilm formation of tested species in nutrient-deficient media such as tap water was observed and was particularly evident in the biofilms formed by six Legionella species. Biofilms of selected species of the Legionella genus differ significantly from the planktonic cells of the same organisms in their lipid amount. Also, all Legionella species have formed biofilms that differ significantly from the biofilms of the other tested genera in the amount of lipids they produced. We believe that the significant increase in the synthesis of this molecular species may be associated with the ability of Legionella species to form biofilms. In addition, a combination of Raman microspectroscopy with chemometric approaches can distinguish between both planktonic form and biofilms of diverse bacteria and could be used to identify samples which were unknown to the identification model. Our results provide valuable data for the development of fast and reliable analytic methods based on Raman microspectroscopy, which can be applied to the analysis of tap water-adapted microorganisms without any cultivation step.

  6. Raman spectroscopic analysis of an important Visigothic historiated manuscript

    Science.gov (United States)

    Carter, Elizabeth A.; Perez, Fernando Rull; Garcia, Jesús Medina; Edwards, Howell G. M.

    2016-12-01

    Raman spectroscopy has been used to study fragments of early Visigothic historiated manuscripts from the important mediaeval library at Santo Domingo de Silos which were a part of a Beato dating from the tenth to the mid-eleventh centuries. These fragments are from some of the oldest manuscripts in the scriptorium of the monastery. In this study, a comparison is made between the pigments and inks used on these manuscripts and those used in a previous study of the unique Visigothic Beato de Valcavado in Santa Cruz, Valladolid, completed in the year 970, which is noted for its quality of execution as well as its content and is remarkable eschatologically in being identifiable as the complete work of only a single scribe. For comparative purposes, the pigments and inks used in the Silos Monastery Beato and a series of historiated early manuscripts from mediaeval times through to the Renaissance also held in the monastic library were analysed. Raman spectroscopy identified a range of mineral and organic pigments such as cinnabar, orpiment, minium, azurite and indigo. In addition, a number of admixtures were found, for example, indigo and orpiment to produce vergaut (green) and a mixture of cinnabar with iron-gall ink and cerussite to produce darker and lighter shades of red. Some interesting conclusions were drawn about the use of iron-gall and carbon-based inks. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

  7. 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.

  8. A Raman spectroscopic comparison of calcite and dolomite.

    Science.gov (United States)

    Sun, Junmin; Wu, Zeguang; Cheng, Hongfei; Zhang, Zhanjun; Frost, Ray L

    2014-01-03

    Raman spectroscopy was used to characterize and differentiate the two minerals calcite and dolomite and the bands related to the mineral structure. The (CO3)(2-) group is characterized by four prominent Raman vibrational modes: (a) the symmetric stretching, (b) the asymmetric deformation, (c) asymmetric stretching and (d) symmetric deformation. These vibrational modes of the calcite and dolomite were observed at 1440, 1088, 715 and 278 cm(-1). The significant differences between the minerals calcite and dolomite are observed by Raman spectroscopy. Calcite shows the typical bands observed at 1361, 1047, 715 and 157 cm(-1), and the special bands at 1393, 1098, 1069, 1019, 299, 258 and 176 cm(-1) for dolomite are observed. The difference is explained on the basis of the structure variation of the two minerals. Calcite has a trigonal structure with two molecules per unit cell, and dolomite has a hexagonal structure. This is more likely to cause the splitting and distorting of the carbonate groups. Another cause for the difference is the cation substituting for Mg in the dolomite mineral.

  9. Raman Spectroscopic Analyses of Jaw Periosteal Cell Mineralization.

    Science.gov (United States)

    Brauchle, Eva; Carvajal Berrio, Daniel; Rieger, Melanie; Schenke-Layland, Katja; Reinert, Siegmar; Alexander, Dorothea

    2017-01-01

    To achieve safer patient treatments, serum-free cell culture conditions have to be established for cell therapies. In previous studies, we demonstrated that serum-free culture favored the proliferation of MSCA-1(+) osteoprogenitors derived from the jaw periosteum. In this study, the in vitro formation of bone-specific matrix by MSCA-1(+) jaw periosteal cells (JPCs, 3 donors) was assessed and compared under serum-free and serum-containing media conditions using the marker-free Raman spectroscopy. Based on a standard fluorescence assay, JPCs from one patient were not able to mineralize under serum-containing culture conditions, whereas the other cells showed similar mineralization levels under both conditions. Raman spectra from mineralizing MSCA-1(+) JPCs revealed higher levels of hydroxyapatite formation and higher mineral to matrix ratios under serum-free culture conditions. Higher carbonate to phosphate ratios and higher crystallinity in JPCs cultured under serum-containing conditions indicated immature bone formation. Due to reduced collagen production under serum-free conditions, we obtained significant differences in collagen maturity and proline to hydroxyproline ratios compared to serum-free conditions. We conclude that Raman spectroscopy is a useful tool for the assessment and noninvasive monitoring of in vitro mineralization of osteoprogenitor cells. Further studies should extend this knowledge and improve JPC mineralization by optimizing culture conditions.

  10. Monitoring the Healing of Combat Wounds Using Raman Spectroscopic Mapping

    Science.gov (United States)

    2010-01-01

    regeneration .2–3 Consequently, the eventual timing of wound closure or definitive cover... Regeneration W R R 5 9 7 B D is p a tc h : 1 3 .5 .1 0 Jo u rn al : W R R C E : Jo u rn a l N a m e M a n u sc ri p t N o . A u th o r R ec ei v ed : N o . o...Leroy G, Penel G, Leroy N, Brès E. Human tooth enamel: a Raman polarized approach. Appl Spectrosc 2002; 56: 1030–4. 19. McGill N, Dieppe PA, Bowden

  11. Raman spectroscopic approach to monitor the in vitro cyclization of creatine → creatinine

    Science.gov (United States)

    Gangopadhyay, Debraj; Sharma, Poornima; Singh, Sachin Kumar; Singh, Pushkar; Tarcea, Nicolae; Deckert, Volker; Popp, Jürgen; Singh, Ranjan K.

    2015-01-01

    The creatine → creatinine cyclization, an important metabolic phenomenon has been initiated in vitro at acidic pH and studied through Raman spectroscopic and DFT approach. The equilibrium composition of neutral, zwitterionic and protonated microspecies of creatine has been monitored with time as the reaction proceeds. Time series Raman spectra show clear signature of creatinine formation at pH 3 after ∼240 min at room temperature and reaction is faster at higher temperature. The spectra at pH 1 and pH 5 do not show such signature up to 270 min implying faster reaction rate at pH 3.

  12. Application of Coherent Anti-Stokes Raman Scattering to Combustion Media.

    Science.gov (United States)

    1981-02-01

    partition function and gI is the nuclear -spin degeneracy. When Maxwell’s equations which describe the propagation of electromagnetic waves are solved...Scanning Spectrometer) shown in Fig. 5. The DARSS unit consists of a linear (one- dimensional) diode array ( reticon ) detector element in conjunction with...electronics scheme it offers. 77 The major problem encountered with the DARSS unit was the single dimensionality of the reticon detector. Previously the

  13. Coherent anti-Stokes Raman spectroscopy in the presence of strong resonant signal from background molecules

    CERN Document Server

    Bitter, Martin

    2012-01-01

    Optical spectroscopy with broadband femtosecond laser pulses often involves simultaneous excitation of multiple molecular species with close resonance frequencies. Interpreting the collective optical response from molecular mixtures typically requires Fourier analysis of the detected time-resolved signal. We propose an alternative method of separating coherent optical responses from two molecular species with neighboring excitation resonances (here, vibrational modes of oxygen and carbon dioxide). We utilize ro-vibrational coupling as a mechanism of suppressing the strong vibrational response from the dominating molecular species (O$_{2}$). Coherent ro-vibrational dynamics lead to long "silence windows" of zero signal from oxygen molecules. In these silence windows, the detected signal stems solely from the minority species (CO$_{2}$) enabling background-free detection and characterization of the O$_2$/CO$_2$ mixing ratio. In comparison to a Fourier analysis, our technique does not require femtosecond time re...

  14. In situ dissolution analysis using coherent anti-Stokes Raman scattering (CARS) and hyperspectral CARS microscopy

    NARCIS (Netherlands)

    Fussell, Andrew; Garbacik, Erik; Offerhaus, Herman; Kleinebudde, Peter; Strachan, Clare

    2013-01-01

    The solid-state form of an active pharmaceutical ingredient (API) in an oral dosage form plays an important role in determining the dissolution rate of the API. As the solid-state form can change during dissolution, there is a need to monitor the oral dosage form during dissolution testing. Coherent

  15. How specific Raman spectroscopic models are: a comparative study between different cancers

    Science.gov (United States)

    Singh, S. P.; Kumar, K. Kalyan; Chowdary, M. V. P.; Maheedhar, K.; Krishna, C. Murali

    2010-02-01

    Optical spectroscopic methods are being contemplated as adjunct/ alternative to existing 'Gold standard' of cancer diagnosis, histopathological examination. Several groups are actively pursuing diagnostic applications of Ramanspectroscopy in cancers. We have developed Raman spectroscopic models for diagnosis of breast, oral, stomach, colon and larynx cancers. So far, specificity and applicability of spectral- models has been limited to particular tissue origin. In this study we have evaluated explicitly of spectroscopic-models by analyzing spectra from already developed spectralmodels representing normal and malignant tissues of breast (46), cervix (52), colon (25), larynx (53), and oral (47). Spectral data was analyzed by Principal Component Analysis (PCA) using scores of factor, Mahalanobis distance and Spectral residuals as discriminating parameters. Multiparametric limit test approach was also explored. The preliminary unsupervised PCA of pooled data indicates that normal tissue types were always exclusive from their malignant counterparts. But when we consider tissue of different origin, large overlap among clusters was found. Supervised analysis by Mahalanobis distance and spectral residuals gave similar results. The 'limit test' approach where classification is based on match / mis-match of the given spectrum against all the available spectra has revealed that spectral models are very exclusive and specific. For example breast normal spectral model show matches only with breast normal spectra and mismatch to rest of the spectra. Same pattern was seen for most of spectral models. Therefore, results of the study indicate the exclusiveness and efficacy of Raman spectroscopic-models. Prospectively, these findings might open new application of Raman spectroscopic models in identifying a tumor as primary or metastatic.

  16. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Marcelo M. Nobrega

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  17. Laser Raman and ac impedance spectroscopic studies of PVA: NH4NO3 polymer electrolyte.

    Science.gov (United States)

    Hema, M; Selvasekarapandian, S; Hirankumar, G; Sakunthala, A; Arunkumar, D; Nithya, H

    2010-01-01

    Ion conducting polymer electrolyte PVA:NH(4)NO(3) has been prepared by solution casting technique and characterized using XRD, Raman and ac impedance spectroscopic analyses. The amorphous nature of the polymer films has been confirmed by XRD and Raman spectroscopy. An insight into the deconvoluted Raman peaks of upsilon(1) vibration of NO(3)(-) anion for the polymer electrolyte reveals the dominancy of ion aggregates at higher NH(4)NO(3) concentration. From the ac impedance studies, the highest ion conductivity at 303 K has been found to be 7.5x10(-3)Scm(-1) for 80PVA:20NH(4)NO(3). The conductivity of the polymer electrolytes has been found to depend on the degree of dissociation of the salt in the host polymer matrix. The combination of the above-mentioned analyses has proven worth while and in fact necessary in order to achieve better understanding of these complex systems.

  18. Laser Raman spectroscopic analysis of polymorphic forms in microliter fluid volumes.

    Science.gov (United States)

    Anquetil, Patrick A; Brenan, Colin J H; Marcolli, Claudia; Hunter, Ian W

    2003-01-01

    Knowledge and control of the polymorphic phase of chemical compounds are important aspects of drug development in the pharmaceutical industry. We report herein in situ and real-time Raman spectroscopic polymorphic analysis of optically trapped microcrystals in a microliter volume format. The system studied in particular was the recrystallization of carbamazepine (CBZ) in methanol. Raman spectrometry enabled noninvasive measurement of the amount of dissolved CBZ in a sample as well as polymorphic characterization, whereas exclusive recrystallization of either CBZ form I or CBZ form III from saturated solutions was achieved by specific selection of sample cell cooling profiles. Additionally, using a microcell versus a macroscopic volume gives the advantage of reaching equilibrium much faster while using little compound quantity. We demonstrate that laser Raman spectral polymorphic analysis in a microliter cell is a potentially viable screening platform for polymorphic analysis and could lead to a new high throughput method for polymorph screening.

  19. Raman spectroscopic analysis of archaeological specimens from the wreck of HMS Swift, 1770

    Science.gov (United States)

    Edwards, Howell G. M.; Elkin, Dolores; Maier, Marta S.

    2016-12-01

    Specimens from underwater archaeological excavations have rarely been analysed by Raman spectroscopy probably due to the problems associated with the presence of water and the use of alternative techniques. The discovery of the remains of the Royal Navy warship HMS Swift off the coast of Patagonia, South America, which was wrecked in 1770 while undertaking a survey from its base in the Falkland/Malvinas Islands, has afforded the opportunity for a first-pass Raman spectroscopic study of the contents of several glass jars from a wooden chest, some of which had suffered deterioration of their contents owing to leakage through their stoppers. From the Raman spectroscopic data, it was possible to identify organic compounds such as anthraquinone and copal resin, which were empirically used as materia medica in the eighteenth century to treat shipboard diseases; it seems very likely, therefore, that the wooden chest belonged to the barber-surgeon on the ship. Spectra were obtained from the wet and desiccated samples, but several samples from containers that had leaked were found to contain only minerals, such as aragonite and sediment. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

  20. Nondestructive and rapid concurrent estimation of paracetamol and nimesulide in their combined dosage form using raman spectroscopic technique

    Directory of Open Access Journals (Sweden)

    Gargi R Lakhwani

    2013-01-01

    Full Text Available A rapid, nondestructive Raman spectroscopic method was developed for quantitative estimation of paracetamol and nimesulide in their combined dosage form. A Raman univariate calibration model was developed by measuring the peak intensities of paracetamol and nimesulide at 853 cm−1 and 1336 cm−1 , respectively. The developed method was successfully applied for in situ, concurrent estimation of paracetamol and nimesulide in their combined dosage and method was also validated according to International Conference on Harmonisation guidelines. Thus, the developed Raman spectroscopic method can be applied for simultaneous estimation of paracetamol and nimesulide in their combined dosage form as a process analytical technology tool by pharmaceutical industries for routine quality control.

  1. Photon-phonon anti-stokes upconversion of a photonically, electronically, and thermally isolated opal

    Science.gov (United States)

    Stem, Michelle R.

    2016-05-01

    The purpose of the present research was to investigate an intense violet shift displayed by a non-toxic, natural silicate material with a highly ordered nanostructure. The material displayed an unexpected, nonlinear 2:3 photon-phonon anti-Stokes upconversion while photonically, electronically, and thermally isolated. Conducted aphotonically and at ambient temperatures, the specimen upconverted a low-power, 650 nm constant wave red laser to an internally highly dispersed 433 nm violet wavelength. The strong dispersion was largely due to nearly total internal reflection of the laser. The upconversion had an efficiency of about 78 %, based on specimen volume, with no detectable thermal variance. The 2:3 anti-Stokes upconversion displayed by this material is likely the result of a previously unknown photon-phonon evanescence response that amplified the energy of a portion of the incident laser photons. Thus, a portion of the incident laser photons were upconverted, and the material converted another portion into an amplified energy that caused the upconversion. Internal micro-lasing appeared to be a means of photon-phonon evanescent energy redistribution, enabling dispersed photonic upconversion. Additional analyses also found an unexpectedly rhythmic photonic structure in spectrophotometric scans, polariscopic color changing, and previously undocumented ultraviolet responses.

  2. Studies on Nephrite and Jadeite Jades by Fourier Transform Infrared (ftir) and Raman Spectroscopic Techniques

    Science.gov (United States)

    Tan, T. L.; Ng, L. L.; Lim, L. C.

    2013-10-01

    The mineralogical properties of black nephrite jade from Western Australia are studied by Fourier transform infrared (FTIR) spectroscopy using both transmission and specular reflectance techniques in the 4000-400 cm-1 wavenumber region. The infrared absorption peaks in the 3700-3600 cm-1 region which are due to the O-H stretching mode provides a quantitative analysis of the Fe/(Fe+Mg) ratio in the mineral composition of jade samples. The Fe/(Fe+Mg) percentage in black nephrite is found to be higher than that in green nephrite, but comparable to that of actinolite (iron-rich nephrite). This implies that the mineralogy of black nephrite is closer to actinolite than tremolite. The jade is also characterized using Raman spectroscopy in the 1200-200 cm-1 region. Results from FTIR and Raman spectroscopic data of black nephrite jade are compared with those of green nephrite jade from New Zealand and jadeite jade from Myanmar. Black nephrite appears to have a slightly different chemical composition from green nephrite. Spectra from FTIR and Raman spectroscopic techniques were found to be useful in differentiating black nephrite, green nephrite, and green jadeite jades. Furthermore, data on refractive index, specific gravity, and hardness of black nephrite jade are measured and compared with those of green nephrite and of jadeite jade.

  3. Reduced and oxidised scytonemin: theoretical protocol for Raman spectroscopic identification of potential key biomolecules for astrobiology.

    Science.gov (United States)

    Varnali, Tereza; Edwards, Howell G M

    2014-01-03

    Scytonemin is an important UV-radiation protective biomolecule synthesised by extremophilic cyanobacteria in stressed terrestrial environments. Scytonemin and its reduced form have been both isolated experimentally and the Raman spectrum for scytonemin has been assigned and characterised experimentally both in extracts and in living extremophilic cyanobacterial colonies. Scytonemin is recognised as a key biomarker molecule for terrestrial organisms in stressed environments. We propose a new, theoretically plausible structure for oxidised scytonemin which has not been mentioned in the literature hitherto. DFT calculations for scytonemin, reduced scytonemin and the new structure modelled and proposed for oxidised scytonemin are reported along with their Raman spectroscopic data and λmax UV-absorption data obtained theoretically. Comparison of the vibrational spectroscopic assignments allows the three forms of scytonemin to be detected and identified and assist not only in the clarification of the major features in the experimentally observed Raman spectral data for the parent scytonemin but also support a protocol proposed for their analytical discrimination. The results of this study provide a basis for the search for molecules of this type in future astrobiological missions of exploration and the search for extinct and extant life terrestrially.

  4. Raman spectroscopic study of “The Malatesta”: A Renaissance painting?

    Science.gov (United States)

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

    2015-02-01

    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.

  5. Raman and terahertz spectroscopical investigation of cocrystal formation process of piracetam and 3-hydroxybenzoic acid

    Science.gov (United States)

    Du, Yong; Zhang, Huili; Xue, Jiadan; Fang, Hongxia; Zhang, Qi; Xia, Yi; Li, Yafang; Hong, Zhi

    2015-03-01

    Cocrystallization can improve physical and chemical properties of active pharmaceutical ingredient, and this feature has great potential in pharmaceutical development. In this study, the cocrystal of piracetam and 3-hydroxybenzoic acid under grinding condition has been characterized by Raman and terahertz spectroscopical techniques. The major vibrational modes of individual starting components and cocrystal are obtained and assigned. Spectral results show that the vibrational modes of the cocrystal are different from those of the corresponding parent materials. The dynamic process of such pharmaceutical cocrystal formation has also been monitored directly with Raman and THz spectra. The formation rate is pretty fast in first several 20 min grinding time, and then it becomes slow. After ∼35 min, such process has been almost completed. These results offer us the unique means and benchmark for characterizing the cocrystal conformation from molecule-level and also provide us rich information about the reaction dynamic during cocrystal formation process in pharmaceutical fields.

  6. Raman spectroscopic sensing of carbonate intercalation in breast microcalcifications at stereotactic biopsy

    Science.gov (United States)

    Sathyavathi, R.; Saha, Anushree; Soares, Jaqueline S.; Spegazzini, Nicolas; McGee, Sasha; Rao Dasari, Ramachandra; Fitzmaurice, Maryann; Barman, Ishan

    2015-04-01

    Microcalcifications are an early mammographic sign of breast cancer and frequent target for stereotactic biopsy. Despite their indisputable value, microcalcifications, particularly of the type II variety that are comprised of calcium hydroxyapatite deposits, remain one of the least understood disease markers. Here we employed Raman spectroscopy to elucidate the relationship between pathogenicity of breast lesions in fresh biopsy cores and composition of type II microcalcifications. Using a chemometric model of chemical-morphological constituents, acquired Raman spectra were translated to characterize chemical makeup of the lesions. We find that increase in carbonate intercalation in the hydroxyapatite lattice can be reliably employed to differentiate benign from malignant lesions, with algorithms based only on carbonate and cytoplasmic protein content exhibiting excellent negative predictive value (93-98%). Our findings highlight the importance of calcium carbonate, an underrated constituent of microcalcifications, as a spectroscopic marker in breast pathology evaluation and pave the way for improved biopsy guidance.

  7. 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.

  8. Raman spectroscopic differentiation of beef and horse meat using a 671 nm microsystem diode laser

    Science.gov (United States)

    Ebrahim, Halah Al; Sowoidnich, Kay; Kronfeldt, Heinz-Detlef

    2013-11-01

    A non-invasive Raman spectroscopic approach for meat species identification and quality detection was successfully demonstrated for the two closely related species beef and horse. Fresh beef and horse muscles were cut and ice-stored at 5 °C, and time-dependent Raman measurements were performed daily up to 12 days postmortem. Applying a 671 nm microsystem diode laser and a laser power of 50 mW, spectra were recorded with integration times of 1-4 s. A pronounced offset of the Raman spectra was observed between horse and beef, with high fluorescence background for horse compared to beef for all days of storage. Principal components analysis was applied for data evaluation revealing a clear distinction between beef and horse meat which can be attributed to differences in the myoglobin content of both species. Furthermore, separations according to aging and spoilage for the two species could be identified simultaneously. Therefore, Raman spectroscopy might be an efficient test method for meat species identification in combination with spoilage detection.

  9. Raman spectroscopic evidence of tissue restructuring in heat-induced tissue fusion.

    Science.gov (United States)

    Su, Lei; Cloyd, Kristy L; Arya, Shobhit; Hedegaard, Martin A B; Steele, Joseph A M; Elson, Daniel S; Stevens, Molly M; Hanna, George B

    2014-09-01

    Heat-induced tissue fusion via radio-frequency (RF) energy has gained wide acceptance clinically and here we present the first optical-Raman-spectroscopy study on tissue fusion samples in vitro. This study provides direct insights into tissue constituent and structural changes on the molecular level, exposing spectroscopic evidence for the loss of distinct collagen fibre rich tissue layers as well as the denaturing and restructuring of collagen crosslinks post RF fusion. These findings open the door for more advanced optical feedback-control methods and characterization during heat-induced tissue fusion, which will lead to new clinical applications of this promising technology.

  10. Infrared and Raman spectroscopic studies of glasses with NASICON-type chemistry

    Indian Academy of Sciences (India)

    K J Rao; K C Sobha; Sundeep Kumar

    2001-10-01

    Structures of NASICON glasses of the general formula AB2(PO4)3, where A = Li, Na or K and B = Fe, Ga, Ti, V or Nb, have been investigated using vibrational (IR and Raman) spectroscopies. Phosphate species appear to establish an equilibrium via a disproportionation reaction involving a dynamical bond-switching mechanism where both charge and bonds are conserved. B ions in the system acquire different coordinations to oxygens. Alkali ions cause absorptions due to cage vibrations. All the observed spectroscopic features are consistent with speciation involving disproportionation reactions.

  11. 13C Solid State Nuclear Magnetic Resonance and µ-Raman Spectroscopic Characterization of Sicilian Amber.

    Science.gov (United States)

    Barone, Germana; Capitani, Donatella; Mazzoleni, Paolo; Proietti, Noemi; Raneri, Simona; Longobardo, Ugo; Di Tullio, Valeria

    2016-08-01

    (13)C cross-polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) and µ-Raman spectroscopy were applied to characterize Sicilian amber samples. The main goal of this work was to supply a complete study of simetite, highlighting discriminating criteria useful to distinguish Sicilian amber from fossil resins from other regions and laying the foundations for building a spectroscopic database of Sicilian amber. With this aim, a private collection of unrefined simetite samples and fossil resins from the Baltic region and Dominican Republic was analyzed. Overall, the obtained spectra permitted simetite to be distinguished from the other resins. In addition, principal component analysis (PCA) was applied to the spectroscopic data, allowing the clustering of simetite samples with respect to the Baltic and Dominican samples and to group the simetite samples in two sets, depending on their maturity. Finally, the analysis of loadings allowed for a better understanding of the spectral features that mainly influenced the discriminating characteristics of the investigated ambers.

  12. Single-Beam Coherent Raman Spectroscopy and Microscopy via Spectral Notch Shaping

    CERN Document Server

    Katz, Ori; Grinvald, Eran; Silberberg, Yaron

    2010-01-01

    Raman spectroscopy is one of the key techniques in the study of vibrational modes and molecular structures. In Coherent Anti-Stokes Raman Scattering (CARS) spectroscopy, a molecular vibrational spectrum is resolved via the third-order nonlinear interaction of pump, Stokes and probe photons, typically using a complex experimental setup with multiple beams and laser sources. Although CARS has become a widespread technique for label-free chemical imaging and detection of contaminants, its multi-source, multi-beam experimental implementation is challenging. In this work we present a simple and easily implementable scheme for performing single-beam CARS spectroscopy and microscopy using a single femtosecond pulse, shaped by a tunable narrowband notch filter. As a substitute for multiple sources, the single broadband pulse simultaneously provides the pump, Stokes and probe photons, exciting a broad band of vibrational levels. High spectroscopic resolution is obtained by utilizing a tunable spectral notch, shaped wi...

  13. Limiting the intensity of femtosecond pulses with anti-stokes excitation of organic dye solutions

    Science.gov (United States)

    Svetlichnyi, V. A.; Meshalkin, Yu. P.; Kirpichnikov, A. V.; Pestryakov, E. V.

    2010-08-01

    Results of experimental investigations into the nonlinear absorption of the symmetric polymethine 1-butyl -3,3-dimethyl-2-[5-(1-butyl-3,3-dimethyl-3H-benz[e]indoline-2-uledene)-1,3-pentadienyl]-3H-benz[e]indolium perchlorate dye solution excited by radiation of a femtosecond titanium-sapphire laser (20 fs, 800 nm, 75 MHz, and 300 mW) by the open aperture z-scan method are presented. Record limitation of the femtosecond laser radiation intensity (by 300 times at a 93% linear transmission of the medium) was achieved. The nonlinear absorption mechanisms in organic dyes with anti-Stokes excitation by wideband high-power pulsed radiation to the absorption band edge and the prospects for organic dye application for limitation of the femtosecond laser radiation intensity are discussed.

  14. High-efficiency broadband anti-Stokes emission from Yb3+-doped bulk crystals.

    Science.gov (United States)

    Zhu, Siqi; Wang, Chunhao; Li, Zhen; Jiang, Wei; Wang, Yichuan; Yin, Hao; Wu, Lidan; Chen, Zhenqiang; Zhang, Ge

    2016-05-15

    We investigate the broadband anti-Stokes emission (BASE) from Yb3+-doped crystals with a laser diode (LD) pumping at 940 nm. Our experiment reveals that Yb3+-doped crystals with random cracks are able to generate bright BASE at room temperature and atmospheric pressure. By examining the various characteristics of the crystals and the emitted light, we supply a theory for interpreting the underlying physics for this variety of BASE. In particular, we take into consideration the effects of energy migration, avalanche process, and charge-transfer luminescence. This represents the first time, to the best of our knowledge, that BASE was obtained from Yb3+-doped bulk crystals with a high optical-optical efficiency.

  15. Utilization of IR laser pumped anti-Stokes emission of Er-Yb doped systems for identification of securities

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmin, A.N.; Ryabtsev, G.I.; Ketko, G.A. [Institute of Physics, Belarussian Academy of Sciences, Minsk (Belarus); Gorelenko, A.Yu.; Demidovich, A.A. [Science Center `Gosznak` of Belarus, Minsk (Belarus); Strek, W.; Maruszewicz, K.; Deren, P. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland)

    1996-12-31

    In this paper we present a utilization of anti-Stokes luminescence of Er-Yb systems for identification of securities. A simple method of detection of an up-conversion phenomenon in such system by means of IR laser operating in the region 960-1010 nm is proposed. (author) 3 refs, 3 figs

  16. Study of Raman spectroscopic analysis method for sodium compounds at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Fumiyoshi; Ohtori, Norikazu [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center

    2002-09-01

    High-temperature sodium on exposure to air produces a corrosive melt including Na{sub 2}O, Na{sub 2}O{sub 2} and NaOH after reaction with oxygen and moisture. If the melt contacts steel, several sodium-iron complex oxides will be produced by the corrosion reaction. To contribute to elucidation of the corrosion mechanism, the Raman spectroscopic technique for analysis of strongly corrosive sodium compounds was developed and the behavior of corrosive chemical species in the compounds was investigated. Several Raman spectra of a series of typical sodium compounds such as Na{sub 2}O{sub 2} were measured in the range from room temperature to 1,073K. Subsequently, a simulated corrosive mixture of molten sodium hydroxide with peroxide was investigated, and peroxide ion was detected up to 823K. Thus, peroxide ion can be a corrosive chemical species in the melt at high temperature. Moreover, Raman spectra obtained for several sodium-iron complex oxides, e.g. Na{sub 4}FeO{sub 3}, indicate that each oxide can be identified up to 573K. (author)

  17. Raman spectroscopic study of phase stability and anharmonicity in Bi{sub 12}TiO{sub 20}

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha, E-mail: rekhar@barc.gov.in [Solid State Physics Division, Bhabha Atomic Research Center, Mumbai 400 085 (India); Salke, Nilesh P. [Solid State Physics Division, Bhabha Atomic Research Center, Mumbai 400 085 (India); Garg, Alka B. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Center, Mumbai 400 085 (India)

    2013-05-15

    Raman spectroscopic studies on lead-free piezo-electric compound Bi{sub 12}TiO{sub 20} is reported as a function of pressure upto 25 GPa at room temperature. Results indicate that the compound remains in stable crystalline phase upto 25 GPa. Temperature dependent Raman spectroscopic investigations on Bi{sub 12}TiO{sub 20} indicate that the compound is also stable at high temperatures upto 850 K. From measurements of temperature and pressure dependence of Raman mode frequencies, intrinsic anharmonic parameters are calculated for each of the Raman active modes which are useful in modeling of thermodynamic entities. The results are compared with that of analogous compound Bi{sub 12}SiO{sub 20}. Highlights: ► Raman spectroscopic study of Bi{sub 12}TiO{sub 20} is carried out at high pressure/temperature. ► This study indicates a good structural stability of Bi{sub 12}TiO{sub 20}. ► Bi{sub 12}TiO{sub 20} is an ideal system to evaluate the anharmonicity of vibrational modes.

  18. [Application of Raman spectroscopic technique to the identification and investigation of Chinese ancient jades and jade artifacts].

    Science.gov (United States)

    Zhao, Hong-Xia; Gan, Fu-Xi

    2009-11-01

    Laser Raman spectroscopic technique is one of the essential methods in scientific archaeological research, which belongs to the nondestructive analysis. As a very good nondestructive analysis approach, it has not been widely applied in the research of the Chinese ancient jade artifacts. First of all in the present paper the fundamentals of laser Raman spectroscopic technique and the new research progress in this field were reviewed. Secondly, the Raman spectra of five familiar jades including nephrite (mainly composed of tremolite), Xiuyan Jade (mainly composed of serpentine), Dushan Jade (mainly composed of anorthite and Zoisite), turquoise and lapis lazuli were summarized respectively. As for an example, the Raman spectra of the four Chinese ancient jade artifacts excavated from Liangzhu Site of Zhejiang Province and Yinxu Site of Anyang in Henan Province were compared with that of the nephrite sample in Hetian of Xinjiang Province. It was shown that the Raman spectroscopic technique is a good nondestructive approach to the identification and investigation of the structures and mineral composition of Chinese ancient jade artifacts. Finally, the limitations and the foreground of this technique were discussed.

  19. Sum-Frequency-Generation-Based Laser Sidebands for Tunable Femtosecond Raman Spectroscopy in the Ultraviolet

    Directory of Open Access Journals (Sweden)

    Liangdong Zhu

    2015-04-01

    Full Text Available Femtosecond stimulated Raman spectroscopy (FSRS is an emerging molecular structural dynamics technique for functional materials characterization typically in the visible to near-IR range. To expand its applications we have developed a versatile FSRS setup in the ultraviolet region. We use the combination of a narrowband, ~400 nm Raman pump from a home-built second harmonic bandwidth compressor and a tunable broadband probe pulse from sum-frequency-generation-based cascaded four-wave mixing (SFG-CFWM laser sidebands in a thin BBO crystal. The ground state Raman spectrum of a laser dye Quinolon 390 in methanol that strongly absorbs at ~355 nm is systematically studied as a standard sample to provide previously unavailable spectroscopic characterization in the vibrational domain. Both the Stokes and anti-Stokes Raman spectra can be collected by selecting different orders of SFG-CFWM sidebands as the probe pulse. The stimulated Raman gain with the 402 nm Raman pump is >21 times larger than that with the 550 nm Raman pump when measured at the 1317 cm−1 peak for the aromatic ring deformation and ring-H rocking mode of the dye molecule, demonstrating that pre-resonance enhancement is effectively achieved in the unique UV-FSRS setup. This added tunability in the versatile and compact optical setup enables FSRS to better capture transient conformational snapshots of photosensitive molecules that absorb in the UV range.

  20. Raman spectroscopic analysis of the interaction between squaric acid and dimethylsulfoxide

    Science.gov (United States)

    Georgopoulos, Stéfanos L.; Edwards, Howell G. M.; de Oliveira, Luiz Fernando C.

    2013-07-01

    The investigation of solutions of squaric acid in dimethylsulfoxide (DMSO) by Raman spectroscopy has facilitated the observation of the presence of different species derived from squaric acid such as the squarate dianion in solutions of 0.3 M and 0.5 M concentration and the hydrogen-squarate ion in solution concentrations greater than 2.0 M. The method described by Alía and coworkers was used to calculate the two pK values corresponding to the ions produced by squaric acid interacting with DMSO: the hydrogen squarate (pK1 = 0.80) ion and the squarate dianion (pK2 = 0.84). From the spectroscopic data it has been also possible to determine the complex formation between associated squaric acid/DMSO in the proportion squaric acid 1:1 DMSO in which the associated squaric acid is hydrogen-bonded to the S atom in the DMSO structure.

  1. Circular dichroism and Raman spectroscopic study of the spider venom toxin V50F17

    Science.gov (United States)

    Alix, A. J. P.; Berjot, M.; Dauchez, M. A. M.; Dhalluin, C.; Lippens, G.

    1999-05-01

    V50F17 is a small 45 amino acid neurotoxin fractionated (F17) from the venom V50 of the spider Segestria florentina, which has eight cysteine residues constituting four disulfide bridges. Using circular dichroism data and vibrational Raman data at both pH 2.9 and 7.0 and preliminary NMR results obtained at pH 2.9, we derived structural information for this small protein. From these data, it is seen that it is possible to characterise well the local conformation of the disulfide bridges and the overall shape of the globular protein. Moreover, using optical spectroscopic data, it is shown that consequent local and/or global modifications are obtained on changing the pH. Results of the secondary structure states, the local conformations of the disulfide bridges, the exposure of side chains of residues and particularly of Tyr41 are discussed.

  2. A Peltier cooling diamond anvil cell for low-temperature Raman spectroscopic measurements

    Science.gov (United States)

    Noguchi, Naoki; Okuchi, Takuo

    2016-12-01

    A new cooling system using Peltier modules is presented for a low-temperature diamond anvil cell instrument. This cooling system has many advantages: it is vibration-free, low-cost, and compact. It consists of double-stacked Peltier modules and heat sinks, where a cooled ethylene glycol-water mixture flows through a chiller. Current is applied to the Peltier modules by two programmable DC power supplies. Sample temperature can be controlled within the range 210-300 K with a precision of ±0.1 K via a Proportional-Integral-Differential (PID) control loop. A Raman spectroscopic study for the H2O ice VII-VIII transition is shown as an example of an application of the Peltier cooling diamond anvil cell system.

  3. Mediaeval cantorals in the Valladolid Biblioteca: FT-Raman spectroscopic study.

    Science.gov (United States)

    Edwards, H G; Farwell, D W; Rull Perez, F; Medina Garcia, J

    2001-03-01

    Raman spectroscopic studies of three mediaeval cantorals in the Biblioteca of the University of Valladolid has revealed information about the pigments used on these large manuscripts. Although executed in a simple colour palette, very pure cinnabar was used as the major colourant, offsetting the carbon black of the verses and script. A dark blue colour was achieved using a mixture of azurite (basic copper carbonate) and carbon, whereas a light blue colour was azurite alone. A grey colour was achieved using azurite, carbon particles and a calcareous 'limewash'. A yellow pigment, used sparely in the cantorals was ascribed to saffron; unusually, there was no evidence for the presence of the yellow mineral pigments orpiment, realgar and massicot. In several regions of the vellum specimens, evidence for biodeterioration was observed through the signatures of hydrated calcium oxalate. We report for the first time the Raman spectra of pigment in situ on a vellum fragment, which also shows evidence of substrate bands; comparison of black and red pigmented regions of vellum specimens has shown the presence of calcium oxalate in the black pigmented script but not in the red pigment regions, which suggests that the cinnabar in the red-pigmented regions acts as a toxic protectant for the vellum substrate against biological colonisation processes.

  4. 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.

  5. Planetary Surface Analysis Using Fast Laser Spectroscopic Techniques: Combined Microscopic Raman, LIBS, and Fluorescence Spectroscopy

    Science.gov (United States)

    Blacksberg, J.; Rossman, G. R.; Maruyama, Y.; Charbon, E.

    2011-12-01

    In situ exploration of planetary surfaces has to date required multiple techniques that, when used together, yield important information about their formation histories and evolution. We present a time-resolved laser spectroscopic technique that could potentially collect complementary sets of data providing information on mineral structure, composition, and hydration state. Using a picosecond-scale pulsed laser and a fast time-resolved detector we can simultaneously collect spectra from Raman, Laser Induced Breakdown Spectroscopy (LIBS), and fluorescence emissions that are separated in time due to the unique decay times of each process. The use of a laser with high rep rate (40 KHz) and low pulse energy (1 μJ/pulse) allows us to rapidly collect high signal to noise Raman spectra while minimizing sample damage. Increasing the pulse energy by about an order of magnitude creates a microscopic plasma near the surface and enables the collection of LIBS spectra at an unusually high rep rate and low pulse energy. Simultaneously, broader fluorescence peaks can be detected with lifetimes varying from nanosecond to microsecond. We will present Raman, LIBS, and fluorescence spectra obtained on natural mineral samples such as sulfates, clays, pyroxenes and carbonates that are of interest for Mars mineralogy. We demonstrate this technique using a photocathode-based streak camera detector as well as a newly-developed solid state Single Photon Avalanche Diode (SPAD) sensor array based on Complementary Metal-Oxide Semiconductor (CMOS) technology. We will discuss the impact of system design and detector choice on science return of a potential planetary surface mission, with a specific focus on size, weight, power, and complexity. The research described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA).

  6. Raman spectroscopic mapping for the analysis of solar radiation induced skin damage.

    Science.gov (United States)

    Ali, S M; Bonnier, F; Ptasinski, K; Lambkin, H; Flynn, K; Lyng, F M; Byrne, H J

    2013-07-21

    The effects of simulated solar irradiation of an artificial skin model have been examined using Raman spectroscopy and the results are compared with cytotoxicological and histological profiling. Samples exposed for times varying between 30 minutes and 240 minutes were incubated post exposure for a period of 96 hours. The cytotoxicological response as measured by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay demonstrated a ~50% loss of viability of the artificial tissue after 120 minutes exposure. Histological staining of tissue sections showed considerable loss of cellular content in the epidermal layer at this endpoint. Raman spectroscopic mapping of tissue sections, coupled with K-means cluster analysis (KMCA) clearly identified the dermal and stratum corneum layers and differentiated further substructures of the epidermis. Post irradiation, a significant loss of DNA features in the basal layer was apparent in the results of the KMCA. Principal Components Analysis (PCA) of layers identified by the KMCA post exposure compared with controls indicated a significant increase in the lipidic signatures of the stratum corneum. In the dermal layer, little photodamage was observed, but a similar increase in lipidic signatures in the basal layer was accompanied by a decrease in DNA and protein contributions. The spectral profiles of the photodamage to the basal layer as identified by PCA are consistent over the exposure periods of 30-240 minutes, but an examination of the evolution of features associated with specific biochemical components indicated DNA damage and loss of lipidic signatures at the early exposure times, whereas changes in protein signatures appeared to evolve over longer periods. In comparison to the cytotoxicological responses, the study demonstrates that Raman spectroscopy can identify biochemical changes as a result of solar exposure at time points significantly earlier than changes in tissue viability are observed.

  7. Raman and photoelectron spectroscopic investigation of high-purity niobium materials: Oxides, hydrides, and hydrocarbons

    Science.gov (United States)

    Singh, Nageshwar; Deo, M. N.; Nand, Mangla; Jha, S. N.; Roy, S. B.

    2016-09-01

    We present investigations of the presence of oxides, hydrides, and hydrocarbons in high-purity (residual resistivity ratio, ˜300) niobium (Nb) materials used in fabrication of superconducting radio frequency (SRF) cavities for particle accelerators. Raman spectroscopy of Nb materials (as-received from the vendor as well as after surface chemical- and thermal processing) revealed numerous peaks, which evidently show the presence of oxides (550 cm-1), hydrides (1277 and 1385 cm-1: ˜80 K temperature), and groups of hydrocarbons (1096, 2330, 2710, 2830, 2868, and 3080 cm-1). The present work provides direct spectroscopic evidence of hydrides in the electropolished Nb materials typically used in SRF cavities. Raman spectroscopy thus can provide vital information about the near-surface chemical species in niobium materials and will help in identifying the cause for the performance degradation of SRF cavities. Furthermore, photoelectron spectroscopy was performed on the Nb samples to complement the Raman spectroscopy study. This study reveals the presence of C and O in the Nb samples. Core level spectra of Nb (doublet 3d5/2 and 3d3/2) show peaks near 206.6 and 209.4 eV, which can be attributed to the Nb5+ oxidation state. The core level spectra of C 1 s of the samples are dominated by graphitic carbon (binding energy, 284.6 eV), while the spectra of O 1 s are asymmetrically peaked near binding energy of ˜529 eV, and that indicates the presence of metal-oxide Nb2O5. The valence-band spectra of the Nb samples are dominated by a broad peak similar to O 2p states, but after sputtering (for 10 min) a peak appears at ˜1 eV, which is a feature of the elemental Nb atom.

  8. Raman spectroscopic evaluation of efficacy of current paraffin wax section dewaxing agents.

    Science.gov (United States)

    Faoláin, Eoghan O; Hunter, Mary B; Byrne, Joe M; Kelehan, Peter; Lambkin, Helen A; Byrne, Hugh J; Lyng, Fiona M

    2005-01-01

    During a spectroscopic study to identify biochemical changes in cervical tissue with the onset of carcinogenesis, residual paraffin wax contributions were observed on almost all dewaxed formalin-fixed paraffin-processed (FFPP) tissue sections examined. Subsequently, the present study was formulated to evaluate the efficacy of current dewaxing agents using Raman spectroscopy. Three cervical FFPP sections were subjected to each of the protocols. Sections were dewaxed using four common dewaxing protocols, namely, xylene, Histoclear, heat-mediated antigen retrieval (HMAR) using xylene and citrate buffer, and Trilogy (combined deparaffinization and unmasking of antigens). The potential for hexane as a dewaxing agent was also evaluated. Sections were dewaxed in multiple dewaxing cycles using xylene, Histoclear, and hexane. Residual paraffin wax contributions remained at 1062 cm(-1), 1296 cm(-1), and 1441 cm(-1). HMAR using xylene and citrate buffer, and HMAR using Trilogy, showed a similar efficacy, resulting in incomplete removal of wax. Hexane was shown to be the most effective dewaxing agent, resulting in almost complete removal of wax. Immunohistochemistry was carried out on dewaxed slides, and those dewaxed with hexane displayed a stronger positivity (approximately 28%). Implications for histopathology and immunohistochemistry are considered, as well as problems that residual wax poses for spectroscopic evaluation of dewaxed FFPP sections with a view to disease diagnosis.

  9. Anti-Stokes Frequency Shift and Evolution in Polarization-Maintaining Photonic Crystal Fiber with Two-Zero Dispersion Wavelengths

    Institute of Scientific and Technical Information of China (English)

    WANG He-Lin; LENG Yu-Xin; XU Zhi-Zhan; QI Yi-Hong; HU Ming-Lie; WANG Ching-Yue

    2009-01-01

    Using the tunable pump pulses with about 100 fs pulse duration and 1064 nm central wavelength; the polarization-,wavelength- and power-dependent anti-Stokes lines are generated and modulated simultaneously in a polarizationmaintaining photonic crystal fiber (PM-PCF) with two zero-dispersion wavelengths.By accurately controlling the polarization directions,the wavelength and the power of the pump pulse in the fiber anomalous region close to the second zero-dispersion wavelength of the PM-PCF,the output anti-Stokes pulse spectra can be tuned between 563nm and 603 nm,which is in good agreement with the theoretical simulation.The color conversion of the mode image from yellow to orange is also observed with the different polarization pump pulses.These results can be attributed to the combined interaction between the fiber birefringence (including linear- and nonlinearbirefringence) and dispersion,and are attributed to phase-matching parametric four-wave mixing.

  10. In-situ Raman Spectroscopic Imaging of a Mussel Coating and Adhesive

    Science.gov (United States)

    Mašić, Admir; Harrington, Matthew; Waite, J. Herbert; Fratzl, Peter

    2010-08-01

    The mussel has evolved a very interesting and efficient way of attaching to hard substrata in wave-swept rocky seashores. This is enabled by a bundle of fine protein based threads called the byssus. The byssus is emerging as an effective model system for studying the requirements for underwater adhesion, wear resistance and combined hardness and extensibility (1, 2). Careful secretion of different mussel foot proteins (mfp) combined with some metal ions (Fe3+, Zn2+ etc.) allows the mussel to tune properties and optimize function of diverse parts of byssus thread (3). Here we report in-situ high-resolution Raman spectroscopic imaging of the byssal coating and plaque showing micron level spatial distribution of various proteins and their interaction with Fe3+ using specific Resonance Raman (RR) spectral features. 3,4-dihydroxyphenylalanine (dopa) is a strong chelator of Fe3+ within a specific pH window (stability constant of [Fe(dopa)3]3- complex can reach values up to Kf˜1045). The charge transfer from the catechol ring to Fe(III) characteristic of such complexes generates absorption bands in whole visible a part of near infra-red spectrum. As a consequence, a characteristic RR signal can be detected using 785 nm laser line. This method was recently utilized to localize Fe-dopa complexation of mfp-1 in the protective cuticles of mussel byssal threads (2), and the same approach was taken here to investigate metal complexation in the plaque. In figure 1A a scanning electron micrograph of a cross section of plaque is presented. Characteristic foam-like morphology of internal part of the plaque is visible. Figure 1B shows the results of Raman spectroscopic imaging (for specifications see reference (2)) on a thin (10 μm) section of the byssus plaque integrated for Fe3+-dopa complexation bands (500-650 cm-1, see Fig. 1D). The components distribution map in Fig. 1C was obtained using the basis analysis and image color combination functions (Witec Project software). In

  11. Green and red Anti-Stokes emission of U3+: LaCl3produced by infrared laser

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Anti-Stokes green and red emission from U3+: LaCl3 can be produced by infrared laser excitation at 975.3 nm, 977.7 nm and 979.4 nm at 8K. The upconversion luminescence intensity dependence upon the excitation laser power was measured and analyzed. The results show that depending on the excitation wavelength, the mechanisms responsible for the upconversion process are two-photon absorption and excited-state absorption.

  12. Stimulated Raman Scattering in Nanorod Silicon Carbide Films

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    When the film is excited by a very low excitation energy, the spontaneous Raman scattering emerges. The intensity of Raman scattering is proportional to the excitation power below the threshold excitation. When the excited power reaches the excitation threshold, the intensity of Stokes light strongly increases. Meanwhile an anti-Stokes light at 495nm and multiple order but small Stokes peaks occur. The intensity of Stokes light is much larger than that of anti-Stokes. The full width of half maximum (FWHM) of Stokes peak is reduced from 0.4nm to less than 0.2nm, the scattering angle between both Stokes and incident lights becomes less than 1°, and the angle between the Stokes and anti-Stokes lights is about 3°. When the exciting power is in excess of the threshold, anti-Stokes and multiple Raman scattering peaks reappear. These experiments can be unlimitedly repeated. From this experiment, we can exclude the possibility of spontaneous Raman scattering. It is suggested that the nanorods are a quantum line dimension having a large surface. There will be Raman differential scattering section so long as the nanorod films become very strong scattering media; the surface-enhanced Raman scattering will be produced, the nanorod films of SiC will form a strong multiple scattering resonance cavities so as to form the stimulated Raman scattering oscillation.

  13. Raman Spectroscopy and Microscopy of Individual Cells andCellular Components

    Energy Technology Data Exchange (ETDEWEB)

    Chan, J; Fore, S; Wachsmann-Hogiu, S; Huser, T

    2008-05-15

    Raman spectroscopy provides the unique opportunity to non-destructively analyze chemical concentrations on the submicron length scale in individual cells without the need for optical labels. This enables the rapid assessment of cellular biochemistry inside living cells, and it allows for their continuous analysis to determine cellular response to external events. Here, we review recent developments in the analysis of single cells, subcellular compartments, and chemical imaging based on Raman spectroscopic techniques. Spontaneous Raman spectroscopy provides for the full spectral assessment of cellular biochemistry, while coherent Raman techniques, such as coherent anti-Stokes Raman scattering is primarily used as an imaging tool comparable to confocal fluorescence microscopy. These techniques are complemented by surface-enhanced Raman spectroscopy, which provides higher sensitivity and local specificity, and also extends the techniques to chemical indicators, i.e. pH sensing. We review the strengths and weaknesses of each technique, demonstrate some of their applications and discuss their potential for future research in cell biology and biomedicine.

  14. Solvatochromism of 9,10-phenanthrenequinone: An electronic and resonance Raman spectroscopic study

    Energy Technology Data Exchange (ETDEWEB)

    Ravi Kumar, Venkatraman; Rajkumar, Nagappan; Umapathy, Siva, E-mail: umapathy@ipc.iisc.ernet.in

    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{sup 1}*; S{sub 1} state) and the shorter (1π-π{sup 1}*; S{sub 2} 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 S{sub 2} state relative to the ground state. Raman excitation profiles of PQ (400–1800 cm{sup −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 C{sub 2ν} symmetry constraint on the S{sub 2} 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.

  15. Laser-Raman and FT-IR spectroscopic studies of peptide-analogues of silkmoth chorion protein segments.

    Science.gov (United States)

    Benaki, D C; Aggeli, A; Chryssikos, G D; Yiannopoulos, Y D; Kamitsos, E I; Brumley, E; Case, S T; Boden, N; Hamodrakas, S J

    1998-07-01

    Silkmoth chorion, the proteinaceous major component of the eggshell, with extraordinary mechanical and physiological properties, consists of a complex set of proteins, which have a tripartite structure: a central, evolutionarily conserved, domain and two more variable 'arms'. Peptide-analogues of silkmoth chorion protein central domain segments have been synthesized. Laser-Raman and infrared spectroscopic studies suggest the preponderance of antiparallel beta-pleated sheet structure for these peptides, both in solution and in the solid state.

  16. Raman spectroscopic signatures of the yellow and ochre paints from artist palette of J. Matejko (1838-1893)

    Science.gov (United States)

    Żmuda-Trzebiatowska, Iwona; Wachowiak, Mirosław; Klisińska-Kopacz, Anna; Trykowski, Grzegorz; Śliwiński, Gerard

    2015-02-01

    The Raman and complementary spectroscopic analyses were performed using the exceptional possibility of research on the XIX c. original paint materials of the artist palette of J. Matejko stored in the National Museum in Cracow. The yellow and ochre-based paints characteristic for Matejko's workshop and selected from the ensemble of 273 labelled tubes (brand of R. Ainé/Paris) supplied during the period of 1880-1893 were investigated. Highly specific Raman spectra were obtained for paints containing mixtures of the Zn- and Sn-modified Pb-Sb pigment, and also for the ochre-based ones. A clear pigment discrimination of the mixture of cadmium yellow (CdS), cinnabar (HgS) and lead white (2PbCO3ṡPb(OH)2) was possible by means of Raman data collected under different excitations at 514 nm and 785 nm. It was shown that the Raman spectra complemented by the XRF, SEM-EDX and in some cases also by the LIPS and FTIR data ensure reliable pigment identification in multi-component paints containing secondary species and impurities. The reported spectral signatures will be used for non-destructive investigation of the collection of about 300 oil paintings of J. Matejko. In view of the comparative research on polish painting which point out that richness of modified Naples yellows clearly distinguish Matejko's artworks from other ones painted in the period of 1850-1883, the Raman data of these paints can provide support in the authentication studies.

  17. Raman spectroscopic investigation of the chemopreventive response of naringenin and its nanoparticles in DMBA-induced oral carcinogenesis

    Science.gov (United States)

    Krishnakumar, N.; Sulfikkarali, N. K.; Manoharan, S.; Venkatachalam, P.

    2013-11-01

    Raman spectroscopy is a vibrational spectroscopic technique that can be used to optically probe the biomolecular changes associated with tumor progression. The aim of the present study is to investigate the biomolecular changes in chemopreventive response of prepared naringenin-loaded nanoparticles (NARNPs) relative to efficacy of free naringenin (NAR) during 7,12-dimethyl benz(a)anthracene (DMBA)-induced oral carcinogenesis by Fourier Transform Raman (FT-Raman) spectroscopy. Oral squamous cell carcinoma (OSCC) was developed in the buccal pouch of golden Syrian hamsters by painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. Raman spectra differed significantly between the control and tumor tissues, with tumors showing higher percentage signals for nucleic acids, phenylalanine and tryptophan and a lower in the percentage of phospholipids. Moreover, oral administration of free NAR and NARNPs significantly increased phospholipids and decreased the levels of tryptophan, phenylalanine and nucleic acid contents. On a comparative basis, NARNPs was found to have a more potent antitumor effect than free NAR in completely preventing the formation of squamous cell carcinoma and in improving the biochemical status to a normal range in DMBA-induced oral carcinogenesis. The present study further suggest that Raman spectroscopy could be a valuable tool for rapid and sensitive detection of specific biomolecular changes in response to chemopreventive agents.

  18. CARS and Raman spectroscopy of function-related conformational changes of chymotrypsin

    NARCIS (Netherlands)

    Brandt, N.N.; Chikishev, A.Yu.; Greve, J.; Koroteev, N.I.; Otto, C.; Sakodynskaya, I.K.

    2000-01-01

    We report on the comparative analysis of the conformation-sensitive bands of free enzyme (chymotrypsin), liganded enzyme (chymotrypsin anthranilate) and enzyme complex with 18-crown-6. The studies were carried out by Raman scattering spectroscopy and polarization-sensitive coherent anti-Stokes Raman

  19. Raman Spectroscopic Measurements of Co2 Dissolved in Seawater for Laser Remote Sensing in Water

    Directory of Open Access Journals (Sweden)

    Somekawa Toshihiro

    2016-01-01

    Full Text Available We examined the applicability of Raman lidar technique as a laser remote sensing tool in water. The Raman technique has already been used successfully for measurements of CO2 gas dissolved in water and bubbles. Here, the effect of seawater on CO2 Raman spectra has been evaluated. A frequency doubled Q-switched Nd:YAG laser (532 nm was irradiated to CO2 gas dissolved in a standard seawater. In seawater, the Raman signals at 984 and 1060-1180 cm-1 from SO42- were detected, which shows no spectral interference caused by Raman signals derived from CO2.

  20. Raman spectroscopic analyses of preserved historical specimens of human hair attributed to Robert Stephenson and Sir Isaac Newton.

    Science.gov (United States)

    Edwards, Howell G M; Hassan, Nik F N; Wilson, Andrew S

    2004-10-01

    The Raman spectra of two historical specimens of human hair attributed to the engineer Robert Stephenson and scientist Sir Isaac Newton, preserved in private collections are reported. Comparisons are made with the Raman spectra of modern hair specimens and with hair from archaeological excavations. The hair spectra collected with a laser excitation of 785 nm are of a better quality than those collected using 1064 nm. The historical hair specimens are remarkably well-defined spectroscopically in terms of the amide I vibrational mode and the [small nu](SS), ascribed to a predominantly gauche-gauche-gauche CSSC conformation. The contrast with degraded hair specimens recovered from archaeological excavations is striking. The presence of a weak feature near 2590 cm(-1) in the hair samples attributed to a [small nu](SH) vibration could be indicative of a reduction process operative on the CSSC cystine keratotic linkages and a possible origin of this is bacterial biodegradation identified histologically. This study demonstrates the molecular information available from non-destructive Raman spectroscopic analysis from single hair shafts or small bundles of fibres which complements information available from histological and destructive analytical techniques for rare biological specimens subjected to conservation or curation procedures in museums or private collections.

  1. 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.

  2. Generation of femtosecond anti-stokes pulses through phase-matched parametric four-wave mixing in a photonic crystal fiber.

    Science.gov (United States)

    Konorov, S O; Serebryannikov, E E; Zheltikov, A M; Zhou, Ping; Tarasevitch, A P; von der Linde, D

    2004-07-01

    Phase-matched parametric four-wave mixing in higher-order guided modes of a photonic crystal fiber is shown to result in an efficient decay of 40-fs 800-nm Ti:sapphire laser pump pulses into an anti-Stokes signal with a central wavelength around 590-600 nm and a Stokes signal centered at 1.25 microm. The photonic crystal fiber is designed in such a way as to minimize the group-velocity dispersion at the pump wavelength, phase match the parametric four-wave-mixing process, and reduce the group delay between the pump and the anti-Stokes pulses. The duration of the anti-Stokes pulse under these conditions, as shown by cross-correlation frequency-resolved optical gating measurements, is less than 200 fs.

  3. New background correction method for liquid chromatography with diode array detection, infrared spectroscopic detection and Raman spectroscopic detection

    NARCIS (Netherlands)

    Boelens, H.; Dijkstra, R.J.; Eilers, P.H.C.; Fitzpatrick, F.; Westerhuis, J.A.

    2004-01-01

    A new method to eliminate the background spectrum (EBS) during analyte elution in column liquid chromatography (LC) coupled to spectroscopic techniques is proposed. This method takes into account the shape and also intensity differences of the background eluent spectrum. This allows the EBS method t

  4. Investigation of Optical Fibers for Coherent Anti-Stokes Raman Scattering (CARS) Spectroscopy in Reacting Flows (Postprint)

    Science.gov (United States)

    2012-03-01

    notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not...OF ABSTRACT: SAR 18. NUMBER OF PAGES 22 19a. NAME OF RESPONSIBLE PERSON (Monitor) a. REPORT Unclassified b. ABSTRACT Unclassified c...Seeger of the University of Erlangen- Nuremberg , Prof. Margaret M. Murnane of the University of Colorado/JILA, and Dr. Hans Stauffer and Ms. Amy Lynch

  5. In situ dissolution analysis of pharmaceutical dosage forms using coherent anti-Stokes Raman scattering (CARS) microscopy

    Science.gov (United States)

    Fussell, A. L.; Garbacik, E. T.; Löbmann, K.; Offerhaus, H. L.; Kleinebudde, P.; Strachan, C. J.

    2014-02-01

    A custom-built intrinsic flow-through dissolution setup was developed and incorporated into a home-built CARS microscope consisting of a synchronously pumped optical parametric oscillator (OPO) and an inverted microscope with a 20X/0.5NA objective. CARS dissolution images (512×512 pixels) were collected every 1.12s for the duration of the dissolution experiment. Hyperspectral CARS images were obtained pre- and postdissolution by rapidly imaging while sweeping the wavelength of the OPO in discrete steps so that each frame in the data stack corresponds to a vibrational frequency. An image-processing routine projects this hyperspectral data into a single image wherein each compound appears with a unique color. Dissolution was conducted using theophylline and cimetidine-naproxen co-amorphous mixture. After 15 minutes of theophylline dissolution, hyperspectral imaging showed a conversion of theophylline anhydrate to the monohydrate, confirmed by a peak shift in the CARS spectra. CARS dissolution images showed that monohydrate crystal growth began immediately and reached a maximum with complete surface coverage at about 300s. This result correlated with the UV dissolution data where surface crystal growth on theophylline compacts resulted in a rapidly reducing dissolution rate during the first 300s. Co-amorphous cimetidinenaproxen didn't appear to crystallize during dissolution. We observed solid-state conversions on the compact's surface in situ during dissolution. Hyperspectral CARS imaging allowed visual discrimination between the solid-state forms on the compact's surface. In the case of theophylline we were able to correlate the solid-state change with a change in dissolution rate.

  6. Chemical Imaging of Oral Solid Dosage Forms and Changes upon Dissolution Using Coherent Anti-Stokes Raman Scattering Microscopy

    NARCIS (Netherlands)

    Windbergs, Maike; Jurna, Martin; Offerhaus, Herman L.; Herek, Jennifer L.; Kleinebudde, Peter; Strachan, Clare J.

    2009-01-01

    Dissolution testing is a crucial part of pharmaceutical dosage form investigations and is generally performed by analyzing the concentration of the released drug in a defined volume of flowing dissolution medium. As solid-state properties of the components affect dissolution behavior to a large and

  7. Fourier transform Raman spectroscopic characterisation of cells of the plant-associated soil bacterium Azospirillum brasilense Sp7

    Science.gov (United States)

    Kamnev, A. A.; Tarantilis, P. A.; Antonyuk, L. P.; Bespalova, L. A.; Polissiou, M. G.; Colina, M.; Gardiner, P. H. E.; Ignatov, V. V.

    2001-05-01

    Structural and compositional features of bacterial cell samples and of lipopolysaccharide-protein complex isolated from the cell surface of the plant-growth-promoting rhizobacterium Azospirillum brasilense (wild-type strain Sp7) were characterised using Fourier transform (FT) Raman spectroscopy. The structural spectroscopic information obtained is analysed and considered together with analytical data on the content of metal cations (Co 2+, Cu 2+ and Zn 2+) in the bacterial cells grown in a standard medium as well as in the presence of each of the cations (0.2 mM). The latter, being taken up by bacterial cells from the culture medium in significant amounts, were shown to induce certain metabolic changes in the bacterium revealed in FT-Raman spectra, which is discussed from the viewpoint of bacterial response to environmental stresses.

  8. Resonance raman spectroscopic study of alumina-supported vanadium oxide catalysts with 220 and 287 nm excitation.

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H. S.; Stair, P. C.; Chemical Sciences and Engineering Division; Northwestern Univ.

    2009-01-01

    We present detailed resonance Raman spectroscopic results excited at 220 and 287 nm for alumina-supported VO{sub x} catalysts. The anharmonic constant, harmonic wavenumber, anharmonic force constant, bond dissociation energy, and bond length change in the excited state for double bonded V{double_bond}O and single bonded V-O were obtained from fundamental and overtone frequencies. Totally symmetric and nontotally symmetric modes could be discerned and assigned on the basis of the overtone and combination progressions found in the resonance Raman spectra. Selective resonance enhancement of two different vibrational modes with two different excitation wavelengths was observed. This allowed us to establish a linear relationship between charge transfer energy and VO bond length and, consequently, to assign the higher-energy charge transfer band centered around 210?250 nm in the UV?vis spectra to the V{double_bond}O transition.

  9. Comparative two- and three-dimensional analysis of nanoparticle localization in different cell types by Raman spectroscopic imaging

    Science.gov (United States)

    Bräutigam, Katharina; Bocklitz, Thomas; Silge, Anja; Dierker, Christian; Ossig, Rainer; Schnekenburger, Jürgen; Cialla, Dana; Rösch, Petra; Popp, Jürgen

    2014-09-01

    The increasing production and application of engineered nanomaterials requires a detailed understanding of the potential toxicity of nanoparticles and their uptake in living cells and tissue. For that purpose, a highly sensitive and selective method for detecting single nonlabeled nanoparticles and nanoparticle agglomerations in cells and animal tissue is required. Here, we show that Raman microspectroscopy allows for the specific detection of TiO2 nanoparticles inside cultured NIH/3T3 fibroblasts and RAW 264.7 macrophages. The spatial position of TiO2 nanoparticles and in parallel the relative intracellular concentration and distribution of cellular constituents such as proteins or DNA residues were identified and displayed by construction of two- and three-dimensional Raman maps. The resulting Raman images reflected the significant differences in nanoparticle uptake and intracellular storage of fibroblasts and macrophages. Furthermore, TiO2 nanomaterials could be characterized and the presence of rutile- and anatase-phase TiO2 were determined inside cells. Together, the data shown here prove that Raman spectroscopic imaging is a promising technique for studying the interaction of nanomaterials with living cells and for differentiating intracellular nanoparticles from those localized on the cell membrane. The technology provides a label-free, non-destructive, material-specific analysis of whole cells with high spatial resolution, along with additional information on the current status of the material properties.

  10. Silicon nanocrystals with high boron and phosphorus concentration hydrophilic shell—Raman scattering and X-ray photoelectron spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Minoru, E-mail: fujii@eedept.kobe-u.ac.jp; Sugimoto, Hiroshi; Hasegawa, Masataka; Imakita, Kenji [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-02-28

    Boron (B) and phosphorus (P) codoped silicon (Si) nanocrystals, which exhibit very wide range tunable luminescence due to the donor to acceptor transitions and can be dispersed in polar liquids without organic ligands, are studied by Raman scattering and X-ray photoelectron spectroscopies. Codoped Si nanocrystals exhibit a Raman spectrum significantly different from those of intrinsic ones. First, the Raman peak energy is almost insensitive to the size and is very close to that of bulk Si crystal in the diameter range of 2.7 to 14 nm. Second, the peak is much broader than that of intrinsic ones. Furthermore, an additional broad peak, the intensity of which is about 20% of the main peak, appears around 650 cm{sup −1}. The peak can be assigned to local vibrational modes of substitutional B and B-P pairs, B clusters, B-interstitial clusters, etc. in Si crystal. The Raman and X-ray photoelectron spectroscopic studies suggest that a crystalline shell heavily doped with these species is formed at the surface of a codoped Si nanocrystal and it induces the specific properties, i.e., hydrophilicity, high-stability in water, high resistance to hydrofluoric acid, etc.

  11. Raman and surface enhanced Raman spectroscopic studies of specific, small molecule activator of histone acetyltransferase p300

    Science.gov (United States)

    Kundu, Partha P.; Pavan Kumar, G. V.; Mantelingu, Kempegowda; Kundu, Tapas K.; Narayana, Chandrabhas

    2011-07-01

    We report for the first time, the Raman and surface enhanced Raman scattering (SERS) studies of N-(4-chloro-3-trifluoromethyl-phenyl)-2-ethoxy-benzamide (CTB). This molecule is specific activator of human histone acetyltransferase (HAT), p300, and serves as lead molecule to design anti-neoplastic therapeutics. A detailed Raman and SERS band assignments have been performed for CTB, which are compared with the density functional theory calculations. The observed red shift of N sbnd H stretching frequency from the computed wavenumber indicates the weakening of N sbnd H bond resulting from proton transfer to the neighboring oxygen atom. We observe Ag sbnd N vibrational mode at 234 cm -1 in SERS of CTB. This indicates there is a metal-molecule bond leading to chemical enhancement in SERS. We also observe, enhancement in the modes pertaining to substituted benzene rings and methyl groups. Based on SERS analysis we propose the adsorption sites and the orientation of CTB on silver surface.

  12. Raman Spectroscopy and Related Techniques in Biomedicine

    Directory of Open Access Journals (Sweden)

    Alistair Elfick

    2010-03-01

    Full Text Available In this review we describe label-free optical spectroscopy techniques which are able to non-invasively measure the (biochemistry in biological systems. Raman spectroscopy uses visible or near-infrared light to measure a spectrum of vibrational bonds in seconds. Coherent anti-Stokes Raman (CARS microscopy and stimulated Raman loss (SRL microscopy are orders of magnitude more efficient than Raman spectroscopy, and are able to acquire high quality chemically-specific images in seconds. We discuss the benefits and limitations of all techniques, with particular emphasis on applications in biomedicine—both in vivo (using fiber endoscopes and in vitro (in optical microscopes.

  13. Nonlinear optical imaging and Raman microspectrometry of the cell nucleus throughout the cell cycle.

    Science.gov (United States)

    Pliss, Artem; Kuzmin, Andrey N; Kachynski, Aliaksandr V; Prasad, Paras N

    2010-11-17

    Fundamental understanding of cellular processes at molecular level is of considerable importance in cell biology as well as in biomedical disciplines for early diagnosis of infection and cancer diseases, and for developing new molecular medicine-based therapies. Modern biophotonics offers exclusive capabilities to obtain information on molecular composition, organization, and dynamics in a cell by utilizing a combination of optical spectroscopy and optical imaging. We introduce here a combination of Raman microspectrometry, together with coherent anti-Stokes Raman scattering (CARS) and two-photon excited fluorescence (TPEF) nonlinear optical microscopy, to study macromolecular organization of the nucleus throughout the cell cycle. Site-specific concentrations of proteins, DNA, RNA, and lipids were determined in nucleoli, nucleoplasmic transcription sites, nuclear speckles, constitutive heterochromatin domains, mitotic chromosomes, and extrachromosomal regions of mitotic cells by quantitative confocal Raman microspectrometry. A surprising finding, obtained in our study, is that the local concentration of proteins does not increase during DNA compaction. We also demonstrate that postmitotic DNA decondensation is a gradual process, continuing for several hours. The quantitative Raman spectroscopic analysis was corroborated with CARS/TPEF multimodal imaging to visualize the distribution of protein, DNA, RNA, and lipid macromolecules throughout the cell cycle.

  14. Raman spectroscopic characterization of ZrO2 and yttrium stabilized zirconias

    DEFF Research Database (Denmark)

    Kjerulf-Jensen, N.; Berg, Rolf W.; Poulsen, Finn Willy

    1996-01-01

    forward. The spectral features of the Raman spectra do furthermore not only depend on the phase composition, but also depend on the frequency of the excitation, temperature of experiment and texture/orientation of zirconia crystallites under investigation. These effects are illustrated by Raman spectra...

  15. Raman spectroscopic characterization of the core-rim structure in reaction bonded boron carbide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Jannotti, Phillip; Subhash, Ghatu, E-mail: subhash@ufl.edu [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States); Zheng, James Q.; Halls, Virginia [Program Executive Office—Soldier Protection and Individual Equipment, US Army, Fort Belvoir, Virginia 22060 (United States); Karandikar, Prashant G.; Salamone, S.; Aghajanian, Michael K. [M-Cubed Technologies, Inc., Newark, Delaware 19711 (United States)

    2015-01-26

    Raman spectroscopy was used to characterize the microstructure of reaction bonded boron carbide ceramics. Compositional and structural gradation in the silicon-doped boron carbide phase (rim), which develops around the parent boron carbide region (core) due to the reaction between silicon and boron carbide, was evaluated using changes in Raman peak position and intensity. Peak shifting and intensity variation from the core to the rim region was attributed to changes in the boron carbide crystal structure based on experimental Raman observations and ab initio calculations reported in literature. The results were consistent with compositional analysis determined by energy dispersive spectroscopy. The Raman analysis revealed the substitution of silicon atoms first into the linear 3-atom chain, and then into icosahedral units of the boron carbide structure. Thus, micro-Raman spectroscopy provided a non-destructive means of identifying the preferential positions of Si atoms in the boron carbide lattice.

  16. Spectroscopic detection of chemotherapeutics and antioxidants

    Science.gov (United States)

    Latka, Ines; Grüner, Roman; Matthäus, Christian; Dietzek, Benjamin; Werncke, W.; Lademann, Jürgen; Popp, Jürgen

    2012-06-01

    The hand-foot-syndrome presents a severe dermal side-effect of chemotherapeutic cancer treatment. The cause of this side-effect is the elimination of systemically administered chemotherapeutics with the sweat. Transported to the skin surface, the drugs subsequently penetrate into the skin in the manner of topically applied substances. Upon accumulation of the chemotherapeutics in the skin the drugs destroy cells and tissue - in the same way as they are supposed to act in cancer cells. Aiming at the development of strategies to illuminate the molecular mechanism underlying the handfoot- syndrome (and, in a second step, strategies to prevent this severe side-effect), it might be important to evaluate the concentration and distribution of chemotherapeutics and antioxidants in the human skin. The latter can be estimated by the carotenoid concentration, as carotenoids serve as marker substances for the dermal antioxidative status.Following the objectives outlined above, this contribution presents a spectroscopic study aiming at the detection and quantification of carotenoids and selected chemotherapeutics in human skin. To this end, spontaneous Raman scattering and coherent anti-Stokes Raman scattering (CARS) microspectroscopy are combined with two-photon excited fluorescence. While the latter technique is Please verify that (1) all pages are present, (2) all figures are correct, (3) all fonts and special characters are correct, and (4) all text and figures fit within the red margin lines shown on this review document. Complete formatting information is available at http://SPIE.org/manuscripts Return to your MySPIE To Do List at http://myspie.org and approve or disapprove this submission. Your manuscript will not be published without this approval.restricted to the detection of fluorescent chemotherapeutics, e.g., doxorubicin, the vibrational spectroscopic techniques can - in principle - be applied to any type of analyte molecules. Furthermore, we will present the

  17. Raman spectroscopic detection of early stages in DMBA-induced tumor evolution in hamster buccal pouch model: an exploratory study

    Science.gov (United States)

    Ghanate, Avinash D.; Kumar, G.; Talathi, Sneha; Maru, G. B.; Krishna, C. Murali

    2011-08-01

    Oral cancers are the serious health problem in developing as well as developed world, and more so in India and other south Asian countries. Survival rate of these cancers, despite advances in treatment modalities are one of the poorest which is attributed to lack of reliable screening and early detection methods. The hamster buccal pouch (HBP)carcinogenesis model closely mimics human oral cancers. Optical spectroscopy methods are sensitive enough to detect subtle biochemical changes and thus hold great potential in early detection of cancers. However, efficacy of these techniques in classifying of sequential evolution of tumors has never been tested. Therefore, in this study, we have explored the feasibility of Raman spectroscopic classification of different stages of cancers in hamster model. Strong vibrational modes of lipids (1440, 1654, and 1746 cm-1) are seen in control tissue spectra, whereas strong protein bands are seen in spectra of DMBA treated tissues. These differences were exploited to classify control and treated tissues using Linear Discriminant Analysis (LDA), Principle Component Analysis (PCA)-Limit test, Factorial Discriminant Analysis (FDA), Quadratic Discriminant Analysis (QDA), PLS-DA and non- linear decision tree methods. All these techniques have shown good classification between spectra of different stages of tumor evolution and results were further successfully verified by leave-one-out and single blinded methods. Thus findings of this study, first of its kind,demonstrate the feasibility of Raman spectroscopic detection of early changes in tumor evolution.

  18. Laser Cooling Using Anti-Stokes Fluorescencein Yb3+-Doped Fluorozirconate Glasses

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The fluorozirconate glasses ZBLANP( ZrF4-BaF2-LaF3-AlF3-NaF-PbF2) doped with different Yb3+ concentration were prepared. The Raman spectra and absorption spectra are measured to substantiate the existence of phonon-assisted emission. After analyzing the normalized absorption spectra of samples with different Yb3+-doped concentration, we calculated the maximum cooling effect in the 3 wt% Yb3+-doped sample pumped at 1 012.5 nm. The corresponding cooling capability is about -4.09 ℃/W and the cooling efficiency reaches 1.76%.

  19. Confocal Raman spectroscopic analysis of cross-linked ultra-high molecular weight polyethylene for application in artificial hip joints.

    Science.gov (United States)

    Pezzotti, Giuseppe; Kumakura, Tsuyoshi; Yamada, Kiyotaka; Tateiwa, Toshiyuki; Puppulin, Leonardo; Zhu, Wenliang; Yamamoto, Kengo

    2007-01-01

    Confocal spectroscopic techniques are applied to selected Raman bands to study the microscopic features of acetabular cups made of ultra-high molecular weight polyethylene (UHMWPE) before and after implantation in vivo. The micrometric lateral resolution of a laser beam focused on the polymeric surface (or subsurface) enables a highly resolved visualization of 2-D conformational population patterns, including crystalline, amorphous, orthorhombic phase fractions, and oxidation index. An optimized confocal probe configuration, aided by a computational deconvolution of the optical probe, allows minimization of the probe size along the in-depth direction and a nondestructive evaluation of microstructural properties along the material subsurface. Computational deconvolution is also attempted, based on an experimental assessment of the probe response function of the polyethylene Raman spectrum, according to a defocusing technique. A statistical set of high-resolution microstructural data are collected on a fully 3-D level on gamma-ray irradiated UHMWPE acetabular cups both as-received from the maker and after retrieval from a human body. Microstructural properties reveal significant gradients along the immediate material subsurface and distinct differences are found due to the loading history in vivo, which cannot be revealed by conventional optical spectroscopy. The applicability of the confocal spectroscopic technique is valid beyond the particular retrieval cases examined in this study, and can be easily extended to evaluate in-vitro tested components or to quality control of new polyethylene brands. Confocal Raman spectroscopy may also contribute to rationalize the complex effects of gamma-ray irradiation on the surface of medical grade UHMWPE for total joint replacement and, ultimately, to predict their actual lifetime in vivo.

  20. Multiferroic CuCrO₂ under high pressure: In situ X-ray diffraction and Raman spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Alka B., E-mail: alkagarg@barc.gov.in; Mishra, A. K.; Pandey, K. K.; Sharma, Surinder M. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-10-07

    The compression behavior of delafossite compound CuCrO₂ has been investigated by in situ x-ray diffraction (XRD) and Raman spectroscopic measurements up to 23.2 and 34 GPa, respectively. X-ray diffraction data show the stability of ambient rhombohedral structure up to ~23 GPa. Material shows large anisotropy in axial compression with c-axis compressibility, κ{sub c} = 1.26 × 10⁻³(1) GPa⁻¹ and a-axis compressibility, κ{sub a} = 8.90 × 10⁻³(6) GPa⁻¹. Our XRD data show an irreversible broadening of diffraction peaks. Pressure volume data when fitted to 3rd order Birch-Murnaghan equation of state give the value of bulk modulus, B₀ = 156.7(2.8) GPa with its pressure derivative, B₀{sup ’} as 5.3(0.5). All the observed vibrational modes in Raman measurements show hardening with pressure. Appearance of a new mode at ~24 GPa indicates the structural phase transition in the compound. Our XRD and Raman results indicate that CuCrO{sub 2} may be transforming to an ordered rocksalt type structure under compression.

  1. FT-IR and Micro-Raman spectroscopic studies of archaeological potteries recently excavated in Poompuhar, Tamilnadu, India

    Science.gov (United States)

    Kiruba, S.; Ganesan, S.

    2015-06-01

    Ancient ceramics are the abundant artifacts that give the knowledge of the past societies. Therefore it is of great importance to acquire knowledge about the chemical composition of the clay in archaeological artifacts. The spectroscopic techniques represent one of the most powerful tools to investigate the structure of all the materials and chemical composition of the cultural object like potteries. An attempt has been made in the present work to estimate the firing temperature of the archaeological pottery shreds excavated from the archaeological site Poompuhar in the state of Tamilnadu in India. The firing temperature of the archaeological pottery shreds were estimated by recording the corresponding FT-IR spectra in the range 4000-450 cm-1 and Micro Raman spectra in the range 1800-400 cm-1. The clay mineral present in the pottery samples are identified through FT-IR method and was confirmed with Micro Raman spectroscopy as both are complement to each other. The major primary mineral present in the samples is Kaolinite and the secondary mineral present is quartz and the accessory minerals present in the samples are hematite, magnetite and feldspar. The results of Raman spectra showed that the potters of this site used a mixture of clays as raw materials. The firing temperature for some of the samples did not exceed 800 °C which suggests the use of open fire.

  2. High-Speed Coherent Raman Fingerprint Imaging of Biological Tissues

    CERN Document Server

    Camp, Charles H; Heddleston, John M; Hartshorn, Christopher M; Walker, Angela R Hight; Rich, Jeremy N; Lathia, Justin D; Cicerone, Marcus T

    2014-01-01

    We have developed a coherent Raman imaging platform using broadband coherent anti-Stokes Raman scattering (BCARS) that provides an unprecedented combination of speed, sensitivity, and spectral breadth. The system utilizes a unique configuration of laser sources that probes the Raman spectrum over 3,000 cm$^{-1}$ and generates an especially strong response in the typically weak Raman "fingerprint" region through heterodyne amplification of the anti-Stokes photons with a large nonresonant background (NRB) while maintaining high spectral resolution of $<$ 13 cm$^{-1}$. For histology and pathology, this system shows promise in highlighting major tissue components in a non-destructive, label-free manner. We demonstrate high-speed chemical imaging in two- and three-dimensional views of healthy murine liver and pancreas tissues and interfaces between xenograft brain tumors and the surrounding healthy brain matter.

  3. A microfluidic surface enhanced Raman spectroscopic biosensor using aptamer functionalized nanopillars

    DEFF Research Database (Denmark)

    Yang, J.; Palla, M.; Bosco, F. G.

    2013-01-01

    This paper presents a microchip incorporating an aptamer-functionalized nanopillar substrate, enabling the specific detection of low-abundance biomolecules using surface enhanced Raman spectroscopy (SERS). In a temperature controlled microchamber, aptamers immobilized on the nanostructure surface...

  4. A Raman spectroscopic study of arsenite and thioarsenite species in aqueous solution at 25°C

    Directory of Open Access Journals (Sweden)

    Janecky David R

    2002-02-01

    Full Text Available The Raman spectra of thioarsenite and arsenite species in aqueous solution were obtained at room temperature. Solutions at constant ΣAs + ΣS of 0.1 and 0.5 mol kg-1 were prepared with various ΣS/ΣAs ratios (0.1–9.0 and pH values (~7–13.2. Our data suggest that the speciation of As under the conditions investigated is more complicated than previously thought. The Raman measurements offer evidence for at least six separate S-bearing As species whose principal bands are centered near 365, 385, 390, 400, 415 and 420 cm-1. The data suggest that at least two different species may give rise to bands at 385 cm-1, bringing the probable minimum number of species to seven. Several additional species are possible but could not be resolved definitively. In general, the relative proportions of these species are dependent on total As concentration, ΣS/ΣAs ratio and pH. At very low ΣS/ΣAs ratios we also observe Raman bands attributable to the dissociation products of H3AsO3(aq. Although we were unable to assign precise stoichiometries for the various thioarsenite species, we were able to map out general pH and ΣS/ΣAs conditions under which the various thioarsenite and arsenite species are predominant. This study provides a basis for more detailed Raman spectroscopic and other types of investigations of the nature of thioarsenite species.

  5. A pH dependent Raman and surface enhanced Raman spectroscopic studies of citrazinic acid aided by theoretical calculations

    Science.gov (United States)

    Sarkar, Sougata; Chowdhury, Joydeep; Dutta, Soumen; Pal, Tarasankar

    2016-12-01

    A pH dependent normal Raman scattering (NRS) and surface enhanced Raman scattering (SERS) spectral patterns of citrazinic acid (CZA), a biologically important molecule, have been investigated. The acid, with different pKa values (~ 4 and ~ 11) for the two different functional groups (-COOH and -OH groups), shows interesting range of color changes (yellow at pH ~ 14 and brown at pH ~ 2) with the variation in solution pH. Thus, depending upon the pH of the medium, CZA molecule can exist in various protonated and/or deprotonated forms. Here we have prescribed the existence different possible forms of CZA at different pH (Forms "C", "H" and "Dprot" at pH ~ 14 and Forms "A", "D", and "P" at pH ~ 2 respectively). The NRS spectra of these solutions and their respective SERS spectra over gold nanoparticles were recorded. The spectra clearly differ in their spectral profiles. For example the SERS spectra recorded with the CZA solution at pH ~ 2 shows blue shift for different bands compared to its NRS window e.g. 406 to 450 cm- 1, 616 to 632 cm- 1, 1332 to 1343 cm- 1 etc. Again, the most enhanced peak at ~ 1548 cm- 1 in NRS while in the SERS window this appears at ~ 1580 cm- 1. Similar observation was also made for CZA at pH ~ 14. For example, the 423 cm- 1 band in the NRS profile experience a blue shift and appears at ~ 447 cm- 1 in the SERS spectrum as well as other bands at ~ 850, ~ 1067 and ~ 1214 cm- 1 in the SERS window are markedly enhanced. It is also worth noting that the SERS spectra at the different pH also differ from each other. These spectral differences indicate the existence of various adsorptive forms of the CZA molecule depending upon the pH of the solution. Therefore based on the experimental findings we propose different possible molecular forms of CZA at different pH (acidic and alkaline) conditions. For example forms 'A', 'D' and 'P' existing in acidic pH (pH ~ 2) and three other deprotonated forms 'C', 'H' and 'Dprot' in alkaline pH (pH ~ 14). The DFT

  6. Glass transition of polystyrene (PS) studied by Raman spectroscopic investigation of its phenyl functional groups

    Science.gov (United States)

    Bertoldo Menezes, D.; Reyer, A.; Marletta, A.; Musso, M.

    2017-01-01

    In polymeric materials the glass transition (GT) is a well-known and very important relaxation process related to movements of functional groups in the polymeric chain. In this work, we show the potential of Raman spectroscopy for exploring the GT process in the polymer polystyrene. We collected Raman spectra during a step-by-step heating process of the sample, which allowed us to collect signatures of the GT process from peak parameters of specific vibrational modes, and to verify the GT temperature. Results of the latter were in accordance with published values obtained via other methods. We identified the aromatic ring vibrational modes of the phenyl functional groups to be those which, due to steric hindrance, suffer the largest influence during the GT process. This confirms that Raman spectroscopy can be used as a complementary technique to perform GT investigations in polymeric materials due to its sensitivity to small intermolecular changes affecting vibrational properties of relevant functional side groups.

  7. Raman spectroscopic study of amorphous and crystalline hydrocarbons from soils, peats and lignite

    Energy Technology Data Exchange (ETDEWEB)

    Jehlicka, J.; Edwards, H.G.M.; Villar, S.E.J.; Pokorny, J. [Charles University, Prague (Czech Republic). Inst. for Geochemical Mineral & Mineral Resources

    2005-08-01

    FT-Raman spectra were obtained from the natural hydrocarbon mixtures ozokerite and hatchettite as well as from the terpenoid minerals fichtelite (norabietane) and hartite (alpha-phyllocladane). Some of these hydrocarbons occur in soil and peat environments of Holocene age. However, hartite occurs in lignite, in fossilised Glyptostrobus (Taxodiaceae) trees and in pelosiderites of the Bilina Miocene series (about 20 Ma); it represents the accumulated and crystallised product of diagenetic transformation of precursor biogenic terpenoids. Raman spectra of earth waxes investigated confirm their dominantly aliphatic character and oxidative degradation (related to weathering and/or subaerial alteration in museum cabinets). Vibrational assignments are proposed and differences in Raman spectra of fichtelite and hartite discussed. Some of the individual features can be used for discrimination (e.g., hartite bands at 1480, 1310, 1287, 1041, 729 and 693 cm{sup -1} and fichtelite bands at 1302, 836, 717 and 533 cm{sup -1}).

  8. Raman spectroscopic study of acute oxidative stress induced changes in mice skeletal muscles

    Science.gov (United States)

    Sriramoju, Vidyasagar; Alimova, Alexandra; Chakraverty, Rahul; Katz, A.; Gayen, S. K.; Larsson, L.; Savage, H. E.; Alfano, R. R.

    2008-02-01

    The oxidative stress due to free radicals is implicated in the pathogenesis of tissue damage in diseases such as muscular dystrophy, Alzheimer dementia, diabetes mellitus, and mitochrondrial myopathies. In this study, the acute oxidative stress induced changes in nicotinamide adenine dinucleotides in mouse skeletal muscles are studied in vitro using Raman spectroscopy. Mammalian skeletal muscles are rich in nicotinamide adenine dinucleotides in both reduced (NADH) and oxidized (NAD) states, as they are sites of aerobic and anaerobic respiration. The relative levels of NAD and NADH are altered in certain physiological and pathological conditions of skeletal muscles. In this study, near infrared Raman spectroscopy is used to identify the molecular fingerprints of NAD and NADH in five-week-old mice biceps femoris muscles. A Raman vibrational mode of NADH is identified in fresh skeletal muscle samples suspended in buffered normal saline. In the same samples, when treated with 1% H IIO II for 5 minutes and 15 minutes, the Raman spectrum shows molecular fingerprints specific to NAD and the disappearance of NADH vibrational bands. The NAD bands after 15 minutes were more intense than after 5 minutes. Since NADH fluoresces and NAD does not, fluorescence spectroscopy is used to confirm the results of the Raman measurements. Fluorescence spectra exhibit an emission peak at 460 nm, corresponding to NADH emission wavelength in fresh muscle samples; while the H IIO II treated muscle samples do not exhibit NADH fluorescence. Raman spectroscopy may be used to develop a minimally invasive, in vivo optical biopsy method to measure the relative NAD and NADH levels in muscle tissues. This may help to detect diseases of muscle, including mitochondrial myopathies and muscular dystrophies.

  9. Raman spectroscopic evaluation of meat batter structural changes induced by thermal treatment and salt addition.

    Science.gov (United States)

    Herrero, A M; Carmona, P; López-López, I; Jiménez-Colmenero, F

    2008-08-27

    Raman spectroscopy, texture, proximate composition, and water binding analysis were carried out to evaluate the effect of thermal treatment and/or salt addition to meat batter. For this purpose, different meat batters were elaborated: control meat batter (no salt) and meat batters with low (1.0%) and high (2.5%) NaCl content with and without thermal treatment (70 degrees C/30 min). Increase (P batter. Raman spectroscopy analysis revealed a significant (P batter. In this way, a significant correlation was found between beta-sheets, salt content, hardness, and chewiness in heated samples.

  10. Vibrational Raman spectroscopic study of scytonemin, the UV-protective cyanobacterial pigment

    Science.gov (United States)

    Edwards, H. G. M.; Garcia-Pichel, F.; Newton, E. M.; Wynn-Williams, D. D.

    2000-01-01

    The Raman spectrum of the photoprotective pigment scytonemin found in cyanobacterial sheaths has been obtained for the first time. Its skeletal structure is extensively conjugated and unique in nature. Detailed molecular vibrational assignments are proposed and a distinctive group of four corroborative vibrational bands have been identified as unique indicators for the compound. These bands, especially a prominent feature at wavenumber 1590 cm -1, are sufficiently conspicuous to be detectable in the mixed biomolecular pools of undisturbed natural microbial communities. This has been confirmed by demonstrating the Raman spectral bands for scytonemin in a sample of an intact intertidal cyanobacterial mat.

  11. Raman Spectroscopic Study of the Vapour Phase of 1-Methylimidazolium Ethanoate, a Protic Ionic Liquid

    DEFF Research Database (Denmark)

    Berg, Rolf W.; Canongia Lopes, Jose N.; Ferreira, Rui;

    2010-01-01

    The gas phase over the ionic liquid 1-methylimidazolium ethanoate, [Hmim][O2CCH3], was studied by means of Raman spectroscopy. Raman spectra are presented, the species in the gas phase are identified, and their bands are assigned. The results are interpreted using ab initio quantum mechanical cal...... calculations that also predict vibrational spectra. The obtained data reinforce a previous interpretation, based on FT-ICR mass spectrometric data, that the vapor phase over [Hmim][O2CCH3] consists predominantly of two neutral molecules, monomeric ethanoic acid and 1-methylimidazole....

  12. Structure, spectra and antioxidant action of ascorbic acid studied by density functional theory, Raman spectroscopic and nuclear magnetic resonance techniques.

    Science.gov (United States)

    Singh, Gurpreet; Mohanty, B P; Saini, G S S

    2016-02-15

    Structure, vibrational and nuclear magnetic resonance spectra, and antioxidant action of ascorbic acid towards hydroxyl radicals have been studied computationally and in vitro by ultraviolet-visible, nuclear magnetic resonance and vibrational spectroscopic techniques. Time dependant density functional theory calculations have been employed to specify various electronic transitions in ultraviolet-visible spectra. Observed chemical shifts and vibrational bands in nuclear magnetic resonance and vibrational spectra, respectively have been assigned with the help of calculations. Changes in the structure of ascorbic acid in aqueous phase have been examined computationally and experimentally by recording Raman spectra in aqueous medium. Theoretical calculations of the interaction between ascorbic acid molecule and hydroxyl radical predicted the formation of dehydroascorbic acid as first product, which has been confirmed by comparing its simulated spectra with the corresponding spectra of ascorbic acid in presence of hydrogen peroxide.

  13. Structure, spectra and antioxidant action of ascorbic acid studied by density functional theory, Raman spectroscopic and nuclear magnetic resonance techniques

    Science.gov (United States)

    Singh, Gurpreet; Mohanty, B. P.; Saini, G. S. S.

    2016-02-01

    Structure, vibrational and nuclear magnetic resonance spectra, and antioxidant action of ascorbic acid towards hydroxyl radicals have been studied computationally and in vitro by ultraviolet-visible, nuclear magnetic resonance and vibrational spectroscopic techniques. Time dependant density functional theory calculations have been employed to specify various electronic transitions in ultraviolet-visible spectra. Observed chemical shifts and vibrational bands in nuclear magnetic resonance and vibrational spectra, respectively have been assigned with the help of calculations. Changes in the structure of ascorbic acid in aqueous phase have been examined computationally and experimentally by recording Raman spectra in aqueous medium. Theoretical calculations of the interaction between ascorbic acid molecule and hydroxyl radical predicted the formation of dehydroascorbic acid as first product, which has been confirmed by comparing its simulated spectra with the corresponding spectra of ascorbic acid in presence of hydrogen peroxide.

  14. Alkali metal salts of rutin - Synthesis, spectroscopic (FT-IR, FT-Raman, UV-VIS), antioxidant and antimicrobial studies.

    Science.gov (United States)

    Samsonowicz, M; Kamińska, I; Kalinowska, M; Lewandowski, W

    2015-12-05

    In this work several metal salts of rutin with lithium, sodium, potassium, rubidium and cesium were synthesized. Their molecular structures were discussed on the basis of spectroscopic (FT-IR, FT-Raman, UV-VIS) studies. Optimized geometrical structure of rutin was calculated by B3LYP/6-311++G(∗∗) method and sodium salt of rutin were calculated by B3LYP/LanL2DZ method. Metal chelation change the biological properties of ligand therefore the antioxidant (FRAP and DPPH) and antimicrobial activities (toward Escherichia coli, Staphylococcus aureus, Enterococcus faecium, Proteus vulgaris, Pseudomonas aeruginosa, Klebsiella pneumonia, Candida albicans and Saccharomyces cerevisiae) of alkali metal salts were evaluated and compared with the biological properties of rutin.

  15. Raman spectroscopic investigations on the interactions of gastric cancer cells with 5-fluorouracil

    Institute of Scientific and Technical Information of China (English)

    Jianyu Guo; Weiying Cai; Jipeng Yang; Zhenrong Sun

    2008-01-01

    To study the efficacy and side effects of antitumor drug by the method of Raman spectroscopy, the cancerous (SGC-7901) and normal (GES-1) gastric cells were treated with 0, 25-, 100-, and 200-mg/L 5-fluorouracil (5-Fu) for 24 h, respectively, then Raman spectra of cells were recorded. The excitation wavelength was 514.5 nm and the Raman spectra in the region of 500 - 1800 cm-1 were recorded. For the gastric cancer cells, as the concentration of 5-Fu increases, the band at 1094 cm-1 attributed to the symmetric stretching vibration mode of PO2- in the DNA backbone gradually decreases, and the intensity ratio of the band at 1315 cm-1 to that at 1340 cm-1 (I1315/I1340) shows the ascending trend, and the ratio of the band area at 1655 cm-1 to that at 1450 cm-1 (A1655/A1450) shows the slight ascending trend. For the normal gastric cells, these peaks also appear changes, however, the changes are weaker than those for the cancer cells. In SGC-7901 cells, 5-Fu can interfere with the DNA synthesis and result in the reduction of the DNA content. Besides, it can affect the unsaturation degree of the hydrocarbon chains and alter the external environment of guanine and adenine residues in cancer cells. The changes of Raman spectra for normal gastric cells reveal the side effect of 5-Fu.

  16. High-pressure measuring cell for Raman spectroscopic studies of natural gas

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

    2001-01-01

    to detect hydrogen sulfide at concentrations of 1-3 mg H2S/Nm(3). An attempt to make a quantitative analysis of natural gas by the so-called "ratio method" is presented. In addition to this, the relative normalized differential Raman scattering cross sections for ethane and i-butane molecules at 8.0 MPa...

  17. Removal of Aqueous Boron by Using Complexation of Boric Acid with Polyols: A Raman Spectroscopic Study

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Ki Heon; Jeong, Hui Cheol; An, Hye Young; Lim, Jun-Heok; Lee, Jea-Keun; Won, Yong Sun [Pukyong National University, Busan (Korea, Republic of)

    2015-12-15

    Boron is difficult to be removed from seawater by simple RO (reverse osmosis) membrane process, because the size of boric acid (B(OH){sub 3}), the major form of aqueous boron, is as small as the nominal pore size of RO membrane. Thus, the complexation of boric acid with polyols was suggested as an alternative way to increase the size of aqueous boron compounds and the complexation behavior was investigated with Raman spectroscopy. As a reference, the Raman peak for symmetric B-O stretching vibrational mode both in boric acid and borate ion (B(OH){sub 4}{sup -}) was selected. A Raman peak shift (877 cm{sup -1} →730 cm{sup -1}) was observed to confirm that boric acid in water is converted to borate ion as the pH increases, which is also correctly predicted by frequency calculation. Meanwhile, the Raman peak of borate ion (730 cm{sup -1}) did not appear as the pH increased when polyols were applied into aqueous solution of boric acid, suggesting that the boric acid forms complexing compounds by combining with polyols.

  18. A micro-Raman spectroscopic investigation of leukemic U-937 cells in aged cultures

    Science.gov (United States)

    Fazio, Enza; Trusso, Sebastiano; Franco, Domenico; Nicolò, Marco Sebastiano; Allegra, Alessandro; Neri, Fortunato; Musolino, Caterina; Guglielmino, Salvatore P. P.

    2016-04-01

    Recently it has been shown that micro-Raman spectroscopy combined with multivariate analysis is able to discriminate among different types of tissues and tumoral cells by the detection of significant alterations and/or reorganizations of complex biological molecules, such as nucleic acids, lipids and proteins. Moreover, its use, being in principle a non-invasive technique, appears an interesting clinical tool for the evaluation of the therapeutical effects and of the disease progression. In this work we analyzed molecular changes in aged cultures of leukemia model U937 cells with respect to fresh cultures of the same cell line. In fact, structural variations of individual neoplastic cells on aging may lead to a heterogeneous data set, therefore falsifying confidence intervals, increasing error levels of analysis and consequently limiting the use of Raman spectroscopy analysis. We found that the observed morphological changes of U937 cells corresponded to well defined modifications of the Raman contributions in selected spectral regions, where markers of specific functional groups, useful to characterize the cell state, are present. A detailed subcellular analysis showed a change in cellular organization as a function of time, and correlated to a significant increase of apoptosis levels. Besides the aforementioned study, Raman spectra were used as input for principal component analysis (PCA) in order to detect and classify spectral changes among U937 cells.

  19. FT-Raman, FT-IR spectroscopic and DFT studies of hexaphenoxycyclotriphosphazene

    Science.gov (United States)

    Furer, V. L.; Vandyukov, A. E.; Padie, C.; Majoral, J. P.; Caminade, A. M.; Kovalenko, V. I.

    2016-07-01

    The FTIR and FT Raman measurements of zero Gc0‧ -H and first Gc1‧ -H generations of phosphorus dendrimer built from cyclotriphosphazene core with phenoxy and deuterophenoxy terminal groups have been performed. In order to evaluate how much the frequencies, shift when changing the electronics of the system the FTIR and FT Raman spectra of phosphorus‒containing dendron with five terminal oxybenzaldehyde and one ester function Gci‧ have been also studied. Structural optimization and normal mode analysis were obtained for Gc0‧ -H and Gc0‧ -D by the density functional theory (DFT). It is discovered that dendrimer molecule exists in a stable conformation with six phenoxy terminal groups spaced above and below the flat cyclotriphosphazene core. Optimized geometric bond length and angles obtained by DFT show good agreement with a previously-published X-ray study. The phenoxy terminal groups are characterized by the well-defined line at 993 cm-1 in the experimental Raman spectrum of Gc0‧ -H and by line at 960 cm-1 in the Raman spectrum of Gc0‧ -D. Relying on DFT calculations a complete vibrational assignment is proposed for the studied dendrimers. The frequencies and relative intensity of the bands at 1589, 1487 cm-1 in the IR spectra show marked difference in dependence of the substituents on the aromatic ring.

  20. Raman spectroscopic investigation of spinal cord injury in a rat model

    Science.gov (United States)

    Saxena, Tarun; Deng, Bin; Stelzner, Dennis; Hasenwinkel, Julie; Chaiken, Joseph

    2011-02-01

    Raman spectroscopy was used to study temporal molecular changes associated with spinal cord injury (SCI) in a rat model. Raman spectra of saline-perfused, injured, and healthy rat spinal cords were obtained and compared. Two injury models, a lateral hemisection and a moderate contusion were investigated. The net fluorescence and the Raman spectra showed clear differences between the injured and healthy spinal cords. Based on extensive histological and biochemical characterization of SCI available in the literature, these differences were hypothesized to be due to cell death, demyelination, and changes in the extracellular matrix composition, such as increased expression of proteoglycans and hyaluronic acid, at the site of injury where the glial scar forms. Further, analysis of difference spectra indicated the presence of carbonyl containing compounds, hypothesized to be products of lipid peroxidation and acid catalyzed hydrolysis of glycosaminoglycan moieties. These results compared well with in vitro experiments conducted on chondroitin sulfate sugars. Since the glial scar is thought to be a potent biochemical barrier to nerve regeneration, this observation suggests the possibility of using near infrared Raman spectroscopy to study injury progression and explore potential treatments ex vivo, and ultimately monitor potential remedial treatments within the spinal cord in vivo.

  1. Behavior of H(sub2)O and OH in lawsonite : a single crystal neutron diffraction and Raman spectroscopic investigation.

    Energy Technology Data Exchange (ETDEWEB)

    Kolesov, B. A.; Lager, G. A.; Schultz, A. J.; Russian Academy of Science; Univ. of Louisville

    2008-01-01

    Neutron diffraction and polarized single-crystal Raman spectroscopic measurements were made on the high-pressure silicate lawsonite, CaAl{sub 2}(Si{sub 2}O{sub 7})(OH){sub 2} {center_dot} H{sub 2}O, from Tiburon Peninsula, California. For the diffraction measurements, intensity reflection data were collected at temperatures of 295, 110 and 20 K using time-of-flight neutron diffraction methods to further examine two reversible, order-disorder type phase transitions occurring at 273 and 155 K [Cmcm (> 273 K) {yields} Pmcn (< 273 K) {yields} P2{sub 1}cn (< 155 K)]. These data are also used to model the H atom displacements in lawsonite as a function of temperature and to provide better insight into the nature of H bonding. The Raman spectroscopic measurements (2500 to 4000 cm{sup -1} at 4 {ge} T {ge} 300 K) were carried out on the same crystal used for the neutron diffraction study. Four OH-related bands are observed between 2700 and 3600 cm{sup -1}. The OH groups and H{sub 2}O molecules, which are linked by hydrogen bonding, build quasi one-dimensional chains in lawsonite, that run parallel to [001] and thus a model consisting of isolated oscillators cannot be used to interpret the spectra at ambient temperature. A notable feature of spectral behavior at 240-260 K in the vicinity of the Cmcm {leftrightarrow} Pmcn phase transition is the change-over of strong hydrogen bonding from the OH group to the H{sub 2}O molecule. The lowest-wavenumber OH(H{sub 2}O) band at 2780 cm{sup -1} at 4 K is broad and asymmetric, which is related to strong hydrogen bonding, and is characterized by strong anharmonicity. This band was deconvoluted into a number of combination modes consisting of an internal-H{sub 2}O and various external-H{sub 2}O vibrations.

  2. Raman Spectroscopic Characterisation of Australian Banded Iron Formation and Iron Ore

    Science.gov (United States)

    Wells, M. A.; Ramanaidou, E. R.

    2012-04-01

    In Australia and world-wide over the past 5-10 years, declining reserves of premium, high-grade (>64% Fe), low-P bearing iron ore, have seen iron ore producers increase their utilisation of lower Fe-grade, higher P/Al/Si ore. In Australia, the channel iron deposits (CID), bedded iron deposits (BID) and, more recently, BIF-derived magnetite iron deposits (MID) have seen increased usage driven mainly by the increased demand from Chinese steel mills (Ramanaidou and Wells, 2011). Efficient exploitation and processing of these lower-grade iron ores requires a detailed understanding of their iron oxide and gangue mineralogy and geochemistry. The common Fe-bearing minerals (e.g., hematite, magnetite, goethite and kenomagnetite) in these deposits, as well as gangue minerals such as quartz and carbonates, are all strongly Raman active (e.g., de Faria et al., 1997). Their distinct Raman spectra enable them to be easily detected and mapped in situ in either unprepared material or samples prepared as polished blocks. In this paper, using representative examples of Australian CID ore, martite-goethite bedded iron deposit (BID) ore and banded iron formation (BIF) examined as polished blocks, we present a range of Raman spectra of the key iron ore minerals, and discuss how Raman spectroscopy can be applied to characterising iron ore mineralogy. Raman imaging micrographs, obtained using a StreamLine Plus Raman imaging system, clearly identified the main Fe-oxide and gangue components in the CID, BID and BIF samples when compared to optical micrographs. Raman analysis enabled the unequivocal identification of diamond in the CID ore as a contaminant from the polishing paste used to prepare the sample, and confirmed the presence of hematite in the BID ore in the form of martite, which can be morphologically similar to magnetite and, thus, difficult to otherwise distinguish. Image analysis of Raman mineral maps could be used to quantify mineral abundance based on the number of 'pixels

  3. Resonance Raman Spectroscopic and Theoretical Study of Geometry Distortion of Thiourea in 21A State

    Institute of Scientific and Technical Information of China (English)

    Hai-bo Zhang; Yan-ying Zhao; Xu-ming Zheng

    2012-01-01

    The A-band resonance Raman spectra of thiourea were obtained in water and acetonitrile solution.B3LYP/6-311++G(3df,3pd) and RCIS/6-311++G(3df,3pd) calculations were done to elucidate the ultraviolet electronic transitions,the distorted geometry structure and the saddle point of thiourea in 21A excited state,respectively.The resonance Raman spectra were assigned.The absorption spectrum and resonance Raman intensities were modeled using Heller's time-dependent wavepacket approach to resonance Raman scattering.The results indicate that largest change in the displacement takes place with the C=S stretch mode v6 (|Δ|=0.95) and noticeable changes appear in the HsN3H6+H8N4H7 wag v5 (|Δ|=0.19),NCN symmetric stretch+C=S stretch+N3H6+H8N4 wag v4 (|Δ|=0.18),while the moderate intensities of 2v15 and 4v15 are mostly due to the large excited state frequency changes of v15,but not due to its significant change in the normal mode displacement.The mechanism of the appearance of even overtones of the S=CN2 out of plane deformation is explored.The results indicate that a Franck-Condon region saddle point is the driving force for the quadric phonon mechanism within the standard A-term of resonance Raman scattering,which leads to the pyramidalization of the carbon center and the geometry distortion of thiourea molecule in 21A excited state.

  4. Lichen biomarkers upon heating: a Raman spectroscopic study with implications for extra-terrestrial exploration

    Science.gov (United States)

    Miralles, I.; Capel Ferrón, C.; Hernández, V.; López-Navarrete, J. T.; Jorge-Villar, S. E.

    2017-01-01

    Lithopanspermia Theory has suggested that life was transferred among planets by meteorites and other rocky bodies. If the planet had an atmosphere, this transfer of life had to survive drastic temperature changes in a very short time in its entry or exit. Only organisms able to endure such a temperature range could colonize a planet from outer space. Many experiments are being carried out by NASA and European Space Agency to understand which organisms were able to survive and how. Among the suite of instruments designed for extraplanetary exploration, particularly for Mars surface exploration, a Raman spectrometer was selected with the main objective of looking for life signals. Among all attributes, Raman spectroscopy is able to identify organic and inorganic compounds, either pure or in admixture, without requiring sample manipulation. In this study, we used Raman spectroscopy to examine the lichen Squamarina lentigera biomarkers. We analyse spectral signature changes after sample heating under different experimental situations, such as (a) laser, (b) analysis accumulations over the same spot and (c) environmental temperature increase. Our goal is to evaluate the capability of Raman spectroscopy to identify unambiguously life markers even if heating has induced spectral changes, reflecting biomolecular transformations. Usnic acid, chlorophyll, carotene and calcium oxalates were identified by the Raman spectra. From our experiments, we have seen that usnic acid, carotene and calcium oxalates (the last two have been suggested to be good biomarkers) respond in a different way to environmental heating. Our main conclusion is that despite their abundance in nature or their inorganic composition the resistance to heat makes some molecules more suitable than others as biomarkers.

  5. Ring distributions in alkali- and alkaline-earth aluminosilicate framework glasses- a raman spectroscopic study

    Science.gov (United States)

    Sharma, S.K.; Philpotts, J.A.; Matson, D.W.

    1985-01-01

    Raman spectra of crystalline polymorphs of a number of tectosilicate minerals having various sizes of smallest rings of TO4 tetrahedra (T = Si, Al) have been investigated to identify the bands that are sensitive indicators of the smallest rings in the network. The information obtained from the Raman spectra of tectosilicate minerals (e.g., SiO2 polymorphs, NaAlSi3O8 (Ab), NaAlSiO4 (Ne), KAlSi3O8 (Or), and KAlSi2O6 (Lc)) is used to interpret the Raman spectra of the isochemical glasses. It is shown that the frequency of the dominant ??s (TOT) band in the spectra of both crystals and glasses is related to the dominant size of TO4 rings in the structure. In agreement with previous X-ray RDF work, it is found that in the glasses of Ab and Jd (NaAlSi2O6) compositions, six-membered rings of TO4 tetrahedra predominate. The Raman spectrum of Or glass, however, indicates that clusters of intermixed four- and six-membered rings of TO4 tetrahedra, similar to those existing in crystalline leucite, are also present in the glass. Raman evidence indicates that four-membered rings of TO4 tetrahedra predominate in the glass of An composition. Similarly, the higher frequency of the ??s (TOT) band in the spectrum of Ne glass as compared with the frequency the ??s (TOT) band in the spectra of crystalline cargenieite and nephelite indicates either an admixture of the four- and six-membered rings or the puckering of six-membered rings in the glass structure. ?? 1985.

  6. Chemometric evaluation of near infrared, fourier transform infrared, and Raman spectroscopic models for the prediction of nimodipine polymorphs.

    Science.gov (United States)

    Siddiqui, Akhtar; Rahman, Ziyaur; Sayeed, Vilayat A; Khan, Mansoor A

    2013-11-01

    The objective of this study was to assess the performance of the chemometric model to predict the proportion of the recrystallized polymorphs of nimodipine from the cosolvent formulations. Ranging from 100% to 0% (w/w) of polymorph I, the two polymorphs mixtures were prepared and characterized spectroscopically using Fourier transformed infrared spectroscopy (FTIR), near-infrared spectroscopy (NIR), and Raman spectroscopy. Instrumental responses were treated to construct multivariate calibration model using principal component regression (PCR) and partial least square regression approaches. Treated data showed better model fitting than without treatment, which demonstrated higher correlation coefficient (R(2) ) and lower root mean square of standard error (RMSE) and standard error (SE). Multiple scattering correction and standard normal variate exhibited higher R(2) and lower RMSE and SE values than second derivative. Goodness of fit for FTIR and NIR (R(2) ∼ 0.99) data was better than Raman (R(2) ∼ 0.95). Furthermore, the models were applied on the recrystallized polymorphs obtained by storing nimodipine-cosolvent formulations at selected stability conditions. The relative composition of the polymorphs differed with storage conditions. NIR-chemical imaging on recrystallized sample of nimodipine at 15°C qualitatively corroborated the model-based prediction of the two polymorphs. Therefore, these studies strongly suggest the importance of the potential utility of the chemometric model in predicting nimodipine polymorphs.

  7. Computational Chemistry Meets Experiments for Explaining the Behavior of Bibenzyl: A Thermochemical and Spectroscopic (Infrared, Raman, and NMR) Investigation.

    Science.gov (United States)

    Latouche, Camille; Barone, Vincenzo

    2014-12-09

    The structure, conformational behavior, and spectroscopic parameters of bibenzyl have been investigated by a computational protocol including proper treatment of anharmonic and hindered rotor contributions. Conventional hybrid functionals overstabilize the anti conformer while low-order post-Hartree-Fock (MP2) approaches strongly favor the gauche conformer. However, inclusion of semiempirical dispersion effects in density functionals or coupled cluster post-Hartree-Fock models agree in forecasting the simultaneous presence of both conformers in the gas phase with a slightly larger stability (0.7 kcal·mol(-1)) of the gauche conformer. Addition of thermal and entropic effects finally leads to very close Gibbs free energies for both conformers and, thus, to a slight preference for the gauche form due to statistical factors (2 vs 1). The situation remains essentially the same in solution. On these grounds, perturbative vibrational computations including both electrical and mechanical anharmonicities lead to IR and Raman spectra in remarkable agreement with experiment. Full assignment of the IR spectra explains the presence of peaks from gauche or anti conformers. Comparison between computed and experimental Raman spectra confirms that both conformers are present in liquid phase, whereas the anti conformer seems to be preponderant in the solid state. Also computed NMR parameters are in good agreement with experiment.

  8. Raman micro-spectroscopic analysis of cultured HCT116 colon cancer cells in the presence of roscovitine

    Science.gov (United States)

    Akyuz, S.; Ozel, A. E.; Balci, K.; Akyuz, T.; Coker, A.; Arisan, E. D.; Palavan-Unsal, N.; Ozalpan, A.

    2011-05-01

    Raman micro-spectroscopic analysis of cultured HCT116 colon cancer cells in the presence of roscovitine, [seliciclib, 2-(1-ethyl-2-hydroxy-ethylamino)-6-benzylamino-9-isopropylpurine], a promising drug candidate in cancer therapy, has been performed for the first time. The aim of this study was to investigate modulations in colon cancer cells induced by roscovitine. Raman spectra of the cultured HCT116 colon cancer cells treated with roscovitine at different concentrations (0, 5, 10, 25 and 50 μM) were recorded in the range 400-1850 cm -1. It was shown that the second derivative profile of the experimental spectrum gives valuable information about the wavenumbers and band widths of the vibrational modes of cell components, and it eliminates the appearance of false peaks arising from incorrect baseline corrections. In samples containing roscovitine, significant spectral changes were observed in the intensities of characteristic protein and DNA bands, which indicate roscovitine-induced apoptosis. Roscovitine-induced apoptosis was also assessed by flow cytometry analysis, and analysis of propidium iodide staining. We observed some modifications in amide I and III bands, which arise from alterations in the secondary structure of cell proteins caused by the presence of roscovitine.

  9. Spectroscopic and structural studies on lactose species in aqueous solution combining the HATR and Raman spectra with SCRF calculations.

    Science.gov (United States)

    Márquez, María Jimena; Brizuela, Alicia Beatriz; Davies, Lilian; Brandán, Silvia Antonia

    2015-04-30

    In this work, the α and β isomers, the α-lactose monohydrate and dihydrate and the dimeric species of lactose were studied from the spectroscopic point of view in gas and aqueous solution phases combining the infrared, Horizontal Attenuated Total Reflectance (HATR) and Raman spectra with the density functional theory (DFT) calculations. Aqueous saturated solutions of α-lactose monohydrate and solutions at different molar concentrations of α-lactose monohydrate in water were completely characterized by infrared, HATR and Raman spectroscopies. For all the species in solution, the solvent effects were studied using the solvation polarizable continuum (PCM) and solvation (SM) models and, then, their corresponding solvation energies were predicted. The vibrational spectra of those species in aqueous solution were completely assigned by employing the Scaled Quantum Mechanics Force Field (SQMFF) methodology and the self-consistent reaction field (SCRF) calculations. The stabilities of all those species were studied by using the natural bond orbital (NBO), and atoms in molecules (AIM) calculations.

  10. A new combined nuclear magnetic resonance and Raman spectroscopic probe applied to in situ investigations of catalysts and catalytic processes

    Energy Technology Data Exchange (ETDEWEB)

    Camp, Jules C. J.; Mantle, Michael D. [Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom); York, Andrew P. E. [Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH (United Kingdom); McGregor, James, E-mail: james.mcgregor@sheffield.ac.uk [Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2014-06-15

    Both Raman and nuclear magnetic resonance (NMR) spectroscopies are valuable analytical techniques capable of providing mechanistic information and thereby providing insights into chemical processes, including catalytic reactions. Since both techniques are chemically sensitive, they yield not only structural information but also quantitative analysis. In this work, for the first time, the combination of the two techniques in a single experimental apparatus is reported. This entailed the design of a new experimental probe capable of recording simultaneous measurements on the same sample and/or system of interest. The individual datasets acquired by each spectroscopic method are compared to their unmodified, stand-alone equivalents on a single sample as a means to benchmark this novel piece of equipment. The application towards monitoring reaction progress is demonstrated through the evolution of the homogeneous catalysed metathesis of 1‑hexene, with both experimental techniques able to detect reactant consumption and product evolution. This is extended by inclusion of magic angle spinning (MAS) NMR capabilities with a custom made MAS 7 mm rotor capable of spinning speeds up to 1600 Hz, quantified by analysis of the spinning sidebands of a sample of KBr. The value of this is demonstrated through an application involving heterogeneous catalysis, namely the metathesis of 2-pentene and ethene. This provides the added benefit of being able to monitor both the reaction progress (by NMR spectroscopy) and also the structure of the catalyst (by Raman spectroscopy) on the very same sample, facilitating the development of structure-performance relationships.

  11. Three-phonon stimulated Raman scattering in an orthorhombic LuAlO3 crystal

    Science.gov (United States)

    Kaminskii, A. A.

    2016-12-01

    High-order stimulated Raman scattering (SRS) has been revealed in a LuAlO3 crystal upon stationary picosecond laser excitation. All recorded Stokes and anti-Stokes χ(3)-nonlinear laser components are attributed to three SRS-promoting A g vibrational modes of its octahedral anionic units (AlO3)-3.

  12. High pressure Raman spectroscopic studies of (p−chloroanilinium){sub 2}CuCl{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Ghalsasi, Pallavi [School of Engineering and Technology, Navrachana University, Vadodara- 391 410 (India); Garg, Nandini; Sharma, S. M. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Center, Mumbai-400 085 (India); Ghalsasi, Prasanna, E-mail: prasanna.ghalsasi@gmail.com; Mande, Hemant, E-mail: prasanna.ghalsasi@gmail.com [Department of Chemistry, The Maharaja Sayajirao Gaikawad University of Baroda, Vadodara - 390 001, Gujarat (India)

    2014-04-24

    (p−chloroanilinium){sub 2}CuCl{sub 4} has a corner shared layered structure of CuCl6{sup 4−} octahedra with p-chloroanilinium cation sandwiched between the layers. The CuCl{sub 6} octahedra are irregular due to Jahn-Teller distortion. We report our high pressure Raman results on this compound in the present manuscript. Our results indicate significant changes in Raman spectra at ∼ 3 GPa and ∼ 8 GPa. The changes at 3 GPa can be attributed to a reduction in puckering of the CuCl{sub 4}{sup 2−} layer and the transition at 8 GPa, which also leads to a colour change of this sample to deep red, could be due to delocalization of the eg electrons along with a reduction of the cooperative Jahn-Teller distortion in this layer. These changes were found to be reversible.

  13. Raman spectroscopic studies of Nd{sub 0.75}Sm{sub 0.25}GaO{sub 3} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Nithya, R., E-mail: nithya@igcar.gov.in; Ravindran, T. R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, TN (India); Daniel, D. J. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam-603110, TN (India)

    2015-06-24

    Single crystals of Nd{sub 1-x}Sm{sub x}GaO{sub 3} (x= 0 and 0.25) were grown by a four mirror IR image furnace using floating zone technique. The crystals are characterized by X-ray diffraction and Raman spectroscopic measurements. NGO adopts orthorhombic structure with Pbnm symmetry and samarium substituted compound also exhibited the same structure as that of the pristine compound without secondary phases. Polarized Raman spectra are measured at ambient temperature in a back scattering geometry. Spectra exhibit low intensity first-order Raman bands. In addition, several high intensity second-order Raman bands have been observed in the frequency range 2000 to 4000 cm{sup −1}.

  14. Raman spectroscopic study of DL valine under pressure up to 20 GPa

    Science.gov (United States)

    Rêgo, F. S. C.; Lima, J. A.; Freire, P. T. C.; Melo, F. E. A.; Mendes Filho, J.; Polian, A.

    2016-04-01

    DL-valine crystal was studied by Raman spectroscopy under hydrostatic pressure using a diamond anvil cell from ambient pressure up to 19.4 GPa in the spectral range from 40 to 3300 cm-1. Modifications in the spectra furnished evidence of the occurrence of two structural phase transitions undergone by this racemic amino acid crystal. The classification of the vibrational modes, the behavior of their wavenumber as a function of the pressure and the reversibility of the phase transitions are discussed.

  15. Demonstration of a Robot-Based Raman Spectroscopic Detector for the Identification of CBE Threat Agents

    Science.gov (United States)

    2006-11-01

    Nerve Agent Simulant Bacillus thuringiensis - Anthrax Simulant O ffs et In te ns ity Fig. 5. Average Raman spectra of several CBE simulants taken on...This model was evaluated using a simulant for anthrax, B. thuringiensis (Bt) spores, and a biological toxin simulant, ovalbumin. This modeling...Sulfur Mustard Simulant 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 2900 3100 DMMP – G-Type Nerve Agent Simulant Bacillus thuringiensis

  16. Raman spectroscopic sensing of carbonate intercalation in breast microcalcifications at stereotactic biopsy

    OpenAIRE

    Sathyavathi, R.; Anushree Saha; Soares, Jaqueline S.; Nicolas Spegazzini; Sasha McGee; Ramachandra Rao Dasari; Maryann Fitzmaurice; Ishan Barman

    2014-01-01

    Microcalcifications are an early mammographic sign of breast cancer and frequent target for stereotactic biopsy. Despite their indisputable value, microcalcifications, particularly of the type II variety that are comprised of calcium hydroxyapatite deposits, remain one of the least understood disease markers. Here we employed Raman spectroscopy to elucidate the relationship between pathogenicity of breast lesions in fresh biopsy cores and composition of type II microcalcifications. Using a ch...

  17. Facile fabrication of dendritic silver structures and their surface enhanced Raman spectroscopic properties

    Indian Academy of Sciences (India)

    Jisheng Yang; Zhengdong Jiang

    2015-01-01

    A simple and efficient approach was developed to fabricate silver dendrites by Cu reducing Ag+ in AgNO3 solution. The growth speed, morphologies and structures of the silver dendrites strongly depend on AgNO3 concentration and reaction time. The silver dendrites were formed from nanosheets and the crystal structure is face-centered cubic. Rhodamine 6G was used as probe molecule to show that the silver dendrites have high sensitivity to surface enhanced Raman spectroscopy response.

  18. A Combined Raman Spectroscopic and Thermogravimetric Analysis Study on Oxidation of Coal with Different Ranks

    Directory of Open Access Journals (Sweden)

    Weiqing Zhang

    2015-01-01

    Full Text Available Raman spectroscopy and nonisothermal thermogravimetric analysis (TGA measurements have been reported for different rank coals (lignite, bituminous coal, and anthracite and the relationship between the measurements was examined. It was found that the Raman spectra parameters can be used to characterize structure changes in the different rank coals, such as the band area ratios based on the curve-fitted results. Higher ranked coal was found to have higher values of IGR/IAll and IG+GR/IAll but lower values of ID/I(G+GR, IDL/I(G+GR, IS+SL/I(G+GR, and I(GL+GL'/I(G+GR. The oxidation properties of the coal samples were characterized by the reactivity indexes Tig, T20%, and Tmax from TGA data which were found to correlate well with the band area ratios of IGR/IAll, IG+GR/IAll, and IS+SL/I(G+GR. Based on these correlations, the Raman band area ratios were found to correlate with the oxidation activity of coal providing additional structural information which can be used to understand the changes in the TGA measurements.

  19. UV resonance Raman spectroscopic studies of protein structure and dynamics (Conference Presentation)

    Science.gov (United States)

    Asher, Sanford A.; Punihaole, David; Dahlburg, Elizabeth M.; Jakubek, Ryan S.; Hong, Zhenmin

    2016-09-01

    UV Raman excitation into the 200 nm peptide bond electronic transitions enhance peptide bond amide vibrations of the backbone. A particular band (the amide III3) reports on the Ramachandran psi angle and peptide bond hydrogen bonding. This band is Raman scattered independently by each peptide bond with insignificant coupling between adjacent peptide bonds. Isotope editing of a peptide bond (by replacing the Calpha- H with Calpha- D) allows us to determine the frequency of individual peptide bonds within a peptide or protein to yield their psi angles. Consideration of the Boltzmann equilibria allows us to determine the psi angle Gibbs free energy landscape along the psi (un)folding coordinate that connects secondary structure conformations. The psi angle coordinate is the most important reaction coordinate necessary to understand mechanism(s) of protein folding. We have also discovered an analogous correlation for the primary amide sidechain of Gln. This allows us to monitor the hydrogen bonding and structure of this sidechain. We examine the details of peptide folding conformation dynamics with laser T-jumps where the water temperature is elevated by an 1.9 mM IR nsec laser pulse and we monitor the 200 nm UV Raman spectrum as a function of time. These spectra show the time evolution of conformation. We will discuss the role of salts on stabilizing conformations in solution

  20. Raman spectroscopic analysis of minerals and organic molecules of relevance to astrobiology.

    Science.gov (United States)

    Alajtal, A I; Edwards, H G M; Scowen, I J

    2010-05-01

    Characteristic geological features and hydrated minerals recently found on the surface of Mars by the NASA planetary rovers Spirit and Opportunity suggest that a possible biosphere could have once existed there. Analytical instrumentation protocols for the unequivocal detection of biomarkers in suitable geological matrices are critical for future unmanned explorations, including the forthcoming ESA-ExoMars mission scheduled for 2018. Raman spectroscopy is currently a part of the Pasteur instrumentation suite of the ExoMars mission scheduled for 2018 for the remote detection of extant or extinct life signatures in the Martian surface and subsurface. Terrestrial analogues of Martian sites have been identified, and the biogeological modifications incurred as a result of extremophilic survival activity have been studied. Polyaromatic hydrocarbons (PAHs) are recognised as a class of degradation product that occur from biological processes terrestrially. In this work, various concentrations of polyaromatic hydrocarbons in matrices of gypsum, calcite and quartz have been investigated by Raman microspectrometry to determine the lowest detectable organic levels. The studies are conceived in simulation of their potential PAHs identification in geobiological conditions in Martian scenarios. Two laser source wavelengths, namely, 785 and 633 nm, were adopted to excite Raman spectra from the PAHs, which represent degraded carbons and therefore potentially provide a key bimolecular marker of ancient life.

  1. Double-clad hollow core photonic crystal fiber for coherent Raman endoscope.

    Science.gov (United States)

    Brustlein, Sophie; Berto, Pascal; Hostein, Richard; Ferrand, Patrick; Billaudeau, Cyrille; Marguet, Didier; Muir, Alistair; Knight, Jonathan; Rigneault, Hervé

    2011-06-20

    Performing label free coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) in endoscope imaging is a challenge, with huge potential clinical benefit. To date, this goal has remained inaccessible because of the inherent coherent Raman noise that is generated in the fiber itself. By developing double-clad hollow core photonic crystal fiber, we demonstrate coherent anti-Stokes Raman scattering and stimulated Raman scattering in an 'endoscope-like' scheme. Both the excitation beams and the collected CARS and SRS signals travel through the same fiber. No CARS and SRS signals are generated within the hollow core fiber even for temporally overlapping pump and Stokes beams, leading to excellent image quality. The CARS and SRS signals generated in the sample are coupled back into a high numerical aperture multimode cladding surrounding the central photonic crystal cladding. We demonstrate this scheme by imaging molecular vibrational bonds of organic crystal deposited on a glass surface.

  2. Anti-Stokes emissions and determination of Stark sub-level diagram of Er{sup 3+} ions in KY{sub 3}F{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Boulma, E [Laboratoire d' Energetique et d' Optique, UTAP, Universite de Reims Champagne-Ardenne, BP 1039, Reims Cedex 51 687 (France); Diaf, M [Departement de Physique, Universite Badji Mokhtar Annaba, BP12, 23000 Annaba, Algerie (Germany); Jouart, J P [Laboratoire d' Energetique et d' Optique, UTAP, Universite de Reims Champagne-Ardenne, BP 1039, Reims Cedex 51 687 (France); Bouffard, M [Laboratoire d' Energetique et d' Optique, UTAP, Universite de Reims Champagne-Ardenne, BP 1039, Reims Cedex 51 687 (France); Doualan, J L [Centre Interdisciplinaire de Recherches Ions Lasers (CIRIL), UMR 6637 CNRS-CEA-ISMRA, ENSI de Caen, 6 Boulevard Marechal Juin, 14050 Caen Cedex (France); Moncorge, R [Centre Interdisciplinaire de Recherches Ions Lasers (CIRIL), UMR 6637 CNRS-CEA-ISMRA, ENSI de Caen, 6 Boulevard Marechal Juin, 14050 Caen Cedex (France)

    2006-07-26

    We are interested, in this work, in determining the Stark sub-level of Er{sup 3+} ions doping a KY{sub 3}F{sub 10} single crystal with a molar concentration of 1%. We have used a new method of measurement of energies of the ground level and emitting levels from excitation and anti-Stokes emission spectra recorded at liquid nitrogen temperature. This technique is based on a spectral analysis of the anti-Stokes emissions recorded after selective excitation with a red dye tunable laser. Thus, we could determine the Stark sub-levels of the ground and the principal emitting levels in the infrared, visible and near-UV ranges with a very good precision.

  3. Raman scattering mediated by neighboring molecules.

    Science.gov (United States)

    Williams, Mathew D; Bradshaw, David S; Andrews, David L

    2016-05-01

    Raman scattering is most commonly associated with a change in vibrational state within individual molecules, the corresponding frequency shift in the scattered light affording a key way of identifying material structures. In theories where both matter and light are treated quantum mechanically, the fundamental scattering process is represented as the concurrent annihilation of a photon from one radiation mode and creation of another in a different mode. Developing this quantum electrodynamical formulation, the focus of the present work is on the spectroscopic consequences of electrodynamic coupling between neighboring molecules or other kinds of optical center. To encompass these nanoscale interactions, through which the molecular states evolve under the dual influence of the input light and local fields, this work identifies and determines two major mechanisms for each of which different selection rules apply. The constituent optical centers are considered to be chemically different and held in a fixed orientation with respect to each other, either as two components of a larger molecule or a molecular assembly that can undergo free rotation in a fluid medium or as parts of a larger, solid material. The two centers are considered to be separated beyond wavefunction overlap but close enough together to fall within an optical near-field limit, which leads to high inverse power dependences on their local separation. In this investigation, individual centers undergo a Stokes transition, whilst each neighbor of a different species remains in its original electronic and vibrational state. Analogous principles are applicable for the anti-Stokes case. The analysis concludes by considering the experimental consequences of applying this spectroscopic interpretation to fluid media; explicitly, the selection rules and the impact of pressure on the radiant intensity of this process.

  4. Raman Studies of Carbon Nanostructures

    Science.gov (United States)

    Jorio, Ado; Souza Filho, Antonio G.

    2016-07-01

    This article reviews recent advances on the use of Raman spectroscopy to study and characterize carbon nanostructures. It starts with a brief survey of Raman spectroscopy of graphene and carbon nanotubes, followed by recent developments in the field. Various novel topics, including Stokes-anti-Stokes correlation, tip-enhanced Raman spectroscopy in two dimensions, phonon coherence, and high-pressure and shielding effects, are presented. Some consequences for other fields—quantum optics, near-field electromagnetism, archeology, materials and soil sciences—are discussed. The review ends with a discussion of new perspectives on Raman spectroscopy of carbon nanostructures, including how this technique can contribute to the development of biotechnological applications and nanotoxicology.

  5. Visible-IR and Raman micro-spectroscopic investigation of three Itokawa particles collected by Hayabusa

    Science.gov (United States)

    Brunetto, R.; Bonal, L.; Beck, P.; Dartois, E.; Dionnet, Z.; Djouadi, Z.; Füri, E.; Kakazu, Y.; Oudayer, P.; Quirico, E.; Engrand, C.

    2014-07-01

    HAYABUSA grains offer a unique perspective to better understand the link between asteroids and cosmomaterials available in the laboratory and to get an insight on the early stages of surface space weathering. The scientific objectives of our consortium are threefold: (i) the characterization of asteroidal surface processes (e.g., space weathering alteration); (ii) the assessment of parent-body alteration processes; (iii) the search for a possible association between S-type asteroids and micrometeorites. To this aim, our strategy is based on a combination of analytical techniques. Here we report a first series of results obtained through Visible-Infrared and Raman spectroscopy of three Itokawa particles (RA-QD02-0163, -0174, and -0213) collected by the Hayabusa spacecraft and provided by JAXA for our consortium. In a first step, our main objective was to collect maximum information without altering the particles. Reported results were thus obtained on the raw particles, both (i) in their original containers, and (ii) deposited on diamond windows. Raman and IR confocal spectra were acquired at the SMIS beamline of the French national synchrotron facility SOLEIL and at the Lyon Raman national facility using spots of 2 μ m for the Raman, and 10--20 μ m for the IR analyses. Point analyses and automatic mapping were performed. Analytical parameters (e.g., laser power on the sample) were optimized to prevent any damage. Diffuse reflectance spectra (i=45°, e=0°) in the visible and near-IR wavelengths were obtained with an IAS-CSNSM in-home system coupling a fiber spectrometer to an optical microscope, providing a 20-μ m spot on sample. In the case of particle -0163, Raman and IR results reveal a heterogeneous mixing of minerals, mostly olivine (Fo76), and Ca-rich (En50, Wo50) and Ca-poor (En85) pyroxenes. The modal distribution of these minerals is determined based on the spectral maps. The mineral compositions of -0163 are consistent with those previously reported on

  6. Raman properties of GaSb nanoparticles embedded in SiO2 films

    Institute of Scientific and Technical Information of China (English)

    Liu Fa-Min; Wang Tian-Min; Zhang Li-De

    2004-01-01

    The Raman shifts of nanocrystalline GaSb excited by an Ar+ ion laser at wavelengths 514.5, 496.5, 488.0, 476.5,and 457.9nm are studied by an SPEX-1403 laser Raman spectrometer respectively, and they are explained by phonon confinement, tensile stress, resonant Raman scattering and quantum size effects. The Stokes and anti-Stokes Raman spectra of GaSb nanocrystals strongly support the Raman feature of GaSb nanocrystals. The calculated optical spectra compare well with experimental data on Raman scattering GaSb nanocrystals.

  7. Fourier transform Raman spectroscopic study of the interaction of water vapor with amorphous polymers.

    Science.gov (United States)

    Taylor, L S; Langkilde, F W; Zografi, G

    2001-07-01

    Water associated with amorphous polymers is known to affect their chemical and physical properties. The purpose of this study was to investigate the nature of water-polymer interactions for some polymers of pharmaceutical interest. Using Raman spectroscopy, polymer-water hydrogen bond interactions were probed for two molecular weight grades of poly(vinylpyrrolidone), namely PVP K90 and PVP K12, and also for poly(vinylacetate) and poly(vinyl pyrrolidone-co-vinyl acetate). Water vapor absorption isotherms were obtained for the polymers, and the effect of the absorbed water on the glass transition temperature was determined. A knowledge of the water content and physical state of the polymer was used to aid interpretation of Raman spectral changes. The strength of the hydrogen bond formed with water was found to depend on the chemistry of the polymer, with the pyrrolidone group interacting more strongly than the acetate group. However, minor differences were also observed between the degree of interaction of water and polymer for PVP K12 and PVP K90 at some water contents. This result is attributed to differences in the structural relaxation changes accompanying plasticization by water for the two molecular weight grades. Using principal components analysis of the spectral data, it was also possible to differentiate between samples in the rubbery state and samples in the glassy state. In conclusion, water sorbed into polymers causes changes in the polymer Raman spectra not only because of hydrogen bonding, but also as a result of the plasticizing effect of water on polymer mobility.

  8. RAMAN SPECTROSCOPIC STUDY ON THE CHAIN CONFORMATION OF ELECTROSYNTHESIZED POLY(p-PHENYLENE) FILMS

    Institute of Scientific and Technical Information of China (English)

    Feng-en Chen; Ming-xiao Fu; Fan Wang; Bin Fan; Gao-quan Shi

    2005-01-01

    Poly(p-phenylene) (PPP) films have been electrochemically deposited on mirrorlike stainless steel (SS) electrode surfaces by direct oxidation of benzene in boron trifluoride diethyl etherate (BFEE) solutions at a constant applied potential of 1.7 V (versus Ag/AgCl). The chain conformations of as-grown PPP films have been studied by Raman spectroscopy. The results demonstrated that high synthesis temperature favors the formation of planar PPP, and the conformation of planar PPP can be changed into torsional PPP by cooling treatment.

  9. Raman spectroscopic determination of the molecular constants of the hydrogen isotopologues with high accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Krasch, Bennet; Mirz, Sebastian; Groessle, Robin [Karlsruhe Institute of Technology KIT (Germany). Institute for Technical Physics (ITEP), Tritium Laboratory Karlsruhe (TLK); Collaboration: KATRIN-Collaboration

    2016-07-01

    The interest in the thermodynamic properties of gases as the chemical equilibrium is faced by the challenge of time-consuming and technical extensive experimental setups. One possible solution is the derivation of these properties from the molecular constants. The rotational and vibrational movement of diatomic molecules, as the hydrogen isotopologues, is described by the concept of the rotational anharmonic oscillator. The molecular constants are the free parameters of this concept. Molecular constants themselves can be determined by measuring the line position of rotational and/or rotational transitions e.g. with Raman spectroscopy for hydrogen as it has been done since several years. In this contribution a Raman method was development to measure the molecular constant of the hydrogen isotopologues with high accuracy to obtain reliable results. But not only the method was development but also a complete measurement uncertainty budget was set up. The uncertainty budget contains all possible sources for uncertainties from the measurement period or the analysis process as well the contribution of each single uncertainty. The method and the uncertainty budget were exemplary tested on Deuterium.

  10. Raman spectroscopic study on archaeological glasses in Thailand: Ancient Thai Glass

    Science.gov (United States)

    Won-in, K.; Thongkam, Y.; Pongkrapan, S.; Intarasiri, S.; Thongleurm, C.; Kamwanna, T.; Leelawathanasuk, T.; Dararutana, P.

    2011-12-01

    Glasses have been used as ornamental and decorative objects in Thailand for several hundred years as seen in archaeological artifacts, such as glass beads found throughout the regions. Decorative glasses can generally be seen as architectural components in Buddhist temples and old-styled palaces. They came in various colors ranging from transparent to amber, blue, green and red of different shades and tones. Fragments of archaeological glass samples were characterized for the first time using Raman spectrophotometer with the aim of obtaining information that would lead to the identification of the glass samples by means of laser scattering. The samples were also investigated using other techniques, such as proton induced X-ray emission spectroscopy, scanning electron microscopy cooperated with energy dispersive X-ray fluorescence spectrometer and synchrotron radiation to induced X-ray fluorescence. The results showed that they were mostly lead-silica based glasses whose colors were induced by metal ions. The differences in chemical compositions were confirmed by Raman signature spectra.

  11. Surface enhanced Raman spectroscopic studies on aspirin : An experimental and theoretical approach

    Science.gov (United States)

    Premkumar, R.; Premkumar, S.; Rekha, T. N.; Parameswari, A.; Mathavan, T.; Benial, A. Milton Franklin

    2016-05-01

    Surface enhanced Raman scattering (SERS) studies on aspirin molecule adsorbed on silver nanoparticles (AgNPs) were investigated by experimental and density functional theory approach. The AgNPs were synthesized by the solution-combustion method and characterized by the X-ray diffraction and high resolution-transmission electron microscopy techniques. The averaged particle size of synthesized AgNPs was calculated as ˜55 nm. The normal Raman spectrum (nRs) and SERS spectrum of the aspirin were recorded. The molecular structure of the aspirin and aspirin adsorbed on silver cluster were optimized by the DFT/ B3PW91 method with LanL2DZ basis set. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation. The calculated nRs and SERS frequencies were correlated well with the observed frequencies. The flat-on orientation was predicted from the nRs and SERS spectra, when the aspirin adsorbed on the AgNPs. Hence, the present studies lead to the understanding of adsorption process of aspirin on the AgNPs, which paves the way for biomedical applications.

  12. In situ Raman spectroscopic study of marble capitals in the Alhambra monumental ensemble

    Science.gov (United States)

    Arjonilla, Paz; Domínguez-Vidal, Ana; de la Torre López, María José; Rubio-Domene, Ramón; Ayora-Cañada, María José

    2016-12-01

    The marble capitals of five different sites in the Alhambra complex (Granada, Spain), namely the Mexuar, the Hall of the Abencerrages, the Hall of the Kings, the Court of the Myrtles and the Court of the Main Canal, have been investigated. The decoration of the capitals exhibits mainly blue, red, black and gilding motifs with different states of conservation. The work has been carried out in situ by means of a portable Raman micro-spectrometer with an excitation laser of 785 nm. In addition to preserving the artwork with a non-invasive study, the on-site investigation gives a more representative knowledge of the art objects because the measurements are not limited to the samples that can be taken (few and small). The obtained Raman spectra were of good quality despite challenging adverse conditions out of the laboratory. Cinnabar, minium, carbon black, natural lapis lazuli and azurite were the main pigments found. Synthetic ultramarine blue was also detected in a capital as a result of a modern restoration. Degradation products as tin oxide in the gildings and weddellite in the preparation layers were also identified. All the results together with a careful visual inspection can be combined to elucidate the different execution techniques employed to apply the pigments on the marble substrate of the capitals in the Nasrid and Christian periods.

  13. Raman spectroscopic study of phosphogypsum thermal reduction with the carbonaceous material.

    Science.gov (United States)

    Msila, Xolani; Barnard, Werner; Billing, Dave G

    2015-10-05

    Elemental sulphur (S) can be produced from hydrogen sulphide (H2S) in a PiPco or Iron process. In turn H2S can be stripped with carbon dioxide (CO2) from calcium sulphide (CaS) obtained from the thermal reduction of phosphogypsum with carbon. The reaction pathway for the thermal reduction of the phosphogypsum with graphite was studied using thermogravimetric analysis and in situ Raman spectroscopy. The dehydration of the phosphogypsum to anhydrite was completed at about 142 °C. The dehydration was followed by the formation of the intermediate compound at about 860 °C which is characterised by a mass loss of about 11%. The intermediate compound, identified using the in situ Raman spectroscopy to be a dehydrated orschallite-type compound (Ca3[SO4][SO3]2), converted to CaS at about 935 °C. The presence of the metal impurities in the phosphogypsum: Ni(2+)(4 mg kg(-1)); Co(2+)(2 mg kg(-1)); Mn(2+)(5 mg kg(-1)); Cu(2+)(14 mg kg(-1)); Fe(2+)(200 mg kg(-1)) and Mg(2+)(300 mg kg(-1)) showed no influence the onset temperature for the reduction reaction.

  14. A RAMAN-SPECTROSCOPIC STUDY OF PHASE STRUCTURE OF DRAWN POLYETHYLENE

    Institute of Scientific and Technical Information of China (English)

    YAN Rongjiang; JIANG Bingzheng

    1993-01-01

    A drawn high density polyethylene(HDPE) has been measured by Raman spectroscopy and differential scanning calorimetry (DSC). The crystalline structure of drawn HDPE is analysed by the Raman internal modes in terms of mass fractions of the crystalline orthorhombic phase, the liquid- like amorphous phase and the disordered anisotropic phase. The mass fractions depend on draw temperature Td and draw ratio Rd . The fraction of disordered anisotropic amorphous phase changes very little with, the Td and increases with increasing Rd. Sum of the mass fractions of crystalline orthorhombic phase and the disordered anisotropic phase increases linearly as the same slope as the crystallinity Wc determined from DSC measurements with increasing Td or Rd and it is higher than the Wc for all the samples. The results show that the mass fraction of disordered anisotropic phase is partially devoted by the taut tie molecules (TTM s) in the amorphous state. The dependence of the disordered anisotropic phase on Td and Rd supports the mechanism of plastic deformation of fibre structure.

  15. Spectroscopic characterization of enzymatic flax retting: Factor analysis of FT-IR and FT-Raman data

    Science.gov (United States)

    Archibald, D. D.; Henrikssen, G.; Akin, D. E.; Barton, F. E.

    1998-06-01

    Flax retting is a chemical, microbial or enzymatic process which releases the bast fibers from the stem matrix so they can be suitable for mechanical processing before spinning into linen yarn. This study aims to determine the vibrational spectral features and sampling methods which can be used to evaluate the retting process. Flax stems were retted on a small scale using an enzyme mixture known to yield good retted flax. Processed stems were harvested at various time points in the process and the retting was evaluated by conventional methods including weight loss, color difference and Fried's test, a visual ranking of how the stems disintegrate in hot water. Spectroscopic measurements were performed on either whole stems or powders of the fibers that were mechanically extracted from the stems. Selected regions of spectra were baseline and amplitude corrected using a variant of the multiplicative signal correction method. Principal component regression and partial least-squares regression with full cross-validation were used to determine the spectral features and rate of spectral transformation by regressing the spectra against the retting time in hours. FT-Raman of fiber powders and FT-IR reflectance of whole stems were the simplest and most precise methods for monitoring the retting transformation. Raman tracks the retting by measuring the decrease in aromatic signal and subtle changes in the C-H stretching vibrations. The IR method uses complex spectral features in the fingerprint and carbonyl region, many of which are due to polysaccharide components. Both spectral techniques monitor the retting process with greater precision than the reference method.

  16. Spectroscopic analysis of works of art using a single LIBS and pulsed Raman setup.

    Science.gov (United States)

    Osticioli, I; Mendes, N F C; Porcinai, S; Cagnini, A; Castellucci, E

    2009-06-01

    A nanosecond pulsed laser setup has been optimized to perform laser-induced breakdown spectroscopy (LIBS) and pulsed Raman spectroscopy measurements in the field of cultural heritage. Three different samples of artistic/architectural interest with different typologies have been analyzed. The results from the two techniques allowed the identification of the materials used in their manufacture or contaminating them, probably coming from atmospheric pollution and biological activity. No sampling and sample preparation was required before the measurements, and no visual or structural damage was observed. Depth profiling using LIBS was performed in one of the samples, providing elemental information along the different layers composing the object and covering its surface. The quality of the results and the rather short time needed for the measurements and for switching between techniques confirmed the instrument's capabilities and specificity for dealing with objects of artistic or historical interest.

  17. Synergistic effects of atmospheric pressure plasma-emitted components on DNA oligomers: a Raman spectroscopic study.

    Science.gov (United States)

    Edengeiser, Eugen; Lackmann, Jan-Wilm; Bründermann, Erik; Schneider, Simon; Benedikt, Jan; Bandow, Julia E; Havenith, Martina

    2015-11-01

    Cold atmospheric-pressure plasmas have become of increasing importance in sterilization processes especially with the growing prevalence of multi-resistant bacteria. Albeit the potential for technological application is obvious, much less is known about the molecular mechanisms underlying bacterial inactivation. X-jet technology separates plasma-generated reactive particles and photons, thus allowing the investigation of their individual and joint effects on DNA. Raman spectroscopy shows that particles and photons cause different modifications in DNA single and double strands. The treatment with the combination of particles and photons does not only result in cumulative, but in synergistic effects. Profilometry confirms that etching is a minor contributor to the observed DNA damage in vitro. Schematics of DNA oligomer treatment with cold atmospheric-pressure plasma.

  18. Raman spectroscopic analysis of arctic nodules: relevance to the astrobiological exploration of Mars.

    Science.gov (United States)

    Jorge-Villar, Susana E; Edwards, Howell G M; Benning, Liane G

    2011-11-01

    The discovery of small, spherical nodules termed 'blueberries' in Gusev Crater on Mars, by the NASA rover Opportunity has given rise to much debate on account of their interesting and novel morphology. A terrestrial analogue in the form of spherical nodules of similar size and morphology has been analysed using Raman spectroscopy; the mineralogical composition has been determined and evidence found for the biological colonisation of these nodules from the spectral signatures of cyanobacterial protective biochemical residues such as scytonemin, carotenoids, phycocyanins and xanthophylls. This is an important result for the recognition of future sites for the planned astrobiological exploration of planetary surfaces using remote robotic instrumentation in the search for extinct and extant life biosignatures and for the expansion of putative terrestrial Mars analogue geological niches and morphologies.

  19. Plasmonic Dimer-Like Nanoassemblies for Surface-Enhanced Raman Spectroscop

    Science.gov (United States)

    Rigo, Maria; Seo, Jaetae; Kim, Wan-Joong; Jung, Sungsoo; Hampton University Team; Etri Collaboration; Kriss Collaboration

    2011-05-01

    We report on the preparation of gold dimers in which the near-field coupling in their subwavelength gap is influenced by the individual gold nanoparticles size and the molecule's length used to assemble the dimers. The nano assemblies display plasmonic modes similar to those observed in rod-like nanoparticles. The longitudinal mode of the gold dimers shift as a function of gold nanoparticles size and concentration and it is influenced by the concentration of Rhodamine 6G (R6G), the molecule used as nanoparticle linker. We report large surface enhanced Raman scattering (SERS) enhancements for R6G when using linked-gold nano-assemblies as a SERS substrate. A discussion about the main origins for the large enhancement of molecular vibrational modes is presented. This work at Hampton University was supported by the National Science Foundation (HRD-0734635 and HRD-0630372).

  20. Raman spectroscopic studies on bismuth nanoparticles prepared by laser ablation technique

    Science.gov (United States)

    Onari, Seinosuke; Miura, Masaaki; Matsuishi, Kiyoto

    2002-09-01

    Bi nanoparticles are prepared by means of laser ablation in Ar atmosphere (0.2-10 Torr) with KrF (248 nm) excimer laser of the power 200 mJ. The size of the Bi particles estimated by TEM measurements is in the range 3-10 nm. Raman active E g mode shifts to a higher frequency and becomes broader for a sample prepared in a lower pressure of Ar atmosphere. However, the peak frequency and the bandwidth of A 1g mode show almost no change with the change of the particle size. These experimental results can be well explained by a phonon confinement model of Campbell and Fauchet by taking the phonon dispersion properties that the E g mode of the crystal has a large dependence on the wave numbers near the Γ point, but the A 1g mode is rather independent of the phonon wave numbers.

  1. Femtosecond laser irradiation of indium phosphide in air: Raman spectroscopic and atomic force microscopic investigations

    Energy Technology Data Exchange (ETDEWEB)

    Bonse, J.; Wrobel, J.M.; Brzezinka, K.-W.; Esser, N.; Kautek, W

    2002-12-30

    Surface modification and ablation of crystalline indium phosphide was performed with single and double 130 fs pulses from a Ti:sapphire laser. The morphological features resulting from laser processing, have been investigated by means of micro Raman spectroscopy as well as by optical, atomic force and scanning electron microscopy. The studies indicate amorphous, ablated and recrystallized zones on the processed surface. In the single-pulse irradiation experimentsveral different threshold fluences could be assigned to the processes of melting, ablation and polycrystalline resolidification. Residual stress has been detected within the irradiated areas. Double-pulse exposure experiments have been analyzed in order to clarify the effect of cumulative damage in the ablation process of indium phosphide.

  2. Water and Solutions at Negative Pressure: Raman Spectroscopic Study to -80 Megapascals

    Science.gov (United States)

    Green, J. L.; Durben, D. J.; Wolf, G. H.; Angell, C. A.

    1990-08-01

    Microscopic inclusions of aqueous fluids trapped in interstices in quartz and other crystals provide novel systems for the deliberate study of liquids under tension. Liquids under tension should differ in interesting ways from those at ambient pressure or compressed liquids because attractive, rather than repulsive, forces should dominate their behavior. Static tensions in excess of 100 megapascals (~1000 atmospheres) have been obtained reproducibly. Video-recorded observations of the final liquid rupture process, coupled with extrapolations of data at positive pressure, suggest that the homogeneous vapor nucleation point was reached in two of the cases studied. Raman spectra of the fluids at -80 megapascals show that an isothermal volume stretch of ~5 percent by volume has only a weak effect on the spectral features and is similar to the effect of isobaric heating.

  3. Raman Spectroscopic Studies of Methane-Ethane Mixtures as a Function of Pressure

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

    2001-01-01

    Raman spectra of methane and methane-ethane mixtures (100, 85, and 49 mole % CH4) have been obtained as a function of pressure in the pressure range 0.1 to 15.3 MPaA (MPa absolute). For these mixtures methane nu (1) (symmetric C-H stretching) band positions are given as a function of pressure......; for pure methane they are in agreement with previous results. The new data on the methane nu (1) band position of ethane-containing mixtures clearly depend on the kind of molecules surrounding the vibrating methane molecule. The nu (1) band position decreases with increasing pressure; the stronger...... the dependency, the higher the content of ethane. The ethane nu (1) band position in the two mixtures showed the same kind of dependency, A qualitative explanation for this behavior is attempted, relating it to changes in van der Waals-type interactions on pressure....

  4. Non-destructive Analysis of the Nuclei of Transgenic Living Cells Using Laser Tweezers and Near-infrared Raman Spectroscopic Technique

    Institute of Scientific and Technical Information of China (English)

    Wei Tang; Ronald J. Newton; Chang-An Xie; Yong-Qing Li; Nicki Whitley

    2005-01-01

    Transgenic cell lines of loblolly pine (Pinus taeda L.) were analyzed by a compact laser-tweezers-Raman-spectroscopy (LTRS) system in this investigation. A low power diode laser at 785 nm was used for both laser optical trapping of single transgenic cells and excitation for near-infrared Raman spectroscopy of the nuclei of synchronized cells, which were treated as single organic particles, at the S-phase of the cell cycle. Transgenic living cells with gfp and uidA genes were used as biological samples to test this LTRS technique. As expected, different Raman spectra were observed from the tested biological samples. This technique provides a high sensitivity and enables real-time spectroscopic measurements of transgenic cell lines. It could be a valuable tool for the study of the fundamental cell and molecular biological process by trapping single nucleus and by providing a wealth of molecular information about the nuclei of cells.

  5. FAST CARS: engineering a laser spectroscopic technique for rapid identification of bacterial spores.

    Science.gov (United States)

    Scully, M O; Kattawar, G W; Lucht, R P; Opatrny, T; Pilloff, H; Rebane, A; Sokolov, A V; Zubairy, M S

    2002-08-20

    Airborne contaminants, e.g., bacterial spores, are usually analyzed by time-consuming microscopic, chemical, and biological assays. Current research into real-time laser spectroscopic detectors of such contaminants is based on e.g., resonance fluorescence. The present approach derives from recent experiments in which atoms and molecules are prepared by one (or more) coherent laser(s) and probed by another set of lasers. However, generating and using maximally coherent oscillation in macromolecules having an enormous number of degrees of freedom is challenging. In particular, the short dephasing times and rapid internal conversion rates are major obstacles. However, adiabatic fast passage techniques and the ability to generate combs of phase-coherent femtosecond pulses provide tools for the generation and utilization of maximal quantum coherence in large molecules and biopolymers. We call this technique FAST CARS (femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman spectroscopy), and the present article proposes and analyses ways in which it could be used to rapidly identify preselected molecules in real time.

  6. Optical cell for combinatorial in situ Raman spectroscopic measurements of hydrogen storage materials at high pressures and temperatures.

    Science.gov (United States)

    Hattrick-Simpers, Jason R; Hurst, Wilbur S; Srinivasan, Sesha S; Maslar, James E

    2011-03-01

    An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storage materials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element lenses. For combinatorial investigations, up to 19 individual powder samples can be loaded into the optical cell at one time. This cell design is also compatible with thin-film samples. To demonstrate the capabilities of the cell, in situ measurements of the Ca(BH(4))(2) and nano-LiBH(4)-LiNH(2)-MgH(2) hydrogen storage systems at elevated temperatures and pressures are reported.

  7. X-ray and Raman spectroscopic studies on Ru substituted LiMn{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kalavathi, S.; Ravindran, T. R.; Sahu, P. Ch. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam -603102 (India); Kalaivani, D., E-mail: kala@igcar.gov.in [Department of Physics, Rajiv Gandhi College of Engineering Technology, Pondicherry-607403 (India)

    2015-06-24

    Phase pure Ru substituted LiMn{sub 2}O{sub 4} charge frustrated spinel compounds have been synthesized. Ru substitution for Mn is possible only up to 7.5%. Powder diffraction measurements confirm sustenance of charge frustrated cubic phase with space group Fd3m upon substitution of Ru for Mn. An increase in lattice parameter has been observed indicating replacement of Mn as Ru{sup 3+} or Ru{sup 4+} rather than Ru{sup 5+}. Raman spectroscopic measurements show that the crystal structure is robust against an increase of laser power and the observed bands show an expected red shift. In the case of Ru substituted LiMn{sub 2}O{sub 4}, the A{sub 1g} symmetric stretching mode, the F{sup (1)}{sub 2g} and the F{sup (2)}{sub 2g} symmetric bending modes identified with the Mn-O octahedra show a red shift up to Ru 0.075 and at higher Ru concentrations, revert back to the frequency corresponding to the pristine LiMn{sub 2}O{sub 4}.

  8. Raman Spectroscopic Analysis of the Effect of Ultraviolet Irradiation on Calf Thymus DNA

    Institute of Scientific and Technical Information of China (English)

    Yu-Long TANG; Zhou-Yi GUO

    2005-01-01

    Raman spectroscopy was used for the first time to detect the effect of independent UVA(ultraviolet-A: 320-400 nm) and UVB (ultraviolet-B: 280-320 nm) irradiation on the calf thymus DNA in aqueous solution. After both UVA and UVB irradiation for 1 h or 3 h, the damage to the conformation of DNA was moderate, but the reduction of the B-form DNA component was obvious. Both UVA and UVB caused significant damage to the deoxyribose moiety and bases, among which the pyrimidine base pairs were more seriously affected. There appeared to be preferential damaging sites on DNA molecules caused by UVA and UVB irradiation. UVA irradiation caused more damage to the deoxyribose than UVB irradiation, while UVB irradiation caused more significant damage to the pyrimidine moiety than UVA irradiation. After UVB irradiation for 3 h, unstacking of the AT base pairs and the cytosine ring took place, severe damage to the thymine moiety occurred, and some base pairs were modified. Moreover, with either UVA or UVB irradiation for 3 h,the photoreactivation of DNA occurred. The damage to the DNA caused by UVB was immediate, while the damage caused by UVA was proportional to the irradiation duration. The experimental results partly indicate the formation of some cyclobutane pyrimidine dimers and (6-4) photoproducts.

  9. The de Brécy Madonna and Child tondo painting: a Raman spectroscopic analysis.

    Science.gov (United States)

    Edwards, Howell G M; Benoy, Timothy J

    2007-02-01

    Raman spectra have been obtained from a Madonna and Child tondo painting, known as the de Brécy Tondo. Despite the provision of only a small number of microscopic samples, definitive spectra were obtained from mineral pigments. From one specimen, spectra of an organic binder enabled the consideration of several possibilities to be accomplished and a suggestion proposed for the medium. In another specimen the identification of the spectral signatures of Prussian blue, which was only synthesised some 200 years after the predicated date of execution of the painting, indicated that some unrecorded restoration had been undertaken later in the painting's history. Research carried out on this tondo from 1987 to 1991 indicated the probability that it is the work of Raphael, a conclusion supported by further research recently undertaken on the provenance. The stylistic similarity of the tondo to Raphael's Sistine Madonna is very clear; the pigments identified in this analysis are consistent with a Renaissance attribution for the de Brécy Tondo.

  10. High-pressure Fourier transform micro-Raman spectroscopic investigation of diiodine-heterocyclic thioamide adducts.

    Science.gov (United States)

    dos Santos, João Henrique Z; Butler, Ian S; Daga, Vasiliki; Hadjikakou, Sotiris; Hadjiliadis, Nick

    2002-10-01

    The pressure dependences of the Fourier transform micro-Raman spectra of four heterocyclic thioamides [[(bztzdtH)I2] x I2] (1) (bztzdtH = benzothiazole-2-thione), [(bztzdtH)I2] (2), [[(tzdtH)2I+] x I3- x 2I2] (3) (tzdtH = thiazoline-2-thione), and [[(bzimtH)I2]2 x I2 x 2H2O] (4) (bzimtH = benzimidazole-2-thione) have been studied between ambient pressure and 50 kbar. For 1, generation of I3- ions through disproportionation reactions is evident as the pressure is increased. There are empirical linear correlations between the frequency and (I-I) bond length and the applied pressure. The iodine adduct of thioamide 2 is more sensitive to pressure when compared to the 1 or 4 iodine adducts. This difference in behavior may be attributed to differences in crystal structures or to a lower I-I bond order. Monitoring of other vibrational transitions of the thiomide structure reveals several less important pressure dependences.

  11. Resonance Raman spectroscopic evaluation of skin carotenoids as a biomarker of carotenoid status for human studies.

    Science.gov (United States)

    Mayne, Susan T; Cartmel, Brenda; Scarmo, Stephanie; Jahns, Lisa; Ermakov, Igor V; Gellermann, Werner

    2013-11-15

    Resonance Raman spectroscopy (RRS) is a non-invasive method that has been developed to assess carotenoid status in human tissues including human skin in vivo. Skin carotenoid status has been suggested as a promising biomarker for human studies. This manuscript describes research done relevant to the development of this biomarker, including its reproducibility, validity, feasibility for use in field settings, and factors that affect the biomarker such as diet, smoking, and adiposity. Recent studies have evaluated the response of the biomarker to controlled carotenoid interventions, both supplement-based and dietary [e.g., provision of a high-carotenoid fruit and vegetable (F/V)-enriched diet], demonstrating consistent response to intervention. The totality of evidence supports the use of skin carotenoid status as an objective biomarker of F/V intake, although in the cross-sectional setting, diet explains only some of the variation in this biomarker. However, this limitation is also a strength in that skin carotenoids may effectively serve as an integrated biomarker of health, with higher status reflecting greater F/V intake, lack of smoking, and lack of adiposity. Thus, this biomarker holds promise as both a health biomarker and an objective indicator of F/V intake, supporting its further development and utilization for medical and public health purposes.

  12. Combined X-Ray and Raman Spectroscopic Techniques for the Characterization of Sea Spray Aerosol

    Science.gov (United States)

    Aller, J. Y.; Alpert, P. A.; Knopf, D. A.; Kilthau, W.; Bothe, D.; Charnawskas, J. C.; Gilles, M. K.; OBrien, R. E.; Moffet, R.; Radway, J.

    2014-12-01

    Sea spray aerosol along with mineral dust dominates the global mass flux of particles to the atmosphere. Marine aerosol particles are of particular interest because of their continual impact on cloud formation, precipitation, atmospheric chemical processes, and thus global climate. Here we report on the physical/chemical characteristics of sub-surface waters, aerosolized sea spray particles, and particles/organic species present in surface microlayer (SML) samples collected during oceanic field campaigns and generated during laboratory experiments, revealing a biogenic primary source of the organic fraction of airborne particles. We also report on ice nucleation experiments with aerosolized particles collected during the May 2014 WACS II North Atlantic cruise and with laboratory generated exudate material from diatom cultures with the potential to impact cirrus and mixed phase clouds. Physicochemical analyses using a multi-modal approach which includes Scanning Transmission X-ray Microscopy coupled with Near-Edge Absorption Fine Structure Spectroscopy (STXM/NEXAFS) and Raman spectroscopy confirm the presence and chemical similarity of polysaccharide-rich transparent exopolymer (TEP) material and proteins in both SML sea spray aerosol and ice forming aerosol particles, regardless of the extent of biological activity in surface waters. Our results demonstrate a direct relationship between the marine environment and composition of marine aerosol through primary particle emission.

  13. Spectroscopic study of surface enhanced Raman scattering of caffeine on borohydride-reduced silver colloids

    Science.gov (United States)

    Chen, Xiaomin; Gu, Huaimin; Shen, Gaoshan; Dong, Xiao; Kang, Jian

    2010-06-01

    The surface enhanced Raman scattering (SERS) of caffeine on borohydride-reduced silver colloids system under different aqueous solution environment has been studied in this paper. The relative intensity of SERS of caffeine significantly varies with different concentrations of sodium chloride and silver particles. However, at too high or too low concentration of sodium chloride and silver particle, the enhancement of SERS spectra is not evident. The SERS spectra of caffeine suggest that the contribution of the charge transfer mechanism to SERS may be dominant. The chloride ions can significantly enhance the efficiency of SERS, while the enhancement is selective, as the efficiency in charge transfer enhancement is higher than in electromagnetic enhancement. Therefore, it can be concluded that the active site of chloride ion locates on the bond between the caffeine and the silver surface. In addition, the SERS spectra of caffeine on borohydride-reduced and citrate-reduced silver colloids are different, which may be due to different states caffeine adsorbed on silver surface under different silver colloids.

  14. IR and Raman spectroscopic studies of sol–gel derived alkaline-earth silicate glasses

    Indian Academy of Sciences (India)

    Angelos G Kalampounias

    2011-04-01

    IR and Raman spectroscopies have been utilized to study the structure and vibrational modes of sol–gel-derived binary silicate glasses. The present study is motivated by the immense geological significance and focuses on the MO–SiO2 (M = Ca, Mg) binary systems in an effort to unveil the role of the CaO and MgO modifiers when incorporated to the 3D silica structure. Glasses in the composition range = 0, 0.1, 0.2, 0.3 and 0.4 prepared by the sol–gel method were compared with the corresponding glasses formed by appropriate mixing of SiO2 and MO powders through melting and fast cooling. The vibrational spectra of the sol–gel-derived glasses have revealed considerable changes in relative intensities as a function of the MO mole fraction. These changes signify structural modifications on the silica network. The population of the 3 species was found to increase for both modified silicate systems. The rate of increase is more pronounced in the CaO–SiO2 glasses. The extent of network depolymerization in the porous glass is higher at the same content of alkaline earth oxide compared to the bulk glass. The results are indicative of a more `defective’ nature of the sol–gel glasses compared to the corresponding melt-quenched ones.

  15. Pulsed Raman measurements of lattice temperature: Validity tests

    Science.gov (United States)

    Compaan, A.; Lee, M. C.; Lo, H. W.; Trott, G. J.; Aydinli, A.

    1983-10-01

    We measure the temperature dependence of the Raman correction factors and present data on the spot size and transverse beam quality of lasers used in the pulsed Raman measurements of lattice temperature in Si. Recent criticisms are also evaluated and shown to be inappropriate or in error. Finally we measure the shift of the 520-cm-1 Raman line and find it also to be consistent with the observed Stokes/anti-Stokes ratios indicating optic phonon populations characteristic of ˜450 °C.

  16. Raman spectroscopic analysis of cyanogenic glucosides in plants: development of a Flow Injection Surface-Enhanced Raman Scatter (FI-SERS) method for determination of cyanide

    DEFF Research Database (Denmark)

    Thygesen, Lisbeth Garbrecht; Jørgensen, Kirsten; Møller, Birger Lindberg;

    2004-01-01

    Cyanogenic glucosides were studied using Raman spectroscopy. Spectra of the crystal forms of linamarin, linustatin, neolinustatin, amygdalin, sambunigrin, and dhurrin were obtained using a Raman spectrograph microscope equipped with a 532 nm laser. The position of the signal from the CdropN triple...

  17. Automatic and objective oral cancer diagnosis by Raman spectroscopic detection of keratin with multivariate curve resolution analysis

    OpenAIRE

    Po-Hsiung Chen; Rintaro Shimada; Sohshi Yabumoto; Hajime Okajima; Masahiro Ando; Chiou-Tzu Chang; Li-Tzu Lee; Yong-Kie Wong; Arthur Chiou; Hiro-o Hamaguchi

    2016-01-01

    We have developed an automatic and objective method for detecting human oral squamous cell carcinoma (OSCC) tissues with Raman microspectroscopy. We measure 196 independent Raman spectra from 196 different points of one oral tissue sample and globally analyze these spectra using a Multivariate Curve Resolution (MCR) analysis. Discrimination of OSCC tissues is automatically and objectively made by spectral matching comparison of the MCR decomposed Raman spectra and the standard Raman spectrum ...

  18. Diffusion Raman et luminescence dans des aerogels de silice purs ou dopes Dy

    Science.gov (United States)

    Guerri, F.; Fabre, F.; Zwick, A.; Bournett, D.

    1994-02-01

    Light scattering studies of pure and Dy doped aerogels are presented. Careful examination of Stokes and anti-Stokes spectra allow the discrimination between Raman and luminescence processes. It is shown that in pure aerogels, scattered intensity is due to Raman processes only, and the density of vibrational states does not exhibit any singularity. The fractal properties of the structure imply modifications not only in the spectral distribution of the low frequency modes (usually labelled phonons and fractons) but alsoin the high frequency one, at least up to 600 cm-1. In Dy-doped dense silica, coupling between electronic and vibronic excitations is evidenced by the presence of anti-Stokes luminescence. In Dy-doped aerogels, the enlarged Dy3+ electronic levels, strongly coupled with vibrational states give rise to emission processes traducing the response of the sample as a whole, rather than resonant Raman scattering or luminescence processes.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-03-14

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

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

    Science.gov (United States)

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

    2005-03-01

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

  1. Vibrational spectroscopic (FT-IR, FT-Raman) studies, Hirshfeld surfaces analysis, and quantum chemical calculations of m-acetotoluidide and m-thioacetotoluidide

    Science.gov (United States)

    Śmiszek-Lindert, Wioleta Edyta; Chełmecka, Elżbieta; Góralczyk, Stefan; Kaczmarek, Marian

    2017-01-01

    Theoretical calculations of the m-acetotoluidide and m-thioacetotoluidide isolated molecules were performed by using density functional theory (DFT) method at B3LYP/6-311++G (d,p) and B3LYP/6-311++G (3df,2pd) basis set levels. The Hirshfeld surfaces analysis and FT-IR and FT-Raman spectroscopy studies have been reported. The geometrical parameters of the title amide and thioamide are in a good agreement with the XRD experiment. The vibrational frequencies were calculated and scaled, and subsequently values have been compared with the experimental Infrared and Raman spectra. The observed and calculated frequencies are found to be in good agreement. The analysis of the Hirshfeld surface has been well correlated to the spectroscopic studies. Additionally, the highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO) and the energy gap between EHOMO and ELUMO (ΔEHOMO-LUMO) have been calculated.

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

    Science.gov (United States)

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

    2007-05-01

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

  3. Broadband Fiber Raman Power-Amplifier for Narrow Linewidth Tunable Seed Lasers Used in Spectroscopic Sensing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an energy and space efficient high power continuous wave (cw) narrow linewidth broadband fiber Raman amplifier (FRA) with spectrally tunable...

  4. FTIR, Raman, and UV-Vis spectroscopic and DFT investigations of the structure of iron-lead-tellurate glasses.

    Science.gov (United States)

    Rada, Simona; Dehelean, Adriana; Culea, Eugen

    2011-08-01

    In this work, the effects of iron ion intercalations on lead-tellurate glasses were investigated via FTIR, Raman and UV-Vis spectroscopies. This homogeneous glass system has compositions xFe(2)O(3)·(100-x)[4TeO(2)·PbO(2)], where x = 0-60 mol%. The presented observations in these mechanisms show that the lead ions have a pronounced affinity towards [TeO(3)] structural units, resulting in the deformation of the Te-O-Te linkages, and leading to the intercalation of [PbO( n )] (n = 3, 4) and [FeO( n )] (n = 4, 6) entities in the [TeO(4)] chain network. The formation of negatively charged [FeO(4)](1-) structural units implies the attraction of Pb(2+) ions in order to compensate for this electrical charge. Upon increasing the Fe(2)O(3) content to 60 mol%, the network can accommodate an excess of oxygen through the formation of [FeO(6)] structural units and the conversion of [TeO(4)] into [TeO(3)] structural units. For even higher Fe(2)O(3) contents, Raman spectra indicate a greater degree of depolymerization of the vitreous network than FTIR spectra do. The bands due to the Pb-O bond vibrations are very strongly polarized and the [TeO(4)] structural units convert into [TeO(3)] units via an intermediate coordination stage termed "[TeO(3+1)]" structural units. Our UV-Vis spectroscopic data show two mechanisms: (i) the conversion of the Fe(3+) to Fe(2+) at the same time as the oxidation of Pb(2+) to Pb(+4) ions for samples with low Fe(2)O(3) contents; (ii) when the Fe(2)O(3) content is high (x ≥ 50 mol%), the Fe(2+) ions capture positive holes and are transferred to Fe(3+) ions through a photochemical reaction, while the Pb(2+) ions are formed by the reduction of Pb(4+) ions. DFT calculations show that the addition of Fe(2)O(3) to lead-tellurate glasses seems to break the axial Te-O bonds, and the [TeO(4)] structural units are gradually transformed into [TeO(3+1)]- and [TeO(3)]-type polyhedra. Analyzing these data further indicates a gradual

  5. Raman spectroscopic study of the mineral shattuckite Cu5(SiO3)4(OH)2.

    Science.gov (United States)

    Frost, Ray L; Xi, Yunfei

    2012-02-15

    Shattuckite Cu(5)(SiO(3))(4)(OH)(2) is a copper hydroxy silicate and is commonly known as a 'healing' mineral. Three shattuckite mineral samples from three different origins were analysed by Raman spectroscopy. Some Raman bands are common in the spectra of the minerals. Raman bands at around 890, 1058 and 1102 are described as the ν(3) -SiO(3) antisymmetric stretching vibrations. The Raman band at 670cm(-1) is assigned to the ν(4) bending modes of the -SiO(3) units and the band at around 785cm(-1)is due to Si-O-Si chain stretching mode. Raman (and infrared) spectroscopy proves that water is in the molecular structure of shattuckite; thus the formula is better written as Cu(5)(SiO(3))(4)(OH)(2)·xH(2)O.

  6. Raman Spectroscopy Of Glass-Crystalline Transformations

    Science.gov (United States)

    Haro, E.; Balkanski, M.

    1988-01-01

    Glass-crystalline transition is induced by laser irradiation on a GeSe bulk glass sample. The structural changes are detected by Raman spectroscopy. The speed of the crystallization process depends on the laser irradiation intensity. We have studied this crystallization process for three different powers of irradiation. It is found that the speed of crystallization increases with power. Stokes and anti-Stokes spectra were recorded during the transformation. From this data temperature was inferred at different stages of crystallization. The significance of this temperature is discussed.

  7. Nanosecond microscopy with a high spectroscopic resolution

    CERN Document Server

    Heinrich, C; Ritsch-Marte, M; Bernet, Stefan; Heinrich, Christoph; Ritsch-Marte, Monika

    2005-01-01

    We demonstrate coherent anti-Stokes Raman scattering (CARS) microscopy in a wide-field setup with nanosecond laser pulse excitation. In contrast to confocal setups, the image of a sample can be recorded with a single pair of excitation pulses. For this purpose the excitation geometry is specially designed in order to satisfy the phase matching condition over the whole sample area. The spectral, temporal and spatial sensitivity of the method is demonstrated by imaging test samples, i.e. oil vesicles in sunflower seeds, on a nanosecond timescale. The method provides snapshot imaging in 3 nanoseconds with a spectral resolution of 25 wavenumbers (cm$^{-1}$).

  8. Femtosecond coherent Raman spectroscopy and its application to porphyrins.

    Science.gov (United States)

    Schmitt, M; Heid, M; Schlücker, S; Kiefer, W

    2002-01-01

    The results on femtosecond time-resolved coherent anti-Stokes Raman scattering (CARS) experiments for the analysis and control of ground state vibrational dynamics of porphyrin systems are briefly reviewed. By detecting the spectrum of the transient CARS signal, a detailed mapping of the dynamics initiated by the stimulated Raman pump process is achieved. The method yields the dephasing behavior and spectral information of the investigated system at the same time. The different contributions to the ground state vibrational dynamics are selected by changing the direction of the CARS signal analyzer in the polarization arrangement used.

  9. Anti-Stokes effect CCD camera and SLD based optical coherence tomography for full-field imaging in the 1550nm region

    Science.gov (United States)

    Kredzinski, Lukasz; Connelly, Michael J.

    2012-06-01

    Full-field Optical coherence tomography is an en-face interferometric imaging technology capable of carrying out high resolution cross-sectional imaging of the internal microstructure of an examined specimen in a non-invasive manner. The presented system is based on competitively priced optical components available at the main optical communications band located in the 1550 nm region. It consists of a superluminescent diode and an anti-stokes imaging device. The single mode fibre coupled SLD was connected to a multi-mode fibre inserted into a mode scrambler to obtain spatially incoherent illumination, suitable for OCT wide-field modality in terms of crosstalk suppression and image enhancement. This relatively inexpensive system with moderate resolution of approximately 24um x 12um (axial x lateral) was constructed to perform a 3D cross sectional imaging of a human tooth. To our knowledge this is the first 1550 nm full-field OCT system reported.

  10. Near infrared Raman spectroscopic study of reactive gliosis and the glial scar in injured rat spinal cords

    Science.gov (United States)

    Saxena, Tarun; Deng, Bin; Lewis-Clark, Eric; Hoellger, Kyle; Stelzner, Dennis; Hasenwinkel, Julie; Chaiken, Joseph

    2010-02-01

    Comparative Raman spectra of ex vivo, saline-perfused, injured and healthy rat spinal cord as well as experiments using enzymatic digestion suggest that proteoglycan over expression may be observable in injured tissue. Comparison with authentic materials in vitro suggest the occurrence of side reactions between products of cord digestion with chondroitinase (cABC) that produce lactones and similar species with distinct Raman features that are often not overlapped with Raman features from other chemical species. Since the glial scar is thought to be a biochemical and physical barrier to nerve regeneration, this observation suggests the possibility of using near infrared Raman spectroscopy to study disease progression and explore potential treatments ex vivo and if potential treatments can be designed, perhaps to monitor potential remedial treatments within the spinal cord in vivo.

  11. A Raman spectroscopic study of zircons on micro-scale and Its significance in explaining the origin of zircons

    CERN Document Server

    Bao, Xuezhao; Lu, Songnian

    1998-01-01

    The magmatic and metamorphic zircons were investigated with Raman spectrum microprobe analysis. We found notable differences between these two kinds of zircons exhibited by the variation trend of Raman peak intensity from core to rim of a crystal. In magmatic zircons, the intensity and the ratio H/W of Raman spectrum peaks gradually decrease from core to rim of a crystal, which is produced by an increase in metamictization degree and suggests an increase in U and Th concentrations from core to rim. In metamorphic zircons, there are two kinds of crystals according to their Raman spectra: the first group of zircons exhibits a variation trend opposite to those of magmatic zircons, tending to increase in the Raman peak intensity and H/W value from core to rim of a crystal, which is produced by a decrease in metamictization degree and indicates a decrease of U and Th concentrations from core to rim of a crystal. The second group of zircons exhibits no change in Raman peak intensity and H/W value through a crystal....

  12. Revisiting the Young's double slit experiment for background-free nonlinear Raman spectroscopy and microscopy.

    Science.gov (United States)

    Gachet, David; Brustlein, Sophie; Rigneault, Hervé

    2010-05-28

    In the Young's double slit experiment, the spatial shift of the interference pattern projected onto a screen is directly related to the phase difference between the fields diffracted by the two slits. We apply this property to fields emitted by nonlinear processes and thus demonstrate background-free coherent anti-Stokes Raman scattering microscopy near an axial interface between a resonant and a nonresonant medium. This method is relevant to remove the nonresonant background in other coherent resonant processes.

  13. Structural Characterization of Atomically Thin Hexagonal Boron Nitride via Raman Spectroscopy

    Science.gov (United States)

    2014-03-27

    successfully been doped with carbon for use in neutron detectors [8]. 3 Figure 1.1: Currently, only graphene on a h-BN substrate has been...collecting the h- BN spectra to include the selection of appropriate excitation sources, use of filtering packages, and focusing objective. Chapter 4...of one another, it is often the practice of Raman spectroscopy to filter out both the Rayleigh laser line and anti- Stokes lines to solely isolate

  14. CARS (Coherent Anti-Stokes Raman Scattering) Spectroscopy of the Reaction Zone of Methane-Nitrous Oxide and RDX Propellant Flames.

    Science.gov (United States)

    1986-01-01

    initio calculations ( Fendell et al., ref 29) and constants (Dabrowski, et al., ref 30) derived from the BEu <--X’ Eg+ and C flu <-- X Eg+ band of H2 (Haw...Harris, Combustion and Flame, vol 53, 1983, p I3. 5. K. Aron, L. H. Harris, and J. Fendell , Applied Optics, vol 22, 1983, p 36U4. h. K. Aron and L. E...vol 92, 1982, p 246. 29. J. FendelL , L. E. Harris, and K. Aron, "Theoretical Calculation of H2 CARS Spectra for Propellant Flames," Technical Report

  15. Confocal Raman depth-scanning spectroscopic study of phonon-plasmon modes in GaN epilayers

    Science.gov (United States)

    Strelchuk, V. V.; Bryksa, V. P.; Avramenko, K. A.; Valakh, M. Ya.; Belyaev, A. E.; Mazur, Yu. I.; Ware, M. E.; DeCuir, E. A.; Salamo, G. J.

    2011-06-01

    Coupled longitudinal-optical (LO)-phonon-plasmon excitations were studied using confocal micro-Raman spectroscopy. The high-quality Si-doped GaN epilayers were grown in a Gunn diode structure on (0001) sapphire substrates by plasma assisted molecular beam epitaxy. Depth-profiled Raman spectra exhibit a spatial variation of both low, ω-, and high, ω+, frequency coupled phonon-plasmon modes (CPPMs) in the n-GaN layers. To describe the features of the CPPMs in the Raman spectra a self-consistent model that includes both the electro-optic and deformation-potential as well as charge-density fluctuation mechanisms as important processes for light scattering in n-GaN has been proposed. An agreement between the theoretical and experimental line shapes of the Raman spectra is obtained. From the best line-shape fitting of the CPPMs the depth profiles of the plasmon and phonon damping, plasmon frequency, free carrier concentrations, and electron mobility as well as the contributions of the electron-phonon interaction and charge density fluctuations to the Raman cross section in the GaN layers are determined. It is found that these depth profiles exhibit considerable nonuniformity and change at different laser pump-power excitations. Despite the high electron concentration in the n+-GaN layers, a strong peak of the unscreened A1(LO) phonon is also observed. A possible origin for the appearance of this mode is discussed.

  16. Graphitic carbon nanospheres: A Raman spectroscopic investigation of thermal conductivity and morphological evolution by pulsed laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Radhe; Sahoo, Satyaprakash, E-mail: satya504@gmail.com, E-mail: rkatiyar@hpcf.upr.edu; Chitturi, Venkateswara Rao; Katiyar, Ram S., E-mail: satya504@gmail.com, E-mail: rkatiyar@hpcf.upr.edu [Department of Physics, University of Puerto Rico, San Juan, Puerto Rico 00936-8377 (United States)

    2015-12-07

    Graphitic carbon nanospheres (GCNSs) were prepared by a unique acidic treatment of multi-walled nanotubes. Spherical morphology with a narrow size distribution was confirmed by transmission electron microscopy studies. The room temperature Raman spectra showed a clear signature of D- and G-peaks at around 1350 and 1591 cm{sup −1}, respectively. Temperature dependent Raman scattering measurements were performed to understand the phonon dynamics and first order temperature coefficients related to the D- and G-peaks. The temperature dependent Raman spectra in a range of 83–473 K were analysed, where the D-peak was observed to show a red-shift with increasing temperature. The relative intensity ratio of D- to G-peaks also showed a significant rise with increasing temperature. Such a temperature dependent behaviour can be attributed to lengthening of the C-C bond due to thermal expansion in material. The estimated value of the thermal conductivity of GCNSs ∼0.97 W m{sup −1} K{sup −1} was calculated using Raman spectroscopy. In addition, the effect of pulsed laser treatment on the GCNSs was demonstrated by analyzing the Raman spectra of post irradiated samples.

  17. The joined use of n.i. spectroscopic analyses - FTIR, Raman, visible reflectance spectrometry and EDXRF - to study drawings and illuminated manuscripts

    Energy Technology Data Exchange (ETDEWEB)

    Bruni, S.; Guglielmi, V. [Universita degli Studi di Milano, Dipartimento di Chimica Inorganica, Metallorganica e Analitica, Milano (Italy); Caglio, S. [Dipartimento di analisi scientifiche, Open Care, Milano (Italy); Poldi, G. [Dipartimento di analisi scientifiche, Open Care, Milano (Italy); LAM, Universita degli Studi di Bergamo, Bergamo (Italy)

    2008-07-15

    Some art objects being small and very precious prevents conservators and conservation scientists from whatever kind of sampling, so that only completely non-invasive (n.i.) studies are permitted. Besides, also moving the object is sometimes forbidden: this happens for jewels as well as for manuscripts, illuminated codices, drawings and paintings. Some important physical n.i. analyses, such as PIXE and PIGE, therefore cannot be used in many cases. With these limitations, only imaging techniques in X, UV, Visible and IR bands, and a few spectroscopic methods that can be carried out with portable instruments can be applied, i.e. molecular spectroscopies like Fourier transform infrared (FTIR), Raman, UV visible and near IR reflectance spectrometry (UV-Vis-NIR RS) and atomic spectroscopy like energy dispersive X-ray fluorescence (EDXRF). The use of only one or two of these techniques is usually far from giving all the information required to achieve a full characterization of materials used by the artist or during restorations, and to understand some conservative problems of the object. On the contrary, a joined use of n.i. analyses can supply a larger set of data, allowing for cross checks. With this aim we show a fully integrated spectroscopic approach to polychrome objects, and, in particular, to drawings and illuminated manuscripts, using portable instruments, specifically {mu}-FTIR, {mu}-Raman, Vis-RS and EDXRF, where also the Raman signal does not suffer fluorescence caused by varnish coating and from binder. We propose the joined use of all these four physical analyses to characterize materials - support, pigments, dyes, binders, etc. - on a complex case: a painted and drawn parchment of the late 15th century, or the beginning of the 16th, partly attributed to Andrea Mantegna. The collected spectroscopic data have been compared to proper spectral databases, some of which specifically realized in our laboratories. Also, mixtures of pigments and their

  18. Measuring changes in chemistry, composition, and molecular structure within hair fibers by infrared and Raman spectroscopic imaging

    Science.gov (United States)

    Zhang, Guojin; Senak, Laurence; Moore, David J.

    2011-05-01

    Spatially resolved infrared (IR) and Raman images are acquired from human hair cross sections or intact hair fibers. The full informational content of these spectra are spatially correlated to hair chemistry, anatomy, and structural organization through univariate and multivariate data analysis. Specific IR and Raman images from untreated human hair describing the spatial dependence of lipid and protein distribution, protein secondary structure, lipid chain conformational order, and distribution of disulfide cross-links in hair protein are presented in this study. Factor analysis of the image plane acquired with IR microscopy in hair sections, permits delineation of specific micro-regions within the hair. These data indicate that both IR and Raman imaging of molecular structural changes in a specific region of hair will prove to be valuable tools in the understanding of hair structure, physiology, and the effect of various stresses upon its integrity.

  19. Influence of Raman effect on the noise characteristics in a dual pump FOPA

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiao-peng; YU Chong-xiu; DENG Yun-yi; SANG Xin-zhu; YUAN Jin-hui; RAO Lan

    2011-01-01

    Influence induced by Raman effect on the noise characteristics of a depleted and lossy dual pump fiber optical parametric amplifier (FOPA) is investigated.Taking the Raman effect into account,the modified coupled amplitude equations are firstly built,then the influences of Raman effect on the Stokes and anti-Stokes wavelengths with different initial signal powers are further analyzed.Besides,the effect on the FOPA gain is also shown with the same initial signal power and constant noise figure (NF).

  20. Surface-enhanced Raman spectroscopic study of DNA and 6-mercapto-1-hexanol interactions using large area mapping

    DEFF Research Database (Denmark)

    Frøhling, Kasper Bayer; Alstrøm, Tommy Sonne; Bache, Michael;

    2016-01-01

    intensities and peak positions it is possible to directly inspect the interplay between DNA and 6-mercapto-1-hexanol on gold covered nanopillars. It is demonstrated that optimised functionalization parameters can be extracted from the Raman spectra directly. Using the peak-fitting approach it is possible...

  1. Raman Spectroscopic Analysis of Biochemical Changes in Individual Triglyceride-Rich Lipoproteins in the Pre- and Postprandial State

    Energy Technology Data Exchange (ETDEWEB)

    Chan, J; Motton, D; Rutledge, J; Keim, N; Huser, T

    2004-09-13

    Individual triglyceride-rich lipoprotein (TGRL) particles derived from human volunteers are non-destructively analyzed by laser tweezers Raman microspectroscopy and information on their composition and distribution is obtained. The Raman signature of single optically trapped very low-density lipoproteins (VLDL), a subclass of TGRL, which play an important role in cardiovascular disease, exhibits distinct peaks associated with molecular vibrations of fatty acids, proteins, lipids, and structural rearrangements of lipids. Our analysis of pre- and postprandial VLDL exhibits the signature of biochemical changes in individual lipoprotein particles following the consumption of meals. Interaction of VLDL with endothelium leads to the breakdown of complex triacylglycerols and the formation of a highly ordered core of free saturated fatty acids in the particle. A particle distribution analysis reveals trends in the degree to which this process has occurred in particles at different times during the postprandial period. Differences in particle distributions based on the different ratios of polyunsaturated to saturated fats in the consumed meals are also easily discerned. Individual lipoprotein particles hydrolyzed in-vitro through addition of lipoprotein lipase (LpL) exhibit strikingly similar changes in their Raman spectra. These results demonstrate the feasibility of monitoring the dynamics of lipid metabolism of individual TGRL particles as they interact with LpL in the endothelial cell wall using Raman spectroscopy.

  2. Three-dimensional topographic scanning electron microscope and Raman spectroscopic analyses of the irradiation effect on teeth by Nd:YAG, Er: YAG, and CO(2) lasers.

    Science.gov (United States)

    Yamada, Magda K; Uo, Motohiro; Ohkawa, Shoji; Akasaka, Tsukasa; Watari, Fumio

    2004-10-15

    A three-dimensional analyzer installed in a scanning electron microscope was used to evaluate the morphology and surface roughness using noncontact profilometry. Observations were carried out on the enamel and dentin surface irradiated by three different lasers: Nd:YAG (wavelength 1.06 microm), Er:YAG (2.94 microm), and CO(2) (10.6 microm). Spectroscopic analysis was done by Raman spectroscopy for nonirradiated and laser-irradiated surfaces. The lasers were applied perpendicularly to vertically sectioned and polished human extracted caries-free molars. The tooth was sectioned at each cavity for cross-section analysis after laser irradiation. Irradiation by Nd:YAG and CO(2) lasers of the enamel surface showed an opaque white color, different from dentin where the surface turned black. The Er:YAG laser induced no changes in color of the dentin. Numerous cracks associated with thermal stress were observed in the CO(2) laser-irradiated dentin. Noncontact surface profile analysis of Er:YAG laser-irradiated enamel and dentin showed the deepest cavities, and direct cross-sectional observations of them showed similar cavity outlines. The CO(2) laser-irradiated dentin had the least surface roughness. Raman spectroscopic analysis showed that fluorescence from the laser-irradiated tooth was generally greater than from nonirradiated teeth. Bands in dentin attributed to organic collagen matrix were lost after Nd:YAG and CO(2) laser irradiation, and a broad peak due to amorphous carbon appeared. The Er:YAG laser-irradiated dentin showed no sign of a carbon band and had more suitable results for dental ablation. Noncontact surface profile analysis was effective to evaluate the structural change in the tooth in the microarea of study after laser irradiation.

  3. Spectroscopic characterization of sixteenth century panel painting references using Raman, surface-enhanced Raman spectroscopy and helium-Raman system for in situ analysis of Ibero-American Colonial paintings

    Science.gov (United States)

    García-Bucio, María Angélica; Casanova-González, Edgar; Ruvalcaba-Sil, José Luis; Arroyo-Lemus, Elsa; Mitrani-Viggiano, Alejandro

    2016-12-01

    Colonial panel paintings constitute an essential part of Latin-American cultural heritage. Their study is vital for understanding the manufacturing process, including its evolution in history, as well as its authorship, dating and other information significant to art history and conservation purposes. Raman spectroscopy supplies a non-destructive characterization tool, which can be implemented for in situ analysis, via portable equipment. Specific methodologies must be developed, comprising the elaboration of reference panel paintings using techniques and materials similar to those of the analysed period, as well as the determination of the best analysis conditions for different pigments and ground preparations. In order to do so, Raman spectroscopy at 532, 785 and 1064 nm, surface-enhanced Raman spectroscopy (SERS) and a helium-Raman system were applied to a panel painting reference, in combination with X-ray fluorescence analysis. We were able to establish the analysis conditions for a number of sixteenth century pigments and dyes, and other relevant components of panel paintings from this period, 1064 nm Raman and SERS being the most successful. The acquired spectra contain valuable specific information for their identification and they conform a very useful database that can be applied to the analysis of Ibero-American Colonial paintings. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

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

    Science.gov (United States)

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

    2012-09-01

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

  5. HF-EPR, Raman, UV/VIS light spectroscopic, and DFT studies of the ribonucleotide reductase R2 tyrosyl radical from Epstein-Barr virus.

    Directory of Open Access Journals (Sweden)

    Ane B Tomter

    Full Text Available Epstein-Barr virus (EBV belongs to the gamma subfamily of herpes viruses, among the most common pathogenic viruses in humans worldwide. The viral ribonucleotide reductase small subunit (RNR R2 is involved in the biosynthesis of nucleotides, the DNA precursors necessary for viral replication, and is an important drug target for EBV. RNR R2 generates a stable tyrosyl radical required for enzymatic turnover. Here, the electronic and magnetic properties of the tyrosyl radical in EBV R2 have been determined by X-band and high-field/high-frequency electron paramagnetic resonance (EPR spectroscopy recorded at cryogenic temperatures. The radical exhibits an unusually low g₁-tensor component at 2.0080, indicative of a positive charge in the vicinity of the radical. Consistent with these EPR results a relatively high C-O stretching frequency associated with the phenoxyl radical (at 1508 cm⁻¹ is observed with resonance Raman spectroscopy. In contrast to mouse R2, EBV R2 does not show a deuterium shift in the resonance Raman spectra. Thus, the presence of a water molecule as a hydrogen bond donor moiety could not be identified unequivocally. Theoretical simulations showed that a water molecule placed at a distance of 2.6 Å from the tyrosyl-oxygen does not result in a detectable deuterium shift in the calculated Raman spectra. UV/VIS light spectroscopic studies with metal chelators and tyrosyl radical scavengers are consistent with a more accessible dimetal binding/radical site and a lower affinity for Fe²⁺ in EBV R2 than in Escherichia coli R2. Comparison with previous studies of RNR R2s from mouse, bacteria, and herpes viruses, demonstrates that finely tuned electronic properties of the radical exist within the same RNR R2 Ia class.

  6. FT-Raman and FT-IR vibrational spectroscopic studies of Sr{sub 2}RESbO{sub 6} (RE = La to Lu and Y) double perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Martinez, F.; Montero, J.L.; Carrillo, I. [Departamento de Quimica Industrial y Polimeros, EUITI, Universidad Politecnica de Madrid, 28012 Madrid (Spain); Colon, C., E-mail: cristobal.colon@upm.es [Departamento Fisica Aplicada, EUITI, Universidad Politecnica de Madrid, 28012 Madrid (Spain)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer 14 double perovskites Sr{sub 2}RESbO{sub 6} were synthesized. Black-Right-Pointing-Pointer Crystal lattice parameters have been obtained. Black-Right-Pointing-Pointer IR and Raman spectra have been obtained. Black-Right-Pointing-Pointer The crystal structure has been studied. - Abstract: The Sr{sub 2}RESbO{sub 6} double perovskites (RE = La to Lu and Y) were synthesized by ceramic method. The structure and phase purity of the prepared double perovskites were examined by X-ray diffraction pattern and vibrational spectroscopy. A systematic analysis of the compounds structure was carried out for the first time by Raman and IR spectroscopies. A simple inspection of the diffraction patterns shows that these compounds have lower symmetry than the cubic which can be usually found in the Ba{sub 2}RESbO{sub 6} double perovskites. The four active modes (A{sub 1g}, E{sub g}, and two T{sub 2g}) in the Raman spectra and the active mode (T{sub 1u}) in the IR spectra previously described in the spectroscopic data of Ba compounds have changed. In the Sr compounds these modes have been split into its components, in some cases, being active in both types of spectra. According to our data the Sr{sub 2}RESbO{sub 6} double perovskites can be described by a monoclinic symmetry cell, space group P2{sub 1}/n. However, in the cases of Sr{sub 2}LaSbO{sub 6} and Sr{sub 2}PrSbO{sub 6} an alternative structure should be searched by neutron diffraction technique.

  7. FT-IR, FT-Raman spectroscopic study of carotenoids from saffron ( Crocus sativus L.) and some derivatives

    Science.gov (United States)

    Tarantilis, Petros A.; Beljebbar, Abdelilah; Manfait, Michel; Polissiou, Moschos

    1998-04-01

    The carotenoids of saffron, crocins (CRCs), were extracted and their derivatives, dimethylcrocetin (DMCRT) and crocetin (CRT) were prepared from the extract by alkaline hydrolysis in methanol (DMCRT) and by alkaline hydrolysis in water followed by acidification (CRT), respectively. FT-IR, FT-Raman spectroscopies were used to study these compounds. The FT-IR spectra of CRCs, DMCRT and CRT have characteristic absorbance bands between 1706 and 1664 cm -1 ( νCO) and in the region between 1243 and 1228 cm -1 ( νC-O). Two main Raman lines were observed near 1540 and 1166 cm -1 which are respectively assigned to ( νCC) and ( νC-C) stretching modes.

  8. Raman spectroscopic evidence of low temperature stability of D,L-glycolic and L-(+)-lactic acid crystals.

    Science.gov (United States)

    Mohaček-Grošev, Vlasta; Šoštarić, Vladimir; Maksimović, Aleksandar

    2015-04-01

    Raman and infrared spectra of polycrystalline D,L-glycolic and L-(+) lactic acid are presented and assigned both by an ab initio calculation of normal modes of free conformers and by self-consistent-charge density-functional-theory computational program DFTB+. Temperature dependent Raman spectra from 295 K to 10 K reveal great stability of crystal lattices, since no soft modes and no band splittings that could be attributed to changes of the number of molecules per unit cell were observed. A semiempirical calculation with GULP program was used to estimate the strength of hydrogen bonds in crystals: in glycolic acid they have energies of -0.337 eV/mol, -0.329 eV/mol, -0.262 eV/mol and -0.242 eV/mol, while in lactic acid two hydrogen bonds have energies of -0.283 eV/mol and -0.202 eV/mol.

  9. FT-Raman spectroscopic characterization of enamel surfaces irradiated with Nd:YAG and Er:YAG lasers

    Science.gov (United States)

    Shahabi, Sima; Fekrazad, Reza; Johari, Maryam; Chiniforoush, Nasim; Rezaei, Yashar

    2016-01-01

    Background. Despite recent advances in dental caries prevention, caries is common and remains a serious health problem. Laser irradiation is one of the most common methods in preventive measures in recent years. Raman spectroscopy technique is utilized to study the microcrystalline structure of dental enamel. In this study, FT-Raman spectroscopy was used to evaluate chemical changes in enamel structure irradiated with Nd:YAG and Er:YAG lasers. Methods. We used 15 freshly-extracted, non-carious, human molars that were treated as follows: No treatment was carried out in group A (control group); Group B was irradiated with Er:YAG laser for 10 seconds under air and water spray; and Group C was irradiated with Nd:YAG laser for 10 seconds under air and water spray. After treatment, the samples were analyzed by FT-Raman spectroscopy. Results. The carbonate content evaluation with regard to the integrated area under the curve (1065/960 cm–1) exhibited a significant reduction in its ratio in groups B and C. The organic content (2935/960 cm-1) area exhibited a significant decrease after laser irradiation in group B and C. Conclusion. The results showed that the mineral and organic matrices of enamel structure were affected by laser irradiation; therefore, it might be a suitable method for caries prevention. PMID:28096945

  10. Development and comparative assessment of Raman spectroscopic classification algorithms for lesion discrimination in stereotactic breast biopsies with microcalcifications.

    Science.gov (United States)

    Dingari, Narahara Chari; Barman, Ishan; Saha, Anushree; McGee, Sasha; Galindo, Luis H; Liu, Wendy; Plecha, Donna; Klein, Nina; Dasari, Ramachandra Rao; Fitzmaurice, Maryann

    2013-04-01

    Microcalcifications are an early mammographic sign of breast cancer and a target for stereotactic breast needle biopsy. Here, we develop and compare different approaches for developing Raman classification algorithms to diagnose invasive and in situ breast cancer, fibrocystic change and fibroadenoma that can be associated with microcalcifications. In this study, Raman spectra were acquired from tissue cores obtained from fresh breast biopsies and analyzed using a constituent-based breast model. Diagnostic algorithms based on the breast model fit coefficients were devised using logistic regression, C4.5 decision tree classification, k-nearest neighbor (k -NN) and support vector machine (SVM) analysis, and subjected to leave-one-out cross validation. The best performing algorithm was based on SVM analysis (with radial basis function), which yielded a positive predictive value of 100% and negative predictive value of 96% for cancer diagnosis. Importantly, these results demonstrate that Raman spectroscopy provides adequate diagnostic information for lesion discrimination even in the presence of microcalcifications, which to the best of our knowledge has not been previously reported.

  11. Raman spectroscopic analysis for grain boundary of Superconducting polycrystalline SmFeAsO1-xFx

    Science.gov (United States)

    Shinohara, Hajime; Fujioka, Masaya; Taniguchi, Hiroki; Itoh, Mitsuru; Atou, Toshiyuki; Takano, Yoshihiko; Kumakura, Hiroaki; Matoba, Masanori; Kamihara, Yoichi

    2013-03-01

    The observation of grain boundary structures is essential technique to fabricate high-Tc superconducting wires. Spatial crystal distribution analysis for grain boundary of superconducting polycrystalline SmFeAsO1-xFx is demonstrated by Raman Spectroscopy. Polycrystalline SmFeAsO1-xFx samples were synthesized using two-step solid state reaction described elsewhere [New J. Phys.12, 033005 (2010)]. Samples' surface and their structures were checked by microscopic optical measurement and electron beam backscattering diffraction (EBSD) analysis. The Raman spectroscopy was performed at the range from 150 cm-1 to 500 cm-1. F contents (x) were 0, 0.019, 0.037, 0.045, 0.069, 0.075. Although our several spectra are similar to which had been reported [Hadjiev, et al, Phys. Rev. B. 77, 220505 (2008)], our results indicate that grain boundary structures are mixtures of small single crystalline SmFeAsO1-xFx and amorphous-FeAs. Details of the Raman spectra will be presented at the conference.

  12. A spectroscopic study of M rate at C{sub 82} metallofullerenes: Raman, far-infrared, and neutron scattering results

    Energy Technology Data Exchange (ETDEWEB)

    Lebedkin, S.; Renker, B.; Rietschel, H. [Forschungszentrum Karlsruhe (Germany). INFP; Heid, R. [Max-Planck-Institut fuer Physik komplexer Systeme, D-01187 Dresden (Germany); Schober, H. [Institut Laue-Langevin, F-38042 Grenoble (France)

    1998-03-01

    Polycrystalline samples of M rate at C{sub 82} metallofullerenes have been studied at room temperature by Raman (for M=La, Y, Ce, Gd), far-infrared (FIR) (for M=La, Y, Ce), and inelastic neutron scattering (INS) (for M=La, Y) spectroscopy. Raman and FIR spectra suggest that these metallofullerenes have a common dominant, if not a single, structure of the C{sub 82} cage and a similar bonding of the encapsulated metal ion, i.e. the bonding is primarily electrostatic and the metal atoms are in the same oxidation state (+3). The metal ion vibrations are located around 160 and 50 cm{sup -1}. INS reveals no gap between internal vibrational and external vibrational and rotational modes in the range {proportional_to}50-200 cm{sup -1} as is typically observed for other fullerides and also predicted by our model calculations. Presumably this is due to strong intermolecular interactions between M rate at C{sub 82} units in the bulk sample. The studied metallofullerenes are air sensitive, and degradation in air could be followed by changes in the Raman spectra. (orig.) With 6 figs., 2 tabs., 47 refs.

  13. Plasmon-enhanced light harvesting of chlorophylls on near-percolating silver films via one-photon anti-Stokes upconversion.

    Science.gov (United States)

    Wang, Ya-Lan; Nan, Fan; Liu, Xiao-Li; Zhou, Li; Peng, Xiao-Niu; Zhou, Zhang-Kai; Yu, Ying; Hao, Zhong-Hua; Wu, Yan; Zhang, Wei; Wang, Qu-Quan; Zhang, Zhenyu

    2013-01-01

    There exists a wealth of means of efficient utilization of solar energy in nature, with photosynthesis of chlorophylls as a prime example. Separately, artificially structured plasmonic materials are versatile in light harvesting and energy conversion. Using a simple and scalable design of near-percolating silver nanostructures, we demonstrate that the light-harvesting efficiency of chlorophylls can be drastically enhanced by tuning the plasmon frequency of the constituent silver nanoparticles to coincide with the maximal photon flux of sunlight. In particular, we show that the photon upconversion efficiency can be readily enhanced by over 20 folds, with the room-temperature fluorescence quantum yield increased by a factor of 2.63. The underlying mechanism for the upconversion enhancement is attributed to a one-electron-per-photon anti-Stokes process, involving absorption of a characteristic phonon mode of the chlorophylls. These findings suggest that chlorophylls can serve as molecular building blocks for high-efficiency light harvesting and solar energy conversion.

  14. Raman Cooling of Solids through Photonic Density of States Engineering

    CERN Document Server

    Chen, Yin-Chung

    2015-01-01

    The laser cooling of vibrational states of solids has been achieved through photoluminescence in rare-earth elements, optical forces in optomechanics, and the Brillouin scattering light-sound interaction. The net cooling of solids through spontaneous Raman scattering, and laser refrigeration of indirect band gap semiconductors, both remain unsolved challenges. Here, we analytically show that photonic density of states (DoS) engineering can address the two fundamental requirements for achieving spontaneous Raman cooling: suppressing the dominance of Stokes (heating) transitions, and the enhancement of anti-Stokes (cooling) efficiency beyond the natural optical absorption of the material. We develop a general model for the DoS modification to spontaneous Raman scattering probabilities, and elucidate the necessary and minimum condition required for achieving net Raman cooling. With a suitably engineered DoS, we establish the enticing possibility of refrigeration of intrinsic silicon by annihilating phonons from ...

  15. Raman crystal lasers in the visible and near-infrared

    Institute of Scientific and Technical Information of China (English)

    EICHLERH.J.; GADG.M.A.; KAMINSKIIA.A.; RHEEH.

    2003-01-01

    Raman lasers based on potassium gadolinium tungstate and lead tungstate crystals pumped by a≈120 ps Nd: YAG laser at 1.064/μm were developed. High reflection mirrors for the Stokes wavelength have been used to generate near-infrared and eye safe spectral region of 1.15 - 1.32/μm. Second harmonic generation of the generated Raman lasers was observed. Eifficient multiple Stokes and anti-Stokes picosecond generation in 64 crystals have been shown to exhibit stimulated Raman scattering on about 700 lines covering the whole visible and near-infrared spectrum. All stimulated Raman scattering (SRS) wavelengths in the visible and near-infrared spectrum are identified and attributed to the SRS-active vibration modes of these crystals.

  16. Raman crystal lasers in the visible and near-infrared

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Raman lasers based on potassium gadolinium tungstate and lead tungstate crystals pumped by a≈120 ps Nd: YAG laser at 1.064 μm were developed. High reflection mirrors for the Stokes wavelength have been used to generate near-infrared and eye safe spectral region of 1.15-1.32 μm. Second harmonic generation of the generated Raman lasers was observed. Eifficient multiple Stokes and anti-Stokes picosecond generation in 64 crystals have been shown to exhibit stimulated Raman scattering on about 700 lines covering the whole visible and near-infrared spectrum. All stimulated Raman scattering (SRS) wavelengths in the visible and near-infrared spectrum are identified and attributed to the SRS-active vibration modes of these crystals.

  17. Raman spectroscopic studies on the structural changes of poly(3-methylthiophene)during heating and cooling processes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Poly(3-methylthiophene) (PMeT) electrosynthesized by direct oxidation of 3-methylthiophene in boron trifluoride diethyl etherate (BFEE) has been studied by Raman spectroscopy in the temperature scale of 123-458 K. Experimental results demonstrate that the thermal stability of PMeT in the oxidized state is much lower than that of the polymer in the neutral state. Furthermore, during the cooling process, the conformation of neutral species changes from a coil-like state into a rod-like state, while the conformation of the oxidized species does not change.

  18. Raman spectroscopic study on structure of human immunodeficiency virus (HIV) and hypericin-induced photosensitive damage of HIV

    Institute of Scientific and Technical Information of China (English)

    XU; Yiming; LU; Chuanzong

    2005-01-01

    The first Raman spectra of HIV1- HIV2 in human sera and hypericin-induced photosensitive damage of the virus have been obtained. The prominent Raman lines in the spectra are assigned respectively to the carbohydrates of viral glycoprotein, RNA, protein and lipid. The spectra are dominated by Raman scattering of the carbohydrates. The lines of D-Mannose and N-acetylglucosamine in carbohydrates are obvious and there is a β-configuration in the anomeric C1 position in D-Mannose. The viral RNA duplexes bound assumes an A-form geometry. The lines of backbone phosphate group, bases (involving interbase hydrogen bonding) and ribose of the RNA are complete and distinct. The secondary structure of the viral protein maintains β-helix, β-sheet, β-turn and random coil. Its side chains are rich and vary from tryptophan, phenylalanine and "buried" tyrosine; the stable conformation of the S-S bond of gauche-gauche-gauche; the two forms of C-S bonds of gauche and trans ; to sulfhydrl group and ionized and unionized carboxyl groups. The viral lipid bilayer molecules are probably in the liquid ordered phase or the gel phase. It was observed that the hypericin-induced photosensitive damage of HIV1-HIV2 in human sera changed various components of HIV1-HIV2 in different degrees : The orderly A-form viral RNA would become a disordered viral RNA. There were a breakage of interbase hydrogen bonds and disruption of vertical base-base stacking interactions. In addition, the groups of ribos and four bases were damaged obviously. A decrease in ordered structure (α-helix and α-sheet) of viral protein is accompanied by an increase in random coil. The Tyr buried in the three-dimensional structure of protein was damaged, but it was still "buried" and the damage of C-S bond of trans form was stronger. The groups of carbohydrates, including D-Mannos and N-acetyl glucosamine, in viral envelope glycoprotein had also been changed. The hydrophilic C-N bond of choline in viral lipid was damaged

  19. Radiation-reaction-force-induced nonlinear mixing of Raman sidebands of an ultraintense laser pulse in a plasma.

    Science.gov (United States)

    Kumar, Naveen; Hatsagortsyan, Karen Z; Keitel, Christoph H

    2013-09-06

    Stimulated Raman scattering of an ultraintense laser pulse in plasmas is studied by perturbatively including the leading order term of the Landau-Lifshitz radiation reaction force in the equation of motion for plasma electrons. In this approximation, the radiation reaction force causes a phase shift in nonlinear current densities that drive the two Raman sidebands (anti-Stokes and Stokes waves), manifesting itself into the nonlinear mixing of two sidebands. This mixing results in a strong enhancement in the growth of the forward Raman scattering instability.

  20. Generation of a VUV-to-visible Raman frequency comb in hydrogen-filled kagom\\'e photonic crystal fiber

    CERN Document Server

    Mridha, M K; Bauerschmidt, S T; Abdolvand, A; Russell, P St J

    2016-01-01

    We report the generation of a purely vibrational Raman comb, extending from the vacuum ultraviolet (184 nm) to the visible (478 nm), in hydrogen-filled kagom\\'e-style photonic crystal fiber pumped at 266 nm. Stimulated Raman scattering and molecular modulation processes are enhanced by higher Raman gain in the ultraviolet. Owing to the pressure-tunable normal dispersion landscape of the fiber-gas system in the ultraviolet, higher-order anti-Stokes bands are generated preferentially in higher-order fiber modes. The results pave the way towards tunable fiber-based sources of deep- and vacuum ultraviolet light for applications in, e.g., spectroscopy and biomedicine.

  1. Localized tip enhanced Raman spectroscopic study of impurity incorporated single GaN nanowire in the sub-diffraction limit

    Energy Technology Data Exchange (ETDEWEB)

    Patsha, Avinash, E-mail: avinash.phy@gmail.com, E-mail: dhara@igcar.gov.in; Dhara, Sandip; Tyagi, A. K. [Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2015-09-21

    The localized effect of impurities in single GaN nanowires in the sub-diffraction limit is reported using the study of lattice vibrational modes in the evanescent field of Au nanoparticle assisted tip enhanced Raman spectroscopy (TERS). GaN nanowires with the O impurity and the Mg dopants were grown by the chemical vapor deposition technique in the catalyst assisted vapor-liquid-solid process. Symmetry allowed Raman modes of wurtzite GaN are observed for undoped and doped nanowires. Unusually very strong intensity of the non-zone center zone boundary mode is observed for the TERS studies of both the undoped and the Mg doped GaN single nanowires. Surface optical mode of A{sub 1} symmetry is also observed for both the undoped and the Mg doped GaN samples. A strong coupling of longitudinal optical (LO) phonons with free electrons, however, is reported only in the O rich single nanowires with the asymmetric A{sub 1}(LO) mode. Study of the local vibration mode shows the presence of Mg as dopant in the single GaN nanowires.

  2. Raman spectroscopic analysis of iron chromium oxide microspheres generated by nanosecond pulsed laser irradiation on stainless steel.

    Science.gov (United States)

    Ortiz-Morales, M; Soto-Bernal, J J; Frausto-Reyes, C; Acosta-Ortiz, S E; Gonzalez-Mota, R; Rosales-Candelas, I

    2015-06-15

    Iron chromium oxide microspheres were generated by pulsed laser irradiation on the surface of two commercial samples of stainless steel at room temperature. An Ytterbium pulsed fiber laser was used for this purpose. Raman spectroscopy was used for the characterization of the microspheres, whose size was found to be about 0.2-1.7 μm, as revealed by SEM analysis. The laser irradiation on the surface of the stainless steel modified the composition of the microspheres generated, affecting the concentration of the main elemental components when laser power was increased. Furthermore, the peak ratio of the main bands in the Raman spectra has been associated to the concentration percentage of the main components of the samples, as revealed by Energy-Dispersive X-ray Spectroscopy (EDS) analysis. These experiments showed that it is possible to generate iron chromium oxide microspheres on stainless steel by laser irradiation and that the concentration percentage of their main components is associated with the laser power applied.

  3. Raman spectroscopic investigation of 13CO 2 labeling and leaf dark respiration of Fagus sylvatica L. (European beech).

    Science.gov (United States)

    Keiner, Robert; Gruselle, Marie-Cécile; Michalzik, Beate; Popp, Jürgen; Frosch, Torsten

    2015-03-01

    An important issue, in times of climate change and more extreme weather events, is the investigation of forest ecosystem reactions to these events. Longer drought periods stress the vitality of trees and promote mass insect outbreaks, which strongly affect ecosystem processes and services. Cavity-enhanced Raman gas spectrometry was applied for online multi-gas analysis of the gas exchange rates of O2 and CO2 and the labeling of Fagus sylvatica L. (European beech) seedlings with (13)CO2. The rapid monitoring of all these gases simultaneously allowed for the separation of photosynthetic uptake of CO2 by the beech seedlings and a constant (12)CO2 efflux via respiration and thus for a correction of the measured (12)CO2 concentrations in course of the labeling experiment. The effects of aphid infestation with the woolly beech aphid (Phyllaphis fagi L.) as well as the effect of a drought period on the respirational gas exchange were investigated. A slightly decreased respirational activity of drought-stressed seedlings in comparison to normally watered seedlings was found already for a low drought intensity. Cavity-enhanced Raman gas monitoring of O2, (12)CO2, and (13)CO2 was proven to be a powerful new tool for studying the effect of drought stress and aphid infestation on the respirational activity of European beech seedlings as an example of important forest species in Central Europe.

  4. Question 2: Raman spectroscopic approach to analytical astrobiology: the detection of key biomolecular markers in the search for life.

    Science.gov (United States)

    Edwards, Howell G M

    2007-10-01

    The recognition of extinct or extant life signatures in the terrestrial geological record is fundamentally dependent upon the understanding of both the structural morphology and chemical composition of relict biomaterials; the identification of cyanobacterial colonies that have adapted biogeologically their mineral matrices in early evolutionary processes is a fundamental step in the acquisition of analytical data from remote planetary probes designed for life-detection experiments, particularly on Mars and on the planetary satellite moons, Europa and Titan. A key factor in the assessment of early life signatures is the molecular presence of chemicals designed to protect the emerging organisms from the damaging effect of radiation exposure and of desiccation and temperature changes; in this respect the non-destructive capability of Raman spectroscopy to delineate the interfacial interactions between substrates and endolithic biology is now deemed an essential part of the ExoMars life-detection suite of instrumentation planned by the European Space Agency in the AURORA programme. A description of the scientific basis for the biogeological discrimination offered by Raman spectroscopy between organic and inorganic moieties in specimens from terrestrial Mars analogue sites is followed by selected examples of the type of analytical information provided, which will be complementary to the elementary and microscopic data obtained from other instrumentation on the same mission.

  5. Correlation steering in the angularly multimode Raman atomic memory.

    Science.gov (United States)

    Mazelanik, Mateusz; Dąbrowski, Michał; Wasilewski, Wojciech

    2016-09-19

    We present the possibility of steering the direction of correlations between the off-resonant Raman scattered photons from the angularly multimode atomic memory based on warm rubidium vapors. Using acousto-optic deflectors (AOD) driven by different modulation frequencies, we experimentally change the angle of incidence of the laser beams on the atomic ensemble. By performing correlation measurements for various deflection angles, we verify that we can choose the anti-Stokes light propagation direction independently of the correlated Stokes scattered light in a continuous way. As a result we can select the spatial mode of photons retrieved from the memory, which may be important for future development of quantum information processing.

  6. Spectroscopic [FT-IR and FT-Raman] and molecular modeling (MM) study of benzene sulfonamide molecule using quantum chemical calculations

    Science.gov (United States)

    Vinod, K. S.; Periandy, S.; Govindarajan, M.

    2016-07-01

    The spectroscopic and molecular modeling (MM) study includes, FT-IR, FT-Raman and 13C NMR and 1H NMR spectra of the Benzene sulfonamide were recorded for the analysis. The observed experimental and theoretical frequencies (IR and Raman) were assigned according to their distinctive region. The present study of this title molecule have been carried out by hybrid computational calculations of HF and DFT (B3LYP) methods with 6-311+G(d,p) and 6-311++G(d,p) basis sets and the corresponding results are tabulated. The structural modifications of the compound due to the substitutions of NH2 and SO2 were investigated. The minimum energy conformers of the compound were studied using conformational analysis. The alternations of the vibrational pattern of the base structure related to the substitutions were analyzed. The thermodynamic parameters (such as zero-point vibrational energy, thermal energy, specific heat capacity, rotational constants, entropy, and dipole moment) of Benzene sulfonamide have been calculated. The donor acceptor interactions of the compound and the corresponding UV transitions are found out using NBO analysis. The NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts related to TMS were compared. A quantum computational study on the electronic and optical properties absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by HF and DFT methods. The energy gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand group. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at different temperatures were calculated in gas phase and

  7. Tuning of near-infrared-to-near-infrared luminescence from one-photon to two-photon anti-Stokes shift in Casub>3sub>Gasub>2-sub> sub>xsub>Crsub>xsub>Gesub>3sub>Osub>12sub> via varying Cr3+ content.

    Science.gov (United States)

    Lin, Huihong; Yu, Ting; Bai, Gongxun; Zhang, Qinyuan; Hao, Jianhua

    2017-02-15

    Near-infrared-to-near-infrared (NIR-to-NIR) anti-Stokes luminescence from Cr3+ singly doped Casub>3sub>Gasub>2sub>Gesub>3sub>Osub>12sub> (CGGG) occurs under the excitation of an 808 nm diode laser. The anti-Stokes processes vary from one photon to two photon, depending on the Cr3+ content (x) in Casub>3sub>Gasub>2-xsub>Crsub>xsub>Gesub>3sub>Osub>12sub>. The results suggest that phonon-assisted anti-Stokes excitation and cooperative energy transfer are involved in the observed upconversion (UC) processes of CGGG:Cr3+. The relevant Cr3+-doping-concentration-dependent NIR-to-NIR anti-Stokes luminescent mechanism, either one-photon or two-photon UC, is investigated. Such an observation on modulating the UC process via varying the doping concentration is helpful in broadening the understanding of UC phenomena.

  8. Spectroscopic (UV/VIS, Raman) and Electrophoresis Study of Cytosine-Guanine Oligonucleotide DNA Influenced by Magnetic Field.

    Science.gov (United States)

    Banihashemian, Seyedeh Maryam; Periasamy, Vengadesh; Boon Tong, Goh; Abdul Rahman, Saadah

    2016-01-01

    Studying the effect of a magnetic field on oligonucleotide DNA can provide a novel DNA manipulation technique for potential application in bioengineering and medicine. In this work, the optical and electrochemical response of a 100 bases oligonucleotides DNA, cytosine-guanine (CG100), is investigated via exposure to different magnetic fields (250, 500, 750, and 1000 mT). As a result of the optical response of CG100 to the magnetic field, the ultra-violet-visible spectrum indicated a slight variation in the band gap of CG100 of about 0.3 eV. Raman spectroscopy showed a significant deviation in hydrogen and phosphate bonds' vibration after exposure to the magnetic field. Oligonucleotide DNA mobility was investigated in the external electric field using the gel electrophoresis technique, which revealed a small decrease in the migration of CG100 after exposure to the magnetic field.

  9. Spectroscopic (FT-IR, FT-Raman, UV-Visible) and quantum chemical studies of 4-Chloro-3-iodobenzophenone

    Science.gov (United States)

    Venkata Prasad, K.; Muthu, S.; Santhamma, C.

    2017-01-01

    The vibrational analysis of the substituted Benzophenone molecule 4-Chloro-3-iodobenzophenone (4, 3-ClIBP) is carried out using both FT-IR and FT-Raman spectra and also quantum chemical calculations of the scaled frequencies using the DFT method B3LYP/LanL2DZ basis set. The natural bond orbital analysis of this molecule has been carried out to describe the various intramolecular interactions responsible for the stabilization of the molecule. The HOMO, LUMO energy gap have been computed with the TD-DFT theory and the differences are compared with UV-absorption spectra. The statistical thermodynamic functions are calculated for the range of 100-1000 k. The Fukui functions are evaluated to describe the activity of the sites.

  10. Spectroscopic (FT-IR, FT-Raman, UV) and microbiological studies of di-substituted benzoates of alkali metals

    Science.gov (United States)

    Kalinowska, M.; Świsłocka, R.; Borawska, M.; Piekut, J.; Lewandowski, W.

    2008-06-01

    The FT-IR, FT-Raman and UV spectra of 3,5-dihydroxybenzoic and 3,5-dichlorobenzoic acids as well as lithium, sodium, potassium, rubidium, caesium 3,5-dihydroxy- and 3,5-dichlorobenzoates were recorded, assigned and compared. The theoretical geometries, Mulliken atomic charges, IR wavenumbers were obtained in B3LYP/6-311++G** level. On the basis of the gathered experimental and theoretical data the effect of metals and substituents on the electronic system of studied compounds were investigated. Moreover, the antimicrobiological activity of studied compounds against two species of bacteria: Bacillus subtilis, Staphylococus aureus and one species of yeast: Candida albicans were studied after 24 and 48 h of incubation. The attempt was made, to find out whether there is any correlation between the first principal component and the degree of growth inhibition exhibited by studied compounds in relation to selected microorganisms.

  11. Optical parametric oscillator-based light source for coherent Raman scattering microscopy: practical overview

    Science.gov (United States)

    Brustlein, Sophie; Ferrand, Patrick; Walther, Nico; Brasselet, Sophie; Billaudeau, Cyrille; Marguet, Didier; Rigneault, Hervé

    2011-02-01

    We present the assets and constraints of using optical parametric oscillators (OPOs) to perform point scanning nonlinear microscopy and spectroscopy with special emphasis on coherent Raman spectroscopy. The difterent possible configurations starting with one OPO and two OPOs are described in detail and with comments that are intended to be practically useful for the user. Explicit examples on test samples such as nonlinear organic crystal, polystyrene beads, and fresh mouse tissues are given. Special emphasis is given to background-free coherent Raman anti-Stokes scattering (CARS) imaging, including CARS hyperspectral imaging in a fully automated mode with commercial OPOs.

  12. High-resolution inverse Raman and resonant-wave-mixing spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rahn, L.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    These research activities consist of high-resolution inverse Raman spectroscopy (IRS) and resonant wave-mixing spectroscopy to support the development of nonlinear-optical techniques for temperature and concentration measurements in combustion research. Objectives of this work include development of spectral models of important molecular species needed to perform coherent anti-Stokes Raman spectroscopy (CARS) measurements and the investigation of new nonlinear-optical processes as potential diagnostic techniques. Some of the techniques being investigated include frequency-degenerate and nearly frequency-degenerate resonant four-wave-mixing (DFWM and NDFWM), and resonant multi-wave mixing (RMWM).

  13. Biomolecular interaction study of hydralazine with bovine serum albumin and effect of β-cyclodextrin on binding by fluorescence, 3D, synchronous, CD, and Raman spectroscopic methods.

    Science.gov (United States)

    Bolattin, Mallavva B; Nandibewoor, Sharanappa T; Chimatadar, Shivamurti A

    2016-07-01

    Spectrofluoremetric technique was employed to study the binding behavior of hydralazine with bovine serum albumin (BSA) at different temperatures. Binding study of bovine serum albumin with hydralazine has been studied by ultraviolet-visible spectroscopy, fluorescence spectroscopy and confirmed by three-dimensional, synchronous, circular dichroism, and Raman spectroscopic methods. Effect of β-cyclodextrin on binding was studied. The experimental results showed a static quenching mechanism in the interaction of hydralazine with bovine serum albumin. The binding constant and the number of binding sites are calculated according to Stern-Volmer equation. The thermodynamic parameters ∆H(o) , ∆G(o) , ∆S(o) at different temperatures were calculated. These indicated that the hydrogen bonding and weak van der Waals forces played an important role in the interaction. Based on the Förster's theory of non-radiation energy transfer, the binding average distance, r, between the donor (BSA) and acceptor (hydralazine) was evaluated and found to be 3.95 nm. Spectral results showed that the binding of hydralazine to BSA induced conformational changes in BSA. The effect of common ions on the binding of hydralazine to BSA was also examined. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Spectroscopic characteristic (FT-IR, FT-Raman, UV, 1H and 13C NMR), theoretical calculations and biological activity of alkali metal homovanillates

    Science.gov (United States)

    Samsonowicz, M.; Kowczyk-Sadowy, M.; Piekut, J.; Regulska, E.; Lewandowski, W.

    2016-04-01

    The structural and vibrational properties of lithium, sodium, potassium, rubidium and cesium homovanillates were investigated in this paper. Supplementary molecular spectroscopic methods such as: FT-IR, FT-Raman in the solid phase, UV and NMR were applied. The geometrical parameters and energies were obtained from density functional theory (DFT) B3LYP method with 6-311++G** basis set calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned. Geometric and magnetic aromaticity indices, atomic charges, dipole moments, HOMO and LUMO energies were also calculated. The microbial activity of investigated compounds was tested against Bacillus subtilis (BS), Pseudomonas aeruginosa (PA), Escherichia coli (EC), Staphylococcus aureus (SA) and Candida albicans (CA). The relationship between the molecular structure of tested compounds and their antimicrobial activity was studied. The principal component analysis (PCA) was applied in order to attempt to distinguish the biological activities of these compounds according to selected band wavenumbers. Obtained data show that the FT-IR spectra can be a rapid and reliable analytical tool and a good source of information for the quantitative analysis of the relationship between the molecular structure of the compound and its biological activity.

  15. Raman spectroscopic analysis of the increase of the carotenoid antioxidant concentration in human skin after a 1-week diet with ecological eggs

    Science.gov (United States)

    Hesterberg, Karoline; Lademann, Jürgen; Patzelt, Alexa; Sterry, Wolfram; Darvin, Maxim E.

    2009-03-01

    Skin aging is mainly caused by the destructive action of free radicals, produced by the UV light of the sun. The human skin has developed a protection system against these highly reactive molecules in the form of the antioxidative potential. Carotenoids are one of the main components of the antioxidants of the human skin. From former studies, it is known that skin aging is reduced in individuals with high levels of carotenoids. Because most of the antioxidants cannot be produced by the human organism, they must be up taken by nutrition. Using noninvasive Raman spectroscopic measurements it is demonstrated that not only fruits and vegetables but also eggs contain high concentrations of antioxidants including carotenoids, which are even doubled in the case of ecological eggs. After a 1-week diet with ecological eggs performed by six volunteers, it is found that the concentration of the carotenoids in the skin of the volunteers increased by approx. 20%. Our study does not intend to recommend exorbitant egg consumption, as eggs also contain harmful cholesterol. But in the case of egg consumption, ecological eggs from hens kept on pasture should be preferred to also receive a benefit for the skin.

  16. NMR, FT-IR, FT-Raman, UV spectroscopic, HOMO-LUMO and NBO analysis of cumene by quantum computational methods

    Science.gov (United States)

    Sivaranjani, T.; Xavier, S.; Periandy, S.

    2015-03-01

    This work presents the investigation of cumene using the FT-IR, FT-Raman, NMR and UV spectra obtained through various spectroscopic techniques. The theoretical vibrational frequencies and optimized geometric parameters have been calculated by using HF and density functional theory with the hybrid methods B3LYP, B3PW91 and 6-311+G(d,p)/6-311++G(d,p) basis sets. The theoretical vibrational frequencies have been scaled and compared with the corresponding experimental data. 1H and 13C NMR spectra were recorded and chemical shifts of the molecule were compared to TMS by using the Gauge-Independent Atomic Orbital (GIAO) method. A study on the electronic and optical properties, absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, and potential energy surface (PES) is performed using HF and DFT methods. The thermodynamic properties (heat capacity, entropy and enthalpy) at different temperatures are also calculated. NBO analysis is carried out to picture the charge transfer between the localized bonds and lone pairs. NLO properties related to polarizability and hyperpolarizability are also discussed.

  17. Tip-enhanced Raman spectroscopic imaging shows segregation within binary self-assembled thiol monolayers at ambient conditions.

    Science.gov (United States)

    Lin, Wan-Ing; Shao, Feng; Stephanidis, Bruno; Zenobi, Renato

    2015-11-01

    Phase segregation of coadsorbed thiol molecules on a gold surface was investigated with nanoscale chemical imaging using tip-enhanced Raman spectroscopy (TERS). Samples were prepared using mixed solutions containing thiophenol (PhS) and an oligomeric phenylene-ethynylene (OPE) thiol, with 10:1, 2:1, and 1:1 molar ratios. Phase segregation into domains with sizes from ≈30 to 240 nm is observed with these molar ratios. A comparison of TERS images with different pixel sizes indicates that a pixel size bigger than 15 nm is not reliable in defining nanodomains, because of undersampling. In this study, the formation of nanodomains was clearly evident based on the molecular fingerprints provided by TERS, while ambient scanning tunneling microscopy (STM) was not capable of discerning individual domains via their apparent height difference. TERS therefore allows to image nanodomains in binary self-assembled monolayers, which are invisible to methods solely relying on topographic or electron density characteristics of self-assembled monolayers. Moreover, TERS mapping provides statistical data to describe the distribution of molecules on the sample surface in a well-defined manner. Peak ratio histograms of selected TERS signals from samples prepared with different mixing ratios give a better understanding of the adsorption preference of the thiols studied, and the relationship of their mixing ratio in solution and adsorbed on the surface.

  18. Raman spectroscopic and microthermometric studies of authigenic quartz (the Pepper Mts., Central Poland) as an indicator of fluids circulation

    Science.gov (United States)

    Naglik, Beata; Toboła, Tomasz; Natkaniec-Nowak, Lucyna; Luptáková, Jarmila; Milovská, Stanislava

    2017-02-01

    Differently colored authigenic quartz crystals were found as the druses compound within mudstone heteroliths from the Pepper Mts. Shale Formation (Cambrian unit of the Holy Cross Mts., Central Poland). The genesis of this mineral was established on the basis of fluid inclusion study. Raman microspectroscopy was the key instrumental technique to identify the nature of the compounds trapped in the fluid inclusions. Methane (2917 cm- 1) or water vapor (broad band 2500-3000 cm- 1) occur within two-phased primary inclusion assemblages, while nitrogen (2329 cm- 1) associated with methane and trace amount of carbon dioxide (1285, 1388 cm- 1) occur within secondary fluid inclusion assemblage. Temperatures of homogenization of primary fluid inclusions was obtained on the basis of heating experiments and ranged from 171° to 266 °C. These values are much higher than expected for the diagenetic system without metamorphic changes what may imply hydrothermal origin of quartz crystals. The source of fluids is uncertain as in the Holy Cross Mts. there was no volcanic activity to the end of Late Devonian. However, fluids originated in metamorphic basin could use deep faults as the migration paths.

  19. Mapping Chemical and Structural Composition of Pharmaceutical and Biological Samples by Raman, Surface-Enhanced Raman and Fluorescence Spectral Imaging

    Science.gov (United States)

    Chourpa, Igor; Cohen-Jonathan, Simone; Dubois, Pierre

    Raman spectroscopy is an analytical technique recognised for its structural and conformational specificity. The efficient discrimination of molecular species by Raman is particularly potent for multidimensional microscopic imaging of complex biological environment, as demonstrated in the present book. The commonly admitted problem of Raman, low sensitivity, can often be circumvented due to high output instruments and via approaches like RRS (resonance Raman scattering), SERS (surface-enhanced Raman scattering), TERS (tip-enhanced Raman scattering) or CARS (coherent anti-Stokes Raman scattering). In contrast to the latter, RRS and SERS are realizable with less sophisticated set-up based on common Raman systems. Although more invasive than RRS, SERS provides better sensitivity and quenching of fluorescence. SERRS (surface-enhanced resonance Raman scattering) spectroscopy can be used in coupling with fluorescence and competes in selectivity and sensitivity with spectrofluorimetry. In the chapter below, we use recent applications made in our group to illustrate the use of Raman and SERRS spectral imaging for characterization of biological samples (animal subcutaneous tissue, human cancer cells) and pharmaceutical samples (microparticles for drug delivery, fibres for wound dressing). After a brief description of experimental details on spectral imaging, the chapter will focus on results concerning (i) biocompatible pharmaceutical materials made of alginates and (ii) anticancer drugs in pharmaceutical forms and in biological systems.

  20. Spectroscopic (infrared, Raman, UV and NMR) analysis, Gaussian hybrid computational investigation (MEP maps/HOMO and LUMO) on cyclohexanone oxime

    Science.gov (United States)

    Ramalingam, S.; Karabacak, M.; Periandy, S.; Puviarasan, N.; Tanuja, D.

    2012-10-01

    In the present analysis, FT-IR/FT-Raman spectra of the cyclohexanone oxime (CHO, C6H11NO) are recorded. The observed vibrational frequencies are assigned and the computational calculations are carried out by HF and DFT (B3LYP and B3PW91) methods with 6-311++G(d,p) basis set and the corresponding results are tabulated. In order to yield good coherence with observed values, the calculated frequencies are scaled by appropriate scale factors. The complete assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The alternation of structure of cyclohexanone due to the substitution of NOH is investigated. The vibrational sequence pattern of the molecule related to the substitutions is analyzed. Comparison of the observed fundamental vibrational frequencies of CHO and calculated results by density functional (B3LYP and B3PW91) and HF methods indicates that B3LYP is superior to the scaled HF and B3PW91 approach for molecular vibrational problems. Moreover, 13C NMR and 1H NMR chemical shifts are calculated by using the gauge independent atomic orbital (GIAO) method with HF/B3LYP/B3PW91 methods and the same basis set. A study on the electronic properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, are performed by HF and DFT methods. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. NLO properties and Mulliken charges of the CHO was also calculated and interpreted. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the title compound at different temperatures are calculated in gas phase.

  1. FT-Raman spectroscopic study of skin wound healing in diabetic rats treated with Cenostigma macrophyllum Tul

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Nayana Pinheiro Machado de Freitas; Martins, Marcelino, E-mail: nayanamachado@oi.com.br [Faculdade Diferencial Integral (FACID), Teresina, PI (Brazil); Costa, Charlytton Luis Sena da; Maia Filho, Antonio Luis [Universidade Estadual do Piaui (UESPI), Teresina, PI (Brazil); Raniero, Leandro; Martin, Airton Abrahao; Arisawa, Emilia Angela Loschiavo [Universidade do Vale do Paraiba (UNIVAP), Sao Jose dos Campos, SP (Brazil). Instituto de Pesquisa e Desenvolvimento

    2014-07-01

    Introduction: patients with diabetes mellitus exhibit a delay in the lesion repair process. The active components of Cenostigma macrophyllum may represent a viable alternative to facilitate the recovery of these lesions. The aim of this study was to evaluate the effects of emulsion oil-water Cenostigma macrophyllum in the repair process of lesions in rats with induced diabetes. Methods: 63 male rats (Wistar, 200-250 g body weight, 30-40 days old) were distributed into the following groups: control (C), diabetic (D) and diabetic treated with Cenostigma macrophyllum (P), subdivided based on the experimental times, days 7, 14 and 28, with 21 animals per main group. Diabetes mellitus (DM) was induced by administration of streptozotocin (50 mg/kg via penile vein and 12-h fasting) and confirmed at day 21 (glycemic index > 240 mg/dL). In the animals of group P, 0.5 ml of the oil-water emulsion obtained from the plant seed was used. The samples were removed and hemisectioned, and one portion was used for the quantitative histological analysis of collagen using Masson's trichrome staining, while another portion was analyzed by FT-Raman spectroscopy. Results: A higher percentage area of the volume of collagen fibers was observed for the experimental time Day 14 in group P compared with group D (p < 0.001). Regarding the ratio of areas of the amides I (1700-1600 cm{sup -1}) and III (1245-1345 cm{sup -1}), the groups D and P show the opposite behavior. Conclusion: Cenostigma macrophyllum accelerated the repair process in skin of diabetic ratsfor14 days. (author)

  2. A resonance Raman spectroscopic and CASSCF investigation of the Franck-Condon region structural dynamics and conical intersections of thiophene.

    Science.gov (United States)

    Wu, Xian-Fang; Zheng, Xuming; Wang, Hui-Gang; Zhao, Yan-Yin; Guan, Xiangguo; Phillips, David Lee; Chen, Xuebo; Fang, Weihai

    2010-10-07

    Resonance Raman spectra were acquired for thiophene in cyclohexane solution with 239.5 and 266 nm excitation wavelengths that were in resonance with ∼240 nm first intense absorption band. The spectra indicate that the Franck-Condon region photodissociation dynamics have multidimensional character with motion mostly along the reaction coordinates of six totally symmetry modes and three nontotally symmetry modes. The appearance of the nontotally symmetry modes, the C-S antisymmetry stretch +C-C=C bend mode ν(21)(B(2)) at 754 cm(-1) and the H(7)C(3)-C(4)H(8) twist ν(9)(A(2)) at 906 cm(-1), suggests the existence of two different types of vibronic-couplings or curve-crossings among the excited states in the Franck-Condon region. The electronic transition energies, the excited state structures, and the conical intersection points (1)B(1)/(1)A(1) and (1)B(2)/(1)A(1) between 2 (1)A(1) and 1 (1)B(2) or 1 (1)B(1) potential energy surfaces of thiophene were determined by using complete active space self-consistent field theory computations. These computational results were correlated with the Franck-Condon region structural dynamics of thiophene. The ring opening photodissociation reaction pathway through cleavage of one of the C-S bonds and via the conical intersection point (1)B(1)/(1)A(1) was revealed to be the predominant ultrafast reaction channel for thiophene in the lowest singlet excited state potential energy hypersurface, while the internal conversion pathway via the conical intersection point (1)B(2)/(1)A(1) was found to be the minor decay channel in the lowest singlet excited state potential energy hypersurface.

  3. Coherent Raman spectro-imaging with laser frequency combs

    CERN Document Server

    Ideguchi, Takuro; Bernhardt, Birgitta; Guelachvili, Guy; Picqué, Nathalie; Hänsch, Theodor W

    2013-01-01

    Optical spectroscopy and imaging of microscopic samples have opened up a wide range of applications throughout the physical, chemical, and biological sciences. High chemical specificity may be achieved by directly interrogating the fundamental or low-lying vibrational energy levels of the compound molecules. Amongst the available prevailing label-free techniques, coherent Raman scattering has the distinguishing features of high spatial resolution down to 200 nm and three-dimensional sectioning. However, combining fast imaging speed and identification of multiple - and possibly unexpected- compounds remains challenging: existing high spectral resolution schemes require long measurement times to achieve broad spectral spans. Here we overcome this difficulty and introduce a novel concept of coherent anti-Stokes Raman scattering (CARS) spectro-imaging with two laser frequency combs. We illustrate the power of our technique with high resolution (4 cm-1) Raman spectra spanning more than 1200 cm-1 recorded within le...

  4. Direct observation of the cyclic dimer in liquid acetic acid by probing the C=O vibration with ultrafast coherent Raman spectroscopy.

    Science.gov (United States)

    Lütgens, Matthias; Friedriszik, Frank; Lochbrunner, Stefan

    2014-09-01

    We present a comparison of spontaneous Raman and ultrafast coherent anti-Stokes Raman scattering (CARS) spectra of the C=O vibration of liquid acetic acid. The former technique cannot clearly reveal the number of contributions in the spectrum. However, the additional time and spectrally resolved CARS experiment supports strictly the existence of four modes, which proves the coexistence of more than one H-bonded configuration in liquid acetic acid. A comparably slowly dephasing mode which is obscured by a broad band in the linear Raman spectrum is assigned to the cyclic dimer and can be observed freed from all other contributions by ultrafast CARS.

  5. Raman Spectroscopic Online Investigation of Respiratory Quotients in Pinus Sylvestris and Picea Abies during Drought and Shading

    Science.gov (United States)

    Hanf, S.; Fischer, S.; Hartmann, H.; Trumbore, S.; Popp, J.; Frosch, T.

    2014-12-01

    Drought and heat waves have been linked to forest mortality event across the globe. The underlying physiological processes are still not elucidated but both tree carbon and water relations have been identified as the driving forces. While studies on tree hydraulics are straightforward, studies on the tree carbon balance are not. For example, the use of different carbon compounds for maintenance respiration during drought cannot be assessed with measurements of carbon pools but requires real-time analyses of respiration stoichiometry. However, so far there were no technical solutions for such applications. Here we introduce cavity-enhanced Raman spectrometry (CERS) for simultaneous real-time monitoring of O2 and CO2 and rapid and continuous quantification of dark respiration rates and the respiratory quotient (RQ), i.e. the ratio of CO2 produced over O2 consumed during respiration. This ratio indicates the proportions of different substrates (carbohydrates [COH], lipids, proteins) used during respiration and allows fundamental insights into tree physiology. CERS combines high temporal resolution with a high dynamic concentration range for all important gases, ranging from few ppm to 100 vol. % with a single measurement every few seconds. The respiration analysis of tree branches was performed in a closed chamber for two species of different drought tolerance, Pinus sylvestris and Picea abies. We applied not only drought but also a shading treatment because both cause reductions in carbon assimilation rates but have different effects on tree hydraulics. Declines in RQ during shading in both species indicate a switch from pure COH metabolism to a mixture of COH, lipids and proteins. During drought such declines occurred only in the drought-tolerant pine but not in spruce and the underlying more dynamic carbon use strategy in pine may provide a physiological basis for its drought tolerance, more detailed investigation still pending. Our study highlights the suitability

  6. Spectroscopic (FT-IR, FT-Raman, UV, NMR, NBO) investigation and molecular docking study of (R)-2-Amino-1-PhenylEthanol

    Science.gov (United States)

    Subashini, K.; Periandy, S.

    2016-08-01

    A systematic spectroscopic study of (R)-2-Amino-1-Phenylethanol was carried out using FT-IR, FT-Raman, NMR and UV analysis. FT-IR (4000-400 cm-1) and FT-Raman (4000-100 cm-1) spectrum of the title molecule were recorded in solid phase, the 1H and 13C NMR spectra were recorded in CDCl3 (deuterated chloroform) solution phase and the UV-Vis (200-800 nm) spectrum was recorded in gas phase and ethanol solution phase. Potential energy surface (PES) scan was performed using B3LYP functional with 6-311++G (d, p) basis set. The geometrical parameters (such as bond length, bond angle, dihedral angles) and theoretical frequencies of the title compound were studied from density functional theory (DFT) using B3LYP and B3PW91 functionals with 6-311++G (d, p) basis sets. The computed frequencies were scaled and compared with the experimental values and potential energy distribution (PED) has been tabulated. A comparative study of atomic charges was made by calculating Mulliken, Natural Population Analysis (NPA) and Electrostatic Potential (ESP) simultaneously, with B3LYP/6-311++G (d, p) basis set. 1H and 13C NMR spectra were recorded and chemical shifts were compared to TMS by Gauge-Independent Atomic Orbital (GIAO) method. Electronic properties such as excitation energy, energy gap between HOMO and LUMO was calculated using time dependent DFT technique. NBO analysis, which predicts the different possibilities of electronic transition in the molecule, was computed using B3PW91 functional with 6-311++G (d, p) basis set. The thermodynamic properties such as heat capacity, entropy and enthalpy at different temperatures were computed and analyzed. Molecular docking study shows that the secondary hydroxyl group and the primary amino group in the aliphatic chain attached to the benzene ring are crucial for binding and the title compound might exhibit inhibitory activity against Bacteroides fragilis (3P24) and may act as anti-bacterial agent.

  7. Hamiltonian design in readout from room-temperature Raman atomic memory.

    Science.gov (United States)

    Dąbrowski, Michał; Chrapkiewicz, Radosław; Wasilewski, Wojciech

    2014-10-20

    We present an experimental demonstration of the Hamiltonian manipulation in light-atom interface in Raman-type warm rubidium-87 vapor atomic memory. By adjusting the detuning of the driving beam we varied the relative contributions of the Stokes and anti-Stokes scattering to the process of four-wave mixing which reads out a spatially multimode state of atomic memory. We measured the temporal evolution of the readout fields and the spatial intensity correlations between write-in and readout as a function of detuning with the use of an intensified camera. The correlation maps enabled us to resolve between the anti-Stokes and the Stokes scattering and to quantify their contributions. Our experimental results agree quantitatively with a simple, plane-wave theoretical model we provide. They allow for a simple interpretation of the coaction of the anti-Stokes and the Stokes scattering at the readout stage. The Stokes contribution yields additional, adjustable gain at the readout stage, albeit with inevitable extra noise. Here we provide a simple and useful framework to trace it and the results can be utilized in the existing atomic memories setups. Furthermore, the shown Hamiltonian manipulation offers a broad range of atom-light interfaces readily applicable in current and future quantum protocols with atomic ensembles.

  8. Rapid Detection of Melamine in Tap Water and Milk Using Conjugated "One-Step" Molecularly Imprinted Polymers-Surface Enhanced Raman Spectroscopic Sensor.

    Science.gov (United States)

    Hu, Yaxi; Lu, Xiaonan

    2016-05-01

    An innovative "one-step" sensor conjugating molecularly imprinted polymers and surface enhanced Raman spectroscopic-active substrate (MIPs-SERS) was investigated for simultaneous extraction and determination of melamine in tap water and milk. This sensor was fabricated by integrating silver nanoparticles (AgNPs) with MIPs synthesized by bulk polymerization of melamine (template), methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linking agent), and 2,2'-azobisisobutyronitrile (initiator). Static and kinetic adsorption tests validated the specific affinity of MIPs-AgNPs to melamine and the rapid adsorption equilibration rate. Principal component analysis segregated SERS spectral features of tap water and milk samples with different melamine concentrations. Partial least squares regression models correlated melamine concentrations in tap water and skim milk with SERS spectral features. The limit of detection (LOD) and limit of quantification (LOQ) of melamine in tap water were determined as 0.0019 and 0.0064 mmol/L, while the LOD and LOQ were 0.0165 and 0.055 mmol/L for the determination of melamine in skim milk. However, this sensor is not ideal to quantify melamine in tap water and skim milk. By conjugating MIPs with SERS-active substrate (that is, AgNPs), reproducibility of SERS spectral features was increased, resulting in more accurate detection. The time required to determine melamine in tap water and milk were 6 and 25 min, respectively. The low LOD, LOQ, and rapid detection confirm the potential of applying this sensor for accurate and high-throughput detection of melamine in tap water and milk.

  9. Spectroscopic (FT-IR, FT-Raman, 1H, 13C NMR, UV/VIS), thermogravimetric and antimicrobial studies of Ca(II), Mn(II), Cu(II), Zn(II) and Cd(II) complexes of ferulic acid

    Science.gov (United States)

    Kalinowska, M.; Piekut, J.; Bruss, A.; Follet, C.; Sienkiewicz-Gromiuk, J.; Świsłocka, R.; Rzączyńska, Z.; Lewandowski, W.

    2014-03-01

    The molecular structure of Mn(II), Cu(II), Zn(II), Cd(II) and Ca(II) ferulates (4-hydroxy-3-methoxycinnamates) was studied. The selected metal ferulates were synthesized. Their composition was established by means of elementary and thermogravimetric analysis. The following spectroscopic methods were used: infrared (FT-IR), Raman (FT-Raman), nuclear magnetic resonance (13C, 1H NMR) and ultraviolet-visible (UV/VIS). On the basis of obtained results the electronic charge distribution in studied metal complexes in comparison with ferulic acid molecule was discussed. The microbiological study of ferulic acid and ferulates toward Escherichia coli, Bacillus subtilis, Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris was done.

  10. Efficient generation of broad Raman sidebands in an index-guided photonic crystal fiber.

    Science.gov (United States)

    Li, Ying; Hou, Jing; Jiang, Zongfu; Leng, Jinyong

    2013-04-01

    The efficient generation of broad Raman sidebands is experimentally demonstrated in a short piece of index-guided photonic crystal fiber, which is pumped by a high-peak-power pulse near the zero-dispersion wavelength and seeded by a continuous-wave Stokes signal centered at 1117 nm. The Raman sidebands generated via stimulated Raman scattering and cascaded four-wave mixing contain five Stokes and six anti-Stokes peaks and span from 827 to 1398 nm, and the 3 dB linewidth for each peak is smaller than 1 nm. However, the pure Raman sidebands are largely dependent on the pulse pump power as well as the fiber length.

  11. Multimode Raman light-atom interface in warm atomic ensemble as multiple three-mode quantum operations

    CERN Document Server

    Parniak, Michał; Wasilewski, Wojciech

    2015-01-01

    We analyze the properties of a Raman quantum light-atom interface in long atomic ensemble and its applications as a quantum memory or two-mode squeezed state generator. We include both Stokes and anti-Stokes scattering and the effects of Doppler broadening in buffer gas assuming frequent velocity-averaging collisions. We find the Green functions describing multimode transformation from input to output fields of photons and atomic excitations. Proper mode basis is found via singular value decomposition. It reveals that triples of modes are coupled by a transformation equivalent to a combination of two beamsplitters and a two-mode squeezing operation. We analyze the possible transformations on an example of warm rubidium-87 vapor. We find that the fidelity of the mapping of a single excitation between the memory and light is strictly limited by the fractional contribution of the Stokes scattering in predominantly anti-Stokes process. The model we present bridges the gap between the Stokes only and anti-Stokes o...

  12. A comparative study of the inhibition effects of benzotriazole and 6-aniline-1,3,5-triazine-2,4-dithiol monosodium salt on the corrosion of copper by potentiodynamic polarization, AC impedance and surface-enhanced Raman spectroscopic techniques

    Science.gov (United States)

    Zhou, Guoding; Cai, Shengmin; Song, Liqun; Yang, Huaquan; Fujishima, A.; Ibrahim, A.; Lee, Y. G.; Loo, B. H.

    1991-11-01

    The inhibition effects of benzotriazole (BTA) and 6-aniline-1,3,5-triazine-2,4-dithiol (ATD) monosodium salt on copper corrosion have been studied by the potentiodynamic polarization, AC impedance and surface-enhanced Raman spectroscopic techniques. The polarization resistance Rp increases with the concentration of either BTA or ATD. From the plots of the phase shift θ versus logarithm of the frequency, it is found that θ is close to 90° after the copper electrode is immersed for a long period of time in BTA-containing solution which indicates the behavior of an ideal capacitor. In ATD-containing solutions, θ is close to 45 ° which shows the appearance of a Warburg impedance for a diffusion process. Surface-enhanced Raman spectroscopic studies of the competitive adsorption of BTA and ATD on copper surfaces indicate that BTA adsorbs better than ATD. Based on these results, it is concluded that the inhibition action of BTA is better than that of ATD.

  13. Infrared and Raman spectroscopic characterizations on new Fe sulphoarsenate hilarionite (Fe2(III)(SO4)(AsO4)(OH)·6H2O): Implications for arsenic mineralogy in supergene environment of mine area

    Science.gov (United States)

    Liu, Jing; He, LiLe; Dong, Faqin; Frost, Ray L.

    2017-01-01

    Hilarionite (Fe2 (SO4)(AsO4)(OH)·6H2O) is a new Fe sulphoarsenates mineral, which recently is found in the famous Lavrion ore district, Atliki Prefecture, Greece. The spectroscopic study of hilarionite enriches the data of arsenic mineralogy in supergene environment of a mine area. The infrared and Raman means are used to characterize the molecular structure of this mineral. The IR bands at 875 and 905 cm- 1 are assigned to the antisymmetric stretching vibrations of AsO43 -. The IR bands at 1021, 1086 and 1136 cm- 1 correspond to the possible antisymmetric and symmetric stretching vibrations of SO42 -. The Raman bands at 807, 843 and 875 cm- 1 clearly show that arsenate components in the mineral structure, which are assigned to the symmetric stretching vibrations (ν1) of AsO43 - (807 and 843 cm- 1) and the antisymmetric vibration (ν3) (875 cm- 1). IR bands provide more sulfate information than Raman, which can be used as the basis to distinguish hilarionite from kaňkite. The powder XRD data shows that hilarionite has obvious differences with the mineral structure of kaňkite. The thermoanalysis and SEM-EDX results show that hilarionite has more sulfate than arsenate.

  14. A time-resolved resonance Raman study of chlorine dioxide photochemistry in water and acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, S.C.; Philpott, M.P.; Mayer, S.G.; Reid, P.J. [Univ. of Washington, Seattle, WA (United States). Dept. of Chemistry

    1999-07-15

    The photochemistry of chlorine dioxide (OClO) has attracted much interest due to its participation in the atmospheric chlorine reservoir as well as its potential role in stratospheric ozone depletion. Since the environmental impact of OClO arises from its ability to produce atomic chlorine, understanding this phase-dependent reactivity is essential if models capable of predicting the environmental impact of OClO in both homogeneous and heterogeneous settings are to be obtained. The photochemistry of chlorine dioxide (OClO) in water and acetonitrile is investigated using time-resolved resonance Raman spectroscopy. Stokes and anti-Stokes spectra are measured as a function of time following photoexcitation using degenerate pump and probe wavelengths of 390 nm. For aqueous OClO, the time-dependent Stokes intensities are found to be consistent with the re-formation of ground-state OClO by subpicosecond geminate recombination of the primary ClO and O photofragments. This represents the first unequivocal demonstration of primary-photoproduct geminate recombination in the condensed-phase photochemistry of OClO. Anti-Stokes intensity corresponding to the OClO symmetric stretch is observed demonstrating that, following geminate recombination, excess vibrational energy is deposited along this coordinate. Analysis of the anti-Stokes decay kinetics demonstrates that, in water, intermolecular vibrational relaxation occurs with a time constant of {approximately}9 ps. For OClO dissolved in acetonitrile, the Stokes scattering intensities are consistent with a significant reduction in the geminate-recombination quantum yield relative to water. Comparison of the OClO anti-Stokes decay kinetics in acetonitrile and water demonstrates that the rate of intermolecular vibrational relaxation is {approximately}4 times smaller in acetonitrile. Finally, in both solvents the appearance of symmetric-stretch anti-Stokes intensity is significantly delayed relative to geminate recombination. This

  15. A Raman spectroscopic study of the mono-hydrogen phosphate mineral dorfmanite Na 2(PO 3OH)·2H 2O and in comparison with brushite

    Science.gov (United States)

    Frost, Ray L.; Palmer, Sara J.; Xi, Yunfei

    2011-11-01

    Aspects of the molecular structure of the mineral dorfmanite Na 2(PO 3OH)·2H 2O were determined by Raman spectroscopy. The mineral originated from the Kedykverpakhk Mt., Lovozero, Kola Peninsula, Russia. Raman bands are assigned to the hydrogen phosphate units. The intense Raman band at 949 cm -1 and the less intense band at 866 cm -1 are assigned to the PO 3 and POH stretching vibrations. Bands at 991, 1066 and 1141 cm -1 are assigned to the ν3 antisymmetric stretching modes. Raman bands at 393, 413 and 448 cm -1 and 514, 541 and 570 cm -1 are attributed to the ν2 and ν4 bending modes of the HPO 4 units, respectively. Raman bands at 3373, 3443 and 3492 cm -1 are assigned to water stretching vibrations. POH stretching vibrations are identified by bands at 2904, 3080 and 3134 cm -1. Raman spectroscopy has proven very useful for the study of the structure of the mineral dorfmanite.

  16. Hyper Raman spectra calculated in a time-dependent Hartree-Fock method

    Science.gov (United States)

    Mohammed, Abdelsalam; Ågren, Hans; Ringholm, Magnus; Thorvaldsen, Andreas J.; Ruud, Kenneth

    2012-10-01

    Hyper Raman scattering (HRS) of the benzonitrile (BN) and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) molecules is studied by means of ab initio calculations. The computational procedure employs a recently developed methodology for the analytic calculations of frequency-dependent polarizability gradients of arbitrary order, including perturbation dependent basis sets. The result are compared to normal Raman scattering (NRS) and coherent anti-Stokes Raman scattering (CARS) that previously have been studied using the same technology. It is found that some suppressed or silent modes in CARS and NRS spectra are clearly seen in HRS, and that although under general excitation conditions the HRS intensities are much lower than for CARS and NRS, HRS provides complementary information useful for target identification.

  17. Characterization of anatase TiO2 nanopowder by variable-temperature Raman spectroscopy

    Directory of Open Access Journals (Sweden)

    Šćepanović Maja J.

    2009-01-01

    Full Text Available Raman spectroscopy has been used for characterization of commercial nanosized TiO2 powder with declared grain size of 5 nm. The Raman spectra measured in Stokes and anti-Stokes regime confirm the anatase phase of TiO2 powder in temperature range 25-1173K. It is shown that phonon-confinement (due to small grain size and nonstoichiometry (caused by laser irradiation in vacuum have a great influence on blueshift and broadening of the main Eg Raman mode at low temperatures, while the influence of the strong anharmonic effect becomes dominant at higher temperatures. The phonon confinement effect decreases due to the crystallite growth at temperatures above 673K.

  18. A UV resonance Raman (UVRR) spectroscopic study on the extractable compounds of Scots pine ( Pinus sylvestris) wood . Part I: Lipophilic compounds

    Science.gov (United States)

    Nuopponen, M.; Willför, S.; Jääskeläinen, A.-S.; Sundberg, A.; Vuorinen, T.

    2004-11-01

    The wood resin in Scots pine ( Pinus sylvestris) stemwood and branch wood were studied using UV resonance Raman (UVRR) spectroscopy. UVRR spectra of the sapwood and heartwood hexane extracts, solid wood samples and model compounds (six resin acids, three fatty acids, a fatty acid ester, sitosterol and sitosterol acetate) were collected using excitation wavelengths of 229, 244 and 257 nm. In addition, visible Raman spectra of the fatty and resin acids were recorded. Resin compositions of heartwood and sapwood hexane extracts were determined using gas chromatography. Raman signals of both conjugated and isolated double bonds of all the model compounds were resonance enhanced by UV excitation. The oleophilic structures showed strong bands in the region of 1660-1630 cm -1. Distinct structures were enhanced depending on the excitation wavelength. The UVRR spectra of the hexane extracts showed characteristic bands for resin and fatty acids. It was possible to identify certain resin acids from the spectra. UV Raman spectra collected from the solid wood samples containing wood resin showed a band at ˜1650 cm -1 due to unsaturated resin components. The Raman signals from extractives in the resin rich branch wood sample gave even more strongly enhanced signals than the aromatic lignin.

  19. Non-invasive in vivo determination of the carotenoids beta-carotene and lycopene concentrations in the human skin using the Raman spectroscopic method

    Energy Technology Data Exchange (ETDEWEB)

    Darvin, M E [Center of Experimental and Applied Cutaneous Physiology (CCP), Department of Dermatology, Charite University Hospital, Berlin (Germany); Gersonde, I [Institute of Medical Physics and Laser Medicine, Charite University Hospital, Berlin (Germany); Meinke, M [Institute of Medical Physics and Laser Medicine, Charite University Hospital, Berlin (Germany); Sterry, W [Center of Experimental and Applied Cutaneous Physiology (CCP), Department of Dermatology, Charite University Hospital, Berlin (Germany); Lademann, J [Center of Experimental and Applied Cutaneous Physiology (CCP), Department of Dermatology, Charite University Hospital, Berlin (Germany)

    2005-08-07

    Resonance Raman spectroscopy was used as a fast and non-invasive optical method of measuring the absolute concentrations of beta-carotene and lycopene in living human skin. Beta-carotene and lycopene have different absorption values at 488 and 514.5 nm and, consequently, the Raman lines for beta-carotene and lycopene have different scattering efficiencies at 488 and 514.5 nm excitations. These differences were used for the determination of the concentrations of beta-carotene and lycopene. Using multiline Ar{sup +} laser excitation, clearly distinguishable carotenoid Raman spectra can be obtained which are superimposed on a large fluorescence background. The Raman signals are characterized by two prominent Stokes lines at 1160 and 1525 cm{sup -1}, which have nearly identical relative intensities. Both substances were detected simultaneously. The Raman spectra are obtained rapidly, i.e. within about 10 s, and the required laser light exposure level is well within safety standards. The disturbance of the measurements by non-homogeneous skin pigmentation was avoided by using a relatively large measuring area of 35 mm{sup 2}. It was shown that beta-carotene and lycopene distribution in human skin strongly depends upon the skin region studied and drastically changed inter-individually. Skin beta-carotene and lycopene concentrations are lower in smokers than in non-smokers and higher in the vegetarian group.

  20. Non-invasive in vivo determination of the carotenoids beta-carotene and lycopene concentrations in the human skin using the Raman spectroscopic method

    Science.gov (United States)

    Darvin, M. E.; Gersonde, I.; Meinke, M.; Sterry, W.; Lademann, J.

    2005-08-01

    Resonance Raman spectroscopy was used as a fast and non-invasive optical method of measuring the absolute concentrations of beta-carotene and lycopene in living human skin. Beta-carotene and lycopene have different absorption values at 488 and 514.5 nm and, consequently, the Raman lines for beta-carotene and lycopene have different scattering efficiencies at 488 and 514.5 nm excitations. These differences were used for the determination of the concentrations of beta-carotene and lycopene. Using multiline Ar+ laser excitation, clearly distinguishable carotenoid Raman spectra can be obtained which are superimposed on a large fluorescence background. The Raman signals are characterized by two prominent Stokes lines at 1160 and 1525 cm-1, which have nearly identical relative intensities. Both substances were detected simultaneously. The Raman spectra are obtained rapidly, i.e. within about 10 s, and the required laser light exposure level is well within safety standards. The disturbance of the measurements by non-homogeneous skin pigmentation was avoided by using a relatively large measuring area of 35 mm2. It was shown that beta-carotene and lycopene distribution in human skin strongly depends upon the skin region studied and drastically changed inter-individually. Skin beta-carotene and lycopene concentrations are lower in smokers than in non-smokers and higher in the vegetarian group.

  1. Phase-shift effect of amplitude spread function on spectrum and image formation in coherent Raman scattering microspectroscopy.

    Science.gov (United States)

    Fukutake, Naoki

    2016-03-01

    Coherent Raman scattering microspectroscopy, which includes coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microspectroscopy, permits label-free hyperspectral imaging. We report the theoretical study of the phase-shift effect of the impulse response function on the spectral and image-forming properties of coherent Raman scattering microspectroscopy. We show that the spectrum and image are influenced by not only the NA of objective for excitation (NA(ex)) but also that for signal collection (NA(col)), in association with the phase-shift effect. We discuss that, under the condition NA(ex)≠NA(col), both the spectrum and the image become deformed by the phase-shift effect, which can be applied to the direct measurement of the imaginary part of the nonlinear susceptibility in CARS spectroscopy. We point out that, even in SRS microscopy, the nonresonant background can contribute to the image formation and cause the artifact in the image.

  2. In situ cryogenic Raman spectroscopic studies on the synthetic fluid inclusions in the systems H2O and NaCl-H2O

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Salt-hydrates have diagnostic cryogenic Raman spectra, which can reflect the composition of the parent solutions. As analogue to the natural fluid inclusions, the synthetic inclusions can be used to validate numerous assumptions related to fluid inclusion research. They can also be used to test the feasibility of application of laser Raman spectroscopy to individual fluid inclusion analysis. Using the technique proposed by Sterner and Bodnar(1984), synthetic inclusions of the systems H2O and NaCl-H2O (with NaCl as 5.12 wt%, 9.06 wt%, 16.6 wt% and 25 wt%) were formed under the pressures from 50Mpa to 100Mpa and at the temperatures from 500℃ to 600℃. In situ cryogenic Raman spectra were collected at about -180℃ by combined use of freezing- heating stage and Laser Raman Microscopy. It is shown that hydrohalite (NaCl·2H2O), the salt-hydrate of NaCl in the fluid inclusions has the specific Raman spectrum and can be used as the standard to verify the existence of NaCl in the aqueous inclusions. The crystalline ice other than amorphous ice (glasses) formed from the aqueous phase whthin the synthetic inclusions during the initial freezing, but hydrohalite did not form. Subsequent warming of these inclusions induced a phase change, typically between approximately -40 and -22℃, that represents the hydrohalite crystallization event but not a eutectic melting event. So, for fluid inclusions in the system NaCl-H2O, interpretation of phase behavior below the eutectic temperature (-20.8℃) should be made with caution. The ratios of the relative intensity and the area of Raman spectra between 3423 cm-1 peak of hydrohalite and 3098 cm-1 peak of ice show positive correlations to the salinities in aqueous inclusions, which can be used to determine the salinity of NaCl- H2O system inclusions.

  3. The mixed anion mineral parnauite Cu9[(OH)10|SO4|(AsO4)2]·7H2O--a Raman spectroscopic study.

    Science.gov (United States)

    Frost, Ray L; Keeffe, Eloise C

    2011-10-15

    The mixed anion mineral parnauite Cu(9)[(OH)(10)|SO(4)|(AsO(4))(2)]·7H(2)O from two localities namely Cap Garonne Mine, Le Pradet, France and Majuba Hill mine, Pershing County, Nevada, USA has been studied by Raman spectroscopy. The Raman spectrum of the French sample is dominated by an intense band at 975 cm(-1) assigned to the ν(1) (SO(4))(2-) symmetric stretching mode and Raman bands at 1077 and 1097 cm(-1) may be attributed to the ν(3) (SO(4))(2-) antisymmetric stretching mode. Two Raman bands 1107 and 1126 cm(-1) are assigned to carbonate CO(3)(2-) symmetric stretching bands and confirms the presence of carbonate in the structure of parnauite. The comparatively sharp band for the Pershing County mineral at 976 cm(-1) is assigned to the ν(1) (SO(4))(2-) symmetric stretching mode and a broad spectral profile centered upon 1097 cm(-1) is attributed to the ν(3) (SO(4))(2-) antisymmetric stretching mode. Two intense bands for the Pershing County mineral at 851 and 810 cm(-1) are assigned to the ν(1) (AsO(4))(3-) symmetric stretching and ν(3) (AsO(4))(3-) antisymmetric stretching modes. Two Raman bands for the French mineral observed at 725 and 777 cm(-1) are attributed to the ν(3) (AsO(4))(3-) antisymmetric stretching mode. For the French mineral, a low intensity Raman band is observed at 869 cm(-1) and is assigned to the ν(1) (AsO(4))(3-) symmetric stretching vibration. Chemical composition of parnauite remains open and the question may be raised is parnauite a solid solution of two or more minerals such as a copper hydroxy-arsenate and a copper hydroxy sulphate.

  4. The mixed anion mineral parnauite Cu 9[(OH) 10|SO 4|(AsO 4) 2]·7H 2O—A Raman spectroscopic study

    Science.gov (United States)

    Frost, Ray L.; Keeffe, Eloise C.

    2011-10-01

    The mixed anion mineral parnauite Cu 9[(OH) 10|SO 4|(AsO 4) 2]·7H 2O from two localities namely Cap Garonne Mine, Le Pradet, France and Majuba Hill mine, Pershing County, Nevada, USA has been studied by Raman spectroscopy. The Raman spectrum of the French sample is dominated by an intense band at 975 cm -1 assigned to the ν1 (SO 4) 2- symmetric stretching mode and Raman bands at 1077 and 1097 cm -1 may be attributed to the ν3 (SO 4) 2- antisymmetric stretching mode. Two Raman bands 1107 and 1126 cm -1 are assigned to carbonate CO 32- symmetric stretching bands and confirms the presence of carbonate in the structure of parnauite. The comparatively sharp band for the Pershing County mineral at 976 cm -1 is assigned to the ν1 (SO 4) 2- symmetric stretching mode and a broad spectral profile centered upon 1097 cm -1 is attributed to the ν3 (SO 4) 2- antisymmetric stretching mode. Two intense bands for the Pershing County mineral at 851 and 810 cm -1 are assigned to the ν1 (AsO 4) 3- symmetric stretching and ν3 (AsO 4) 3- antisymmetric stretching modes. Two Raman bands for the French mineral observed at 725 and 777 cm -1 are attributed to the ν3 (AsO 4) 3- antisymmetric stretching mode. For the French mineral, a low intensity Raman band is observed at 869 cm -1 and is assigned to the ν1 (AsO 4) 3- symmetric stretching vibration. Chemical composition of parnauite remains open and the question may be raised is parnauite a solid solution of two or more minerals such as a copper hydroxy-arsenate and a copper hydroxy sulphate.

  5. A Raman scattering and FT-IR spectroscopic study on the effect of the solar radiation in Antarctica on bovine cornea

    Science.gov (United States)

    Yamamoto, Tatsuyuki; Murakami, Naoki; Yoshikiyo, Keisuke; Takahashi, Tetsuya; Yamamoto, Naoyuki

    2010-01-01

    The Raman scattering and FT-IR spectra of the corneas, transported to the Syowa station in Antarctica and exposed to the solar radiation of the mid-summer for four weeks, were studied to reveal that type IV collagen involved in corneas were fragmented. The amide I and III Raman bands were observed at 1660 and 1245 cm -1, respectively, and the amide I and II infrared bands were observed at 1655 and 1545 cm -1, respectively, for original corneas before exposure. The background of Raman signals prominently increased and the ratio of amide II infrared band versus amide I decreased by the solar radiation in Antarctica. The control experiment using an artificial UV lamp was also performed in laboratory. The decline rate of the amide II/amide I was utilized for estimating the degree of fragmentation of collagen, to reveal that the addition of vitamin C suppressed the reaction while the addition of sugars promoted it. The effect of the solar radiation in Antarctica on the corneas was estimated as the same as the artificial UV lamp of four weeks (Raman) or one week (FT-IR) exposure.

  6. Structural and spectroscopic study of a pectin isolated from citrus peel by using FTIR and FT-Raman spectra and DFT calculations

    Science.gov (United States)

    Bichara, Laura C.; Alvarez, Patricia E.; Fiori Bimbi, María V.; Vaca, Hugo; Gervasi, Claudio; Brandán, Silvia Antonia

    2016-05-01

    In this work, pectin isolated from citrus peel with a degree of esterification of 76% was characterized by Fourier Transform Infrared (FTIR) and Fourier Transform Raman (FT-Raman) spectroscopies. Structural studies were carried out taking into account their partial degree of esterification and considering the polygalacturonic acid chain as formed by two different subunits, one with both COOH and COOsbnd CH3 groups (Ac) and the other one as constituted by two subunits with two COOsbnd CH3 groups (Es). Their structural properties, harmonic frequencies, force fields and force constants in gas and aqueous solution phases were calculated by using the hybrid B3LYP/6-31G∗ method. Then, their complete vibrational analyses were performed by using the IR and Raman spectra accomplished with the scaled quantum mechanical (SQM) methodology. Reactivities and behaviors in both media were predicted for Ac and Es by using natural bond orbital (NBO), atoms in molecules (AIM), and frontier orbitals calculations. We report for first time the complete assignments of those two different units of polygalacturonic acid chain which are the 132 normal vibration modes of Ac and the 141 normal vibration modes of Es, combining the normal internal coordinates with the SQM methodology. In addition, three subunits were also studied. Reasonable correlations between the experimental and theoretical spectra were obtained. Thus, this work would allow the quick identification of pectin by using infrared and Raman spectroscopies and also provides new insight into the interactions that exist between subunits of a large pectin chain.

  7. FT-IR and micro-Raman spectroscopic study of decorated potteries from VI and VII century BC, excavated in ancient Ainos Turkey

    Science.gov (United States)

    Akyuz, S.; Akyuz, T.; Basaran, S.; Bolcal, C.; Gulec, A.

    2007-05-01

    Ancient decorated pottery fragments belong to sixth and seventh century BC, excavated in the archaeological district of Enez - Turkey (Ancient Ainos) were analysed using micro-Raman and FT-IR spectroscopy. The experimental results allowed us to identify the peculiar components of the ceramic body and the main pigments of the decoration. The presence of albite and anatase suggests low firing temperatures.

  8. Protonation state and structural changes of the tetrapyrrole chromophore during the Pr --> Pfr phototransformation of phytochrome: a resonance Raman spectroscopic study.

    Science.gov (United States)

    Kneip, C; Hildebrandt, P; Schlamann, W; Braslavsky, S E; Mark, F; Schaffner, K

    1999-11-16

    The photoconversion of phytochrome (phytochrome A from Avena satina) from the inactive (Pr) to the physiologically active form (Pfr) was studied by near-infrared Fourier transform resonance Raman spectroscopy at cryogenic temperatures, which allow us to trap the intermediate states. Nondeuterated and deuterated buffer solutions were used to determine the effect of H/D exchange on the resonance Raman spectra. For the first time, reliable spectra of the "bleached" intermediates meta-R(A) and meta-R(C) were obtained. The vibrational bands in the region 1300-1700 cm(-)(1), which is particularly indicative of structural changes in tetrapyrroles, were assigned on the basis of recent calculations of the Raman spectra of the chromophore in C-phycocyanin and model compounds [Kneip, C., Hildebrandt, P., Németh, K., Mark, F., Schaffner, K. (1999) Chem. Phys. Lett. 311, 479-485]. The experimental resonance Raman spectra Pr are compatible with the Raman spectra calculated for the protonated ZZZasa configuration, which hence is suggested to be the chromophore structure in this parent state of phytochrome. Furthermore, marker bands could be identified that are of high diagnostic value for monitoring structural changes in individual parts of the chromophore. Specifically, it could be shown that not only in the parent states Pr and Pfr but also in all intermediates the chromophore is protonated at the pyrroleninic nitrogen. The spectral changes observed for lumi-R confirm the view that the photoreaction of Pr is a Z --> E isomerization of the CD methine bridge. The subsequent thermal decay reaction to meta-R(A) includes relaxations of the CD methine bridge double bond, whereas the formation of meta-R(C) is accompanied by structural adaptations of the pyrrole rings B and C in the protein pocket. The far-reaching similarities between the chromophores of meta-R(A) and Pfr suggest that in the step meta-R(A) --> Pfr the ultimate structural changes of the protein matrix occur.

  9. Spectroscopic (FT-IR, FT-Raman, 1H- and 13C-NMR, Theoretical and Microbiological Study of trans o-Coumaric Acid and Alkali Metal o-Coumarates

    Directory of Open Access Journals (Sweden)

    Małgorzata Kowczyk-Sadowy

    2015-02-01

    Full Text Available This work is a continuation of research on a correlation between the molecular structure and electronic charge distribution of phenolic compounds and their biological activity. The influence of lithium, sodium, potassium, rubidium and cesium cations on the electronic system of trans o-coumaric (2-hydroxy-cinnamic acid was studied. We investigated the relationship between the molecular structure of the tested compounds and their antimicrobial activity. Complementary molecular spectroscopic techniques such as infrared (FT-IR, Raman (FT-Raman, ultraviolet-visible (UV-VIS and nuclear magnetic resonance (1H- and 13C-NMR were applied. Structures of the molecules were optimized and their structural characteristics were calculated by the density functional theory (DFT using the B3LYP method with 6-311++G** as a basis set. Geometric and magnetic aromaticity indices, atomic charges, dipole moments and energies were also calculated. Theoretical parameters were compared to the experimental characteristics of investigated compounds. Correlations between certain vibrational bands and some metal parameters, such as electronegativity, ionization energy, atomic and ionic radius, were found. The microbial activity of studied compounds was tested against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, Proteus vulgaris and Candida albicans.

  10. Structural, Raman spectroscopic and microwave dielectric studies on spinel Li{sub 2}Zn{sub (1−x)}Ni{sub x}Ti{sub 3}O{sub 8} compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Santosh Kumar; Kiran, S. Roopas; Murthy, V.R.K., E-mail: vrkm@iitm.ac.in

    2013-09-16

    Li{sub 2}Zn{sub (1−x)}Ni{sub x}Ti{sub 3}O{sub 8} (x = 0, 0.1, 0.2, 0.4 and 1.0) microwave dielectric ceramics were studied with the help of powder X-ray diffraction and Raman spectroscopic measurements. These ceramic materials were synthesized by conventional solid state reaction method and observed to crystallize in cubic crystal system with P4{sub 3}32 space group. The cation's occupancies in tetrahedral and octahedral sites were quantified by performing Rietveld refinement. The occupancy of the Li{sup 1+} and Ni{sup 2+} in the respective tetrahedral and octahedral sites were found to increase, whereas occupancy of Zn{sup 2+} in tetrahedral site was observed to decrease with increase in Ni substitution. This decrease in occupancy of Zn{sup 2+} in tetrahedral site increased the AC conductivity by allowing the migration path 8c-12d-8c, which in turn increases the dielectric loss in these compounds. Dielectric constant and observed ionic polarizability were linearly decreased by increasing the Ni substitution. Raman spectra revealed that the shift in A{sub 1g} mode of ZnO{sub 4} tetrahedra to higher wavenumber side was due to increase of Li{sup 1+} at tetrahedral site and narrower FWHM of symmetric stretching mode of Zn–O corresponded to the higher quality factor. - Highlights: • Li{sub 2}Zn{sub (1−x)}Ni{sub x}Ti{sub 3}O{sub 8} compounds were synthesized by solid state reaction method. • Tetrahedral occupancy of different cations was obtained by Rietveld refinement. • The variation of Q × f with tetrahedral occupancy of Zn{sup 2+} was studied. • Raman spectroscopy also revealed the variation of AC conductivity with occupancy.

  11. Molecular structure, spectroscopic (FT-IR, FT Raman, UV, NMR and THz) investigation and hyperpolarizability studies of 3-(2-Chloro-6-fluorophenyl)-1-(2-thienyl) prop-2-en-1-one

    Science.gov (United States)

    Kumar, Rajesh; Kumar, Amit; Deval, Vipin; Gupta, Archana; Tandon, Poonam; Patil, P. S.; Deshmukh, Prathmesh; Chaturvedi, Deepika; Watve, J. G.

    2017-02-01

    In the present work, a combined experimental and theoretical study on ground state molecular structure, spectroscopic and nonlinear optical properties of the chalcone derivative 3-(2-Chloro-6-fluorophenyl)-1-(2-thienyl) prop-2-en-1-one (2C6F2SC) is reported. Initial geometry generated from single crystal X-ray diffraction parameters was minimized at DFT level employing B3LYP/6-311++G (d,p) without any constraint to the potential energy surface. The molecule has been characterized using various experimental techniques FT-IR, FT-Raman, UV-Vis, 1H NMR, TD-THz and the spectroscopic data have been analyzed theoretically by Density Functional Theory (DFT) method. Harmonic vibrational frequencies were calculated theoretically using the optimized ground state geometry and the spectra were interpreted by means of potential energy distribution. Time Dependent Density Functional Theory (TD-DFT) has been used to calculate energies, absorption wavelengths, oscillator strengths of electronic singlet-singlet transitions. The calculated energy and oscillator strength complement with the experimental findings. The HOMO-LUMO energy gap explains the charge interaction taking place within the molecule. Good correlations between the experimental 1H NMR chemical shifts and calculated GIAO shielding tensors were found. Stability of the molecule, hyperconjugative interactions and charge delocalization has been analyzed by natural bond orbital (NBO) analysis. The first order hyperpolarizability (β) of this molecular system and related properties (μ, and Δα) have been calculated using the finite-field approach.

  12. Laser-induced alteration of Raman spectra for micron-sized solid particles

    Science.gov (United States)

    Böttger, U.; Pavlov, S. G.; Deßmann, N.; Hanke, F.; Weber, I.; Fritz, J.; Hübers, H.-W.

    2017-04-01

    The Raman Laser Spectrometer (RLS) instrument on board of the future ESAs ExoMars mission will analyze micron-sized powder samples in a low pressure atmosphere. Such micron-sized polycrystalline solid particles might be heated by the laser during the Raman measurements. Here, we report on the temperature-induced alteration of Raman spectra from micron-sized polycrystalline solid particles by comparing Raman spectra on silicon and the rock forming minerals olivine and pyroxene taken at different laser intensities and different ambient temperatures. Our analyses indicate that laser-induced heating results in both broadening and shifting of characteristic Raman lines in the Stokes and anti-Stokes spectral regions. For elementary crystalline silicon a significant local temperature increase and relevant changes in Raman spectra have been observed in particles with median sizes below 250 μm. In comparison, significantly weaker laser-induced Raman spectral changes were observed in more complex rock-forming silicate minerals; even for lower grain sizes. Laser power densities realized in the RLS ExoMars instrument should cause only low local heating effects and, thus, negligible frequency shifts of the major Raman lines in common silicate minerals such as olivine and pyroxene.

  13. A Raman spectroscopic study of a hydrated molybdate mineral ferrimolybdite, Fe2(MoO4)3·7-8H2O.

    Science.gov (United States)

    Sejkora, Jiří; Cejka, Jiří; Malíková, Radana; López, Andrés; Xi, Yunfei; Frost, Ray L

    2014-09-15

    Raman spectra of two well-defined ferrimolybdite samples, Fe2(3+)(Mo6+O4)3·7-8H2O, from the Krupka deposit (northern Bohemia, Czech Republic) and Hůrky near Rakovník occurrence (central Bohemia, Czech Republic) were studied and tentatively interpreted. Observed bands were assigned to the stretching and bending vibrations of molybdate anions, Fe-O units and water molecules. Number of Raman and infrared bands assigned to (MoO4)(2-) units and water molecules proved that symmetrically (structurally) nonequivalent (MoO4)(2-) and H2O are present in the crystal structure of ferrimolybdite. Approximate O-H⋯O hydrogen bond lengths (2.80-2.73 Å) were inferred from the published infrared spectra.

  14. Influence of curvature strain and Van der Waals force on the inter-layer vibration mode of WS2 nanotubes: A confocal micro-Raman spectroscopic study

    Science.gov (United States)

    Wang, Xiao Hu; Zheng, Chang Cheng; Ning, Ji Qiang

    2016-09-01

    Transition-metal dichalcogenides (TMDs) nanostructures including nanotubes and monolayers have attracted great interests in materials science, chemistry to condensed matter physics. We present an interesting study of the vibration modes in multi-walled tungsten sulfide (WS2) nanotubes prepared via sulfurizing tungsten oxide (WO3) nanowires which are investigated by confocal micro-Raman spectroscopy. The inter-layer vibration mode of WS2 nanotubes, A1g, is found to be sensitive to the diameter and curvature strain, while the in-plane vibration mode, E12g, is not. A1g mode frequency shows a redshift by 2.5 cm-1 for the multi-layered nanotubes with small outer-diameters, which is an outcome of the competition between the Van der Waals force stiffening and the curvature strain softening. We also show that the Raman peak intensity ratio is significantly different between the 1-2 wall layered nanotubes and monolayer flat sheets.

  15. A Raman and FIR spectroscopic study of the solid solution (N(CH3)4)2ZnCl4-xBrx

    NARCIS (Netherlands)

    Loosdrecht, P.H.M. van; Janner, A.

    1991-01-01

    Polarized Raman and far-infrared spectra (10-350 cm-1) of the solid solution (N(CH3)4)2ZnCl4-xBrx are presented for several compositions (x = 0, 1, 2, 2.9 and 4) in the high- (300 K) and low- (60 K) temperature phases of the crystals. Apart from the internal modes of the ZnCl42- and ZnBr42- ions, se

  16. Raman spectroscopic analysis of dragon's blood resins-basis for distinguishing between Dracaena(Convallariaceae), Daemonorops(Palmae) and Croton(Euphorbiaceae).

    Science.gov (United States)

    Edwards, Howell G M; de Oliveira, Luiz F C; Prendergast, Hew D V

    2004-02-01

    "Dragon[prime or minute]s blood" is the name applied to the deep-red coloured resin obtained from various plants. The original source in Roman times, used by many cultures and esteemed for its depth of colour and mystical association, was the dragon tree Dracaena cinnabari(Convallariaceae), found only on the Indian Ocean island of Socotra, (Yemen). Additional sources emerged later, including another species of Dracaena, D. draco, from the Canary Islands and Madeira, and species in the genera Daemonorops(Palmae) from South East Asia and Croton(Euphorbiaceae) from tropical parts of both the New and Old Worlds. In this study, examples of dragon's blood resins from the Economic Botany Collections at the Royal Botanic Gardens, Kew, dating from 1851 to 1993, have been analysed non-destructively using Raman spectroscopy. The Raman spectra of well-documented, provenanced specimens have been used to establish the source of specimens of questionable or unknown origin. It has also been possible from the Raman spectra to indicate whether processing of the resins has been undertaken in the preparation of the specimens before their deposition at Kew.

  17. Raman spectroscopic determination of the length, strength, compressibility, Debye temperature, elasticity, and force constant of the C-C bond in graphene.

    Science.gov (United States)

    Yang, X X; Li, J W; Zhou, Z F; Wang, Y; Yang, L W; Zheng, W T; Sun, Chang Q

    2012-01-21

    From the perspective of bond relaxation and bond vibration, we have formulated the Raman phonon relaxation of graphene, under the stimuli of the number-of-layers, the uni-axial strain, the pressure, and the temperature, in terms of the response of the length and strength of the representative bond of the entire specimen to the applied stimuli. Theoretical unification of the measurements clarifies that: (i) the opposite trends of the Raman shifts, which are due to the number-of-layers reduction, of the G-peak shift and arises from the vibration of a pair of atoms, while the D- and the 2D-peak shifts involve the z-neighbor of a specific atom; (ii) the tensile strain-induced phonon softening and phonon-band splitting arise from the asymmetric response of the C(3v) bond geometry to the C(2v) uni-axial bond elongation; (iii) the thermal softening of the phonons originates from bond expansion and weakening; and (iv) the pressure stiffening of the phonons results from bond compression and work hardening. Reproduction of the measurements has led to quantitative information about the referential frequencies from which the Raman frequencies shift as well as the length, energy, force constant, Debye temperature, compressibility and elastic modulus of the C-C bond in graphene, which is of instrumental importance in the understanding of the unusual behavior of graphene.

  18. Quantum mechanical, spectroscopic studies (FT-IR, FT-Raman, NMR, UV) and normal coordinates analysis on 3-([2-(diaminomethyleneamino) thiazol-4-yl] methylthio)-N'-sulfamoylpropanimidamide

    Science.gov (United States)

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

    2013-05-01

    Famotidine (3-([2-(diaminomethyleneamino) thiazol-4-yl] methylthio)-N'-sulfamoylpropanimidamide) is a histamine H2-receptor antagonist that inhibits stomach acid production, and it is commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD/GORD). Quantum chemical calculations of the equilibrium geometry of famotidine in the ground state were carried out using density functional theory (DFT/B3LYP) with the 6-311G(d,p) basis set. In addition, harmonic vibrational frequencies, infrared intensities and Raman activities were calculated at the same level of theory. A detailed interpretation of the infrared and Raman spectrum of the drug is also reported. Theoretical simulations of the FT-IR, and FT-Raman spectra of the title compound have been calculated. Good correlations between the experimental 1H and 13C NMR chemical shifts and calculated GIAO shielding tensors were found. The results of the energy and oscillator strength calculations by time-dependent density functional theory (TD-DFT) supplement the experimental findings. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (COOP or OPDOS) diagrams analysis were presented. The dipole moment, linear polarizability and first order hyperpolarizability values were also computed. The linear polarizability and first order hyperpolarizabilities of the studied molecule indicate that the compound is a good candidate for nonlinear optical materials.

  19. Implementation of Rotational Raman Channel in Multiwavelength Aerosol Lidar to Improve Measurements of Particle Extinction and Backscattering at 532 NM

    Directory of Open Access Journals (Sweden)

    Veselovskii Igor

    2016-01-01

    Full Text Available We describe a practical implementation of rotational Raman (RR measurements in an existing Mie-Raman lidar to obtain measurements of aerosol extinction and backscattering at 532 nm. A 2.3 nm width interference filter was used to select a spectral range characterized by low temperature sensitivity within the anti-Stokes branch of the RR spectrum. Simulations demonstrate that the temperature dependence of the scattering cross section does not exceed 1.0% in the 230-300K range making accurate correction for this dependence quite easy. With this upgrade, the NASA/GSFC multiwavelength Raman lidar has demonstrated useful α532 measurements and was used for regular observations. Examples of lidar measurements and inversion of optical data to the particle microphysics will be given in presentation.

  20. Theoretical and experimental research on high-order stimulated Raman scattering in KGd(WO4)2

    Science.gov (United States)

    Wang, Xiaobin; Kang, Wenyun; Song, Xiaoquan; Xie, Ping; Zong, Nan; Tu, Wei

    2017-02-01

    Eight wavelengths (465, 485, 508, 532, 559, 588, 621, and 658 nm) were synchronously generated by a single-pass potassium gadolinium tungstate (KGW) crystal Raman arrangement, which was pumped by a 532 nm, picosecond Nd: YAG laser with high peak power. To the best of our knowledge, this single-pass arrangement synchronously generated the highest-order Stokes and anti-Stokes among all known KGW Raman lasers. The first- to seventh-order Stokes conversion efficiency was calculated using Raman coupled equations. Further, the numerical results of third-order Stokes (621 nm) conversion efficiency were in good agreement with the experimental ones. We also analyze and discuss the factors because of which higher-order Stokes were not generated.

  1. 光子晶体光纤中高效的反斯托克斯信号产生%High efficient anti-Stokes signal conversion in photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    申向伟; 余重秀; 桑新柱; 苑金辉; 韩颖; 夏长明; 侯蓝田; 饶芬; 夏民; 尹霄丽

    2012-01-01

    基于四波混频的反斯托克斯变换,被广泛应用于短波辐射高分辨率成像以及直接激发分子的电子跃迁等方面.为了实现更加高效的反斯托克斯变换,利用中心波长为810 nm脉冲宽度为120 fs的钛蓝宝石(Ti:sapphire)飞秒激光器作为抽运光源,在长度为0.5 m和3 m的光子晶体光纤中分别实现了高阶模和基膜的简并四波混频.实验中,采用的光子晶体光纤的零色散波长在820 nm附近.在基模相位匹配条件下,在560 nm附近实现了高效地反斯托克斯信号的产生,反斯托克斯信号与残余抽运信号的最大功率比为33:1;反斯托克斯信号和斯托克斯信号的最大功率比25:1;反斯托克斯信号最大功率转换效率P_a/P_(p0)为34%.抽运波长从790 nm逐渐增加到810 nm过程中,在长为3 m的光子晶体光纤中相位从不匹配状态转化为高阶模匹配状态后,再转化为基模匹配状态.通过实验研究得出了相位匹配程度随抽运功率、波长和光纤长度的变化规律,同时分析了造成理论计算与实验结果存在差异的主要因素.本文为研究在光子晶体光纤基模中实现相位匹配和产生高效反斯托克斯信号提供了理论和实验依据.%The anti-Stokes frequency conversion based on four-wave mixing(FWM) has been widely used to generate short-wavelength radiation for high resolution imaging,direct excitation of electronic molecular transitions,and so on.For achieving more effective anti- Stokes conversion,we use the Ti:sapphire laser with a central wavelength of 810 nm and a pulse width of 120 fs as a pump source,and the degenerated FWMs of the higher mode and the fundamental mode are achieved respectively in 0.5 m long and 3 m long photonic crystal fibers(PCFs) with a zero dispersion wavelength of fundamental mode around 820nm in our experiment.The anti-Stokes signals around 560nm are generated efficiently at the fundamental phase matching.The maximum

  2. High precision stress measurements in semiconductor structures by Raman microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Uhlig, Benjamin

    2009-07-01

    Stress in silicon structures plays an essential role in modern semiconductor technology. This stress has to be measured and due to the ongoing miniaturization in today's semiconductor industry, the measuring method has to meet certain requirements. The present thesis deals with the question how Raman spectroscopy can be used to measure the state of stress in semiconductor structures. In the first chapter the relation between Raman peakshift and stress in the material is explained. It is shown that detailed stress maps with a spatial resolution close to the diffraction limit can be obtained in structured semiconductor samples. Furthermore a novel procedure, the so called Stokes-AntiStokes-Difference method is introduced. With this method, topography, tool or drift effects can be distinguished from stress related influences in the sample. In the next chapter Tip-enhanced Raman Scattering (TERS) and its application for an improvement in lateral resolution is discussed. For this, a study is presented, which shows the influence of metal particles on the intensity and localization of the Raman signal. A method to attach metal particles to scannable tips is successfully applied. First TERS scans are shown and their impact on and challenges for high resolution stress measurements on semiconductor structures is explained. (orig.)

  3. Raman micro-spectroscopic investigation of the interaction of cultured HCT116 colon cancer cells with alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase

    Science.gov (United States)

    Akyuz, S.; Ozel, A. E.; Balci, K.; Akyuz, T.; Coker, A.; Arisan, E. D.; Palavan-Unsal, N.; Ozalpan, A.

    2011-05-01

    The interaction of cultured colon cancer cells with alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase, has been investigated, using Raman micro-spectroscopy, in order to investigate DFMO induced effects. Raman spectra of the cultured HCT116 colon cancer cells treated with DFMO at different concentrations (0, 1, 2.5, 5, and 7.5 mM) were recorded in the range 550-2300 cm -1. It has been shown that second derivative profile of the raw Raman spectrum of the colon cancer cells (i.e., the original experimental spectrum without any computational corrections) discriminates the weak but sharp bands from the strong, broad fluorescence background, and gives information about the position of the peaks and their band widths. The relative integrated intensities of the 781 cm -1 and 788 cm -1 DNA/RNA marker bands to that of 1451 cm -1 band are found to decrease by addition of DFMO. Up to 65% reduction in the magnitude of the 1003 cm -1 band, the characteristic phenylalanine ring breathing mode, in comparison to that of 1451 band, is observed. The results indicate DFMO induced apoptosis. On the other hand the intensity ratio of the tyrosine Fermi doubled around 830 cm -1 and 850 cm -1, which is a marker of hydrogen-bonding state of phenolic OH, is changed. The addition of DFMO may alter the tyrosine environment in cells, and parts of tyrosine residues are exposed. We also observed some modifications in amide I band, pointing out the alterations of the secondary structure of cell proteins by the presence of DFMO.

  4. Enhanced Raman spectroscopic study of the coordination chemistry of malononitrile on copper surfaces - Removal of nu(C=N) degeneracy through pi-coordination

    Science.gov (United States)

    Loo, B. H.; Lee, Y. G.; Frazier, D. O.

    1985-01-01

    Surface-enhanced Raman spectroscopy has been used to study the molecular interactions of malononitrile with copper electrode surfaces. The doubly degenerate CN stretching frequency at 2263/cm is removed when malononitrile adsorbs on copper. Two nu(CN) bands are observed at 2096 and 2204/cm at -0.6 V(SCE). The result shows that only one CN group is pi-coordinated with Cu, which contributes to the observed large shift (-167/cm) in nu(CN). The other CN group is not coordinated to the metal surface.

  5. Validation of an in-line Raman spectroscopic method for continuous active pharmaceutical ingredient quantification during pharmaceutical hot-melt extrusion.

    Science.gov (United States)

    Saerens, L; Segher, N; Vervaet, C; Remon, J P; De Beer, T

    2014-01-02

    A calibration model for in-line API determination was developed based on Raman spectra collected during hot-melt extrusion. This predictive model was validated by calculating the accuracy profile based on the analysis results of validation experiments. Furthermore, based on the data of the accuracy profile, the measurement uncertainty was determined. Finally, the robustness of the model was evaluated. A Raman probe was implemented in the die of a twin-screw extruder, to monitor the drug concentration during extrusion of physical mixtures containing 15, 20, 25, 30 and 35% (w/w) metoprolol tartrate (MPT) in Eudragit(®) RS PO, an amorphous copolymer of acrylic and methacrylic acid esters with a low content of quaternary ammonium groups, which are present as salts. Several different calibration models for the prediction of the MPT content were developed, based on the use of single spectra or averaged spectra, and using partial least squares (PLS) regression or multivariate curve resolution (MCR). These predictive models were validated by extruding and monitoring mixtures containing 17.5, 22.5, 25.0, 27.5 and 32.5% (w/w) MPT. Each validated concentration was monitored on three different days, by two different operators. The β-expectation tolerance intervals were calculated for each model and for each of the validated MPT concentration levels (β was set at 95%), and acceptance limits were set at 10% (relative bias), indicating that at least 95% of future measurements should not deviate more than 10% from the true value. The only model where these acceptance limits were not exceeded was the MCR model based on averaged Raman spectra. The uncertainty measurements for this model showed that the unknown true value can be found at a maximum of ±7.00% around the measured result, with a confidence level of 95%. The robustness of this model was evaluated via an experimental design varying throughput, screw speed and barrel temperature. The robustness designs showed no

  6. [The measurement of temperature with Raman scattering spectra of polycrystal (SrNO3)2].

    Science.gov (United States)

    Yu, F; Gong, G; Zeng, Z; Liu, G

    2000-04-01

    We have developed a new method for the determination of temperature with Raman scattering spectra. The strontium nitrate was chosen as an experiment substance. It has two bands of Raman scattering, and their wavenumbers are 738 and 1,057 cm-1 in 600-1,700 cm-1. We have obtained the intensities of their Stokes and Anti-Stokes scattering, then we have got two temperatures of strontium nitrate according to the formula. The result from the 738 cm-1 scattering band has larger error than that from the 1,057 cm-1. This may account for the noise of the photocounter. This no touch method is fit to measure the temperature of the molecular.

  7. Generation and delayed retrieval of spatially multimode Raman scattering in warm rubidium vapors

    CERN Document Server

    Chrapkiewicz, Radoslaw

    2014-01-01

    We apply collective Raman scattering to create, store and retrieve spatially multimode light in warm rubidium-87 vapors. The light is created in a spontaneous Stokes scattering process. This is accompanied by the creation of counterpart collective excitations in the atomic ensemble -- the spin waves. After a certain storage time we coherently convert the spin waves into the light in deterministic anti-Stokes scattering. The whole process can be regarded as a delayed four-wave mixing which produces pairs of correlated, delayed random images. Storage of higher order spatial modes up to microseconds is possible owing to usage of a buffer gas. We study the performance of the Raman scattering, storage and retrieval of collective excitations focusing on spatial effects and the influence of decoherence caused by diffusion of rubidium atoms in different buffer gases. We quantify the number of modes created and retrieved by analyzing statistical correlations of intensity fluctuations between portions of the light scat...

  8. Generation and delayed retrieval of spatially multimode Raman scattering in warm rubidium vapors.

    Science.gov (United States)

    Chrapkiewicz, Radosław; Wasilewski, Wojciech

    2012-12-31

    We apply collective Raman scattering to create, store and retrieve spatially multimode light in warm rubidium-87 vapors. The light is created in a spontaneous Stokes scattering process. This is accompanied by the creation of counterpart collective excitations in the atomic ensemble - the spin waves. After a certain storage time we coherently convert the spin waves into the light in deterministic anti-Stokes scattering. The whole process can be regarded as a delayed four-wave mixing which produces pairs of correlated, delayed random images. Storage of higher order spatial modes up to microseconds is possible owing to usage of a buffer gas. We study the performance of the Raman scattering, storage and retrieval of collective excitations focusing on spatial effects and the influence of decoherence caused by diffusion of rubidium atoms in different buffer gases. We quantify the number of modes created and retrieved by analyzing statistical correlations of intensity fluctuations between portions of the light scattered in the far field.

  9. Raman spectroscopic detection of rapid, reversible, early-stage inflammatory cytokine-induced apoptosis of adult hippocampal progenitors/stem cells

    CERN Document Server

    Ladiwala, Uma; Thakur, Bhushan; Santhosh, Chidangil; Mathur, Deepak

    2014-01-01

    The role of neuro-inflammation in diverse, acute and chronic brain pathologies is being increasingly recognized. Neuro-inflammation is accompanied by increased levels of both pro- and anti-inflammatory cytokines; these have deleterious as well as protective/reparative effects. Inflammation has varying effects on neurogenesis and is a subject of intense contemporary interest. We show that TNF-alpha and IFN-gamma, used concomitantly, cause apoptosis of adult rat hippocampal progenitor/stem cells in vitro as detected by the TUNEL and MTT assays on time scales of several hours. We have coupled Raman spectroscopy to an optical trap to probe early changes of apoptosis in single, live neural stem cells that have been treated with pro-inflammatory cytokines, TNF-alpha and IFN-gamma. Changes caused by inflammation-induced denaturation of DNA are observed in the Raman spectra that correspond to very early stages of apoptosis, occurring on very fast time scales: as short as 10 minutes. Addition of the anti-inflammatory ...

  10. Raman spectroscopic measurements of CO2 density: Experimental calibration with high-pressure optical cell (HPOC) and fused silica capillary capsule (FSCC) with application to fluid inclusion observations

    Science.gov (United States)

    Wang, X.; Chou, I.-Ming; Hu, W.; Burruss, R.C.; Sun, Q.; Song, Y.

    2011-01-01

    Raman spectroscopy is a powerful method for the determination of CO2 densities in fluid inclusions, especially for those with small size and/or low fluid density. The relationship between CO2 Fermi diad split (??, cm-1) and CO2 density (??, g/cm3) has been documented by several previous studies. However, significant discrepancies exist among these studies mainly because of inconsistent calibration procedures and lack of measurements for CO2 fluids having densities between 0.21 and 0.75g/cm3, where liquid and vapor phases coexist near room temperature.In this study, a high-pressure optical cell and fused silica capillary capsules were used to prepare pure CO2 samples with densities between 0.0472 and 1.0060g/cm3. The measured CO2 Fermi diad splits were calibrated with two well established Raman bands of benzonitrile at 1192.6 and 1598.9cm-1. The relationship between the CO2 Fermi diad split and density can be represented by: ??=47513.64243-1374.824414????+13.25586152????2-0.04258891551????3 (r2=0.99835, ??=0.0253g/cm3), and this relationship was tested by synthetic fluid inclusions and natural CO2-rich fluid inclusions. The effects of temperature and the presence of H2O and CH4 on this relationship were also examined. ?? 2011 Elsevier Ltd.

  11. Effect of pressure on conformational equilibria of 1-chloropropane and 1-bromopropane in water and organic solvents: a Raman spectroscopic study.

    Science.gov (United States)

    Kasezawa, Kunihiro; Kato, Minoru

    2009-06-25

    We have investigated the effect of pressure on the conformational equilibria of 1-chloropropane and 1-bromopropane in water and organic solvents using Raman spectroscopy. In particular, we focus on 1-chloropropane and 1-bromopropane in water as a model for characterizing the hydrophobic effect on the molecular conformation. From the pressure dependence of the Raman intensities of the carbon-halogen stretching bands, the volume differences (DeltaV(t-->g)) between trans and gauche conformers of 1-chloropropane and 1-bromopropane in water and organic solvents are determined. All the values are found to be negative. The values of DeltaV for aqueous solutions deviate significantly from the expected results obtained for organic solvents. The DeltaV is divided into several contributions and interpretation of these contributions indicates that the significantly large negative DeltaV for aqueous solutions is explained by the considerably low packing density of solvent water compared to the density of the organic solvents. The results for the aqueous solutions are compared with the pressure effect on the dimerization of methane in water calculated by Hummer et al. ( Hummer , G. ; et al. Proc. Natl. Acad. Sci. U.S.A. 1998 , 95 , 1552. ). Our results strongly support the validity of the increasing desolvation barrier with increasing pressure predicted by Hummer et al. Finally, we discuss the biological relevance of the results for aqueous solutions in terms of the pressure denaturation of proteins.

  12. Application of spectroscopic methods for identification (FT-IR, Raman spectroscopy) and determination (UV, EPR) of quercetin-3-O-rutinoside. Experimental and DFT based approach

    Science.gov (United States)

    Paczkowska, Magdalena; Lewandowska, Kornelia; Bednarski, Waldemar; Mizera, Mikołaj; Podborska, Agnieszka; Krause, Anna; Cielecka-Piontek, Judyta

    2015-04-01

    Vibrational (FT-IR, Raman) and electronic (UV, EPR) spectral measurements were performed for an analysis of rutin (quercetin-3-O-rutinoside) obtained from Rutaofficinalis. The identification of rutin was done with the use of FT-IR and Raman spectra. Those experimental spectra were determined with the support of theoretical calculations based on a DFT method with the B3LYP hybrid functional and 6-31G(d,p) basis set. The application of UV and EPR spectra was found to be a suitable analytical approach to the evaluation of changes in rutin exposed to certain physicochemical factors. Differences in absorbance observed in direct UV spectra were used to monitor changes in the concentration of rutin in degraded samples. Spectra of electron paramagnetic resonance allowed studying the process of free-radical quenching in rutin following its exposure to light. The molecular electrostatic potential (MEP) and frontier molecular orbitals (LUMO-HOMO) were also determined in order to predict structural changes and reactive sites in rutin.

  13. Effects of a Protic Ionic Liquid on the Reaction Pathway during Non-Aqueous Sol–Gel Synthesis of Silica: A Raman Spectroscopic Investigation

    Directory of Open Access Journals (Sweden)

    Anna Martinelli

    2014-04-01

    Full Text Available The reaction pathway during the formation of silica via a two-component “non-aqueou” sol-gel synthesis is studied by in situ time-resolved Raman spectroscopy. This synthetic route is followed with and without the addition of the protic ionic liquid 1-ethylimidazolium bis(trifluoromethanesulfonylimide (C2HImTFSI in order to investigate its effect on the reaction pathway. We demonstrate that Raman spectroscopy is suitable to discriminate between different silica intermediates, which are produced and consumed at different rates with respect to the point of gelation. We find that half-way to gelation monomers and shorter chains are the most abundant silica species, while the formation of silica rings strongly correlates to the sol-to-gel transition. Thus, curling up of linear chains is here proposed as a plausible mechanism for the formation of small rings. These in turn act as nucleation sites for the condensation of larger rings and thus the formation of the open and polymeric silica network. We find that the protic ionic liquid does not change the reaction pathway per se, but accelerates the cyclization process, intermediated by the faster inclusion of monomeric species.

  14. Comprehensive quantum chemical and spectroscopic (FTIR, FT-Raman, 1H, 13C NMR) investigations of O-desmethyltramadol hydrochloride an active metabolite in tramadol - An analgesic drug

    Science.gov (United States)

    Arjunan, V.; Santhanam, R.; Marchewka, M. K.; Mohan, S.

    2014-03-01

    O-desmethyltramadol is one of the main metabolites of tramadol widely used clinically and has analgesic activity. The FTIR and FT-Raman spectra of O-desmethyl tramadol hydrochloride are recorded in the solid phase in the regions 4000-400 cm-1 and 4000-100 cm-1, respectively. The observed fundamentals are assigned to different normal modes of vibration. Theoretical studies have been performed as its hydrochloride salt. The structure of the compound has been optimised with B3LYP method using 6-31G** and cc-pVDZ basis sets. The optimised bond length and bond angles are correlated with the X-ray data. The experimental wavenumbers were compared with the scaled vibrational frequencies determined by DFT methods. The IR and Raman intensities are determined with B3LYP method using cc-pVDZ and 6-31G(d,p) basic sets. The total electron density and molecular electrostatic potential surfaces of the molecule are constructed by using B3LYP/cc-pVDZ method to display electrostatic potential (electron + nuclei) distribution. The electronic properties HOMO and LUMO energies were measured. Natural bond orbital analysis of O-desmethyltramadol hydrochloride has been performed to indicate the presence of intramolecular charge transfer. The 1H and 13C NMR chemical shifts of the molecule have been anlysed.

  15. Structural Changes Induced in Grapevine (Vitis vinifera L. DNA by Femtosecond IR Laser Pulses: A Surface-Enhanced Raman Spectroscopic Study

    Directory of Open Access Journals (Sweden)

    Nicoleta E. Dina

    2016-05-01

    Full Text Available In this work, surface-enhanced Raman spectra of ten genomic DNAs extracted from leaf tissues of different grapevine (Vitis vinifera L. varieties, respectively, are analyzed in the wavenumber range 300–1800 cm−1. Furthermore, structural changes induced in grapevine genomic nucleic acids upon femtosecond (170 fs infrared (IR laser pulse irradiation (λ = 1100 nm are discussed in detail for seven genomic DNAs, respectively. Surface-enhanced Raman spectroscopy (SERS signatures, vibrational band assignments and structural characterization of genomic DNAs are reported for each case. As a general observation, the wavenumber range between 1500 and 1660 cm−1 of the spectra seems to be modified upon laser treatment. This finding could reflect changes in the base-stacking interactions in DNA. Spectral shifts are mainly attributed to purines (dA, dG and deoxyribose. Pyrimidine residues seem to be less affected by IR femtosecond laser pulse irradiation. Furthermore, changes in the conformational properties of nucleic acid segments are observed after laser treatment. We have found that DNA isolated from Feteasca Neagra grapevine leaf tissues is the most structurally-responsive system to the femtosecond IR laser irradiation process. In addition, using unbiased computational resources by means of principal component analysis (PCA, eight different grapevine varieties were discriminated.

  16. A grid matrix-based Raman spectroscopic method to characterize different cell milieu in biopsied axillary sentinel lymph nodes of breast cancer patients.

    Science.gov (United States)

    Som, Dipasree; Tak, Megha; Setia, Mohit; Patil, Asawari; Sengupta, Amit; Chilakapati, C Murali Krishna; Srivastava, Anurag; Parmar, Vani; Nair, Nita; Sarin, Rajiv; Badwe, R

    2016-01-01

    Raman spectroscopy which is based upon inelastic scattering of photons has a potential to emerge as a noninvasive bedside in vivo or ex vivo molecular diagnostic tool. There is a need to improve the sensitivity and predictability of Raman spectroscopy. We developed a grid matrix-based tissue mapping protocol to acquire cellular-specific spectra that also involved digital microscopy for localizing malignant and lymphocytic cells in sentinel lymph node biopsy sample. Biosignals acquired from specific cellular milieu were subjected to an advanced supervised analytical method, i.e., cross-correlation and peak-to-peak ratio in addition to PCA and PC-LDA. We observed decreased spectral intensity as well as shift in the spectral peaks of amides and lipid bands in the completely metastatic (cancer cells) lymph nodes with high cellular density. Spectral library of normal lymphocytes and metastatic cancer cells created using the cellular specific mapping technique can be utilized to create an automated smart diagnostic tool for bench side screening of sampled lymph nodes. Spectral library of normal lymphocytes and metastatic cancer cells created using the cellular specific mapping technique can be utilized to develop an automated smart diagnostic tool for bench side screening of sampled lymph nodes supported by ongoing global research in developing better technology and signal and big data processing algorithms.

  17. Combined experimental and quantum chemical studies on spectroscopic (FT-IR, FT-Raman, UV-Vis, and NMR) and structural characteristics of quinoline-5-carboxaldehyde

    Science.gov (United States)

    Kumru, Mustafa; Altun, Ahmet; Kocademir, Mustafa; Küçük, Vesile; Bardakçı, Tayyibe; Şaşmaz, İbrahim

    2016-12-01

    Comparative experimental and theoretical studies have been performed on the structure and spectral (FT-IR, FT-Raman, UV-Vis and NMR) features of quinoline-5-carboxaldehyde. Quantum chemical calculations have been carried out at Hartree-Fock and density functional B3LYP levels with the triple-zeta 6-311++G** basis set. Two stable conformers of quinoline-5-carboxaldehyde arising from the orientation of the carboxaldehyde moiety have been located at the room temperature. The energetic separation of these conformers is as small as 2.5 kcal/mol with a low transition barrier (around 9 kcal/mol). Therefore, these conformers are expected to coexist at the room temperature. Several molecular characteristics of quinoline-5-carboxaldehyde obtained through B3LYP and time-dependent B3LYP calculations, such as conformational stability, key geometry parameters, vibrational frequencies, IR and Raman intensities, UV-Vis vertical excitation energies and the corresponding oscillator strengths have been analyzed. The 1H and 13C NMR chemical shifts of quinoline-5-carboxaldehyde were also investigated.

  18. Application of spectroscopic methods for identification (FT-IR, Raman spectroscopy) and determination (UV, EPR) of quercetin-3-O-rutinoside. Experimental and DFT based approach.

    Science.gov (United States)

    Paczkowska, Magdalena; Lewandowska, Kornelia; Bednarski, Waldemar; Mizera, Mikołaj; Podborska, Agnieszka; Krause, Anna; Cielecka-Piontek, Judyta

    2015-04-05

    Vibrational (FT-IR, Raman) and electronic (UV, EPR) spectral measurements were performed for an analysis of rutin (quercetin-3-O-rutinoside) obtained from Rutaofficinalis. The identification of rutin was done with the use of FT-IR and Raman spectra. Those experimental spectra were determined with the support of theoretical calculations based on a DFT method with the B3LYP hybrid functional and 6-31G(d,p) basis set. The application of UV and EPR spectra was found to be a suitable analytical approach to the evaluation of changes in rutin exposed to certain physicochemical factors. Differences in absorbance observed in direct UV spectra were used to monitor changes in the concentration of rutin in degraded samples. Spectra of electron paramagnetic resonance allowed studying the process of free-radical quenching in rutin following its exposure to light. The molecular electrostatic potential (MEP) and frontier molecular orbitals (LUMO-HOMO) were also determined in order to predict structural changes and reactive sites in rutin.

  19. Synthesis, spectroscopic (FT-IR, FT-Raman, NMR, UV-Visible), first order hyperpolarizability, NBO and molecular docking study of (E)-1-(4-bromobenzylidene)semicarbazide

    Science.gov (United States)

    Raja, M.; Muhamed, R. Raj; Muthu, S.; Suresh, M.

    2017-01-01

    The compound (E)-1-(4-bromobenzylidene)semicarbazide(4BSC) was synthesized and characterized by FT-IR, FT-Raman, UV-Visible, 1HNMR and 13CNMR spectra. The optimized molecular geometry(bond length, bond angle), the complete vibrational frequency, the infrared intensities and the Raman scattering activities were calculated by using density functional theory(DFT) B3LYP method with the help of 6-311++G(d,p) basis set. From the recorded UV-Visible spectrum, the electronic properties such as excitation energies, wavelength, band gap and oscillator strength are evaluated by TD-DFT in DMSO solution and gas phase methods using 6-311++G(d,p) basis set. The calculated HOMO - LUMO band gap energies confirm that charge transfer occurs within the molecule. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule are calculated by the gauge-independent atomic orbital (GIAO) method and compared with experimental results. The hyperconjugative interaction energy E(2) and electron densities of donor (i) and acceptor (j) bonds were calculated using NBO analysis. Besides NLO and MEP were also calculated and interpreted. To study the biological activity of the investigation molecule, molecular docking was done to identify the hydrogen bond lengths and binding energy with different antimicrobial protein. Thermodynamic properties of the title compound at different temperatures have been calculated, revealing the correlations the heat capacity (C), entropy (S) and enthalpy changes (H) and temperatures.

  20. Conformational stability, spectroscopic (FT-IR, FT-Raman and UV-Vis) analysis, NLO, NBO, FMO and Fukui function analysis of 4-hexylacetophenone by density functional theory.

    Science.gov (United States)

    Saravanan, S; Balachandran, V

    2015-03-05

    The experimental and theoretical study on the structures and vibrations of 4-hexylacetophenone (abbreviated as 4HAP) are presented. The FT-IR and FT-Raman spectra of the title compound have been recorded in the region 4000-400cm(-1) and 3500-100cm(-1) respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) method with 6-311++G(d,p) basis set. The most stable conformer of 4HAP is identified from the computational results. The assignments of the vibrational spectra have been carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMEF). The linear polarizability (α) and the first hyperpolarizability (βtot) values of the investigated molecule have been computed using B3LYP and LSDA with 6-311++G(d,p) basis set. Stability of the molecule arising from hyper conjugative interaction and charge transfer delocalization has been analyzed using natural bond orbital (NBO) analysis. The molecule orbital contributions are studied by density of energy states (DOSs). UV-Vis spectrum and effects of solvents have been discussed effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach. Fukui function and Mulliken analysis on atomic charges of the title compound have been calculated. Finally, electrophilic and nucleophilic descriptors of the title molecule have been calculated.

  1. Combined quantum chemical density functional theory and spectroscopic Raman and UV-vis-NIR study of oligothienoacenes with five and seven rings.

    Science.gov (United States)

    Osuna, Reyes Malavé; Zhang, Xinnan; Matzger, Adam Jay; Hernandez, Víctor; López Navarrete, Juan Teodomiro

    2006-04-20

    In this article, we report the characterization of novel oligothienoacenes with five and seven fused thiophene rings, materials with potential applications in organic electronics. In contrast to usual alpha-linked oligothiophenes, these fused oligothiophenes have a larger band gap than most semiconductors currently used in the fabrication of organic field-effect transistors (OFETs) and therefore they are expected to be more stable in air. The synthesis of these fused-ring oligomers was motivated by the notion that a more rigid and planar structure should reduce defects (such as torsion about single bonds between alpha-linked units or S-syn defects) and thus improve conjugation for better charge-carrier mobility. The conjugational properties of these two molecular materials have been investigated by means of FT-Raman spectroscopy, revealing that conjugation still increases in passing from the five-ring oligomer to that with seven-rings. DFT and TDDFT quantum chemical calculations have been performed, at the B3LYP/6-31G level, to assess information regarding the minimum-energy molecular structure, topologies, and absolute energies of the frontier molecular orbitals (MOs.) around the gap, vibrational normal modes related to the main Raman features, and vertical one-electron excitations giving rise to the main optical absorptions.

  2. Excited state proton transfer dynamics of thioacetamide in S2(ππ*) state: resonance Raman spectroscopic and quantum mechanical calculations study.

    Science.gov (United States)

    Chen, Xiao; Zhao, Yanying; Zhang, Haibo; Xue, Jiadan; Zheng, Xuming

    2015-02-05

    The photophysics and photochemistry of thioacetamide (CH3CSNH2) after excitation to the S2 electronic state were investigated by using resonance Raman spectroscopy in conjunction with the complete active space self-consistent field (CASSCF) method and density functional theory (DFT) calculations. The A-band resonance Raman spectra in acetonitrile, methanol, and water were obtained at 299.1, 282.4, 266.0, 252.7, and 245.9 nm excitation wavelengths to probe the structural dynamics of thioacetamide in the S2 state. CASSCF calculations were done to determine the transition energies and structures of the lower-lying excited states, the conical intersection points CI(S2/S1) and CI(S1/S0), and intersystem crossing points. The structural dynamics of thioacetamide in the S2 state was revealed to be along eight Franck-Condon active vibrational modes ν15, ν11, ν14, ν10, ν8, ν12, ν18, and ν19, mostly in the CC/CS/CN stretches and the CNH8,9/CCH5,6,7/CCN/CCS in-plane bends as indicated by the corresponding normal mode descriptions. The S2 → S1 decay process via the S2/S1 conical intersection point as the major channel were excluded. The thione-thiol photoisomerization reaction mechanism of thioacetamide via the S2,FC → S'1,min excited state proton transfer (ESPT) reaction channel was proposed.

  3. Raman spectroscopic studies on single crystals of the iron-based superconductor SmFeAsO{sub 1-x}F{sub x}

    Energy Technology Data Exchange (ETDEWEB)

    Jursic, Ivan; Schoenes, Joachim [Technische Universitaet Braunschweig, Institut fuer Physik der Kondensierten Materie, 38106 Braunschweig (Germany); Bukowski, Zbigniew; Karpinski, Janusz [ETH Zuerich, Laboratorium fuer Festkoerperphysik, 8093 Zuerich (Switzerland)

    2009-07-01

    The recent discovery of superconductivity in iron-based oxypnctides has led to a great interest in this new class of non-cuprate high-T{sub c} superconductors. Though theoretical work predicts a small electron-phonon coupling, which means that this should not be the driving mechanism for the observed T{sub c}'s in this class of material, the exact coupling mechanism is still under debate. We present Raman studies on superconducting SmFeAsO{sub 1-x}F{sub x} single crystals where the T{sub c} was determined by SQUID magnetometric measurements to be 34 K. At room temperature polarized measurements were performed to assign the phonon modes. Furthermore studies at different temperatures reaching from 5K to 300K were done to investigate the phonon behavior. The phonon frequencies shift with temperature and we investigate this shift in terms of electron-phonon coupling.

  4. Vibrational spectroscopic (FT-IR, FT-Raman, ¹H NMR and UV) investigations and computational study of 5-nitro-2-(4-nitrobenzyl) benzoxazole.

    Science.gov (United States)

    Bhagyasree, J B; Varghese, Hema Tresa; Panicker, C Yohannan; Samuel, Jadu; Van Alsenoy, Christian; Bolelli, Kayhan; Yildiz, Ilkay; Aki, Esin

    2013-02-01

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 5-nitro-2-(4-nitrobenzyl) benzoxazole have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of the normal modes of vibrations was done using GAR2PED program. The energy and oscillator strength calculated by time dependent density functional theory almost compliments with experimental findings. Gauge-including atomic orbital (1)H NMR chemical shifts calculations were carried out by using B3LYP functional with 6-31G basis set. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization have been analyzed using NBO analysis. MEP was performed by the DFT method and the predicted infrared intensities and Raman activities have also been reported. The calculated geometrical parameters are in agreement with that of similar derivatives.

  5. Non-invasive in-vivo Raman spectroscopic measurement of the dynamics of the antioxidant substance lycopene in the human skin after a dietary supplementation

    Science.gov (United States)

    Darvin, M. E.; Gersonde, I.; Albrecht, H.; Sterry, W.; Lademann, J.

    2007-05-01

    A non-invasive optical method based on resonance Raman spectroscopy was used for the in vivo detection of the concentration of the carotenoid antioxidant substance lycopene in the human skin. The physiological variation of the level of lycopene in the skin during a 6 month period was measured daily in 7 volunteers. It was shown that all volunteers had a different individual level of lycopene in the skin, depending on the lifestyle of volunteers. It was shown that the supplementation of the foodstuffs containing lycopene, such as tomato products and some fruits, increases the level of lycopene in the skin. The increase in the lycopene level can be usually observed on the next day after the supplementation. The present results demonstrate that a diet rich in products containing a high amount of carotenoids, such as lycopene, can be an efficient strategy to increase the carotenoid level of the skin.

  6. Quantum chemical studies on molecular structure, spectroscopic (IR, Raman, UV-Vis), NBO and HOMO-LUMO analysis of 1-benzyl-3-(2-furoyl) thiourea.

    Science.gov (United States)

    Gil, Diego M; Defonsi Lestard, M E; Estévez-Hernández, O; Duque, J; Reguera, E

    2015-06-15

    Vibrational and electronic spectra for 1-benzyl-3-(2-furoyl) thiourea were calculated by using density functional method (B3LYP) with different basis sets. The complete assignment of all vibrational modes was performed on basis of the calculated frequencies and comparing with the reported IR and Raman spectra for that thiourea derivative. UV-visible absorption spectra of the compound dissolved in methanol were recorded and analyzed using time dependent density functional theory (TD-DFT). The calculated values for the geometrical parameters of the title compound are consistent with the ones reported from XRD studies. The stability of the molecule, related to hyper-conjugative interactions, and electron delocalization were evaluated using natural bond orbital (NBO) analysis. Intra-molecular interactions were studied by AIM approach. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. Molecular electrostatic potential map was performed by the DFT method.

  7. Polymerization behavior within adhesive layer of one- and two-step self-etch adhesives: a micro-Raman spectroscopic study.

    Science.gov (United States)

    Sakano, Wakae; Nakajima, Masatoshi; Prasansuttiporn, Taweesak; Foxton, Richard M; Tagami, Junji

    2013-01-01

    This study investigated the polymerization behavior within the adhesive layer of one- and two-step self-etch adhesives at the dentincomposite interface. Dentin surfaces were applied with Clearfil S(3) Bond (TS), Clearfil S(3) Bond Plus (TSP) and Clearfil SE Bond (SE), and then placed with a light-curing resin composite. After water storage for 24 h, the bonded teeth were sectioned and polished perpendicular to the adhesive interface, and the degree of conversion (DC) of the adhesive layer between the dentin and composite were determined using micro-Raman analysis. For all the adhesives, the DCs of the adhesive layers significantly decreased near the adhesive-composite join (padhesive-composite join (Pitf), TS was significantly lower than TSP and SE (padhesive could not reach maximum DC even after polymerization of the overlying resin composite.

  8. Electronic [UV-Visible] and vibrational [FT-IR, FT-Raman] investigation and NMR-mass spectroscopic analysis of terephthalic acid using quantum Gaussian calculations.

    Science.gov (United States)

    Karthikeyan, N; Prince, J Joseph; Ramalingam, S; Periandy, S

    2015-03-15

    In this research work, the vibrational IR, polarization Raman, NMR and mass spectra of terephthalic acid (TA) were recorded. The observed fundamental peaks (IR, Raman) were assigned according to their distinctiveness region. The hybrid computational calculations were carried out for calculating geometrical and vibrational parameters by DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The molecular mass spectral data related to base molecule and substitutional group of the compound was analyzed. The modification of the chemical property by the reaction mechanism of the injection of dicarboxylic group in the base molecule was investigated. The (13)C and (1)H NMR spectra were simulated by using the gauge independent atomic orbital (GIAO) method and the absolute chemical shifts related to TMS were compared with experimental spectra. The study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by hybrid Gaussian calculation methods. The orbital energies of different levels of HOMO and LUMO were calculated and the molecular orbital lobe overlapping showed the inter charge transformation between the base molecule and ligand group. From the frontier molecular orbitals (FMO), the possibility of electrophilic and nucleophilic hit also analyzed. The NLO activity of the title compound related to Polarizability and hyperpolarizability were also discussed. The present molecule was fragmented with respect to atomic mass and the mass variation depends on the substitutions have also been studied.

  9. Molecular structure, spectroscopic characterization (FT-IR, FT-Raman, UV and NMR), HOMO and LUMO analysis of 3-ethynylthiophene with DFT quantum chemical calculations

    Science.gov (United States)

    Karabacak, Mehmet; Bilgili, Sibel; Mavis, Tugba; Eskici, Mustafa; Atac, Ahmet

    2013-11-01

    In this work, FT-IR, FT-Raman, UV and NMR spectra of 3-ethynylthiophene (3-ETP, C6H4S) were carried out by using density functional theory DFT/B3LYP method with the 6-311++G(d,p), 6-311+G(d,p), 6-311G(d,p), 6-31++G(d,p), 6-31+G(d,p), 6-31G(d,p) basis sets. FT-IR and FT-Raman spectra were recorded in the regions of 3500-400 cm-1 and 3500-50 cm-1, respectively. The geometrical parameters, energies and wavenumbers were obtained and the complete assignments of fundamental vibrations were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. The 1H, 13C and HMQC (1H-13C correlation) NMR spectra in chloroform (CDCl3) were recorded and calculated. The UV spectrum of investigated compound were recorded in the region of 200-400 nm in ethanol solution. The electronic properties, such as excitation energies, absorption wavelengths, HOMO and LUMO energies were performed by DFT/B3LYP approach and the results were compared with experimental observations. The thermodynamic properties such zero-point vibrational energy, thermal energy, specific heat capacity, rotational constants, entropy, and dipole moment of the studied compound were calculated. As a result, the calculated results were compared with the observed data and found to be in good agreement.

  10. Raman spectrum of asphaltene

    KAUST Repository

    Abdallah, Wael A.

    2012-11-05

    Asphaltenes extracted from seven different crude oils representing different geological formations from around the globe were analyzed using the Raman spectroscopic technique. Each spectrum is fitted with four main peaks using the Gaussian function. On the basis of D1 and G bands of the Raman spectrum, asphaltene indicated an ordered structure with the presence of boundary defected edges. The average aromatic sheet size of the asphaltene molecules is estimated within the range of 1.52-1.88 nm, which represents approximately seven to eight aromatic fused rings. This estimation is based on the integrated intensity of D1 and G bands, as proposed by Tunistra and Koenig. The results here are in perfect agreement with so many other used techniques and indicate the potential applicability of Raman measurements to determine the average aromatic ring size and its boundary. © 2012 American Chemical Society.

  11. FT-Raman, FT-IR, UV spectroscopic, NBO and DFT quantum chemical study on the molecular structure, vibrational and electronic transitions of clopidogrel hydrogen sulfate form 1: A comparison to form 2

    Science.gov (United States)

    Srivastava, Anubha; Mishra, Rashmi; Tandon, Poonam; Bansal, A. K.

    2013-03-01

    Clopidogrel hydrogen sulfate (+)-(S)-(2-chlorophenyl)-6,7-dihydrothieno[3,2-c]pyridine-5(4H)-acetate sulfate (1:1), is a selective adenosine diphosphate (ADP) receptor antagonist often used in the treatment of coronary artery, peripheral vascular and cerebrovascular diseases. In the present communication, a comparative study of two polymorphic forms (forms 1 and 2) of clopidogrel hydrogen sulfate (CLP) has been reported. There is difference in conformation and intermolecular hydrogen bonding pattern of two forms. These differences are nicely reflected in the vibrational spectra. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands of CLP form 1 are interpreted with the aid of structure optimizations and normal mode analysis based on ab initio HF and DFT method employing 6-311++G(d,p) basis. Polymorphism in CLP have been studied using various characterization tools like FT-Raman, FT-IR spectroscopy and DSC in combination with the quantum chemical calculations. UV-vis spectroscopic studies along with HOMO-LUMO analysis of both polymorphs were performed. The solvent effect calculated by TD-DFT/IEF-PCM/6-31G model results complements with the experimental findings. Stability of the molecule arising from hyper conjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis.

  12. FT-Raman, FT-IR, UV spectroscopic, NBO and DFT quantum chemical study on the molecular structure, vibrational and electronic transitions of clopidogrel hydrogen sulfate form 1: a comparison to form 2.

    Science.gov (United States)

    Srivastava, Anubha; Mishra, Rashmi; Tandon, Poonam; Bansal, A K

    2013-03-01

    Clopidogrel hydrogen sulfate (+)-(S)-(2-chlorophenyl)-6,7-dihydrothieno[3,2-c]pyridine-5(4H)-acetate sulfate (1:1), is a selective adenosine diphosphate (ADP) receptor antagonist often used in the treatment of coronary artery, peripheral vascular and cerebrovascular diseases. In the present communication, a comparative study of two polymorphic forms (forms 1 and 2) of clopidogrel hydrogen sulfate (CLP) has been reported. There is difference in conformation and intermolecular hydrogen bonding pattern of two forms. These differences are nicely reflected in the vibrational spectra. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands of CLP form 1 are interpreted with the aid of structure optimizations and normal mode analysis based on ab initio HF and DFT method employing 6-311++G(d,p) basis. Polymorphism in CLP have been studied using various characterization tools like FT-Raman, FT-IR spectroscopy and DSC in combination with the quantum chemical calculations. UV-vis spectroscopic studies along with HOMO-LUMO analysis of both polymorphs were performed. The solvent effect calculated by TD-DFT/IEF-PCM/6-31G model results complements with the experimental findings. Stability of the molecule arising from hyper conjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis.

  13. Raman spectroscopy as a tool for reagent free estimation

    CERN Document Server

    Kumar, S

    2014-01-01

    We present results of Raman spectroscopic studies of urine to determine the suitability of near-infrared Raman spectroscopy for quantitative estimation of urinary urea. The Raman spectra were acquired from the urine samples with an inbuilt Raman spectroscopy setup that employs a 785-nm diode laser as the Raman excitation source. A multivariate algorithm based on partial least square (PLS) regression was developed to predict the concentration of urea depending on the measured sets of Raman spectra and the reference urea concentration. The computed results shows that Raman spectroscopy in amalgamation with PLS-based multivariate chemometric algorithm can detect urea in urine samples with an accuracy of >90 %.

  14. Transcutaneous in vivo Raman spectroscopic studies in a mouse model: evaluation of changes in the breast associated with pregnancy and lactation

    Science.gov (United States)

    Bhattacharjee, Tanmoy; Maru, Girish; Ingle, Arvind; Krishna, C. Murali

    2013-04-01

    Raman spectroscopy (RS) has been extensively explored as an alternative diagnostic tool for breast cancer. This can be attributed to its sensitivity to malignancy-associated biochemical changes. However, biochemical changes due to nonmalignant conditions like benign lesions, inflammatory diseases, aging, menstrual cycle, pregnancy, and lactation may act as confounding factors in diagnosis of breast cancer. Therefore, in this study, the efficacy of RS to classify pregnancy and lactation-associated changes as well as its effect on breast tumor diagnosis was evaluated. Since such studies are difficult in human subjects, a mouse model was used. Spectra were recorded transcutaneously from the breast region of six Swiss bare mice postmating, during pregnancy, and during lactation. Data were analyzed using multivariate statistical tool Principal Component-Linear Discriminant Analysis. Results suggest that RS can differentiate breasts of pregnant/lactating mice from those of normal mice, the classification efficiencies being 100%, 60%, and 88% for normal, pregnant, and lactating mice, respectively. Frank breast tumors could be classified with 97.5% efficiency, suggesting that these physiological changes do not affect the ability of RS to detect breast tumors.

  15. Preparation and characterizations of SnO2 nanopowder and spectroscopic (FT-IR, FT-Raman, UV-Visible and NMR) analysis using HF and DFT calculations.

    Science.gov (United States)

    Ayeshamariam, A; Ramalingam, S; Bououdina, M; Jayachandran, M

    2014-01-24

    In this work, pure and singe phase SnO2 Nano powder is successfully prepared by simple sol-gel combustion route. The photo luminescence and XRD measurements are made and compared the geometrical parameters with calculated values. The FT-IR and FT-Raman spectra are recorded and the fundamental frequencies are assigned. The optimized parameters and the frequencies are calculated using HF and DFT (LSDA, B3LYP and B3PW91) theory in bulk phase of SnO2 and are compared with its Nano phase. The vibrational frequency pattern in nano phase gets realigned and the frequencies are shifted up to higher region of spectra when compared with bulk phase. The NMR and UV-Visible spectra are simulated and analyzed. Transmittance studies showed that the HOMO-LUMO band gap (Kubo gap) is reduced from 3.47 eV to 3.04 eV while it is heated up to 800°C. The Photoluminescence spectra of SnO2 powder showed a peak shift towards lower energy side with the change of Kubo gap from 3.73 eV to 3.229 eV for as-prepared and heated up to 800°C.

  16. Shedding new light on the molecular architecture of oocytes using a combination of synchrotron Fourier transform-infrared and Raman spectroscopic mapping.

    Science.gov (United States)

    Wood, Bayden R; Chernenko, Tatyana; Matthäus, Christian; Diem, Max; Chong, Connie; Bernhard, Uditha; Jene, Cassandra; Brandli, Alice A; McNaughton, Don; Tobin, Mark J; Trounson, Alan; Lacham-Kaplan, Orly

    2008-12-01

    Synchrotron Fourier transform-infrared (FT-IR) and Raman microspectroscopy were applied to investigate changes in the molecular architecture of mouse oocytes and demonstrate the overall morphology of the maturing oocyte. Here we show that differences were identified between immature mouse oocytes at the germinal vesicle (GV) and mature metaphase II (MII) stage when using this technology, without the introduction of any extrinsic markers, labels, or dyes. GV mouse oocytes were found to have a small, centrally located lipid deposit and another larger polar deposit of similar composition. MII oocytes have very large, centrally located lipid deposits. Each lipid deposit for both cell types contains an inner and outer lipid environment that differs in composition. To assess interoocyte variability, line scans were recorded across the diameter of the oocytes and compared from three independent trials (GV, n = 91; MII, n = 172), and the data were analyzed with principal component analysis (PCA). The average spectra and PCA loading plots show distinct and reproducible changes in the CH stretching region that can be used as molecular maturation markers. The method paves the way for developing an independent assay to assess oocyte status during maturation providing new insights into lipid distribution at the single cell level.

  17. Infrared and Raman spectroscopic studies of tris-[3-(trimethoxysilyl)propyl] isocyanurate, its sol-gel process, and coating on aluminum and copper.

    Science.gov (United States)

    Li, Ying-Sing; Church, Jeffrey S; Woodhead, Andrea L; Vecchio, Nicolas E; Yang, Johnny

    2014-11-11

    Tris-[3-(trimethoxysilyl)propyl] isocyanurate (TTPI) has been used as a precursor to prepare a sol using ethanol as the solvent under acidic conditions. The sol-gel was applied for the surface treatment of aluminum and copper. Infrared and Raman spectra have been recorded for pure TTPI and the TTPI sol, xerogel and TTPI sol-gel coated metals. From the vibrational spectra, TTPI is likely to have the C1 point group. Vibrational assignments are suggested based on group frequencies, the expected reactions in the sol-gel process and the vibrational studies of some related molecules. From the experimental infrared spectra of xerogels annealed at different temperatures and from the thermal-gravimetric analysis, it is found that the TTPI xerogel decomposes at around 450°C with silica being the major decomposition product. A cyclic voltammetric study of the metal electrodes coated with different concentrations of TTPI ranging from 5% to 42% (v/v) has shown that the films with high concentrations of sol would provide better corrosion protection for aluminum and copper.

  18. Raman spectroscopy in pharmaceutical product design

    DEFF Research Database (Denmark)

    Paudel, Amrit; Raijada, Dhara; Rantanen, Jukka

    2015-01-01

    molecular-based drug discovery, design of innovative drug delivery systems and quality control of finished products. This review presents concise accounts of various conventional and emerging Raman instrumentations including associated hyphenated tools of pharmaceutical interest. Moreover, relevant...... application cases of Raman spectroscopy in early and late phase pharmaceutical development, process analysis and micro-structural analysis of drug delivery systems are introduced. Finally, potential areas of future advancement and application of Raman spectroscopic techniques are discussed....

  19. Raman Spectroscopy for Clinical Oncology

    Directory of Open Access Journals (Sweden)

    Michael B. Fenn

    2011-01-01

    Full Text Available Cancer is one of the leading causes of death throughout the world. Advancements in early and improved diagnosis could help prevent a significant number of these deaths. Raman spectroscopy is a vibrational spectroscopic technique which has received considerable attention recently with regards to applications in clinical oncology. Raman spectroscopy has the potential not only to improve diagnosis of cancer but also to advance the treatment of cancer. A number of studies have investigated Raman spectroscopy for its potential to improve diagnosis and treatment of a wide variety of cancers. In this paper the most recent advances in dispersive Raman spectroscopy, which have demonstrated promising leads to real world application for clinical oncology are reviewed. The application of Raman spectroscopy to breast, brain, skin, cervical, gastrointestinal, oral, and lung cancers is reviewed as well as a special focus on the data analysis techniques, which have been employed in the studies.

  20. Nonlinear microscopy, infrared, and Raman microspectroscopy for brain tumor analysis

    Science.gov (United States)

    Meyer, Tobias; Bergner, Norbert; Bielecki, Christiane; Krafft, Christoph; Akimov, Denis; Romeike, Bernd F. M.; Reichart, Rupert; Kalff, Rolf; Dietzek, Benjamin; Popp, Jürgen

    2011-02-01

    Contemporary brain tumor research focuses on two challenges: First, tumor typing and grading by analyzing excised tissue is of utmost importance for choosing a therapy. Second, for prognostication the tumor has to be removed as completely as possible. Nowadays, histopathology of excised tissue using haematoxylin-eosine staining is the gold standard for the definitive diagnosis of surgical pathology specimens. However, it is neither applicable in vivo, nor does it allow for precise tumor typing in those cases when only nonrepresentative specimens are procured. Infrared and Raman spectroscopy allow for very precise cancer analysis due to their molecular specificity, while nonlinear microscopy is a suitable tool for rapid imaging of large tissue sections. Here, unstained samples from the brain of a domestic pig have been investigated by a multimodal nonlinear imaging approach combining coherent anti-Stokes Raman scattering, second harmonic generation, and two photon excited fluorescence microscopy. Furthermore, a brain tumor specimen was additionally analyzed by linear Raman and Fourier transform infrared imaging for a detailed assessment of the tissue types that is required for classification and to validate the multimodal imaging approach. Hence label-free vibrational microspectroscopic imaging is a promising tool for fast and precise in vivo diagnostics of brain tumors.

  1. The Impact of Array Detectors on Raman Spectroscopy

    Science.gov (United States)

    Denson, Stephen C.; Pommier, Carolyn J. S.; Denton, M. Bonner

    2007-01-01

    The impact of array detectors in the field of Raman spectroscopy and all low-light-level spectroscopic techniques is examined. The high sensitivity of array detectors has allowed Raman spectroscopy to be used to detect compounds at part per million concentrations and to perform Raman analyses at advantageous wavelengths.

  2. The effect of an anti-hydrogen bond on Fermi resonance:A Raman spectroscopic study of the Fermi doublet v1-v12 of liquid pyridine

    Institute of Scientific and Technical Information of China (English)

    Li Dong-Fei; Gao Shu-Qin; Sun Cheng-Lin; Li Zuo-Wei

    2012-01-01

    The effects of an anti-hydrogen bond on the v1-v12 Fermi resonance (FR) of pyridine are experimentally investigated by using Raman scattering spectroscopy.Three systems,pyridine/water,pyridine/formamide,and pyridine/carbon tetrachloride,provide varying degrees of strength for the diluent-pyridine anti-hydrogen bond complex.Water forms a stronger anti-hydrogen bond with pyridine than with formamide,and in the case of adding non-polar solvent carbon tetrachloride,which is neither a hydrogen bond donor nor an acceptor and incapable of forming a hydrogen bond with pyridine,the intermolecular distance of pyridine will increase and the interaction of pyridine molecules will reduce.The dilution studies are performed on the three systems.Comparing with the values of the Fermi coupling coefficient W of the ring breathing mode v1 and triangle mode v12 of pyridine at different volume concentrations,which are calculated according to the Bertran equations,in three systems,we find that the solution with the strongest anti-hydrogen bond,water,shows the fastest change in thev1-v12 Fermi coupling coefficient W with the volume concentration varying,followed by the formamide and carbon tetrachloride solutions.These results suggest that the stronger anti-hydrogen bond-forming effect will cause a greater reduction in the strength of the v1-v12 FR of pyridine.According to the mechanism of the formation of an anti-hydrogen bond in the complexes and the FR theory,a qualitative explanation for the anti-hydrogen bond effect in reducing the strength of the v1 - v12 FR of pyridine is given.

  3. Spectroscopic studies of thiatri-, penta- and heptamethine cyanine dyes II. Infrared and resonance Raman spectra of thiatri-, penta- and heptamethine cyanine dyes

    Science.gov (United States)

    Fujimoto, Yasuhiko; Katayama, Norihisa; Ozaki, Yukihiro; Yasui, Shigeo; Iriyama, Keiji

    1992-11-01

    Infrared (IR) and resonance Raman (RR) spectra of thiatri-, penta- and heptamethine cyanine dyes in the solid state and in solution have been measured. Most of the intense bands observed in the 1600-1100 cm -1 region of the RR spectra may be assigned to totally symmetric stretching modes of the central conjugated system of the cyanines, while most of the strong IR bands in the 1600-1300 cm -1 region are probably due to antisymmetric stretching modes. The intense RR bands do not have their counterparts in the IR spectra and vice versa. A pseudo-mutual exclusion rule seems to be operative for the cyanine vibrational spectra in the 1600-1300 cm -1 region, indicating that the central conjugated systems of the cyanines have nearly symmetrical structure, i.e. the extended all-trans forms of the methine chains and the bond orders of 1.5 of the CC and CN bonds in both the solution and solid states. The IR spectra of 3-ethyl-2-[3-(3-ethyl-2-benzothiazolinylidene)-1-propenyl]benzothiazolium iodide (NK-76) and 3-ethyl-2-[7-(3-ethyl-2-benzothiazolinylidene)-1,3,5-heptatrienyl]benzothiazolium iodide (NK-126) change little between the solid and solution states while those of 3-octadecyl-2-[3-(3-octadecyl-2-benzothiazolinylidene)-1-propenyl]benzothiazolium iodide (NK-2560) and 3-octadecyl-2-[7-(3-octadecyl-2-benzothiazolinylidene)-1,3,5-heptatrienyl]benzothiazolium perchlorate (NK-2861) alter significantly between the two states in the frequencies of bands due to the stretching modes of their central conjugated systems. The results suggest that the electronic states of the central conjugated systems of NK-2560 and NK-2861 undergo appreciable changes on going from the solid to the solution states.

  4. Spectroscopic (FT-IR, FT-Raman, UV, NMR, NBO, NLO) investigation and molecular docking study of (R)-2-Methylamino-1-Phenylethanol (Halostachine)

    Science.gov (United States)

    Subashini, K.; Govindarajan, R.; Surendran, R.; Mukund, K.; Periandy, S.

    2016-12-01

    FT-IR (4000-400 cm-1) and FT-Raman (4000-100 cm-1) spectra of (R)-2-Methylamino-1-Phenylethanol have been recorded in solid phase, 1H and 13C NMR in deuterated chloroform (CDCl3) phase and UV spectrum (200-400 nm) in solid phase and in ethanol solution. The different conformers of the compound and their minimum energies were studied by potential energy surface scan, using semi-empirical method PM6. The computed wavenumbers obtained from B3LYP and B3PW91 functionals along with 6-311++G (d, p) basis sets were scaled so as to agree with the experimental values and the scaling factors have been reported. All the fundamental modes have been assigned based on the potential energy distribution (PED) values and the structure of the molecule was analyzed in parameters like bond length, bond angle and dihedral angles through B3LYP and B3PW91 functionals along with 6-311++G(d,p) basis set. The values of dipole moment (μ), polarizability (α) and hyper polarizability (β) of the molecule were calculated using which, the non-linear optical property of the molecule has been discussed. The observed HOMO-LUMO mappings reveals the different charge transfer possibilities within the molecule. Natural Bond Orbital analysis was computed and possible transitions were correlated with the electronic transitions. Mulliken charges, electrostatic potential charges and natural charges are also predicted. The theoretical 1H and 13C NMR chemical shifts were computed using B3LYP functionals using 6-311++G (2d, p) basis sets. The temperature dependence of the thermodynamic properties; heat capacity, entropy and enthalpy for the title compound were also determined by B3LYP functionals with 6-311++G (d, p) basis set. Molecular docking study shows that the title compound might exhibit inhibitory activity against Bacillus anthracis (3V5O).

  5. Spectroscopic (FT-IR, FT-Raman, UV, NMR, NLO) investigation and molecular docking study of 1-(4-Methylbenzyl) piperazine

    Science.gov (United States)

    Subashini, K.; Periandy, S.

    2017-04-01

    The title compound, 1-(4-Methylbenzyl) piperazine, was analyzed by recording FT-IR (4000-400 cm-1) and FT-Raman (4000-100 cm-1) spectra in solid phase, 1H and 13C NMR in CDCl3 (deuterated chloroform) and UV spectrum (200-400 nm) in solid phase and in ethanol solution. The different conformers of the compound and their minimum energies were studied by potential energy surface scan, using semi-empirical method PM6. Density functional theory (DFT) calculation with 6-311++G (d, p) basis set along with B3LYP and B3PW91 functionals have been used to compute ground state molecular geometries and vibrational frequencies. The assignments of the vibrational spectra have carried out with the help of Potential Energy distribution (PED) analysis. Factor group analysis has also been tabulated. Charge distribution, Frontier Molecular Orbitals, UV-Vis spectra, Molecular Electrostatic Potential (MEP) maps, Non-linear optical (NLO) property and thermodynamic properties of the title compound at different temperatures, were determined using B3LYP functional along with 6-311++G (d, p) basis set. The theoretical 1H and 13C NMR chemical shifts were computed using B3LYP functional with 6-311++G (2d, p) basis sets. Natural Bond orbital analysis were computed and possible transitions were correlated with the electronic transitions. The title compound not only exhibits appreciable dipole moment and hyper polarizability (indicating good NLO properties) but also forms a stable complex with Bacillus cereus, (2HUC), with binding affinity -6.7 kcal/mol through molecular docking, suggesting that, it might exhibit inhibitory activity against Bacillus cereus.

  6. Structural and spectroscopic (UV-Vis, IR, Raman, and NMR) characteristics of anisaldehydes that are flavoring food additives: A density functional study in comparison with experiments

    Science.gov (United States)

    Altun, Ahmet; Swesi, O. A. A.; Alhatab, B. S. S.

    2017-01-01

    The molecular structures, vibrational spectra (IR and Raman), electronic spectra (UV-Vis and DOS), and NMR spectra (13C and 1H) of p-anisaldehyde, m-anisaldehyde, and o-anisaldehyde have been studied by using the B3LYP density functional and the 6-311++G** basis set. While p-anisaldehyde has been found to contain two stable conformers at room temperature, m-anisaldehyde and o-anisaldehyde contain four stable conformers. In agreement with the calculated ground-state energetics and small transition barriers, the comparison of the experimental and calculated spectra of the anisaldehydes indicates equilibrium between all conformers at room temperature. However, the two conformers of o-anisaldehyde, in which the methoxy group lies out of the ring plane, are too rare at the equilibrium. The equilibrium conditions of the conformers of the anisaldehyde isomers have been shown readily accessible through UV-Vis and 13C NMR spectral studies but requiring very detailed vibrational analyses. The effect of the solvent has been found to red-shift the electronic absorption bands and to make the anisaldehydes more reactive and soft. Molecular electrostatic potential maps of the anisaldehydes show that their oxygen atoms are the sites for nucleophilic reactivity. Compared with the most sophisticated NBO method, ESP charges have been found mostly reliable while Mulliken charges fail badly with the present large 6-311++G** basis set. The present calculations reproduce not only the experimental spectral characteristics of the anisaldehydes but also reveal their several structural features.

  7. Effects of LED or laser phototherapy on bone defects grafted with MTA and irradiated with laser or LED light: a comparative Raman spectroscopic study

    Science.gov (United States)

    Pinheiro, Antonio L. B.; Soares, Luiz G. P.; Barbosa, Artur Felipe S.; Silveira, Landulfo, Jr.

    2012-03-01

    We studied peaks of calcium hydroxyapatite - CHA on defects grafted with MTA, treated or not with Light Emitting Diode - LED or IR Laser. 54 rats were divided in 6 groups each subdivided into 3 subgroups (15,21,30d). LED (λ850 +/- 10nm) or IR Laser (λ850 nm) was applied over (LED) or in 4 points around the defect at 48 h intervals for 15 days. Raman readings were taken at the surface of the defect. The smaller overall intensity of the peak was found in Group MTA + Laser (1510.2 +/- 274.1) and the highest on Group LED (2322 +/- 715). There were no statistically significant differences between non-irradiated subjects on regards the CHA peaks. On the other hand, there were statistically significant differences between the Group Clot and LED, Clot and Laser, and Clot and MTA + Laser (p =0.01, p = 0.02, p = 0.003). There were no significant differences between Group MTA and MTA + LED (p=0.2) but significant differences were seen between Groups MTA and MTA + Laser (p=0.01). Significant differences were also observed between Groups LED and Laser (p MTA + LED and MTA + Laser (p=0.009). MTA, due to its characteristics, seemed to be directly affected by the light. However, the use of either phototherapy positively affected bone healing similarly as observed on different studies using other biomaterials. The overall analysis of our results indicated that the use of either light source resulted in a better, more advanced, and of quality bone repair.

  8. STRUCTURE FEATURES OF THE SODIUM-GERMANATE GLASSES DOPED WITH YTTERBIUM ERBIUM RETRIEVED FROM RAMAN SPECTROSCOPY

    Directory of Open Access Journals (Sweden)

    I. M. Sevastianova

    2016-09-01

    Full Text Available Subject of Research.The paper deals with study of Raman spectra and luminescence spectra in the visible region of the sodium-germanate glass: 49 GeO2 – 13 Na2O – 27 Yb2O3 – 11 La2O3 - 0,25 Er2O3 and presents research results. In addition, this glass is doped with 5 mol% of the following components MgO, BaO, Al2O3, PbO, Nb2O5, TiO2, SiO2, P2O5 in order to study the effect of these additives on the structure of the glassy matrix and the anti-Stokes luminescence spectra of erbium ions. Method. Raman scatteringspectra were recorded by Renishaw inVia Raman Microscope. Excitation source is a helium neon laser (λ= 633 nm with power equal to 50Wt. Anti-Stokes luminescence of erbium ions was registered in spectral region of 450–750 nm at room temperature (excitation laser wavelength is 975 nm, power is 1Wt. Main Results. It was shown that the structure of the initial glass does not change with the introduction of niobium as Nb2O5 in any coordination plays a role of network forming, building a single mixed grid with tetrahedrons [GeO4]. Introduction of the second glass former P2O5 leads to loosening germanate structure due to the appearance of the phosphate sublattice. This leads to a redistribution of the relative intensity of up-conversion luminescence bands with maxima at 540 and 670 nm compared with the initial glass. Introduction of additives PbO, MgO, Al2O3, TiO2 results in a multicenter structure. In case of titanium oxide addition it leads to a change in the relative intensities of the erbium luminescence.

  9. Monitoring intra-cellular lipid metabolism in macrophages by Raman- and CARS-microscopy

    Science.gov (United States)

    Matthäus, Christian; Bergner, Gero; Krafft, Christoph; Dietzek, Benjamin; Lorkowski, Stefan; Popp, Jürgen

    2010-04-01

    Monocyte-derived macrophages play a key role in lipid metabolism in vessel wall tissues. Macrophages can take up lipids by various mechanisms. As phagocytes, macrophages are important for the decomposition of lipid plaques within arterial walls that contribute to arteriosclerosis. Of special interest are uptake dynamics and intra-cellular fate of different individual types of lipids as, for example, fatty acids, triglycerides or free and esterified cholesterol. Here we utilize Raman microscopy to image the metabolism of such lipids and follow subsequent storage or degradation patterns. The combination of optical microscopy with Raman spectroscopy allows visualization at the diffraction limit of the employed laser light and biochemical characterization through the associated spectral information. Relatively long measuring times, due to the weakness of Raman scattering can be overcome by non-linear effects such as coherent anti-Stokes Raman scattering (CARS). With this contribution we introduce first results to monitor the incorporation of lipid components into individual cells employing Raman and CARS microscopy.

  10. Inflammation-related alterations of lipids after spinal cord injury revealed by Raman spectroscopy

    Science.gov (United States)

    Tamosaityte, Sandra; Galli, Roberta; Uckermann, Ortrud; Sitoci-Ficici, Kerim H.; Koch, Maria; Later, Robert; Schackert, Gabriele; Koch, Edmund; Steiner, Gerald; Kirsch, Matthias

    2016-06-01

    Spinal cord injury (SCI) triggers several lipid alterations in nervous tissue. It is characterized by extensive demyelination and the inflammatory response leads to accumulation of activated microglia/macrophages, which often transform into foam cells by accumulation of lipid droplets after engulfment of the damaged myelin sheaths. Using an experimental rat model, Raman microspectroscopy was applied to retrieve the modifications of the lipid distribution following SCI. Coherent anti-Stokes Raman scattering (CARS) and endogenous two-photon fluorescence (TPEF) microscopies were used for the detection of lipid-laden inflammatory cells. The Raman mapping of CH2 deformation mode intensity at 1440 cm-1 retrieved the lipid-depleted injury core. Preserved white matter and inflammatory regions with myelin fragmentation and foam cells were localized by specifically addressing the distribution of esterified lipids, i.e., by mapping the intensity of the carbonyl Raman band at 1743 cm-1, and were in agreement with CARS/TPEF microscopy. Principal component analysis revealed that the inflammatory regions are notably rich in saturated fatty acids. Therefore, Raman spectroscopy enabled to specifically detect inflammation after SCI and myelin degradation products.

  11. Universality of Coherent Raman Gain Suppression in Gas-Filled Broadband-Guiding Photonic Crystal Fibers

    Science.gov (United States)

    Hosseini, P.; Mridha, M. K.; Novoa, D.; Abdolvand, A.; Russell, P. St. J.

    2017-03-01

    As shown in the early 1960s, the gain in stimulated Raman scattering (SRS) is drastically suppressed when the rate of creation of phonons (via a pump-to-Stokes conversion) is exactly balanced by the rate of phonon annihilation (via a pump-to-anti-Stokes conversion). This occurs when the phonon coherence waves—synchronized vibrations of a large population of molecules—have identical propagation constants for both processes; i.e., they are phase-velocity matched. As recently demonstrated, hydrogen-filled photonic crystal fiber pumped in the vicinity of its zero-dispersion wavelength provides an ideal system for observing this effect. Here we report that Raman gain suppression is actually a universal feature of SRS in gas-filled hollow-core fibers and that it can strongly impair SRS even when the phase mismatch is high, particularly at high pump powers when it is normally assumed that nonlinear processes become more (not less) efficient. This counterintuitive result means that intermodal stimulated Raman scattering (for example, between LP01 and LP11 core modes) begins to dominate at high power levels. The results reported have important implications for fiber-based Raman shifters, amplifiers, or frequency combs, especially for operation in the ultraviolet, where the Raman gain is much higher.

  12. Surface-Enhanced Raman Scattering Physics and Applications

    CERN Document Server

    Kneipp, Katrin; Kneipp, Harald

    2006-01-01

    Almost 30 years after the first reports on surface-enhanced Raman signals, the phenomenon of surface-enhanced Raman scattering (SERS) is now well established. Yet, explaining the enhancement of a spectroscopic signal by fouteen orders of magnitude continues to attract the attention of physicists and chemists alike. And, at the same time and rapidly growing, SERS is becoming a very useful spectroscopic tool with exciting applications in many fields. SERS gained particular interest after single-molecule Raman spectroscopy had been demonstrated. This bookl summarizes and discusses present theoretical approaches that explain the phenomenon of SERS and reports on new and exciting experiments and applications of the fascinating spectroscopic effect.

  13. Raman facility

    Data.gov (United States)

    Federal Laboratory Consortium — Raman scattering is a powerful light scattering technique used to diagnose the internal structure of molecules and crystals. In a light scattering experiment, light...

  14. Quantum mechanical and spectroscopic (FT-IR, FT-Raman,1H,13C NMR, UV-Vis) studies, NBO, NLO, HOMO, LUMO and Fukui function analysis of 5-Methoxy-1H-benzo[d]imidazole-2(3H)-thione by DFT studies

    Science.gov (United States)

    Pandey, Manju; Muthu, S.; Nanje Gowda, N. M.

    2017-02-01

    Theoretical analysis of the molecular structure, spectroscopic (FT-IR, FT-Raman, 1H, 13C NMR, UV-Vis) studies, and thermodynamic characteristics of 5-Methoxy-1H-benzo[d]imidazole-2(3H)-thione (5MBIT) molecule were done by DFT/B3LYP using 6-311++G(d, p) basis set. Theoretical parameters were compared with experimental data. The dipole moment (μ), polarizability (Δα) and first order hyperpolarizability (β) of the molecule were calculated. Thermodynamic properties, HOMO and LUMO energies were determined. Global reactivity parameters and Fukui function of the 5MBIT molecule were predicted.

  15. Femtosecond stimulated Raman scattering for polyatomics with harmonic potentials: Application to rhodamine 6G

    Science.gov (United States)

    Niu, Kai; Cong, Shulin; Lee, Soo-Y.

    2009-08-01

    The perturbation theory of stimulated Raman scattering (SRS), with Raman pump on minus pump off and heterodyne detection along the probe direction, is reviewed. It has four third-order polarization terms, labeled as SRS or inverse Raman scattering (IRS): SRS(I), SRS(II), IRS(I), and IRS(II). These four polarizations have a wave packet interpretation. The polarizations, with homogenous and inhomogeneous broadening included, can be written as integrals over four-time correlation functions, and analytic formulas are derived for the latter for multidimensional harmonic potential surfaces with Franck-Condon displacements in the modes which facilitates the calculation of the SRS cross sections. The theory is applied to understand recent experimental results on the femtosecond SRS (FSRS) of a fluorescent dye, rhodamine 6G (R6G), where the Raman pump pulse is about 1 ps long, and the probe pulse is about 10 fs. The calculations compared very well with the R6G experimental results for off-resonance and resonance FSRS spectra spanning both Stokes and anti-Stokes bands, and for negative and positive pump-probe delay times on resonance.

  16. 基于SERS光谱的银溶胶溶液中腺嘌呤的定量分析%Quantitative Analysis with Adenine in Silver Colloidal Sol by Surface-enhanced Raman Scattering Spectroscopic Technique

    Institute of Scientific and Technical Information of China (English)

    冯小平; 曹晓卫; 汪佳俐; 李玲; 张志学

    2012-01-01

    Surface-enhanced Raman scattering (SERS) spectroscopic technique was used to perform quantitative analyses with adenine, an important basic group from nucleic acid, by using silver colloidal sol as the SERS substrate. Sodium polyacrylate was added into the silver colloidal sol in order to improve its stability. In addition, during different SERS measurements, pyridine was used an internal standard to eliminate the impact of the variations in laser power, optical alignment and focusing on the SERS signal intensity of the an-alyte. It reveals that a good linear relationship is presented between the concentration of adenine and the characteristic SERS signal intensity ratio of the analyte adenine (733 cm-1) to the internal standard pyridine (1003 cm-1) in the range of 1× 10-4~1× 10-3mol ·L-1.%碱基是构成核酸的物质基础.碱基的含量分析对于生物体的生理活动及新陈代谢过程研究具有重要意义.本文利用表面增强拉曼散射(SERS)光谱技术研究了腺嘌呤在相对稳定的银溶胶溶液中的SERS光谱信号强度与浓度的定量关系.研究表明添加聚合物作为稳定剂的银溶胶具有良好的稳定性.进一步研究表明,在1×10-4~1×10-2mol·L-1的浓度范围内,以吡啶作为内标,分析物腺嘌呤与内标物特征谱峰强度之比与腺嘌呤的浓度之间呈现良好的线性关系.

  17. Dramatic Raman Gain Suppression in the Vicinity of the Zero Dispersion Point in Gas-Filled Hollow-Core Photonic Crystal Fiber

    CERN Document Server

    Bauerschmidt, Sebastian T; Russell, Philip St J

    2015-01-01

    In 1964 Bloembergen and Shen predicted that Raman gain could be suppressed if the rates of phonon creation and annihilation (by inelastic scattering) exactly balance. This is only possible if the momentum required for each process is identical, i.e., phonon coherence waves created by pump-to-Stokes scattering are identical to those annihilated in pump-to-anti-Stokes scattering. In bulk gas cells, this can only be achieved over limited interaction lengths at an oblique angle to the pump axis. Here we report a simple system that provides dramatic Raman gain suppression over long collinear path-lengths in hydrogen. It consists of a gas-filled hollow-core photonic crystal fiber whose zero dispersion point is pressure-adjusted to lie close to the pump laser wavelength. At a certain precise pressure, generation of Stokes light in the fundamental mode is completely suppressed, allowing other much weaker nonlinear processes to be explored.

  18. Applications of Raman Spectroscopy to Virology and Microbial Analysis

    Science.gov (United States)

    Harz, Michaela; Stöckel, Stephan; Ciobotă, Valerian; Cialla, Dana; Rösch, Petra; Popp, Jürgen

    This chapter reports from the utilization of Raman spectroscopic techniques like Raman microscopy, Raman optical activity (ROA), UV-resonance Raman (UVRR)-spectroscopy, surface enhanced Raman spectroscopy (SERS), and tip-enhanced Raman spectroscopy (TERS) for the investigation of viruses and microorganisms, especially bacteria and yeasts for medical and pharmaceutical applications. The application of these Raman techniques allows for the analysis of chemical components of cells and subcellular regions, as well as the monitoring of chemical differences occurring as a result of the growth of microorganisms. In addition, the interaction of microorganisms with active pharmaceutical agents can be investigated. In combination with chemometric methods Raman spectroscopy can also be applied to identify microorganisms both in micro colonies and even on single cells.

  19. Rotational Raman lidar to measure the atmospheric temperature from the ground to 30 km

    Energy Technology Data Exchange (ETDEWEB)

    Nedeljkovic, D.; Hauchecorne, A.; Chanin, M.L. (CNRS, Verrieres le Buisson (France))

    1993-01-01

    The authors describe in this paper a lidar method using the anti-Stokes rotational lines of N[sub 2] and O[sub 2] Raman spectrum to determine the temperature of the atmosphere up to 30 km. The method uses the variation with the temperature of the envelop of the intensities of the backscattered rotational Raman spectrum, or more precisely the variations of the ratio of the intensities at two close-by wavelengths. For each temperature of the gas, the ratio of the fluxes through two narrow and close-by filters takes a definite value directly related to the temperature. The difficulty of eliminating the near-by contribution of the Mie backscattering was solved by doubling the filters to produce a rejection factor of 10[sub +8] at the central wavelength. The validity of the method was illustrated by comparing a number of temperature profiles obtained simultaneously with radiosonde and by this new Raman lidar. The theoretical calculation of the method led to an analytic calibration function which, once adjusted with a radiosonde, can provide the temperature on successive days of measurement in the height range 50 to 25 km.

  20. Polarized Raman spectroscopy unravels the biomolecular structural changes in cervical cancer

    Science.gov (United States)

    Daniel, Amuthachelvi; Prakasarao, Aruna; Dornadula, Koteeswaran; Ganesan, Singaravelu

    2016-01-01

    Polarized Raman spectroscopy has emerged as a promising technique giving a wealth of information about the orientation and symmetry of bond vibrations in addition to the general chemical information from the conventional Raman spectroscopy. In this regard, polarized Raman Spectroscopic technique was employed to study the changes in the orientation of biomolecules in normal and cancerous conditions. This technique was compared to the conventional Raman spectroscopic technique and was found to yield additional information about the orientation of tyrosine, collagen and DNA. The statistically analyzed depolarization ratios by Linear Discriminant Analysis yielded better accuracy than the statistical results of conventional Raman spectroscopy. Thus, this study reveals that polarized Raman spectroscopy has better diagnostic potential than the conventional Raman spectroscopic technique.

  1. The research of improvements in Raman distributed temperature sensor

    Science.gov (United States)

    Zhang, Ge; Zhang, Li-na; Zhang, Shu-juan

    2014-12-01

    Temperature measurement system has been applied in industrial areas extensively. The fiber optic distributed temperature system is one of the most popular means. Measurement error is relatively large when using the distributed temperature sensors (DTS) based on Raman scattering to measure ambient temperature in harsh environments. In this paper, we propose a novel calibration technique to measure the temperature highly accurately over a wide range of temperatures. We also propose an improved double-ended configuration that is insusceptible to the differential loss change in the fiber. By using the improved double-ended configuration, through the anti-Stokes and Stokes signal intensity comparison, the differential mode signal loss in the temperature measurement can be suppressed in optical fiber. So, the measurement results of automatic calibration are irrespectively with the wastage of optical fiber sensors. The result shows that we can obtain the temperature parameters accuracy in wide temperature range, and temperature measurement system has high robustness in harsh environments, suitable for field use.

  2. Raman spectroscopic study of the mineral qingheiite Na2(Mn2+,Mg,Fe2+)2(Al,Fe3+)(PO4)3, a pegmatite phosphate mineral from Santa Ana pegmatite, Argentina

    Science.gov (United States)

    Frost, Ray L.; Xi, Yunfei; Scholz, Ricardo; López, Andrés; Moreira, Caio; de Lena, Jorge Carvalho

    2013-10-01

    The pegmatite mineral qingheiite Na2(Mn2+,Mg,Fe2+)2(Al,Fe3+)(PO4)3 has been studied by a combination of SEM and EMP, Raman and infrared spectroscopy. The studied sample was collected from the Santa Ana pegmatite, Argentina. The mineral occurs as a primary mineral in lithium bearing pegmatite, in association with beausite and lithiophilite. The Raman spectrum is characterized by a very sharp intense Raman band at 980 cm-1 assigned to the PO43- symmetric stretching mode. Multiple Raman bands are observed in the PO43- antisymmetric stretching region, providing evidence for the existence of more than one phosphate unit in the structure of qingheiite and evidence for the reduction in symmetry of the phosphate units. This concept is affirmed by the number of bands in the ν4 and ν2 bending regions. No intensity was observed in the OH stretching region in the Raman spectrum but significant intensity is found in the infrared spectrum. Infrared bands are observed at 2917, 3195, 3414 and 3498 cm-1 are assigned to water stretching vibrations. It is suggested that some water is coordinating the metal cations in the structure of qingheiite.

  3. Chemistry, Raman and infrared spectroscopic characterization of the phosphate mineral reddingite: (MnFe)3(PO4)2(H2O,OH)3, a mineral found in lithium-bearing pegmatite

    Science.gov (United States)

    Frost, Ray L.; Xi, Yunfei; Scholz, Ricardo; Belotti, Fernanda M.; Lagoeiro, Leonardo E.

    2012-11-01

    Detailed investigation of an intermediate member of the reddingite-phosphoferrite series, using infrared and Raman spectroscopy, scanning electron microcopy and electron microprobe analysis, has been carried out on a homogeneous sample from a lithium-bearing pegmatite named Cigana mine, near Conselheiro Pena, Minas Gerais, Brazil. The determined formula is ({{Mn}}_{1.60} {{Fe}}_{1.21} {{Ca}}_{0.01} {{Mg}}_{0.01} )_{sum 2.83} ({{PO}}4 )_{2.12} \\cdot ({{H}}2 {{O}}_{2.85} {{F}}_{0.01} )_{sum 2.86} , indicating predominance in the reddingite member. Raman spectroscopy coupled with infrared spectroscopy supports the concept of phosphate, hydrogen phosphate and dihydrogen phosphate units in the structure of reddingite-phosphoferrite. Infrared and Raman bands attributed to water and hydroxyl stretching modes are identified. Vibrational spectroscopy adds useful information to the molecular structure of reddingite-phosphoferrite.

  4. Crystallization and spectroscopic studies of manganese malonate

    Indian Academy of Sciences (India)

    Varghese Mathew; Jochan Joseph; Sabu Jacob; K E Abraham

    2010-08-01

    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 reflectance spectroscopy (DRS) is used to measure the bandgap (g) of the material.

  5. Raman spectroscopy of bone metastasis

    Science.gov (United States)

    Esmonde-White, Karen A.; Sottnik, Joseph; Morris, Michael; Keller, Evan

    2012-02-01

    Raman spectroscopy of bone has been used to characterize chemical changes occurring in diseases such as osteoporosis, osteoarthritis and osteomyelitis. Metastasis of cancer into bone causes changes to bone quality that are similar to those observed in osteoporosis, such as decreased bone strength, but with an accelerated timeframe. In particular, osteolytic (bone degrading) lesions in bone metastasis have a marked effect on patient quality of life because of increased risk of fractures, pain, and hypercalcemia. We use Raman spectroscopy to examine bone from two different mouse models of osteolytic bone metastasis. Raman spectroscopy measures physicochemical information which cannot be obtained through standard biochemical and histological measurements. This study was reviewed and approved by the University of Michigan University Committee on the Care and Use of Animals. Two mouse models of prostate cancer bone metastasis, RM1 (n=3) and PC3-luc (n=4) were examined. Tibiae were injected with RM1 or PC3-luc cancer cells, while the contralateral tibiae received a placebo injection for use as controls. After 2 weeks of incubation, the mice were sacrificed and the tibiae were examined by Raman microspectroscopy (λ=785 nm). Spectroscopic markers corresponding to mineral stoichiometry, bone mineralization, and mineral crystallinity were compared in spectra from the cancerous and control tibiae. X-ray imaging of the tibia confirmed extensive osteolysis in the RM1 mice, with tumor invasion into adjoining soft tissue and moderate osteolysis in the PC3-luc mice. Raman spectroscopic markers indicate that osteolytic lesions are less mineralized than normal bone tissue, with an altered mineral stoichiometry and crystallinity.

  6. Raman spectroscopy: the gateway into tomorrow's virology.

    Science.gov (United States)

    Lambert, Phelps J; Whitman, Audy G; Dyson, Ossie F; Akula, Shaw M

    2006-06-28

    In the molecular world, researchers act as detectives working hard to unravel the mysteries surrounding cells. One of the researchers' greatest tools in this endeavor has been Raman spectroscopy. Raman spectroscopy is a spectroscopic technique that measures the unique Raman spectra for every type of biological molecule. As such, Raman spectroscopy has the potential to provide scientists with a library of spectra that can be used to unravel the makeup of an unknown molecule. However, this technique is limited in that it is not able to manipulate particular structures without disturbing their unique environment. Recently, a novel technology that combines Raman spectroscopy with optical tweezers, termed Raman tweezers, evades this problem due to its ability to manipulate a sample without physical contact. As such, Raman tweezers has the potential to become an incredibly effective diagnostic tool for differentially distinguishing tissue, and therefore holds great promise in the field of virology for distinguishing between various virally infected cells. This review provides an introduction for a virologist into the world of spectroscopy and explores many of the potential applications of Raman tweezers in virology.

  7. Raman spectroscopy: the gateway into tomorrow's virology

    Directory of Open Access Journals (Sweden)

    Dyson Ossie F

    2006-06-01

    Full Text Available Abstract In the molecular world, researchers act as detectives working hard to unravel the mysteries surrounding cells. One of the researchers' greatest tools in this endeavor has been Raman spectroscopy. Raman spectroscopy is a spectroscopic technique that measures the unique Raman spectra for every type of biological molecule. As such, Raman spectroscopy has the potential to provide scientists with a library of spectra that can be used to unravel the makeup of an unknown molecule. However, this technique is limited in that it is not able to manipulate particular structures without disturbing their unique environment. Recently, a novel technology that combines Raman spectroscopy with optical tweezers, termed Raman tweezers, evades this problem due to its ability to manipulate a sample without physical contact. As such, Raman tweezers has the potential to become an incredibly effective diagnostic tool for differentially distinguishing tissue, and therefore holds great promise in the field of virology for distinguishing between various virally infected cells. This review provides an introduction for a virologist into the world of spectroscopy and explores many of the potential applications of Raman tweezers in virology.

  8. On the emergence of Raman signals characterizing multicenter nanoscale interactions

    Science.gov (United States)

    Williams, Mathew D.; Bradshaw, David S.; Andrews, David L.

    2016-04-01

    Raman scattering is most commonly associated with a change in vibrational state within one molecule, with signals in the corresponding spectrum widely used to identify material structures. When the corresponding theory is developed using quantum electrodynamics, the fundamental scattering process is described by a single photon of one radiation mode being annihilated with the concurrent creation of another photon; the two photon energies differ by an amount corresponding to the transfer of vibrational energy within the system. Here, we consider nanoscale interactions between neighboring molecules to mediate the process, by way of a virtual photon exchange to connect the evolution of the two molecular states. We consider both a single and pair of virtual photon exchanges. Our analysis deploys two realistic assumptions: in each pairwise interaction the two components are considered to be (i) chemically different and (ii) held in a fixed orientation with respect to each other, displaced by an amount equivalent to the near-field region; resulting in higher order dependences on displacement R becoming increasingly significant, and at the limit the short-range R-6 term can even dominate over R-3 dependence. In our investigation one center undergoes a change in vibrational energy; each neighboring molecule returns to the electronic and vibrational state in which it began. For the purposes of providing results, a Stokes transition has been assumed; analogous principles hold for the anti-Stokes counterpart. Experimentally, there is no change to the dependence on the intensity of laser light. However, the various mechanisms presented herein lead to different selection rules applying in each instance. In some cases specifically identifiable mechanisms will be active for a given transition, leading to new and characteristic lines in the Raman spectrum. A thorough investigation of all physically achievable mechanisms will be detailed in this work.

  9. Micro-Raman Spectroscopy for the Determination of Local Temperature Increases in TiO2 Thin Films due to the Effect of Radiation.

    Science.gov (United States)

    Gallardo, Juan Jesús; Navas, Javier; Zorrilla, David; Alcántara, Rodrigo; Valor, Diego; Fernández-Lorenzo, Concha; Martín-Calleja, Joaquín

    2016-07-01

    This study applied a classic method involving Raman spectroscopy and the use of Stokes and anti-Stokes peaks to measure the temperature of TiO2 thin films found in dye-sensitized solar cells (DSSCs). In addition, three mathematical formulae were used and analyzed to estimate the increase in temperature generated solely by the effect of the radiation. The tests and calculations performed showed an increase in the temperature of the TiO2 film. That is, the films were heated by the radiation they were exposed to. A temperature increase of up to 30 K was detected for the sample with a single layer of TiO2, and over 40 K for the sample with three layers for the highest radiation powers used, and greater increases in temperature were observed in the thicker films.

  10. Live-cell stimulated Raman scattering imaging of alkyne-tagged biomolecules.

    Science.gov (United States)

    Hong, Senlian; Chen, Tao; Zhu, Yuntao; Li, Ang; Huang, Yanyi; Chen, Xing

    2014-06-02

    Alkynes can be metabolically incorporated into biomolecules including nucleic acids, proteins, lipids, and glycans. In addition to the clickable chemical reactivity, alkynes possess a unique Raman scattering within the Raman-silent region of a cell. Coupling this spectroscopic signature with Raman microscopy yields a new imaging modality beyond fluorescence and label-free microscopies. The bioorthogonal Raman imaging of various biomolecules tagged with an alkyne by a state-of-the-art Raman imaging technique, stimulated Raman scattering (SRS) microscopy, is reported. This imaging method affords non-invasiveness, high sensitivity, and molecular specificity and therefore should find broad applications in live-cell imaging.

  11. Raman Spectroscopic Study of Tungsten(VI) Oxosulfato Complexes in WO3–K2S2O7–K2SO4 Molten Mixtures: Stoichiometry, Vibrational Properties and Molecular Structure

    DEFF Research Database (Denmark)

    Paulson, Andreas L.; Kalampounias, Angelos G.; Berg, Rolf W.

    2011-01-01

    The dissolution reaction of WO3 in pure molten K2S2O7 and in molten K2S2O7-K2SO4 mixtures is studied under static equilibrium conditions in the XWO3 0 = 0-0.33 mol fraction range at temperatures up to 860 C. High temperature Raman spectroscopy shows that the dissolution leads to formation of WVI ...

  12. Investigating the phase-dependent photochemical reaction dynamics of chlorine dioxide using resonance Raman spectroscopy

    Science.gov (United States)

    Hayes, Sophia C.; Wallace, Paul M.; Bolinger, Josh C.; Reid, Philip J.

    Recent progress in understanding the phase-dependent reactivity demonstrated by halooxides is outlined. Specifically, resonance Raman intensity analysis (RRIA) and time-resolved resonance Raman (TRRR) studies of chlorine dioxide (OClO) photochemistry in solution are presented. Using RRIA, it has been determined that the excited-state structural evolution that occurs along the asymmetric-stretch coordinate in the gas phase is restricted in solution. The absence of evolution along this coordinate results in the preservation of groundstate symmetry in the excited state. The role of symmetry in defining the reaction coordinate and the solvent-solute interactions responsible for modification of the excited-state potential energy surface are discussed. TRRR studies are presented which demonstrate that geminate recombination of the primary photoproducts resulting in the reformation of ground-state OClO is a central feature of OClO photochemistry in solution. These studies also demonstrate that a fraction of photoexcited OClO undergoes photoisomerization to form ClOO, with the ground-state thermal decomposition of this species resulting in Cl production on the subnanosecond timescale. Finally, time-resolved anti-Stokes experiments are presented which demonstrate that the OClO vibrational-relaxation dynamics are solvent dependent. The current picture of OClO photochemistry derived from these studies is discussed, and future directions for study are outlined.

  13. Ex vivo and in vivo coherent Raman imaging of the peripheral and central nervous system

    Science.gov (United States)

    Huff, Terry Brandon

    A hallmark of nervous system disorders is damage or degradation of the myelin sheath. Unraveling the mechanisms underlying myelin degeneration and repair represent one of the great challenges in medicine. This thesis work details the development and utilization of advanced optical imaging methods to gain insight into the structure and function of myelin in both healthy and diseased states in the in vivo environment. This first part of this thesis discusses ex vivo studies of the effects of high-frequency stimulation of spinal tissues on the structure of the node of Ranvier as investigated by coherent anti-Stokes Raman scattering (CARS) imaging (manuscript submitted to Journal of Neurosciece). Reversible paranodal myelin retraction at the nodes of Ranvier was observed during 200 Hz electrical stimulation, beginning minutes after the onset and continuing for up to 10 min after stimulation was ceased. A mechanistic study revealed a Ca2+ dependent pathway: high-frequency stimulation induced paranodal myelin retraction via pathologic calcium influx into axons, calpain activation, and cytoskeleton degradation through spectrin break-down. Also, the construction of dual-scanning CARS microscope for large area mapping of CNS tissues is detailed (Optics Express, 2008, 16:19396-193409). A confocal scanning head equipped with a rotating polygon mirror provides high speed, high resolution imaging and is coupled with a motorized sample stage to generate high-resolution large-area images of mouse brain coronal section and guinea pig spinal cord cross section. The polygon mirror decreases the mosaic acquisition time significantly without reducing the resolution of individual images. The ex vivo studies are then extended to in vivo imaging of mouse sciatic nerve tissue by CARS and second harmonic generation (SHG) imaging (Journal of Microscopy, 2007, 225: 175-182). Following a minimally invasive surgery to open the skin, CARS imaging of myelinated axons and SHG imaging of the

  14. Vibrational spectroscopic characterization of fluoroquinolones

    Science.gov (United States)

    Neugebauer, U.; Szeghalmi, A.; Schmitt, M.; Kiefer, W.; Popp, J.; Holzgrabe, U.

    2005-05-01

    Quinolones are important gyrase inhibitors. Even though they are used as active agents in many antibiotics, the detailed mechanism of action on a molecular level is so far not known. It is of greatest interest to shed light on this drug-target interaction to provide useful information in the fight against growing resistances and obtain new insights for the development of new powerful drugs. To reach this goal, on a first step it is essential to understand the structural characteristics of the drugs and the effects that are caused by the environment in detail. In this work we report on Raman spectroscopical investigations of a variety of gyrase inhibitors (nalidixic acid, oxolinic acid, cinoxacin, flumequine, norfloxacin, ciprofloxacin, lomefloxacin, ofloxacin, enoxacin, sarafloxacin and moxifloxacin) by means of micro-Raman spectroscopy excited with various excitation wavelengths, both in the off-resonance region (532, 633, 830 and 1064 nm) and in the resonance region (resonance Raman spectroscopy at 244, 257 and 275 nm). Furthermore DFT calculations were performed to assign the vibrational modes, as well as for an identification of intramolecular hydrogen bonding motifs. The effect of small changes in the drug environment was studied by adding successively small amounts of water until physiological low concentrations of the drugs in aqueous solution were obtained. At these low concentrations resonance Raman spectroscopy proved to be a useful and sensitive technique. Supplementary information was obtained from IR and UV/vis spectroscopy.

  15. Identification of minerals and meteoritic materials via Raman techniques after capture in hypervelocity impacts on aerogel

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, M J; Mann, J; Creighton, J A; Kearsley, A; Graham, G A; Esposito, A P; Franchi, I A; Westphal, A J; Snead, C

    2004-10-04

    For this study, an extensive suite of mineral particles analogous to components of cosmic dust were tested to determine if their Raman signatures can be recognized after hypervelocity capture in aerogel. The mineral particles were mainly of greater than 20 micrometers in size and were accelerated onto the silica aerogel by light gas gun shots. It was found that all the individual minerals captured in aerogel could be subsequently identified using Raman (or fluorescent) spectra. The beam spot size used for the laser illumination was of the order of 5 micrometers, and in some cases the captured particles were of a similar small size. In some samples fired into aerogel there was observed a shift in the wavenumbers of some of the Raman bands, a result of the trapped particles being at quite high temperatures due to heating by the laser. Temperatures of samples under laser illumination were estimated from the relative intensities of Stokes and anti-Stokes Raman bands, or, in the case of ruby particles, from the wavenumber of fluorescence bands excited by the laser. It was found that the temperature of particles in aerogel varied greatly, dependent upon laser power and the nature of the particle. In the worst case, some particles were shown to have temperatures in the 500-700 C range at a laser power of about 3 mW at the sample. However most of the mineral particles examined at this laser power had temperatures below 200 C. This is sufficiently low a temperature not to damage most materials expected to be found captured in aerogel in space. In addition, selected meteorite samples were examined to obtain Raman signatures of their constituent minerals and were then shot into aerogel. It was possible to find several Raman signatures after capture in aerogel and obtain a Raman map of a whole grain in situ in the aerogel. Finally, a Raman analysis was carried out of a particle captured in aerogel in space and carbonaceous material identified. In general therefore it is

  16. 唇腺炎性病变组织的共聚焦显微拉曼光谱特征研究%Research on the Confocal Raman micro­spectroscopic Characters of Inflammatory Labial Gland Tissues

    Institute of Scientific and Technical Information of China (English)

    薛丽丽; 骆献阳; 蔡巧玲; 孙佩; 陈培琼; 闫冰

    2015-01-01

    目的:研究唇腺炎性病变组织的拉曼光谱指纹特征,为拉曼光谱技术临床鉴别诊断唇腺炎性病变提供理论基础。方法:收集舍格伦综合征病变唇腺30例、唇腺急性炎症组织18例及正常唇腺组织30例,应用激光共聚焦显微拉曼光谱仪对唇腺组织进行拉曼光谱检测。应用主成分分析法(Principal component analysis,PCA)及判别函数(Discrimination function analysis,DFA)对光谱数据进行分析,研究唇腺组织光谱指纹诊断价值。结果:唇腺炎症组织与正常组织光谱间存在光谱指纹差异,这些差异代表了某些蛋白、核酸及脂类物质等生物大分子发生改变。PCA-DFA 分析发现这些差异性拉曼光谱具有鉴别诊断价值,可以区分不同唇腺组织,总体诊断准确率达91.8%,经交互验证后准确率为89.4%。结论:不同唇腺炎症组织及正常组织间拉曼光谱存在差异,不仅揭示生物大分子改变,还具有临床鉴别诊断价值。拉曼光谱技术在唇腺炎性病变组织鉴别诊断具有巨大应用潜力。%Objective:Research the Raman spectra of inflammatory labial gland tissues in order to provide a research-based theoretical foundation for applying Raman spectroscopy to diagnoses the inflammatory labial gland diseases.Meth­ods:30 samples of Sjogren’s syndrome labial glands,18 samples of acute inflammatory labial glands and 30 samples of normal labial glands were collected and scanned by confocal Raman micro-spectrometer.The methods of principal com-ponent analysis (PCA)and discrimination function analysis (DFA)were employed to analyze the spectral data and dis-criminate the different tissues.Results:Differences were discovered between in the Raman spectra of various labial gland tissues,which were assigned to biomolecules such as proteins,nucleic acids and lipids.The accuracy of discrimination carried out by PCA-DFA reached 91.8% and the accuracy of cross

  17. Raman Scattering by Molecular Hydrogen and Nitrogen in Exoplanetary Atmospheres

    CERN Document Server

    Oklopčić, Antonija; Heng, Kevin

    2016-01-01

    An important source of opacity in the atmospheres of exoplanets at short visible and near-UV wavelengths is Rayleigh scattering of light on molecules. It is accompanied by a related, albeit weaker process -- Raman scattering. In this paper, we analyze the signatures of Raman scattering imprinted in the reflected light and the geometric albedo of exoplanets, which could provide valuable information about planetary atmospheres. Raman scattering affects the geometric albedo spectra of planets in two main ways. Firstly, it causes filling-in of strong absorption lines in the incident radiation, thus producing sharp peaks in the albedo. Secondly, it shifts the wavelengths of spectral features in the reflected light causing the so-called Raman ghost lines. Observing the Raman peaks in the albedo could be used to measure the column density of the scattering molecule, thus providing constrains on the presence of clouds and hazes in the atmosphere. Observing the Raman ghost lines could be used to spectroscopically iden...

  18. X-ray diffraction and Raman spectroscopic investigations on CaZrTi2O7sbnd Y2Ti2O7 system: Delineation of phase fields consisting of potential ceramic host materials

    Science.gov (United States)

    Jafar, M.; Achary, S. N.; Salke, Niliesh P.; Sahu, A. K.; Rao, Rekha; Tyagi, A. K.

    2016-07-01

    Phase evolution from CaZrTi2O7 (zirconolite) to Y2Ti2O7 (pyrochlore) have been delineated by systematic characterization of a series of sample with composition as Ca1-xZr1-xY2xTi2O7 (0.00 ≤ x ≤ 1.00) by powder XRD, Raman spectroscopy, SEM and EDS analyses. Comparative analyses of XRD and Raman spectra revealed sequential evolution of phases with increasing concentration of Y3+ in the compositions. From the XRD studies, three distinct phase fields, namely two layer (2M) and four layer (4M) zirconolite-types and cubic pyrochlore-type are observed in between zirconolite (CaZrTi2O7) and Y2Ti2O7. 4M-zirconolite phase is observed in a narrow range of composition, viz. 0.35 ≤ x ≤ 0.40 while cubic pyrochlore type phase is observed in the compositions with x ≥ 1.20. The unit cell volume of different phases shows a non-linear increasing trend with Y3+ ion concentration which has been attributed to the distribution of cations in different structure and change in their coordination number.

  19. Quantum mechanical study of the structure and spectroscopic (FT-IR, FT-Raman, 13C, 1H and UV), NBO and HOMO-LUMO analysis of 2-quinoxaline carboxylic acid

    Science.gov (United States)

    Prabavathi, N.; Nilufer, A.; Krishnakumar, V.

    The FTIR and FT-Raman spectra of 2-quinoxaline carboxylic acid (2-QCA) has been recorded in the region 4000-450 and 4000-100 cm-1, respectively. The conformational analysis, optimized geometry, frequency and intensity of the vibrational bands of 2-QCA were obtained by the density functional theory (DFT) with complete relaxation in the potential energy surface using 6-31G(d) basis set. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The 1H and13C NMR spectra have been recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method and their respective linear correlations were obtained. The theoretical UV-visible spectrum of the compound using CIS method and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The Mulliken charges, the values of electric dipole moment (μ) of the molecule were computed using DFT calculations. The change in electron density (ED) in the σ* antibonding orbitals and stabilization energies E(2) have been calculated by natural bond (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interactions.

  20. Molecular structure, spectroscopic (FT-IR, FT-Raman, NMR, UV) studies and first-order molecular hyperpolarizabilities of 1,2-bis(3-methoxy-4-hydroxybenzylidene)hydrazine by density functional method

    Science.gov (United States)

    Subramanian, N.; Sundaraganesan, N.; Jayabharathi, J.

    2010-07-01

    Quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of 1,2-bis(3-methoxy-4-hydroxybenzylidene)hydrazine [vanillin azine (VA)] were carried out by using density functional (DFT/B3LYP) method with 6-31G(d) as basis set. The optimized geometrical parameters obtained by DFT calculations are in good agreement with single crystal XRD data. The vibrational spectral data obtained from solid phase FT-IR and FT-Raman spectra are assigned based on the results of the theoretical calculations. The observed spectra are found to be in good agreement with calculated values. The electric dipole moment ( μ) and the first hyperpolarizability ( β) values of the investigated molecule have been computed using ab initio quantum mechanical calculations. The calculation results also show that the VA molecule might have microscopic nonlinear optical (NLO) behavior with non-zero values. A detailed interpretation of the infrared and Raman spectra of VA was also reported. The energy and oscillator strength calculated by time-dependent density functional theory (TD-DFT) results complements with the experimental findings. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The theoretical NMR chemical shifts complement with experimentally measured ones.

  1. Spectroscopic properties of KGd(WO{sub 4}){sub 2} single crystals doped with Er{sup 3+}, Ho{sup 3+}, Tm{sup 3+} and Yb{sup 3+} ions: Luminescence and micro-Raman investigations

    Energy Technology Data Exchange (ETDEWEB)

    Kasprowicz, D., E-mail: Dobroslawa.Kasprowicz@put.poznan.pl [Faculty of Technical Physics, Poznan University of Technology, Nieszawska 13 A, 60-965 Poznan (Poland); Brik, M.G. [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Majchrowski, A. [Institute of Applied Physics, Military University of Technology, Kaliskiego 2, 00-908 Warszawa (Poland); Michalski, E. [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warszawa (Poland); Głuchowski, P. [Institute of Low Temperature and Structure Research of Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw (Poland)

    2013-11-15

    Highlights: •Investigations of KGd(WO{sub 4}){sub 2} crystals doped with Ho/Yb/Er and Ho/Tm/Yb/Er ions. •The vibrational properties were studied using micro-Raman spectroscopy. •The multicolor up-converted luminescence was investigated. -- Abstract: KGd(WO{sub 4}){sub 2} single crystals doped with Ho{sup 3+}/Yb{sup 3+}/Er{sup 3+} and Ho{sup 3+}/Tm{sup 3+}/Yb{sup 3+}/Er{sup 3+} ions were grown by means of the Top Seeded Solution Growth (TSSG) method. It was shown that these systems exhibit multicolor up-conversion luminescence in the visible and near-infrared spectral ranges under 980 nm laser excitation. In the investigated crystals the Yb{sup 3+} ions were used as the energy sensitizer ion and the up-converted luminescence originates from transitions between the energy levels of other co-doped rare earth ions such as Er{sup 3+}, Ho{sup 3+} or Tm{sup 3+}, which play the role of the energy activator ions. The vibrational properties of the crystals were investigated using micro-Raman spectroscopy and the role of vibrational energy in the effective energy transfer process between the rare earth ions was discussed. The proposed combinations of activator ions may be suitable for gaining novel materials with effective green, red and near-infrared emission.

  2. Spectroscopic (FT-IR, FT-Raman, NMR and UV-Visible) and quantum chemical studies of molecular geometry, Frontier molecular orbital, NLO, NBO and thermodynamic properties of salicylic acid

    Science.gov (United States)

    Suresh, S.; Gunasekaran, S.; Srinivasan, S.

    2014-11-01

    The solid phase FT-IR and FT-Raman spectra of 2-hydroxybenzoic acid (salicylic acid) have been recorded in the region 4000-400 and 4000-100 cm-1 respectively. The optimized molecular geometry and fundamental vibrational frequencies are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) method and a comparative study between Hartree Fork (HF) method at 6-311++G(d,p) level basis set. The calculated harmonic vibrational frequencies are scaled and they are compared with experimentally obtained FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated potential energy distribution (PED). The time dependent DFT method is employed to predict its absorption energy and oscillator strength. The linear polarizability (α) and the first order hyper polarizability (β) values of the investigated molecule have been computed. The electronic properties, such as HOMO and LUMO energies, molecular electrostatic potential (MEP) are also performed. Stability of the molecule arising from hyper conjugative interaction, charge delocalization has been analyzed using natural bond orbital (NBO) analysis.

  3. Synthesis, spectroscopic (FT-IR, FT-Raman, NMR, UV-Visible), Fukui function, antimicrobial and molecular docking study of (E)-1-(3-bromobenzylidene)semicarbazide by DFT method

    Science.gov (United States)

    Raja, M.; Raj Muhamed, R.; Muthu, S.; Suresh, M.; Muthu, K.

    2017-02-01

    The title compound, (E)-1-(3-bromobenzylidene)semicarbazide (3BSC) was synthesized and characterized by FT-IR, FT-Raman, UV, 1HNMR and 13CNMR spectral analysis. The optimized molecular geometry, the vibrational wavenumbers, the infrared intensities and the Raman scattering activities were calculated by using density functional theory (DFT) B3LYP method with 6-311++G(d,p) basis set. The calculated HOMO and LUMO energies show that charge transfer within the molecule. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital analysis (NBO). The hyperpolarizability calculation reveals the present material has a reasonably good propensity for nonlinear optical activity. Molecular electrostatic potential (MEP) and Fukui functions were also performed. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the 3BSC at different temperatures have been calculated. The biological applications of 3BSC have been screened for its antimicrobial activity and found to exhibit antifungal and antibacterial effects. In addition, the Molecular docking was also performed for the different receptors.

  4. Comprehensive quantum chemical and spectroscopic (FTIR, FT-Raman, 1H, 13C NMR) investigations of (1,2-epoxyethyl)benzene and (1,2-epoxy-2-phenyl)propane

    Science.gov (United States)

    Arjunan, V.; Anitha, R.; Devi, L.; Mohan, S.; Yang, Haifeng

    2015-01-01

    Aromatic epoxides are causative factors for mutagenic and carcinogenic activity of polycyclic arenes. The 1,2- or 2,3-epoxy compounds are widely used to a considerable extent in the textile, plastics, pharmaceutical, cosmetics, detergent and photochemical industries. The FTIR and FT-Raman spectra of (1,2-epoxyethyl)benzene and (1,2-epoxy-2-phenyl)propane are recorded in the regions 4000-400 cm-1 and 4000-100 cm-1, respectively. The observed fundamentals are assigned to different normal modes of vibration. The structure of the compound has been optimised with B3LYP method using 6-311++G** and cc-pVTZ basis sets. The IR and Raman intensities are determined. The total electron density and molecular electrostatic potential surfaces of the molecule are constructed by using B3LYP/6-311++G(d,p) method to display electrostatic potential (electron + nuclei) distribution. The electronic properties HOMO and LUMO energies were measured. Natural bond orbital analysis of the compounds has been performed to indicate the presence of intramolecular charge transfer. The 1H and 13C NMR chemical shifts of the molecules have been analysed.

  5. Molecular structure, vibrational spectroscopic (FT-IR, FT-Raman), UV-vis spectra, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis, thermodynamic properties of benzophenone 2,4-dicarboxylic acid by ab initio HF and density functional method.

    Science.gov (United States)

    Chaitanya, K

    2012-02-01

    The FT-IR (4000-450 cm(-1)) and FT-Raman spectra (3500-100 cm(-1)) of benzophenone 2,4-dicarboxylic acid (2,4-BDA) have been recorded in the condensed state. Density functional theory calculation with B3LYP/6-31G(d,p) basis set have been used to determine ground state molecular geometries (bond lengths and bond angles), harmonic vibrational frequencies, infrared intensities, Raman activities and bonding features of the title compounds. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of 2,4-BDA is calculated using HF/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO analysis. The calculated first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charges is also calculated. Because of vibrational analyses, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV-vis spectra and electronic absorption properties were explained and illustrated from the frontier molecular orbitals.

  6. 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...

  7. MicroRaman Spectroscopy and Raman Imaging of Basal Cell Carcinoma

    Science.gov (United States)

    Short, M. A.; Zeng, H.; Lui, H.

    2005-03-01

    We have measured the Raman spectra of normal and cancerous skin tissues using a confocal microRaman spectrograph with a sub-micron spatial resolution. We found that the Raman spectrum of a cell nucleolus is different from the spectra measured outside the nucleolus and considerably different from those measured outside the nucleus. In addition, we found significant spectroscopic differences between normal and cancer-bearing sites in the dermis region. In order to utilize these differences for non-invasive skin cancer diagnosis, we have developed a Raman imaging system that clearly demonstrates the structure, location and distribution of cells in unstained skin biopsy samples. Our method is expected to be useful for the detection and characterization of skin cancer based on the known distinct cellular differences between normal and malignant skin.

  8. Thiol-thione tautomeric analysis, spectroscopic (FT-IR, Laser-Raman, NMR and UV-vis) properties and DFT computations of 5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol molecule

    Science.gov (United States)

    Gökce, Halil; Öztürk, Nuri; Ceylan, Ümit; Alpaslan, Yelda Bingöl; Alpaslan, Gökhan

    2016-06-01

    In this study, the 5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol molecule (C7H6N4S) molecule has been characterized by using FT-IR, Laser-Raman, NMR and UV-vis spectroscopies. Quantum chemical calculations have been performed to investigate the molecular structure (thione-thiol tautomerism), vibrational wavenumbers, electronic transition absorption wavelengths in DMSO solvent and vacuum, proton and carbon-13 NMR chemical shifts and HOMOs-LUMOs energies at DFT/B3LYP/6-311 ++G(d,p) level for all five tautomers of the title molecule. The obtained results show that the calculated vibrational wavenumbers, NMR chemical shifts and UV-vis wavelengths are in a good agreement with experimental data.

  9. 不同初始pH值的乙醇发酵过程拉曼光谱分析%Raman Spectroscopic Analysis of Ethanol Fermentation at Various Initial pH Levels

    Institute of Scientific and Technical Information of China (English)

    覃赵军; 赖钧灼; 刘斌; 刘军贤; 王桂文

    2013-01-01

    pH值是影响酵母乙醇发酵的重要因素.应用拉曼光谱初步分析不同初始pH值对乙醇发酵过程的影响.结果显示:1)在3.0、4.5、6.5三个不同初始pH值的培养基中,pH4.5下乙醇产量最高,pH 3.0下最低.2)在发酵的前15h,不同初始pH值下的酵母细胞生物大分子的拉曼信号变化波动大;后期,pH3.0下胞内脂类和蛋白质的拉曼信号最强,pH 6.5最弱;显示在低pH值环境下部分底物可能被转化为胞内储藏物质.3)主成分分析显示,pH值对酵母细胞生理状态的影响从发酵的初始阶段就开始;1440 cm-1和1600 cm-1峰一直是影响主成分PC1、PC2、PC3分值的主要特征峰;说明pH环境可能影响了酵母细胞的脂类物质合成和细胞的呼吸代谢,进而影响了底物的代谢方向和产物的合成.结果表明,拉曼光谱和单细胞分析可以用于剖析微生物发酵过程的生理机制,为乙醇发酵提供全新的参考信息.%The pH level is a prominent factor affects the ethanol fermentation. Optical tweezers Raman spectroscopy is used to analyze the process of ethanol fermentation at the initial pH levels of 3.0, 4.5, 6.5. Major results from this work are as follows: 1) The pH 4. 5 level get the highest ethanol production and the pH 3.0 get the lowest one. 2) Raman intensities of bio-macromolecules of yeast cells at all pH levels exhibite dramatic changes in the first 15 hours. However, at the later stage of the fermentation, the pH 3. 0 level displayes strong Raman intensities of intracellular lipids and proteins while pH 6. 5 level shows weak. This indicates that a portion of substrate may be transformed into intracellular storage material by yeast cells at lower pH level. 3) Principal component analysis reveals that fermentation pH influences the physiological status of yeast cells from the beginning of fermentation, and bands 1440 cm-1 and 1600 cm-1 are the prominent contributors to the component loadings in different

  10. Raman Spectroscopic Profile of Ethanol Fermentation in High Gravity Cassava Starch Brewing%浓醪乙醇发酵的单细胞拉曼光谱表征

    Institute of Scientific and Technical Information of China (English)

    李自达; 赖钧灼; 廖威; 刘军贤; 王桂文

    2012-01-01

    应用激光镊子拉曼光谱技术收集500 L发酵罐中木薯淀粉浓醪乙醇发酵过程底物、产物及酵母单细胞的拉曼光谱,以期从单细胞水平为乙醇发酵提供新的认识.结果显示:1)拉曼光谱可以实时监测浓醪乙醇发酵过程底物与产物的变化;2)酵母细胞胞内物质的变化存在类似于产物变化的前发酵期、主发酵期和后发酵期3个阶段,但出现的时间要比产物变化晚约4 h;3)为适应浓醪发酵环境,酵母细胞的生理状态和胞内物质在不断地进行调整,随着环境乙醇浓度的升高,酵母细胞在胞内累积蛋白质和脂类物质,蛋白质二级结构逐渐变为以无规则卷曲为主;4)发酵后期,酵母细胞在胞内累积大量的嘌呤类物质,但细胞间含量存在异质性.上述结果表明,单细胞拉曼光谱技术提供了一种研究微生物发酵的新方法,可从新的角度获知乙醇发酵过程酵母细胞内外的变化信息.%Raman spectroscopy is used to characterize the process of ethanol fermentation and look into the Saccharomyces cerevisiae cells at single-cell level. The ethanol fermentation using high-concentration cassava starch as feedstock is processed in a 500 L fermentor and the Raman spectra of substrate, product and individual yeast cell are acquired by using laser tweezers Raman spectroscopy (LTRS). Major results are as follows: 1) Raman spectroscopy can monitor the dynamic changes of substrate and product during the ethanol fermentation; 2) the changes of intracellular components of yeast cells exhibit three stages, I. E., primary fermentation, main fermentation and later fermentation, which are similar to those of products, but there is a delay of about 4 hi 3) yeast cells amend its physiological state and intracellular compounds to adapt to the high osmotic stress at the initial stage and the high ethanol concentration at the later stage of fermentation. Random coiling dominates the secondary structure of

  11. Analysis of molecular structure, spectroscopic properties (FT-IR, micro-Raman and UV-vis) and quantum chemical calculations of free and ligand 2-thiopheneglyoxylic acid in metal halides (Cd, Co, Cu, Ni and Zn).

    Science.gov (United States)

    Gökce, Halil; Bahçeli, Semiha

    2013-12-01

    In this study, molecular geometries, experimental vibrational wavenumbers, electronic properties and quantum chemical calculations of 2-thiopheneglyoxylic acid molecule, (C6H4O3S), and its metal halides (Cd, Co, Cu, Ni and Zn) which are used as pharmacologic agents have been investigated experimentally by FT-IR, micro-Raman and UV-visible spectroscopies and elemental analysis. Meanwhile the vibrational calculations were verified by DFT/B3LYP method with 6-311++G(d,p) and LANL2DZ basis sets in the ground state, for free TPGA molecule and its metal halide complexes, respectively, for the first time. The calculated fundamental vibrational frequencies for the title compounds are in a good agreement with the experimental data.

  12. Spectroscopic (FT-IR, FT-Raman and UV) investigation, NLO, NBO, molecular orbital and MESP analysis of 2-{2-[(2,6-dichlorophenyl)amino]phenyl}acetic acid

    Science.gov (United States)

    Govindasamy, P.; Gunasekaran, S.

    2015-02-01

    In this work, FT-IR and FT-Raman spectra of 2-{2-[(2,6-dichlorophenyl)amino]phenyl}acetic acid (abbreviated as 2DCPAPAA) have been reported in the regions 4000-450 cm-1 and 4000-50 cm-1, respectively. The molecular structure, geometry optimization, intensities, vibrational frequencies were obtained by the ab initio and DFT levels of theory B3LYP with 6-311++G(d,p) standard basis set and a different scaling of the calculated wave numbers. The complete vibrational assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes calculated using vibrational energy distribution analysis (VEDA 4) program. The harmonic frequencies were calculated and the scaled values were compared with experimental FT-IR and FT-Raman data. The observed and the calculated frequencies are found to be in good agreement. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The thermodynamic properties of the title compound at different temperature reveal the correlations between standard heat capacities (C) standard entropies (S) standard enthalpy changes (ΔH). The important non-linear optical properties such as electric dipole momentum, polarizability and first hyperpolarizability of 2DCPAPAA have been computed using B3LYP/6-311++G(d,p) quantum chemical calculations. The Natural charges, HOMO, LUMO, chemical hardness (η), chemical potential (μ), Electro negativity (χ) and electrophilicity values (ω) are calculated and reported. The oscillator's strength, wave length, and energy calculated by TD-DFT and 2DCPAPAA is approach complement with the experimental findings. The molecular electrostatic potential (MESP) surfaces of the molecule were constructed.

  13. Spectroscopic Chemical Analysis Methods and Apparatus

    Science.gov (United States)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor); Lane, Arthur L. (Inventor)

    2017-01-01

    Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

  14. Non-invasive chemically specific measurement of subsurface temperature in biological tissues using surface-enhanced spatially offset Raman spectroscopy.

    Science.gov (United States)

    Gardner, Benjamin; Stone, Nicholas; Matousek, Pavel

    2016-06-23

    Here we demonstrate for the first time the viability of characterising non-invasively the subsurface temperature of SERS nanoparticles embedded within biological tissues using spatially offset Raman spectroscopy (SORS). The proposed analytical method (T-SESORS) is applicable in general to diffusely scattering (turbid) media and features high sensitivity and high chemical selectivity. The method relies on monitoring the Stokes and anti-Stokes bands of SERS nanoparticles in depth using SORS. The approach has been conceptually demonstrated using a SORS variant, transmission Raman spectroscopy (TRS), by measuring subsurface temperatures within a slab of porcine tissue (5 mm thick). Root-mean-square errors (RMSEs) of 0.20 °C were achieved when measuring temperatures over ranges between 25 and 44 °C. This unique capability complements the array of existing, predominantly surface-based, temperature monitoring techniques. It expands on a previously demonstrated SORS temperature monitoring capability by adding extra sensitivity stemming from SERS to low concentration analytes. The technique paves the way for a wide range of applications including subsurface, chemical-specific, non-invasive temperature analysis within turbid translucent media including: the human body, subsurface monitoring of chemical (e.g. catalytic) processes in manufacture quality and process control and research. Additionally, the method opens prospects for control of thermal treatment of cancer in vivo with direct non-invasive feedback on the temperature of mediating plasmonic nanoparticles.

  15. Catching Conical Intersections in the Act; Monitoring Transient Electronic Coherences by Attosecond Stimulated X-Ray Raman Signals

    Science.gov (United States)

    Bennett, Kochise; Kowalewski, Markus; Dorfman, Konstantin; Mukamel, Shaul

    Conical intersections (CIs) dominate the pathways and outcomes of virtually all photochemical molecular processes. Despite extensive experimental and theoretical effort, CIs have not been directly observed yet and the experimental evidence is inferred from fast reaction rates and vibrational signatures. We show that short X-ray pulses can directly detect the passage through a CI with the adequate temporal and spectral sensitivity. The non-adiabatic coupling that exists in the region of a CI redistributes electronic population but also generates electronic coherence. This coherent oscillation can then be detected via a coherent Raman process that employs a composite femtosecond/attosecond X-ray pulse. This technique, dubbed Transient Redistribution of Ultrafast Electronic Coherences (TRUECARS) is reminiscent of Coherent Anti-Stokes Raman Spectroscopy (CARS) in that a coherent oscillation is set in motion and then monitored, but differs in that the dynamics is electronic (CARS generally observes nuclear dynamics) and the coherence is generated internally by passage through a region of non-adiabatic coupling rather than by an externally applied laser. Support provided by U.S. Department of Energy through Award No. DE-FG02-04ER15571, the National Science Foundation (Grant No CHE-1361516), and the Alexander von Humboldt foundation through the Feodor Lynen program.

  16. Spectroscopic (FT-IR, FT-Raman, UV, 1H and 13C NMR) profiling and computational studies on methyl 5-methoxy-1H-indole-2-carboxylate: A potential precursor to biologically active molecules

    Science.gov (United States)

    Almutairi, Maha S.; Xavier, S.; Sathish, M.; Ghabbour, Hazem A.; Sebastian, S.; Periandy, S.; Al-Wabli, Reem I.; Attia, Mohamed I.

    2017-04-01

    Methyl 5-methoxy-1H-indole-2-carboxylate (MMIC) was prepared via esterification of commercially available 5-methoxyindole-2-carboxylic acid. The title molecule MMIC was characterised using FT-IR and FT-Raman in the ranges of 4000-500 and 4000-50 cm-1, respectively. The fundamental modes of the vibrations were assigned and the UV-visible spectrum of the MMIC molecule was recorded in the range of 200-400 nm to explore its electronic nature. The HOMO-LUMO energy distribution was calculated and the bonding and anti-bonding structures of the title molecule were studied and analysed using the natural bond orbital (NBO) approach. The reactivity of the MMIC molecule was also investigated and both the positive and negative centres of the molecule were identified using chemical descriptors and molecular electrostatic potential (MEP) analysis. The chemical shifts of the 1H and 13C NMR spectra were noted and the magnetic field environment of the MMIC molecule are discussed. The non-linear optical (NLO) properties of the title molecule were studied based on its calculated values of polarisability and hyperpolarisability. All computations were obtained by DFT methods using the 6-311++G (d,p) basis set.

  17. Spectroscopic investigation (FT-IR and FT-Raman), vibrational assignments, HOMO-LUMO analysis and molecular docking study of 2-(Adamantan-1-yl)-5-(4-nitrophenyl)-1,3,4-oxadiazole

    Science.gov (United States)

    Haress, Nadia G.; Al-Omary, Fatmah; El-Emam, Ali A.; Mary, Y. Sheena; Panicker, C. Yohannan; Al-Saadi, Abdulaziz A.; War, Javeed Ahmad; Van Alsenoy, Christian

    2015-01-01

    FT-IR and FT-Raman spectra of 2-(Adamantan-1-yl)-5-(4-nitrophenyl)-1,3,4-oxadiazole were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations. The data obtained from wavenumber calculations are used to assign vibrational bands obtained experimentally. The energy barriers of the internal rotations about the Csbnd C bonds connecting the oxadiazole to the adamantane and benzene rings are reported. The geometrical parameters (DFT) of the title compound are in agreement with the XRD results. The calculated HOMO and LUMO energies allow the calculations of atomic and molecular properties and they also showed that charge transfer occurs in the molecule. A detailed molecular picture of the title compound and its interactions were obtained from NBO analysis. As can be seen from the MEP map of the title compound, which regions having the negative potential are over the electro negative atoms, the region having the positive potential are over the phenyl and adamantine rings and the remaining species are surrounded by zero potential. The molecular docking studies reveal that the adamantyl derivative may exhibit C-South African HIV-proteas inhibitory activity.

  18. Label-free biochemical characterization of bovine sperm cells using Raman microscopy

    Science.gov (United States)

    De Luca, A. C.; Managò, S.; Ferrara, M. A.; Sirleto, L.; Puglisi, R.; Balduzzi, D.; Galli, A.; Rendina, I.; Ferraro, P.; Coppola, G.

    2014-02-01

    The current study relates to a Raman spectroscopy-based method for addressing the problem of sex assessment in mammals. A direct method for sex predetermination in animals is based on the X- and Y-bearing sperm cells sorting before insemination. Our Raman spectroscope allows distinguishing and characterizing the difference between X- and Y-bearing sperm cells by detecting and analyzing their Raman spectra in a non-invasive and non-destructive way.

  19. Transcutaneous Raman Spectroscopy of Bone

    Science.gov (United States)

    Maher, Jason R.

    Clinical diagnoses of bone health and fracture risk typically rely upon measurements of bone density or structure, but the strength of a bone is also dependent upon its chemical composition. One technology that has been used extensively in ex vivo, exposed-bone studies to measure the chemical composition of bone is Raman spectroscopy. This spectroscopic technique provides chemical information about a sample by probing its molecular vibrations. In the case of bone tissue, Raman spectra provide chemical information about both the inorganic mineral and organic matrix components, which each contribute to bone strength. To explore the relationship between bone strength and chemical composition, our laboratory has contributed to ex vivo, exposed-bone animal studies of rheumatoid arthritis, glucocorticoid-induced osteoporosis, and prolonged lead exposure. All of these studies suggest that Raman-based predictions of biomechanical strength may be more accurate than those produced by the clinically-used parameter of bone mineral density. The utility of Raman spectroscopy in ex vivo, exposed-bone studies has inspired attempts to perform bone spectroscopy transcutaneously. Although the results are promising, further advancements are necessary to make non-invasive, in vivo measurements of bone that are of sufficient quality to generate accurate predictions of fracture risk. In order to separate the signals from bone and soft tissue that contribute to a transcutaneous measurement, we developed an overconstrained extraction algorithm that is based upon fitting with spectral libraries derived from separately-acquired measurements of the underlying tissue components. This approach allows for accurate spectral unmixing despite the fact that similar chemical components (e.g., type I collagen) are present in both soft tissue and bone and was applied to experimental data in order to transcutaneously detect, to our knowledge for the first time, age- and disease-related spectral

  20. Transmission resonance Raman spectroscopy: experimental results versus theoretical model calculations.

    Science.gov (United States)

    Gonzálvez, Alicia G; González Ureña, Ángel

    2012-10-01

    A laser spectroscopic technique is described that combines transmission and resonance-enhanced Raman inelastic scattering together with low laser power (view, a model for the Raman signal dependence on the sample thickness is also presented. Essentially, the model considers the sample to be homogeneous and describes the underlying physics using only three parameters: the Raman cross-section, the laser-radiation attenuation cross-section, and the Raman signal attenuation cross-section. The model was applied successfully to describe the sample-size dependence of the Raman signal in both β-carotene standards and carrot roots. The present technique could be useful for direct, fast, and nondestructive investigations in food quality control and analytical or physiological studies of animal and human tissues.

  1. Split-probe hybrid femtosecond/picosecond rotational CARS for time-domain measurement of S-branch Raman linewidths within a single laser shot.

    Science.gov (United States)

    Patterson, Brian D; Gao, Yi; Seeger, Thomas; Kliewer, Christopher J

    2013-11-15

    We introduce a multiplex technique for the single-laser-shot determination of S-branch Raman linewidths with high accuracy and precision by implementing hybrid femtosecond (fs)/picosecond (ps) rotational coherent anti-Stokes Raman spectroscopy (CARS) with multiple spatially and temporally separated probe beams derived from a single laser pulse. The probe beams scatter from the rotational coherence driven by the fs pump and Stokes pulses at four different probe pulse delay times spanning 360 ps, thereby mapping collisional coherence dephasing in time for the populated rotational levels. The probe beams scatter at different folded BOXCARS angles, yielding spatially separated CARS signals which are collected simultaneously on the charge coupled device camera. The technique yields a single-shot standard deviation (1σ) of less than 3.5% in the determination of Raman linewidths and the average linewidth values obtained for N(2) are within 1% of those previously reported. The presented technique opens the possibility for correcting CARS spectra for time-varying collisional environments in operando.

  2. 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

    2016-12-01

    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 488 nm and 785 nm 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.

  3. In vivo coherent Raman imaging of the melanomagenesis-associated pigment pheomelanin

    Science.gov (United States)

    Wang, Hequn; Osseiran, Sam; Igras, Vivien; Nichols, Alexander J.; Roider, Elisabeth M.; Pruessner, Joachim; Tsao, Hensin; Fisher, David E.; Evans, Conor L.

    2016-11-01

    Melanoma is the most deadly form of skin cancer with a yearly global incidence over 232,000 patients. Individuals with fair skin and red hair exhibit the highest risk for developing melanoma, with evidence suggesting the red/blond pigment known as pheomelanin may elevate melanoma risk through both UV radiation-dependent and -independent mechanisms. Although the ability to identify, characterize, and monitor pheomelanin within skin is vital for improving our understanding of the underlying biology of these lesions, no tools exist for real-time, in vivo detection of the pigment. Here we show that the distribution of pheomelanin in cells and tissues can be visually characterized non-destructively and noninvasively in vivo with coherent anti-Stokes Raman scattering (CARS) microscopy, a label-free vibrational imaging technique. We validated our CARS imaging strategy in vitro to in vivo with synthetic pheomelanin, isolated melanocytes, and the Mc1re/e, red-haired mouse model. Nests of pheomelanotic melanocytes were observed in the red-haired animals, but not in the genetically matched Mc1re/e; Tyrc/c (“albino-red-haired”) mice. Importantly, samples from human amelanotic melanomas subjected to CARS imaging exhibited strong pheomelanotic signals. This is the first time, to our knowledge, that pheomelanin has been visualized and spatially localized in melanocytes, skin, and human amelanotic melanomas.

  4. 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…

  5. Gauss-Newton based kurtosis blind deconvolution of spectroscopic data

    Institute of Scientific and Technical Information of China (English)

    Jinghe Yuan; Ziqiang Hu

    2006-01-01

    @@ The spectroscopic data recorded by dispersion spectrophotometer are usually degraded by the response function of the instrument. To improve the resolving power, double or triple cascade spectrophotometer and narrow slits have been employed, but the total flux of the radiation decreases accordingly, resulting in a lower signal-to-noise ratio (SNR) and a longer measuring time. However, the spectral resolution can be improved by mathematically removing the effect of the instrument response function. Based on the ShalviWeinstein criterion, a Gauss-Newton based kurtosis blind deconvolution algorithm for spectroscopic data is proposed. Experiments with some real measured Raman spectroscopic data show that this algorithm has excellent deconvolution capability.

  6. 大别山高压-超高压片麻岩锆石的拉曼光谱学研究%Laser-Raman spectroscopic studies on zircons from the HP-UHP gneisses of Dabie Mountains

    Institute of Scientific and Technical Information of China (English)

    刘文元; 刘景波

    2009-01-01

    The zircons from gneisses in high and ultrahigh-pressure (HP-UHP) metamorphic zones of the Dabie Mountains have been investigated by using Laser Raman microprobe analysis, cathodoluminescence (CL) images, U-Pb ages and trace elements measured by LA-ICP-MS. Most of the FWHMs (full widths at half-maximum) of 1008cm~(-1) band of zircons are less than 20cm~(-1), suggesting that zircons are well crystallized to moderately damaged. The early inherited zircons from gneisses had undergone significant annealing and recrystallization during the HP-UHP metamorphic event. The α-doses that zircons suffered are probably accumulated from about 200Ma, indicating that HP-UHP metamorphic rocks have been exhumed to the surface of the earth at this time. The magmatic events of Cretaceous age in North Dabie may exert little effect on the HP-UHP rocks, which most of FWHMs and frequencies of zircons in Dabie Moutains fall into the natural radiation damage trend (RDT) , indicating completely recrystalization of zircons during the HP-UHP metamorphic event.%对大别山高压-超高压片麻岩的锆石进行了激光拉曼探针、阴极发光(CL)、U-Pb年龄和U、Th等微量元素的测定分析.研究结果表明:锆石拉曼光谱1008cm~(-1)峰的半高宽普遍小于20cm~(-1),指示锆石结晶程度较好到中等程度的蜕晶化;早期继承锆石在三叠纪高压-超高压变质作用中经历了退火和重结晶作用,所受的放射性通量是从200Ma的早侏罗纪开始积累的,表明高压-超高压岩石在这一时间已出露地表;北大别白垩纪岩浆热事件对高压-超高压岩石的影响很小;大多数锆石数据都落在天然锆石的放射性破坏趋势(RDT)中,表明锆石在高压、超高压过程中基本发生了完全的重结晶.

  7. In Situ Raman Spectroscopic of Cerium Surface Oxidation and Reduction Processes%金属铈表面氧化还原过程的原位拉曼光谱研究

    Institute of Scientific and Technical Information of China (English)

    吕俊波; 郭淑兰; 李赣

    2013-01-01

    The surface oxidation and reduction processes of cerium were monitored by in situ microscope Raman spectroscopy.A peak at 462 cm-1 attributed to the characteristic vibration of CeO2 disappeared and two sharp peaks at 2132 and 2239 cm-1 attributed to the electronic scattering of Ce3+ were observed at high temperature and vacuum conditions.The results indicated that the surface oxide on cerium sample were transformed from CeO2 to Ce2O3.According to the changes of peak intensities at 1503,1796,2100cm-1,also attributed to electronic scattering of Ce3+and the characteristic vibration peak of CeO2,the surface oxidation process of cerium in the air could be divided into three steps.First,all cerium oxide layers with different cerium valence increased quickly.Then,the outer CeO2 layer stopped growing,but those cerium oxide layers contained Ce3+ continued growing.Finally,CeO2 layer increased quickly again with the appearance of OH-at 3603 cm-1%采用显微拉曼光谱仪原位监测了金属铈表面的氧化和还原过程.2132和2239 cm-1处尖锐Ce3+电子散射峰的出现及462 cm-1处CeO2特征振动峰的消失表明,在高温、高真空条件下金属铈表层的CeO2已转变为Ce2O3.根据1503,1796和2113 cm-1处多个Ce3+电子散射峰及CeO2特征振动峰强度随时间的变化关系,可将金属Ce在空气中的氧化过程分为3个阶段,首先不同价态铈氧物层均快速增长,随后外层的CeO2陷入停顿,含Ce3+的铈氧物层继续增长,最后随着3603 cm-1处OH-的出现,CeO2再次快速增长.

  8. Rapid determination of pork sensory quality using Raman spectroscopy.

    Science.gov (United States)

    Wang, Qi; Lonergan, Steven M; Yu, Chenxu

    2012-07-01

    Existing objective methods to predict sensory attributes of pork in general do not yield satisfactory correlation to panel evaluations, and their applications in meat industry are limited. In this study, a Raman spectroscopic method was developed to evaluate and predict tenderness, juiciness and chewiness of fresh, uncooked pork loins from 169 pigs. Partial Least Square Regression models were developed based on Raman spectroscopic characteristics of the pork loins to predict the values of the sensory attributes. Furthermore, binary barcodes were created based on spectroscopic characteristics of the pork loins, and subjected to multivariate statistical discriminant analysis (i.e., Support Vector Machine) to differentiate and classify pork loins into quality grades ("good" and "bad" in terms of tenderness and chewiness). Good agreement (>83% correct predictions) with sensory panel results was obtained. The method developed in this report has the potential to become a rapid objective assay for tenderness and chewiness of pork products that may find practical applications in pork industry.

  9. An empirical evaluation of three vibrational spectroscopic methods for detection of aflatoxins in maize.

    Science.gov (United States)

    Lee, Kyung-Min; Davis, Jessica; Herrman, Timothy J; Murray, Seth C; Deng, Youjun

    2015-04-15

    Three commercially available vibrational spectroscopic techniques, including Raman, Fourier transform near infrared reflectance (FT-NIR), and Fourier transform infrared (FTIR) were evaluated to help users determine the spectroscopic method best suitable for aflatoxin analysis in maize (Zea mays L.) grain based on their relative efficiency and predictive ability. Spectral differences of Raman and FTIR spectra were more marked and pronounced among aflatoxin contamination groups than those of FT-NIR spectra. From the observations and findings in our current and previous studies, Raman and FTIR spectroscopic methods are superior to FT-NIR method in terms of predictive power and model performance for aflatoxin analysis and they are equally effective and accurate in predicting aflatoxin concentration in maize. The present study is considered as the first attempt to assess how spectroscopic techniques with different physical processes can influence and improve accuracy and reliability for rapid screening of aflatoxin contaminated maize samples.

  10. Coherent Raman spectroscopy

    CERN Document Server

    Eesley, G L

    1981-01-01

    Coherent Raman Spectroscopy provides a unified and general account of the fundamental aspects of nonlinear Raman spectroscopy, also known as coherent Raman spectroscopy. The theoretical basis from which coherent Raman spectroscopy developed is described, along with its applications, utility, and implementation as well as advantages and disadvantages. Experimental data which typifies each technique is presented. This book is comprised of four chapters and opens with an overview of nonlinear optics and coherent Raman spectroscopy, followed by a discussion on nonlinear transfer function of matter

  11. Application of Raman multivariate curve resolution to solvation-shell spectroscopy.

    Science.gov (United States)

    Fega, Kathryn Rebecca; Wilcox, David Scott; Ben-Amotz, Dor

    2012-03-01

    Raman spectroscopy and multivariate curve resolution (Raman-MCR) are combined to yield a powerful spectroscopic method for identifying solute-induced perturbations of solvent molecules. The principles and applications of the resulting solvation-shell spectroscopy are described and illustrated using both numerical model spectra and experimental Raman spectra, including water in acetone and aqueous OH(-), as well as of both neutral and ionic acetic acid solutions. The results illustrate the quantitative capabilities of Raman-MCR as a solvation-shell spectroscopy, including fundamental limitations arising from "intensity" and "rotational" ambiguities.

  12. Label-free in vivo analysis of intracellular lipid droplets in the oleaginous microalga Monoraphidium neglectum by coherent Raman scattering microscopy.

    Science.gov (United States)

    Jaeger, Daniel; Pilger, Christian; Hachmeister, Henning; Oberländer, Elina; Wördenweber, Robin; Wichmann, Julian; Mussgnug, Jan H; Huser, Thomas; Kruse, Olaf

    2016-10-21

    Oleaginous photosynthetic microalgae hold great promise as non-food feedstocks for the sustainable production of bio-commodities. The algal lipid quality can be analysed by Raman micro-spectroscopy, and the lipid content can be imaged in vivo in a label-free and non-destructive manner by coherent anti-Stokes Raman scattering (CARS) microscopy. In this study, both techniques were applied to the oleaginous microalga Monoraphidium neglectum, a biotechnologically promising microalga resistant to commonly applied lipid staining techniques. The lipid-specific CARS signal was successfully separated from the interfering two-photon excited fluorescence of chlorophyll and for the first time, lipid droplet formation during nitrogen starvation could directly be analysed. We found that the neutral lipid content deduced from CARS image analysis strongly correlated with the neutral lipid content measured gravimetrically and furthermore, that the relative degree of unsaturation of fatty acids stored in lipid droplets remained similar. Interestingly, the lipid profile during cellular adaption to nitrogen starvation showed a two-phase characteristic with initially fatty acid recycling and subsequent de novo lipid synthesis. This works demonstrates the potential of quantitative CARS microscopy as a label-free lipid analysis technique for any microalgal species, which is highly relevant for future biotechnological applications and to elucidate the process of microalgal lipid accumulation.

  13. Raman microspectroscopy for visualization of peripheral nerves

    Science.gov (United States)

    Minamikawa, Takeo; Harada, Yoshinori; Koizumi, Noriaki; Takamatsu, Tetsuro

    2013-02-01

    The peripheral nervous system plays an important role in motility, sensory, and autonomic functions of the human body. Preservation of peripheral nerves in surgery is essential for improving quality of life of patients. To preserve peripheral nerves, detection of ne peripheral nerves that cannot be identi ed by human eye or under white light imaging is necessary. In this study, we sought to provide a proof-of-principle demonstration of a label-free detection technique of peripheral nerve tissues against adjacent tissues that employs spontaneous Raman microspectroscopy. A line-illumination confocal Raman microscope was used for the experiment. A laser operating at the wavelength of 532 nm was used as an excitation laser light. We obtained Raman spectra of peripheral nerve, brous connective tissue, skeletal muscle, blood vessel, and adipose tissue of Wistar rats, and extracted speci c spectral features of peripheral nerves and adjacent tissues. By applying multivariate image analysis, peripheral nerves were clearly detected against adjacent tissues without any preprocessing neither xation nor staining. These results suggest the potential of the Raman spectroscopic observation for noninvasive and label-free nerve detection, and we expect this method could be a key technique for nerve-sparing surgery.

  14. Raman Spectra of Nanodiamonds: New Treatment Procedure Directed for Improved Raman Signal Marker Detection

    Directory of Open Access Journals (Sweden)

    Raoul R. Nigmatullin

    2013-01-01

    Full Text Available Detonation nanodiamonds (NDs have shown to be promising agents in several industries, ranging from electronic to biomedical applications. These NDs are characterized by small particle size ranging from 3 to 6 nm, while having a reactive surface and a stable inert core. Nanodiamonds can exhibit novel intrinsic properties such as fluorescence, high refractive index, and unique Raman signal making them very attractive imaging agents. In this work, we used several nanodiamond preparations for Raman spectroscopic studies. We exposed these nanodiamonds to increasing temperature treatments at constant heating rates (425–575°C aiding graphite release. We wanted to correlate changes in the nanodiamond surface and properties with Raman signal which could be used as a detection marker. These observations would hold potential utility in biomedical imaging applications. First, the procedure of optimal linear smoothing was applied successfully to eliminate the high-frequency fluctuations and to extract the smoothed Raman spectra. After that we applied the secondary Fourier transform as the fitting function based on some significant set of frequencies. The remnant noise was described in terms of the beta-distribution function. We expect this data treatment to provide better results in biomolecule tracking using nanodiamond base Raman labeling.

  15. Confocal Raman Microscopy

    CERN Document Server

    Dieing, Thomas; Toporski, Jan

    2011-01-01

    Confocal Raman Microscopy is a relatively new technique that allows chemical imaging without specific sample preparation. By integrating a sensitive Raman spectrometer within a state-of-the-art microscope, Raman microscopy with a spatial resolution down to 200nm laterally and 500nm vertically can be achieved using visible light excitation. Recent developments in detector and computer technology as well as optimized instrument design have reduced integration times of Raman spectra by orders of magnitude, so that complete images consisting of tens of thousands of Raman spectra can be acquired in seconds or minutes rather than hours, which used to be standard just one decade ago. The purpose of this book is to provide the reader a comprehensive overview of the rapidly developing field of Confocal Raman Microscopy and its applications.

  16. Raman Spectra of Glasses

    Science.gov (United States)

    1986-11-30

    17), Raman spectra, plus a , . theoretical treatment of the data, f complex fluorozirconate 14 I anions in ZBLAN glasses and melts (16), and...based ZBLAN glasses ) 17. ICORS (International Conference on Raman Spectroscopy) Proceedings, London, England. Conferencf 5-9 Sep 88. (Molten silica...RESEARCH FINAL REPORT DTIC CONTRACT N00014-81-K-0501 &JELECTE 1 MAY 81 -- 30 NOV 86 EJJAN041989 V "RAMAN SPECTRA OF GLASSES " 0 During the five years of the

  17. Characterization of Thalidomide using Raman Spectroscopy

    Science.gov (United States)

    Cipriani, Penelope; Smith, Candace Y.

    2008-02-01

    Thalidomide is a potent anticancer therapeutic drug whose mechanism of action has not yet been elucidated. In this report, experimental Raman spectroscopy is used to determine and characterize the vibrational frequencies of the drug. These normal modes are then compared to their quantum mechanical counterparts, which have been computed using density functional theory. Upon analysis of the spectra, we found that there was a high level of agreement between the wavenumbers. As such, this spectroscopic technique may be a viable tool for examining the way in which this drug interacts with its target molecules.

  18. Characterization of amino acids using Raman spectroscopy

    Science.gov (United States)

    Jenkins, Amanda L.; Larsen, Richard A.; Williams, Timothy B.

    2005-05-01

    A key process in the development of new drugs is elucidation of the interaction between the drug molecule and the target protein. Such knowledge then makes it possible to make systematic structural modifications of the drug molecule to optimize the interaction. Many analytical techniques can be applied to proteins in solution such as circular dichroism, ultraviolet, and fluorescence spectroscopy but these all have limitations. In this paper, we investigate the feasibility of using relatively simple, visible light Raman spectroscopic methods to investigate amino acids and related biopolymers.

  19. Shining light on neurosurgery diagnostics using Raman spectroscopy.

    Science.gov (United States)

    Broadbent, Brandy; Tseng, James; Kast, Rachel; Noh, Thomas; Brusatori, Michelle; Kalkanis, Steven N; Auner, Gregory W

    2016-10-01

    Surgical excision of brain tumors provides a means of cytoreduction and diagnosis while minimizing neurologic deficit and improving overall survival. Despite advances in functional and three-dimensional stereotactic navigation and intraoperative magnetic resonance imaging, delineating tissue in real time with physiological confirmation is challenging. Raman spectroscopy is a promising investigative and diagnostic tool for neurosurgery, which provides rapid, non-destructive molecular characterization in vivo or in vitro for biopsy, margin assessment, or laboratory uses. The Raman Effect occurs when light temporarily changes a bond's polarizability, causing change in the vibrational frequency, with a corresponding change in energy/wavelength of the scattered photon. The recorded inelastic scattering results in a "fingerprint" or Raman spectrum of the constituent under investigation. The amount, location, and intensity of peaks in the fingerprint vary based on the amount of vibrational bonds in a molecule and their ensemble interactions with each other. Distinct differences between various pathologic conditions are shown as different intensities of the same peak, or shifting of a peak based on the binding conformation. Raman spectroscopy has potential for integration into clinical practice, particularly in distinguishing normal and diseased tissue as an adjunct to standard pathologic diagnosis. Further, development of fiber-optic Raman probes that fit through the instrument port of a standard endoscope now allows researchers and clinicians to utilize spectroscopic information for evaluation of in vivo tissue. This review highlights the need for such an instrument, summarizes neurosurgical Raman work performed to date, and discusses the future applications of neurosurgical Raman spectroscopy.

  20. Design and analysis of new spectroscopic system of Raman lidar for detection of atmospheric water vapor∗%水汽探测拉曼激光雷达的新型光谱分光系统设计与分析*

    Institute of Scientific and Technical Information of China (English)

    王红伟; 华灯鑫; 王玉峰; 高朋; 赵虎

    2013-01-01

      提出并设计了一套新型的大气水汽和气溶胶探测用紫外域拉曼激光雷达系统,以二向色镜和超窄带滤光片构成高效率拉曼光谱分光系统,实现激光雷达大气回波信号中米-瑞利散射信号、氮气和水汽的振动拉曼散射信号的精细分离和高效率提取。利用美国标准大气的分子散射模型和实测的大气米散射信号模型,对分光系统的米-瑞利散射信号的抑制率、大气水汽测量的信噪比和误差进行数值仿真设计。搭建实验系统对西安地区夜间的大气水汽进行实验观测,并利用有云天气下实测的激光雷达回波信号,反演获得大气后向散射比和水汽混合比的相关特性,验证了该拉曼光谱分光系统对米-瑞利信号的抑制率达到10−7以上量级。理论和实验结果表明,设计的新型拉曼光谱分光系统可以在大气后向散射比为17时,实现水汽探测误差小于15%,满足拉曼激光雷达系统对大气水汽的高效率探测。%  A new ultraviolet Raman lidar system is proposed and developed for detecting atmospheric water vapor and aerosol study. The combination of dichroic mirrors and narrow-band interference filters is used as high-performance spectroscopic system to obtain the fine-separation and high-efficiency extraction of Mie-Rayleigh scattering signals, the vibrational Raman scattering signal of H2O and N2. By the American standard model and a set of atmospheric scattering signal model, the signal-to-noise ratio (SNR) and the water vapor measurement error are simulated and analyzed. The preliminary experiments are carried out at nighttime in Xi’an area for detecting the atmospheric water vapor and aerosols. Taking a set of the atmospheric returned signals measured under cloudy weather for example, the profiles of atmospheric backscatter ratio and water vapor mixing ratio are retrieved, and the SNR profiles of the three channels are discussed and