bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface‐enhanced resonance Raman study of avidin–dye interactions: A model for chromophore‐containing proteins
Authors: Ni Fan , Cotton Therese M. 
Published: May 2005

AbstractResonance Raman (RR) and surface‐enhanced resonance Raman (SERR) spectroscopy were used to study the behavior of 2‐(4′‐hydroxyphenylazo)benzoic acid (HABA) at different pH values (2.7–11.8) in solution and bound to avidin. Major changes in the RR spectrum of the dye are observed near pH 8.0 and 3.0. These pH values are close to the pKa values for the phenolic and carboxylic acid functional groups of HABA and reflect deprotonation of these groups. In addition, however, tautomeric forms of the dye are possible within each pH range and these can be identified from the characteristic vibrational modes of the azo and hydrazone forms of HABA. Similar changes in the SERR spectrum of HABA were also observed as a function of pH. However, a comparison of the RR and SERR spectra has shown that the tautomeric equilbrium is shifted toward the hydrazone form on the Ag surface compared with the effect in solution.The RR and SERR spectra of the HABA‐avidin complex are nearly identical and indicative of the hydrazone form of the dye. Hence the complex is not dissociated on the Ag surface. This finding is encouraging with regard to the application of SERR techniques to the study of native proteins containing chromophores.
Surface‐enhanced Raman scattering (SERS) from silver colloids of vanadate, phosphate and arsenate
Authors: Greaves Sarah J. , Griffith William P. 
Published: May 2005

AbstractSurface‐enhanced Raman scattering (SERS) of [HVO4]2−, [HPO4]2− and [HAsO4]2− has been studied on silver sol in H2O and 2H2O; in H2O the spectra were recorded from pH 3 to 12 with excitation at 488.0, 514.5, 568.2 and 647.1 nm. Considerable enhancement was observed compared with conventional Raman spectra, and deuteriation was observed to have no effect on the band positions in the SER spectra.
Raman scattering and phase transition in orthorhombic crystals of K3Mn(CN)6 and K3Cr(CN)6
Authors: Morioka Y. , Saito A. , Nakagawa I. 
Published: May 2005

AbstractIn the polarized Raman spectra of K3Mn(CN)6 and K3Cr(CN)6, soft modes are observed in both the roomtemperature and the low‐temperature phases. The frequencies of these modes decrease as the transition temperatures [205 K for K3Mn(CN)6 and 215 K for K3Cr(CN)6] are approached from both sides. Unambiguous spectroscopic evidence for the second‐order displacive phase transition was obtained on the basis of the soft mode behaviour in both crystals. High‐pressure Raman spectra of K3Cr(CN)6 were measured up to 35 kbar using a diamond anvil cell. A pressure‐induced phase transition occurs at ca 10 kbar.
Vibrational spectra of pyrazole and deuterium‐substituted analogues
Authors: Majoube Michel 
Published: May 2005

AbstractAccurate vibrational frequencies are reported for pyrazole and for seven N‐ and C‐deuterated analogues from FT‐IR spectra for the vapour phase at room temperature, diluted CCl4 solutions and polycrystalline solids and from Raman spectra in aqueous solutions. Several frequencies are reported for fundamentals not previously observed in the vapour phase in particular. Assignments were carried out by performing a normal coordinate analysis for in‐plane and out‐of‐plane modes, using either Urey–Bradley or general valence force fields. Great care was taken to determine a refined force constant set which agrees as far as possible with observed isotopic shifts. A detailed description of all the normal modes and atomic displacements for in‐plane modes is given.
The effect of excited state absorption of dimeric chlorophyll on the Raman spectrum of the solvent
Authors: Koningstein J. A. 
Published: May 2005

AbstractPulsed laser‐induced Raman spectra of dimeric chlorophyll α in the solvent hexane are reported where the wavelength of the exciting radiation is in resonance with the position of the Soret band of the solute. As a result of the occurrence of effective population saturation of nanosecond‐ and picosecond‐lived S1 and S3 excited states of the dimer, changes take place in the absorption spectrum of the irradiated part of the solution from which Raman emission of the solvent occurs. The intensity of the observed Raman bands of hexane of different shifts are influenced in a different way by the change in the transmission of the medium. A correlation is made of these changes and the said Raman intensities.
High‐pressure phonon behavior in ammonium halides
Authors: Scott J. F. 
Published: May 2005

AbstractThis note comments on the paper ‘High‐pressure Raman Study of Ammonium Halides’ [S.‐J. Jeon, R. F. Porter, and A. L. Ruoff, J. Raman Spectrosc. 19, 179 (1988)]. It is shown that their proposed degeneracy of ν1 and ν3 modes at high pressure is symmetry‐forbidden, but that a near degeneracy follows logically from the Urey–Bradley force model and plausible assumptions about the pressure dependence of force constants.
Resonance CARS spectroscopy of the ground and low‐lying excited electronic states of nickel octaethylporphin solution
Authors: Apanasevich P. A. , Kvach V. V. , Orlovich V. A. 
Published: May 2005

AbstractNanosecond time domain transient resonant CARS (RCARS) techniques have been used to investigate photophysical transformations of Ni‐octaethylporphin (Ni‐OEP) in tetrahydrofuran (THF) solution. For the first time the RCARS spectra have been obtained from the short‐lived (280 ps) low‐lying excited electronic state 3B1g, populated under the effect of intense resonant laser pulses. The amplitude‐polarization sensitive techniques of nondegenerate RCARS have been used to perform symmetry species assignments for the Raman‐active vibrational modes in the 1A1g and 3B1g electronic states. Only non‐totally symmetric in‐plane vibrations of the porphyrin skeleton with the b1g, b2g and a2g symmetry species in the D4h point symmetry group show up in the coherent scattering spectra under excitation within the visible Q absorption bands. The character of electronic resonance enhancement for the RCARS process has been studied when the excitation laser frequencies match one‐photon resonances with the frequencies of vibronic transitions between the 3B1g and 3Q″ excited states, and excitation and probing nondegenerate RCARS profiles have been measured for the Raman modes at 1562 and 1627 cm−1. It has been found that the Raman modes intensity in the RCARS spectra from the 3B1g state is borrowed from the Herzberg–Teller scattering when resonances with the 3B1g↔3Q″ transition take place. The data of the saturation degenerate RCARS experiments combined with the numerical analysis of the stationary rate equations for populations of the low‐lying electronic states made it possible to reveal the influence of the resonant radiation intensity on the RCARS efficiency.
Raman spectra of polymerized tetra‐n‐butoxy titanate formed on the surface of several types of silica gel
Authors: Shinoda Takako 
Published: May 2005

AbstractThe Raman spectra of polymerized tetra‐n‐butoxy titanate [pol‐Ti(OBu)4] formed on the surface of five different types of silica gel were studied. Characteristic peaks were found in the range 1000‐1200 cm−1 in all the spectra. The observed Raman spectra showed that the network structure of pol‐Ti(OBu)4 formed on the surface of silica gels, that is, the TiOTiO chain, seems to depend on the properties of the pores of the silica gels. The butoxy groups might be located in a state with a different degree of order. On the other hand, the catalysts which were prepared by using pol‐Ti(OBu)4 showed different photocatalytic activities.
Micro‐Raman analysis of pyrolytic graphite platforms used in atomic absorption spectrometry
Authors: Haley L. V. , Chakrabarti C. L. , Wu Shaole 
Published: May 2005

AbstractAn anisotropic pyrolytic graphite platform used in atomic absorption furnaces was probed with a Raman microscope. Raman spectra of the platform were obtained before heat treatment and after a specified number of thermal cycles. Results are related to the surface crystallite size by comparing the intensity ratio of the 1355 and the 1582 cm−1 bands. Two types of material were identified.
Raman studies of the vibrational dynamics and phase transitions in uranyl nitrate hexahydrate
Authors: Khulbe P. K. , Agarwal Anshu , Raghuvanshi G. S. , Bist H. D. , Hashimoto H. , Kitagawa T. , Little T. S. , Durig J. R. 
Published: May 2005

AbstractThe temperature‐dependent Raman spectra of crystalline uranyl nitrate hexahydrate, UO2(NO3)2 · 6H2O, are reported in the temperature range 15‐290 K. A group theoretically consistent assignment of the bands in terms of UO, NO3− and H2O vibrations is proposed. The temperature‐dependent studies of thermosensitive bands associated with these entities were used to study the previously reported phase transition at 140 ± 5 K and to detect another phase transition at 190 ± 5 K. The latter transition shows up prominently in the temperature‐dependent fluorescence studies and is also accompanied by a sharp increase in the Rayleigh scattering. The transition at 190 ± 5 K is triggered by the dynamics of H2O‐II and UO whereas that at 140 ± 5 K is associated with the dynamics of H2O‐II/NO3−. Both the transitions are of second order.
The origin of two new Raman bands in the surface‐enhanced Raman spectra of pyridine adsorbed on colloidal silver particles
Authors: Feng‐qi Yu , Chun‐ping Zhang , Guang‐yin Zhang 
Published: May 2005

AbstractTwo new broad and strong Raman bands in the surface‐enhanced Raman spectrum of pyridine adsorbed on colloidal silver particles were observed, one near 612 cm−1 and the other near 924 cm−1. It is concluded that these bands are caused by a boron compound in silver sol.
Vibrational analysis of substituted anisoles. II–Transferability of valence force constants
Authors: Lakshmaiah B. , Ramana Rao G. 
Published: May 2005

AbstractA zero‐order vibrational analysis of the in‐plane vibrations is made for m‐fluoro‐, o‐chloro‐, p‐chloro‐, o‐bromo‐and p‐bromo‐anisole, transferring the force constants from Part I. The observed and calculated frequencies agree with an average error of 13 cm−1, demonstration the transferability of the force field obtained in Part I. On the basis of the calculated potential energy distributions and eigenvectors, several assignments suggested by earlier workers have been revised.
Raman spectra of the tetrabutylammonium diiodoaurate(I) crystal, TBA‐AuI2, without I3− impurity bands
Authors: Ohtsuka Itaru , Nakayama Hideyuki , Ishii Kikujiro 
Published: May 2005

AbstractRaman spectra of carefully purified (n‐C4H9)4N+ AuI2− (TBA‐AuI2) were measured between 89 K and room temperature. The bands observed around 110 cm−1 in one of the previously reported spectra are ascribed to I3− impurity. Spectra of TBA‐AuI2 and TBA‐I3 were compared, and the principal bands assigned. The resonance Raman effect of I3− makes its Raman bands prominent in the impure TBA‐AuI2 samples. The crystal symmetries of the above two salts at low temperature are briefly discussed.
Non‐resonant background suppression in preresonance CARS spectra of flavin adenine dinucleotide: Demonstration of a background suppression technique using phase mismatching and comparison with the polarization‐sensitive CARS technique
Authors: Scholten T. A. H. M. , Lucassen G. W. , Koelewijn E. , De Mul F. F. M. , Greve J. 
Published: May 2005

AbstractPolarization‐sensitive CARS spectra of a 5.7 × 10−3 mol dm−3 flavin adenine dinucleotide (FAD) solution were recorded under preresonance conditions at a pump wavelength of 532 nm. The depolarization ratios of the vibrations are shown to be close to the depolarization ratio of the non‐resonant background. This results in a severe reduction of the vibration resonant signal (a factor of 700‐900) in the polarization CARS spectrum, and a poor improvement in the ratio of the resonant signal and the non‐resonant background (<10).In this context, a non‐resonant background suppression technique is discussed and demonstrated for 5.7 × 10−3 and 1.4 × 10−3 mol dm−3 FAD solutions excited at 532 nm; the non‐resonant susceptibility of the walls of the cuvette, which contains the FAD solution, is used to compensate the non‐resonant signal contribution of the solution. An improvement in the signal‐to‐noise ratio of ca. 50 is achieved at the cost of a factor of 30 in the resonant signal strength. Lorentzian‐shaped spectral bands are obtained, facilitating the determination of band position, width and intensity. Line shape parameters and depolarization ratios for FAD are extracted from the presented spectra by curve fitting. The signal strength and background suppression achieved with these techniques and the resonance CARS technique (at a pump wavelength of 480 nm) are compared and discussed.
Laser Raman and infrared spectra of dipotassium tartrate hemihydrate
Authors: Bhattacharjee R. , Jain Y. S. , Bist H. D. 
Published: May 2005

AbstractA systematic analysis of the IR and Raman spectra of dipotassium tartrate hemihydrate (K2C4H4O6 · ½H2O) in terms of the standard frequency correlations, deuteration shift and typical nature (with respect to intensity and width) of bands due to different modes is reported. The bands due to the internal modes (excluding some skeletal modes) of the C4H4O ion appear as doublets. For certain modes (e.g. βCH, νC(OH) and δCOO), doublets arise due to interaction between two identical oscillators of two identical groups in COO(HO)HCCH(OH)COO2−, whereas for other modes (e.g. νCH, ν, ν, δCOH, and τCOO) they arise due to crystallographically distinguishable sites for two identical oscillators.
Vibrational spectra of some crown ether complexes of manganese(II) halides
Authors: Li Hongqi , Jiang Tian‐lai , Butler Ian S. 
Published: May 2005

AbstractThe FT‐IR and Raman spectra of six 1 : 1 complexes produced by reaction of 1,4,7,10‐tetraoxacyclotetradecane [12‐crown(4)], 1,4,7,10,13‐pentaoxacyclopentadecane [15‐crown(5)] and 1,4,7,10,13,16‐hexaoxacyclooctadecane [18‐crown(6)] with MnX2 (X = CL, Br) were recorded in the solid state. Vibrational assignements are proposed for the major bands observed in the spectra of these new crown ether complexes, especially the antisymmetric and symmetric COC stretching modes in the 1200–800 cm−1 region and the MnO and MnX stretching vibrations in the region below 400 cm−1. Probable structures of these complexes are also discussed.
Raman study of phosphate dimerization in aqueous KH2PO4 solutions using a self‐deconvolution method
Authors: Rull F. , Del Valle A. , Sobron F. , Veintemillas S. 
Published: May 2005

AbstractA Raman spectroscopic study of aqueous solutions of KH2PO4 as a function of concentration and temperature has been made. Attention is focused on the analysis of the bands arising from the internal modes of the H2PO4− anions. The band profile of these internal modes has been analysed by a Fourier transform self‐deconvolution method which allowed quantitative information about phosphate dimerization to be obtained. The results seem to indicate the existence of two different configurations for the dimers. The association constant for each dimer and their thermodynamic parameters were obtained from the spectroscopic data.
Vibrational spectra of thallium and rubidium phosphotellurates
Authors: Philip Daizy , Aruldhas G. 
Published: May 2005

AbstractRaman and infrared spectra of Te(OH)6 · 2TlH2PO4 · Tl2HPO4, Te(OH)6 · 2TlH2PO4 and Te(OH)6 · RbH2PO4 · Rb2HPO4 have been recorded and analysed. It is found that hydrogen atoms are strongly bonded to the oxygen atoms of the PO4 tetrahedron forming HPO and H2PO4− ions. Vibrational coupling between the internal modes of HPO and H2PO4− ions is observed in Te(OH)6 · 2TlH2PO4 · Tl2HPO4 and Te(OH)6 · RbH2PO4 · Rb2HPO4. It is found that the TeO6 ion is not occupying a centrosymmetric site in Te(OH)6 · 2TlH2PO4.
Infrared and Raman spectra of bis(fluorocarbonyl) disulphide, [FC(O)]2S2
Authors: Ulic S. E. , Védova C. O. Della , Aymonino P. J. 
Published: May 2005

AbstractIR data for gaseous, liquid, solid and matrix isolated bis(fluorocarbonyl) disulphide together with the Raman spectrum of the liquid suggest the existence of two planar conformers (I and II) in equilibrium in the gaseous phase and of a planar one and other conformers of undetermined structure in the other neat phases. Wavenumbers reported for the vibration of conformer I are used to calculate an approximated force field.
Etude par Microscopie Raman de la Couche Liquide Située au Contact d'un Cristal en Cours de Dissolution dans sa Solution Mère: Systèmes LiNO3H2O et KNO3H2O
Authors: Koussinsa F. , Bertin F. , Bouix J. 
Published: May 2005

AbstractThe composition of the dissolution layer of LiNO3 and KNO3 crystals in their respective unsaturated mother liquors was studied by Raman microscopy coupled with a multi‐channel acquisition of data. Preliminary examination of homogenous solutions at various concentrations of LiNO3 and KNO3 revealed the existence of individual Raman bands assigned to different solvated species, namely free aquated ions, solvent‐separated ion pairs and/or contact ion pairs. Weak bands due to a small amount of aggregates (LiNO3)n or (KNO3)n were also identified. Spectral parameters of each individual band were calculated. Raman spectra of dissolution layers recorded at different steps of the crystal dissolution revealed considerable reinforcement of aggregates and contact ion pair concentrations compared with that existing in the bulk of the unsaturated mother liquors. The aggregate concentration in the dissolution layer was found to be even higher than that calculated for the corresponding saturated solution. The behaviours of LiNO3 and KNO3 were shown to differ considerably.
Raman studies of NiX2 · 6H2O and FeCl2 · 4H2O
Authors: Cariati F. , Masserano F. , Martini M. , Spinolo G. 
Published: May 2005

AbstractThe Raman spectra of NiCl2 · 6H2O, NiBr2 · 6H2O and FeCl2 · 4H2O single crystals were measured in the range 50–3600 cm−1 at liquid nitrogen temperature. A new assignment of the lattice water translations in the two hexahydrates was made and the metal‐halogen stretching mode was identified. A comparison with recent IR data provided a good characterization of the water libration region. Some proposals for discriminating between the lattice water modes and the coordinated water modes are given for the water internal modes (bending and stretching).
Raman scattering from sapphire fibers
Authors: Jia Weiyi , Yen W. M. 
Published: May 2005

AbstractAn index matching technique for Raman scattering from sapphire fibers is presented; the technique is shown to be effective in suppressing the stray laser background and leads to an improved signal‐to‐noise ratio of the Raman signal. Red shifts of phonon frequencies for bothA1gandEgsymmetry modes were observed under tensile uniaxial stress parallel to thecaxis. The unexpected shifts of theEgmodes may be attributable to effects due to restricted dimensions.
Quenching of stimulated Raman scattering by two‐photon absorption in fuels
Authors: Golombok M. , Bergin F. J. , Pye D. B. 
Published: May 2005

AbstractThere is renewed interest in stimulated Raman scattering in organic liquids because of its potential for droplet sizing in fuel sprays. Contrary to the accepted theories, we observed gain on more than one line simultaneously. In all but the simplest aromatics multiple lines are observed and some expected lines are missing. Absorption spectra suggest that two‐photon absorption could quench the expected Raman signal. A model using real values of two photon cross‐sections shows that in polyaromatics, these are a source loss term for the Raman signal. The resulting disperion in the loss profile leads to gain on the CH stretch rather than the ring breathing mode predicted from the spontaneous spectrum.
Resonance Raman spectra and normal modes of vibration of 2,2′‐bipyridine anion radicals
Authors: Danzer Gerald D. , Golus Janusz A. , Strommen Dennis P. , Kincaid James R. 
Published: May 2005

AbstractThe resonance Raman spectra of the lithium complexes of the 2,2′‐bipyridine anion radical and five isotopically labeled analogues, including the 15N‐labeled species, are reported. All of the fundamental modes of vibration, excluding the CH stretching and several low‐frequency modes, have been identified. Care must be taken to avoid contamination of the sample with the dianion Li2bpy. In order to eliminate possible misassignment of bands to traces of Li2bpy, the spectra of the latter species were also investigated. The assignments of the vibrational frequencies to the fundamental modes of Libpy are supported by a normal coordinate calculation and the structural implications of the vibrational frequency shifts, relative to the neutral parent, are discussed.
Fourier transform Raman and infrared vibrational study of diazepam and four closely related 1,4‐benzodiazepines
Authors: Neville G. A. , Shurvell H. F. 
Published: May 2005

AbstractFourier transform Raman and infrared spectra have been recorded of diazepam (7‐chloro‐1,3‐dihydro‐1‐methyl‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐one) and four compounds with closely related structures. These compounds are all 7‐chloro‐1,3‐dihydro‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐ones and differ only in the nature of the substituent (R) at N‐1. The five compounds are nordazepam (R  H), diazepam (R  CH3), pinazepam (R  CH2 CCH), halazepam (R  CH2 CF3) and prazepam (R  cyclopropylmethyl). Prominent features of the infrared and Raman spectra have been assigned to functional groups of the parent structure and the substituent groups. The spectra of nordazepam suggest that the compound exists as a centrosymmetric cyclic dimer in the solid state. Complete tabulations of the observed wavenumbers of the five molecules are given. The spectra provide a means of identification of these drugs.
Surface‐enhanced Raman spectroscopy of biomolecules. Part II. Application of short‐ and long‐range components of SERS to the study of the structure and function of membrane proteins
Authors: Nabiev I. R. , Chumanov G. D. , Efremov R. G. 
Published: May 2005

AbstractSurface enhanced Raman (SER) spectra of bacteriorhodopsin (BRh) in the purple membranes of Halobacterium halobium, rhodopsin (Rh) in the photoreceptor dises of rod outer segments and complexes of Rh with monoclonal antibodies and photoreceptor dises closed with the cytoplasmic surface inwards were analysed. After adsorption of the membrane proteins on silver electrodes treated via an oxidation‐reduction cycle (ORC) and on unaggregated silver hydrosols with a mean particle diameter about 15 nm, the short‐range enhancement mechanisms was shown; it may be used to study the topography of the membrane‐bound complexes. In this case adsorption prevents photoinduced conformational transitions of the pigments. If the BRh or Rh molecules are adsorbed on partially aggregated hydrosols with a characteristic particle size aout 100 nm or on “smooth” (i.e. not roughened by the ORC) electrodes, the SERS mechanism has a longer range character. Hence it is possible to detect SER spectra which are similar to those obtained in solution but at concentrations two to three orders of magnitude lower. Under such conditions adsorption does not influence photochemical transformations of bacterial and visual rhodopsins. The potential variation on the “smooth” electrode near the zero charge for silver is accompanied by accumulation of K610, the kinetic intermediate of the BRh photocycle. At the same time, the content of the main form, BRh570, decreases.
Investigations of vibronic transitions by resonance CARS
Authors: Kircheva P. P. , Simeonov S. D. 
Published: May 2005

AbstractThe influence of thermally excited vibrations on vibronic spectra (absorption, CARS excitation profile and resonance background) has been modelled for polyatomic molecules in solution. It is shown that for a model describing some polymethine compounds, the spectra depend only slightly on temperature except in the case of a resonance background and an excitation profile of vibrations with a relatively high value of the origin shift parameter (Δ > 1). The investigations of low‐frequency vibrations by resonance CARS to giving information about some molecular parameters is proposed.