bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface‐enhanced resonance Raman spectroscopy of highly fluorescent complexes
Authors: Chambers Jeffrey A. , Buck Richard P. 
Published: May 2005

AbstractSurface‐enhanced resonance Raman (SERR) spectra of a series of highly fluorescent complexes of ruthenium(II), 2,2′‐bipyridine and 1,10‐phenanthroline are presented. The effect of applied potential on the SERR spectra is discussed. SERR spectra of mixed ligand complexes can be predicted from weighted averages of spectral features for the tris complexes.
Pressure dependence of the Raman spectra of LiNbO3 and LiTaO3
Authors: Mendes‐Filho J. , Lemos V. , Cerdelra F. 
Published: May 2005

AbstractThe pressure dependence of the room‐temperature Raman spectrum of LiNbO3 and LiTaO3 in the range 1 bar‐80 kbar is reported. The studies were confined to the transverse optical modes, since these are the modes which could be involved in the ferroelectric‐paraelectric phase transition occurring in both materials at high temperatures. All mode frequencies increase linearly as the pressure increases and no distinctive behaviour is observed in the lowest frequency A1 (TO) modes, identified by some workers as soft modes.
Raman and infrared spectra and normal coordinate analysis of the molecular adducts H3NGaX3 and H3PGaX3 (X = Cl or Br)
Authors: Taylor Michael J. , Riethmiller Steven 
Published: May 2005

AbstractThe preparation of 1 : 1 molecular adducts H3NGaX3 and H3PGaX3 (X = Cl or Br) is described. The IR (40–4000 cm−1) and Raman (50–3500 cm−1) spectra of these compounds have been recorded and 11 of the 12 fundamental vibrations are assigned on the basis of C3ν molecular symmetry. A force field of seven valence force constants and three or four interaction constants is utilized in calculating the frequencies and potential energy distributions. Changes in NH3 and PH3 frequencies and force constants are consistent with structural changes upon coordination. Modes of GaN stretching, 480–500 cm−1, and GaP stretching, 280–305 cm−1, are assigned and force constants k(GaN) = 1.85−2.0 mdyn Å−1 and k(GaP) = 1.0–1.2 mdyn Å−1 are obtained. Normal modes of vibration of the ammonia adducts are nearly pure but some coupling is found between gallium‐phosphorus and gallium‐halogen stretches in the case of the phosphine adducts.
Analyse Vibrationnelle et Structurale des Acides Cyclobutanedicarboxyliques‐1,2‐cis et ‐trans et de Leurs Sels de Potassium en Solution Aqueuse
Authors: Fabrégue Eliane , Cassanas Geneviève , Bardet Lucette 
Published: May 2005

AbstractLes spectres Raman et infrarouge des acides cyclobutanedicarboxyliques‐1,2‐cis et ‐trans en solution aqueuse et de leurs sels de potassium ont été analysés. L'absence de symétrie est en faveur d'une conformation plissée pour tous les composés. Une attribution des fréquences de vibration est proposée.
Carbon association of surface‐enhanced Raman scattering (SERS) by pyridine on gold electrodes: A Raman and Auger spectroscopic study
Authors: Mernagh Terrence P. , Cooney Ralph P. , Spink John A. 
Published: May 2005

AbstractSurface‐enhanced Raman scattering (SERS) by pyridine on gold electrode surfaces to arise from the adsorption of pyridine in or on surface carbon present after the oxidation‐reduction cycle (ORC). Similar Raman ring‐breathing mode spectra for both gold and silver electrodes and sols indicate a common intensely scattering phase which is independent of the metal substrate. The common phase proposed is [carbon‐pyridine]. Auger electron spectroscopy indicates that the SERS spectrum arises from a surface microzone having a C to Au ratio of ca 7. Cathodic elimination of microzone carbon results in the elimination of pyridine SERS. Carbon‐enriched (sputtered) gold surfaces exhibit the same ring‐breathing mode pattern as for the conventional SERS surface. Laser carbonization effects are suggested by differences in the SERS intensities observed for the presence and absence of laser flux during the ORC. Laser decarbonization appears to be the origin of the characteristic decay of SERS from gold electrodes. It is proposed that the decay is instantaneous for 514.5 nm Ar+ excitation and slower for 647.1 nm Kr+. Differences in pyridine SERS intensities from silver and gold electrodes are attributed to differences detected by Auger spectroscopy in the extent of laser microzone carbonization. On the basis of these findings Au/pyridine SERS has been classified as Type I.
Resonance CARS spectrum of the short‐lived dimethyl terephthalate Anion radical
Authors: Werncke W. , Weigmann H.‐J. , Lau A. , Tschol Tschö Jong , Dat T. P. 
Published: May 2005

AbstractResonance coherent anti‐Stokes Raman scattering was used to obtain vibrational spectra of the short‐lived dimethyl terephthalate anion radical. Changes in the double bond character of the carbonyl group were clearly observed in the CARS spectrum.
Raman studies of orientational disorder in crystals: The hexamethylethane plastic phase, T> Tc=152 K
Authors: Gharbi H. , Sauvajol J. L. , Fontaine H. , More M. 
Published: May 2005

AbstractRaman spectra of some bands in the plastic phase of hexamethylethane have been recorded as a function of temperature. Interesting features related to the molecular reorientations and librations have been derived from the band shape analysis of F2g and Eg low‐frequency spectra. A novel temperature dependence of the libration width has been observed. The analysis of the internal modes' bandwidths at ν1 = 878 cm−1 and ν2 = 475 cm−1 provides consistent results for the monomolecular reorientational dynamics.
Extended measurement and assignment of isotropic Raman transitions in the ν1 region of 12CD4
Authors: Lolck Jens‐Erik , Owyoung Adelbert , Esherick Peter 
Published: May 2005

AbstractThe isotropic Raman spectrum of 12CD4 is presented in the range from 2101 to 2113 cm−1, thus covering the ν1(A1) Q‐branch and part of the ν2 + ν4(F1 + F2) Q‐branch. Experimental results for the 2101‐2108 cm−1 range were obtained using the ‘inverse Raman spectroscopy’ technique and have been published previously. New measurements in the 2108 cm−1‐2113 cm−1 range were obtained using the very similar ‘stimulated Raman gain spectroscopy’ technique. In both spectra the resolution is limited by the Doppler width of the lines. Formally, only transitions to the upper state of the ν1 band are allowed in isotropic Raman scattering, but strong resonances enhance transitions to the upper state of ν2 + ν4. An effective Hamiltonian which takes these resonances into account was used to interpret the spectra and led to the assignment of all significant lines. In all, 165 Raman transitions were assigned, and these transitions are fitted by the model Hamiltonian with a standard deviation of 0.008 cm−1.
Infrared and Raman spectra of trichloromethanesulphenyl bromide and its reactions with some inorganic halides
Authors: Mazzieri M. R. , Della Védova C. O. , Cutín E. H. , Varetti E. L. , Aymonino P. J. 
Published: May 2005

AbstractThe infrared and Raman spectra of liquid and the infrared spectrum of solid CCl3SBr have been obtained. It was observed that CCl3SBr reacts both with infrared windows made of CsI and with powdered KI, producing CSCl2, and that it also reacts with AgCl windows giving CCl3SCl as a gaseous product.
Vibrational spectrum and normal coordinate analysis of CX3CO2NX4(X=H or D)
Authors: Kanesakar Isao , Tanbo Hironori , Kawahara Hisakazu , Kawai Kiyoyasu 
Published: May 2005

AbstractThe vibrational spectrum of ammonium acetate at room temperature and 77 K is reported. The observed factor group splitting between four acetate ions is slight in each internal mode. The normal coordinate analysis is carried out under the assumption of neglect of hydrogen atoms. Good agreement between observed and calculated frequencies is obtained for the lattice vibrations. It is clarified that the hydrogen bond has considerable strength and a very strong Raman band at 58 cm−1 in CH3CO2NH4 is a libration of the acetate ion about an axis perpendicular to the molecular plane. The strong IR band at 260 cm−1 in CH3CO2NH4 is discussed.
Effect of electrolytes on the Raman bands of dimethylformamide and acetone
Authors: Thyagarajan G. , Gurunadham G. , Dhamejani R. 
Published: May 2005

AbstractThe CO stretching Raman bands of dimethylformamide and acetone have been studied for the pure liquids and for solutions of alkali metal halides and perchlorates in these liquids. An enormous reduction in the intensity of these bands was found in the presence of the perchlorate ions, especially in the case of dimethylformamide. In each case a new band appears in the CI–O stretching region of the perchlorate. The results indicate the formation of stable complexes between the organic molecule and perchlorate ion through the CO bond.
Vibrational spectra and symmetry of 3,3,6,6‐tetramethylcyclohexa‐1,4‐diene
Authors: Sjøgren Carl E. , Kloster‐Jensen Else , Nielsen Claus J. 
Published: May 2005

AbstractThe vibrational spectra of 3,3,6,6‐tetramethylcyclohexa‐1,4‐diene as a vapour, a liquid, a crystalline solid and isolated in argon and nitrogen matrices at 13K have been recorded and interpreted in terms of a planar ring structure (D2h). The fundamental modes of vibration have been assigned with the aid of a normal coordinate calculation and by comparison with the spectra of cyclohexa‐1,4‐diene.
Surface enhanced resonance Raman study on fluorescein dyes
Authors: Hildebrandt Peter , Stockburger Manfred 
Published: May 2005

AbstractFluorescein and its derivatives fluoresceinamine and diiodofluoresceiniodoacetamide have been studied by surface enhanced resonance Raman spectroscopy (SERRS). Adsorption of the dyes at the silver/electrolyte interface requires attractive interactions between polar side groups (such as NH2, OH and COOH) with the metal as a prerequisite for Raman enhancement and fluorescence quenching. It was possible to characterize two prototropic forms of fluorescein and fluoresceinamine by their SERR spectra. Only vibrations of the chromophoric part (xanthene) of the molecule contribute to the measured spectra. Substituents in the phenyl ring influence only the ability of adsorption and the structure of the adsorbed molecules.
Raman scattering by polaritons in Ti:LiNbO3 waveguides
Authors: Langbein U. , Lederer F. , Ponath H.‐E. , Trutschel U. 
Published: May 2005

AbstractA general theory of Raman scattering in piezoelectric slab waveguides is presented. If the anisotropy of the uniaxial waveguide material is sufficiently large, incident slab‐guided waves can be scattered by polaritons of the upper branch of the polariton dispersion curve. The angular dependence ω2(θ) of the scattered‐wave frequency has been calculated in detail, for both y‐ and z‐cut Ti:LiNbO3 waveguides in the polariton frequency range ωp=900–5160 cm−1 (pump wavelength 4880 Å). The detection of weak proton vibrations within the strong polariton Raman spectrum of proton‐exchanged Ti:LiNbO3 waveguides is discussed.
Raman spectroscopic and X‐ray diffraction study of Na2Se·9(H, D)2O and comparison between OH(D)…︁Se and OH(D)…︁S hydrogen bonds
Authors: Derkosch J. , Mikenda W. , Baumgartner O. , Mereiter K. , Preisinger A. 
Published: May 2005

AbstractRaman spectroscopic (75 K) and X‐ray crystal structure (135 K) data for Na2Se·9(H, D)2O and Na2S·9(H, D)2O are compared, paying particular attention to the hydrogen bond networks in the two isostructural compounds. The crystal structures differ essentially only with respect to the hydrogen bond lengths of corresponding OH…︁Se and OH…︁S bonds, those to Se being uniformly larger by about 0.1 Å than those to S. The uncoupled νOD frequencies of isotopically dilute HOD molecules are very similar in both compounds, being larger only by about 10 cm−1 on average for the selenide than for the sulphide. It can therefore be claimed that the hydrogen‐bond capabilities of the selenide and the sulphide ions are almost equal.
Pulse shapes of Raman and Rayleigh scattering
Authors: Morozov V. A. , Shorygin P. P. 
Published: May 2005

AbstractThe expressions for the pulse shapes of secondary radiation in the frequency range of Rayleigh scattering and resonance fluorescence and in the range of Raman scattering and shifted resonance fluorescence are obtained on the basis of the quantum treatment of transformation of light pulses, the resonance conditions for Raman and Rayleigh scattering being considerably different. The characteristic cases of different pulse shapes of Raman and Rayleigh scattering are considered for the condition when the molecules are irradiated by light pulses which are shorter then the lifetime of the excited state of the molecule and are weak enough not to result in saturation.
New results in incommensurate crystals: Kink diffusion and long‐period lock‐in phases
Authors: Scott J. F. 
Published: May 2005

AbstractTwo new results for incommensurate phases of crystals are discussed: the experimental observation of a q2 dependence of the inverse relaxation time observed in the hypersonic regime via near‐forward Brillouin scattering experiments, tentatively interpreted as kink diffusion, and the theoretical demonstration that long‐period lock‐in phases observed in crystals which are simultaneously ferroelectric in their incommensurate phases are stabilized by the spontaneous polarization field. This theory explains the observed limits of incommensurate wave vector in BaMnF4 as a function of temperature: 2a*/5 = 0.399a*–0.389a* = 5a*/13, where the 2/5 value is the low‐temperature limit and the 5/13 value is the high‐temperature limit. It also explains one mechanism for stabilizing the 2/5 phase at lower temperatures than are permitted in the ANNNI (axial next‐nearest neighbour Ising) model of Yamada and Hamaya in the absence of a spontaneous polarization field.
OH torsion of some chlorophenols
Authors: González‐Díaz P. F. , Sigüenza C. 
Published: May 2005

AbstractThe νt(OH) and νt(OD) torsional modes in some chloro‐substituted derivatives of phenol were assigned from their Raman spectra in CS2 solution. The corresponding rotation barriers were then calculated by means of a rigorous optimization method. Some theoretical calculations have allowed an extension of the discussion to the vapour phase.
Étude Raman des Verres xB2O3(1–x)GeO2 avec 0<x<1
Authors: Beys Louis , Hillaire Paul , Assih Toyi , Phalippou J. 
Published: May 2005

AbstractL'étude Raman des verres de la série xB2O3(1–x)GeO2 obtenus par fusion a été rélisée pour des poucentages molaires en B2O3 compris entre x = 0.2 et 0.9. L'apparition de raies, inexistantes dans les spectres des deux constituants purs, est la principlae catactéristique des spectres enregistrés. En particulier, les bandes de fréquences 720 et 1060 cm−1 sont attribuées à des liaisons GeOB. La premiére, apparaissant en měme temps que la raie 808 cm−1 caractéristique des groupements boroxols, correspond à une liaison GeOB dans laquelle B appartient à un groupement boroxol; la seconde à une liaison de měme type dans laquelle B est à I'intérieur d'un groupement triangulaire BO3. La variation d'intensité de ces raies en fonction de x permet de suivre l'évolution des proportious relatives de triangles et de groupements boroxols.
Laser Raman study of phase transformation in single crystals of cadmium fluorotitanate hexahydrate
Authors: Thakur Ganesh , Verma A. L. 
Published: May 2005

AbstractA detailed temperature‐dependent Raman study of oriented single crystals of CdTiF6·6H2O down to 10 K was carried out in the regions of internal vibrations and lattice modes. The line width, frequency shift and intensities of the modes associated with the [Cd(H2O)6]2+ and [TiF6]2− octahedra show abrupt changes at temperatures around 200 and 80 K, respectively, and many doubly degenerate modes split into two components. These studies suggest that this system undergoes two structural phase transitions at 200 and 80 K. A mechanism for these phase transitions is suggested.
Surface chemistry of MoO3γ‐Al2O3 catalysts studied by laser Raman spectroscopy: Hydration and dehydration reactions and generalization to other supported systems
Authors: Payen E. , Kasztelan S. , Grimblot J. , Bonnelle J. P. 
Published: May 2005

AbstractThe Raman spectra of supported molybdena‐alumina catalysts are reversibly modified by changing the laser power falling on the sample, which was examined in air. O2 calcination or evacuation at 500–700°C produces the same modification if in situ characterization is performed. Subsequent contact with the ambient atmosphere restores the original spectra. The shift from 950 to 1000 cm−1 of the main Raman line assigned to the MoO (t) stretch is interpreted as a reversible dehydration of the supported molybdate. Dehydration of the catalysts appears to be easier when a promoter is present. In agreement with Iiterature observations, this hydration phenomenon can be generalized to other supported systems such as WO3γ‐Al2O3 and V2O5γ‐Al2O3. The OH groups present on the supported polymolybdate or polytungstate have a Brönsted acidity as shown by pyridine chemisorption.
Darstellung, Schwingungsspektrum und Normalkoordinatenanalyse des Gold‐ortho‐Thiophosphates, AuPS4
Authors: Pätzmann U. , Brockner W. , Cyvin B. N. , Cyvin S. J. 
Published: May 2005

AbstractAuPS4 has been prepared and characterized by vibrational spectroscopy, differential thermal analysis and chemical analysis. The frequencies are tentatively assigned. A polymer chain structure is proposed. Normal coordinate analyses have been carried out for different fragments of the AuPS4 chain. PED calculations show strong v(AuS) and δ(SPS) couplings and remarkably high AuS frequencies.
Resonance Raman spectrum of the 4, 4′‐bipyridine radical anion
Authors: Kihara Hayato , Gondo Yasuhiko 
Published: May 2005

AbstractResonance Raman, ESR and visible absorption spectra have been observed at room temperature for the 4, 4′‐bipyridine radical anion in tetrahydrofuran and for 4, 4′‐bipyridine adsorbed on metallic potassium. Based on the quinoid structure of the radical anion, as predicted by the MO theory, a normal coordinate analysis has been carried out. The relative Raman intensities have also been calculated satisfactorily for the totally symmetric modes of the radical anion. Thus, the main Raman bands are interpreted in terms of the molecular structure change caused by the resonant electronic transition in the visible region. The results are compared with those of the biphenyl radical anion, 2,2′‐bipyridine radical anion and the methylviolegen radical cation reported in the literature.
Intensity measurement of resonance Raman spectra of dye solutions with the divided Raman cell
Authors: Tsukamoto Ikuko , Nagai Hisako , Machida Katsunosuke 
Published: May 2005

AbstractThe resonance Raman intensities of methyl orange and brilliant blue FCF in aqueous solutions were measured by using a rotating divided Raman cell which provides an external intensity standard. The logarithms of the apparent intensities of the sample bands revealed a good linear dependence on the light path length. The relative Raman scattering coefficients of the samples with respect to a common reference band were determined from the intercepts. The effects of the excitation wavelength and the presence of surfactant on the apparent Raman intensities and the relative Raman scattering coefficients are discussed.
Vibrational spectra of cyclopropyl cyanide and cyclopropyl cyanide‐α‐d1
Authors: Green P. M. , Wurrey C. J. , Krishnamoorthi R. , Yeh Y. Y. 
Published: May 2005

AbstractRaman spectra of cyclopropyl cyanide‐α‐d1 (CPCN‐d) in its condensed phases have been recorded for the first time, along with the solid‐phase Raman spectrum of the parent compound, cyclopropyl cyanide (CPCN). In addition, liquid‐ and solid‐phase infrared spectra were obtained for the isotopic derivative, and gas‐phase Fourier transform infrared spectra were obtained for both compounds. The data for CPCN‐d, combined with information deduced from gas‐phase infrared band contours and Raman depolarization ratios, enable vibrational assignments to be proposed for 47 of the 48 normal modes of these two molecules. Strong mixing of several modes in CPCN is revealed by the deuterium labeling, and evidenc for self‐association in the condensed phases is discussed. The vibrational frequencies and assignments are compared with similar results for other cyanide‐ and halogen‐substituted cyclopropanes.
Characterization of some derivatives of ferrocene and (η6‐benzene)tricarbonylchromium(0) by micro‐Raman spectroscopy
Authors: Butler Ian S. , Harvey Pierre D. , Allen Geoffrey C. 
Published: May 2005

AbstractThe micro‐Raman spectra of eight ferrocene derivatives [CpFeCp′; Cp; Cp = η5−C5H5, Cp′= η5−C5H4R where R = C(O)Me, C(O)Ph, C(O)CH2Ph, etc.] and three (η6‐C6H5R)Cr(CO)3 complexes have been recorded for the solids at room temperature in order to demonstrate the applicability of this new spectroscopic technique to organometallic complexes. Much lower laser powers than are normally used for Raman measurements have proved possible (0.5–3 mW at the samples) because of the high collection efficiency of the microscope optics and the multiscanning capability of the spectrometer. Raman spectra can now be obtained for materials earlier thought to be too unstable to survive the long periods of continuous laser irradiation necessary. Some vibrational assignments are proposed for the organometallic complexes examined.
Spectra and structure of phosphorus–boron compounds. XXIII–Raman and infrared spectra, vibrational assignment and normal coordinate analysis of methyldifluorophosphineborane
Authors: Odom J. D. , Stanley A. E. , Cheng Mei‐Shiow , Durig J. R. 
Published: May 2005

AbstractThe Raman (3500−10 cm−1) and infrared (3500−20 cm−1) spectra of CH3PF2BH3 and CH3PF2BD3 were recorded for the gaseous and solid states. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were measured. All the fundamental modes except the two internal rotations were assigned utilizing band contours, depolarization values, isotopic shifts and group frequencies. A normal coordinate calculation was carried out utilizing a modified valence force field to calculate the frequencies and the potential energy distributions. The observation of five Raman lines in the spectrum of the solid, and the observation of the doubling of several of the intramolecular fundamentals, indicate that there are at least two molecules per primitive cell. These results are compared with similar quantities in some corresponding molecules.
Raman tensors for the 1614 and 633 cm−1 modes of bis(2‐hydroxyethyl) terephthalate
Authors: Lewis E. L. V. , Bower D. I. 
Published: May 2005

AbstractRaman spectroscopy has been used extensively over the last 12 years in the study of molecular orientation in polymers and liquid crystals. It has become increasingly clear that fundamental information about the anisotropy of the Raman scattering from molecules is needed, including its dependence on internal field effects. This paper reports the results of a study of the Raman scattering due to two benzene ring modes in a single crystal of a model compound for poly(ethylene terephthalate) (PET). The ratios of the observed scattered intensities for various scattering geometries and polarizations have been corrected in several alternative ways for internal field effects, before being used to evaluate the ratios of the Raman tensor components. It was not possible, however, to decide which of the internal field corrections considered was the most appropriate and the results were in some cases significantly different for different corrections. Several alternative assumptions were also made about the orientations of the principal axes of the Raman tensor with respect to the symmetry axes of the para‐disubstituted benzene rings. Even when complete freedom of the axes was allowed, the greatest departure of any principal axis from the corresponding symmetry axis of the ring was found to be only 9±4° for the 1614 cm−1 mode whereas the greatest departure for the 633 cm−1 mode was 13±5°, supporting other evidence that the latter mode is less localized to the benzene ring than the former. The implications of the results for the use of Raman spectroscopy in studying molecular orientation in PET are discussed.