bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman spectrum of anatase, TiO2
Authors: Ohsaka Toshiaki , Izumi Fujio , Fujiki Yoshinori 
Published: May 2005

AbstractRaman spectra of anatase have been observed in natural and synthetic crystals. Both crystals show the same spectral features. The Raman band occurring at 516 cm−1 at room temperature is split into two peaks centred at 519 cm−1 and 513 cm−1 at low temperature (73 K). The six Raman active fundamentals predicted by group theory are all observed and assigned. The spectra are analyzed by a simple model considering only short‐range forces and the calculated vibrational frequencies are in good agreement with the observed Raman frequencies.
Raman spectra of matrix‐isolated and solid chromiumhexacarbonyl
Authors: Scheuermann Walter , Nakamoto Kazuo 
Published: May 2005

AbstractThe Raman spectra of Cr(CO)6 have been measured in an Argon matrix at 13 K and in the solid state at 292 and 13 K. As expected only the A1g, Eg and F2g modes were observed in the matrix spectra. The ν4(Eg) mode was observed split into a polarized and a depolarized component. This indicated a lowering of the symmetry from Oh to D4h or one of its subgroups. Depolarization ratios obtained in the matrix were close to values obtainable in liquids. In the low temperature solid state spectra all thirteen fundamental modes as well as several overtones and combination bands were observed. The six modes ν5(F1g) (inactive), ν6(F1u), ν7(F1u), ν8(F1u), ν12(F2u) (inactive) and ν13(F2u) (inactive), which were previously inferred from overtones and combinations, were observed for the first time.
Mechanistic interpretations of vibrational dephasing processes in 1,1,1‐trichloroethane by spontaneous Raman spectroscopy
Authors: Baglin F. G. 
Published: May 2005

AbstractThe Raman signals from modes ν1, ν2, ν3, 2ν2, and 2ν8, of 1,1,1‐trichloroethane have been examined by varying the concentration of this molecule in several solvents. In addition temperature studies were conducted, including data from the disordered solid phase of the neat sample. The results of these studies show that (a) the fundamentals (ν1, ν2, and ν3) are involved in a dephasing process controlled by the intramolecular potential function, (b) dephasing processes of the overtones are dominated by intermolecular processes and (c) the ν2 and ν3 modes of this molecule show very little dilution effects (some broadening), whereas the same modes of the structurally similar molecule CH3I show a definite narrowing in similar solvents. The theoretical model, proposed by Rothschild, is used to strengthen the interpretative case offered for the mechanistics of the dephasing processes of the fundamental modes.
A polarized infrared and Raman spectroscopic study of the electrooptic crystal m‐nitroaniline. I—assignments of internal vibrations
Authors: Szostak M. M. 
Published: May 2005

AbstractThe spectra of m ‐ nitroaniline solution in the middle infrared region (300–4000 cm−1) and in the Raman scattering region (150–1650 cm−1) as well as the polarized infrared (240–3500 cm−1) and Raman (170–1650 cm−1) spectra of monocrystalline samples of this compound have been measured. The dichroic ratios of infrared bands for (010) platelets and the depolarization ratios of the bands in the Raman spectra of acetone solution were determined and compared with theoretical values. On the basis of the results obtained and the assignments previously given by other authors, the assignments of all fundamentals of m ‐ nitoaniline have been either confirmed or proposed for the first time. Some relations between the electronic transition directions and the relative intensities of the infrared bands have also been found.
High temperature Raman scattering in Sm0.8La0.2AlO3 Compound: A relation to the phase transition in rare earth orthoaluminates
Authors: Alain P. , Coutures J. P. , Piriou B. 
Published: May 2005

AbstractRaman spectra of molten Sm0.8La0.2AlO3 have been recorded from room temperature to 1470 K. Experimental results show that a first‐order phase transition occurs at 580 K and that two phonon modes appear very unstable in the high temperature phase. Comparison with Raman data obtained on rare earth aluminate single crystals indicates that these ‘soft’ modes may be associated with a rhombohedral to cubic phase transition.
On the possibility of recording picosecond spontaneous Raman spectra
Authors: Valat P. , Tourbez H. 
Published: May 2005

AbstractWe report the conditions under which it is possible to record the complete spontaneous Raman spectrum of a sample excited by a single ultra‐short laser pulse. A method for exciting such spectra is described; it uses cylindrical lens focusing of the laser and enables us to get the same amount of Raman signal from much lower energy densities.
Etude par Spectrométrie Raman Rapide de la Cinétique d'Addition de l'Acide Chlorhydrique à des Doubles Liaisons Conjuguées: Cas du cis‐2, trans‐4‐Hexadiène
Authors: Beny J. M. , Bassez C. , Sombret B. , Wallart F. 
Published: May 2005

AbstractThe kinetic study of thermal dehydrochlorination of 4‐chloro‐2‐hexene (model of an allylic unstable structure occurring in polyvinyl chloride during its degradation) has shown that the reaction is reversible and has an ionic mechanism. The activation energies for the addition of hydrogen chloride to conjugated double bonds of cis‐2‐, trans‐4‐hexadiene in ethanol or dichloroethane have been determined by rapid Raman spectroscopy as 71.1 ± 10.4 kJ mol−1 and 36.8 ± 5.0 kJ mol−1 respectively from plots of the intensity ratio Iν(CC)/I against time at various temperatures.
Infrared and Raman studies of rotational isomerism in meso‐2,3‐dibromo‐1,4‐dichlorobutane
Authors: Crowder G. A. 
Published: May 2005

AbstractInfrared and Raman spectra were obtained for meso‐2,3‐dibromo‐1,4‐dichlorobutane in the solid state and in solution. Only one conformation is present in the solid, it being one with a center of symmetry (all carbons and chlorines coplanar, bromines on opposite sides of that plane). The other two stable conformers are present to a small extent in solution. A vibrational assignment of the solid state bands is proposed.
Evidence for short range orientation effects in pure liquid SO2 from vibrational Raman spectroscopy
Authors: Kamoun Mohamed 
Published: May 2005

AbstractIn the Raman spectrum of pure liquid SO2 a difference is observed between the wavenumbers of the isotropic and anisotropic components of the totally symmetric vibrations ν1 and ν2, the anisotropic component being at a higher frequency than the isotropic one. The separations are Δν1 = 5 cm−1, Δν2 ≃ 3.5 cm−1. This effect is approximately independent of temperature in the range −60 to +40°C. It disappears with dilution of SO2 in an inert solvent. The same shift is observed in solid SO2. Mirone and Fini2 and Josien3 have observed and interpreted such an effect in the case of larger molecules. They assume the liquid to be composed of clusters in which the molecules are partially ordered. In the case of SO2 our calculations based on such a model are in good agreement with the experimental results for ν2 but not for ν1.
Vibrations de Basses Fréquences du Cristal de m‐Chloronitrobenzène
Authors: Le Calvé N. , Romain F. , Pasquier B. 
Published: May 2005

AbstractPolarized Raman and infrared spectra of meta‐chloronitrobenzene single crystals have been investigated in the ranges 140‐5 cm−1 and 140–20 cm−1 respectively. They are compared to those of meta‐bromonitrobenzene recorded for comparison. All 21 lattice vibrations expected have been observed and assigned to their symmetry species and in terms of translational and rotatory vibrations. The only intramolecular mode, a NO2 torsion, has been identified near 93 cm−1 giving rise to four components in the crystal. The corresponding potential barrier V2 = V*/4 has been calculated.
Resonance Raman spectrum of crystal violet
Authors: Angeloni L. , Smulevich G. , Marzocchi M. P. 
Published: May 2005

AbstractThe preresonance Raman spectra, taken under various conditions, of crystal violet have been obtained using the exciting lines of an Ar+ laser. The analysis of the Raman data and of the IR and UV visible absorption spectra allowed us to determine the structure of the ion (propeller‐like in shape with D3 symmetry), to characterize the unstable single protonated dye cation, and to propose a detailed vibrational assignment in terms of coupled vibrations of the substituted benzenes. In addition, the measurements of the Raman excitation profiles furnished information on the vibronic couplings and provided evidence for a close correlation in the resonance mechanisms between crystal violet and benzene and its monosubstituted derivatives.
Anomalous polarization in the resonance Raman spectra of acetylene–cumulene dehydro annulenes
Authors: Fujimoto Etsuko , Yoshimizu Nobuaki , Maeda Shiro , Iyoda Masahiko , Nakagawa Masazumi 
Published: May 2005

AbstractAnomalous polarization (ρ = 3/4 ˜∞) has been observed in the resonance Raman spectra of some acetylenecumulene dehydro annulenes of a D2h rectangular configuration. Because of no orbital degeneracy, the observed anomaly may certainly be explained by the vibronic coupling of the resonant level with nearby states. From the nature of those relevant electronic levels, the anomalous lines are assigned to the B1g modes of vibration. For a typical anomalous polarization case, the polarization dispersion and excitation profile have been investigated.
Low frequency vibrational spectra of bromo‐and iodoantimonates
Authors: Jagodzinski Paul W. , Laane Jaan 
Published: May 2005

AbstractThe Raman and far‐infrared spectra of a dozen antimony halide complexes of formula SbX6−3, SbX5−2, Sb2X9−3 and SbX4−1 have been recorded and analyzed for X = Br and I. The stretching frequencies for the bromo complexes range from about 135 to 220 cm−1 for external bonds and from about 110 to 130 cm−1 for bridging bonds. For the iodo complexes the ranges observed are 138–174 cm−1 (external) and 87–127 cm−1 (bridging). Approximate force constants were calculated for the anions and these were compared to values previously determined for halobismuthates. In general, the ordering of the force constants was found to be SbBr>SbI˜BiBr>BiI. As was found for the bismuth complexes, the stretching force constants were greatest for bonds in the anions in which the largest number of other bonds were to bridging halogens.
Polarized Raman and resonance Raman spectra of single crystals of mixed valence metal complexes
Authors: Papavassiliou G. C. , Layek D. , Theophanides T. 
Published: May 2005

AbstractPolarized Raman and resonance Raman spectra of single crystals of one‐dimensional mixed valence platinum complexes have been recorded and studied. Polarized Raman spectra of single crystals of [M(II) (en)2M(IV)(en)2X2](ClO4)4, where X = Cl or Br, M = Pt or Pd and en = ethylenediamine, show strong resonance enhancement of the…XM(IV)X…symmetric stretching vibration in the chain. Analysis of the spectra shows that the metals are coupled in the chain through the halide atoms. The coupling occurs by electron charge transfer via the dz2‐orbitals of the metal from the lower to the higher oxidation state.
Vibrational spectra of C2v deuterium substituted pyridines. 2—Pyridine, pyridine‐4‐d, pyridine‐2,6‐d2 and pyridine‐2,4,6‐d3
Authors: Dilella Daniel P. , Stidham Howard D. 
Published: May 2005

AbstractPyridine‐4‐d, pyridine‐2,6‐d2 and pyridine 2,4,6‐d3 have been prepared. The isotopic composition and label specificity of each of several preparations were verified by mass spectroscopy and proton NMR. The liquid phase Raman and the liquid and vapor phase infrared spectra are reported for these materials and for pyridine at room temperature. A new vibrational assignment consistent with frequency sum and product rule constraints is proposed. Thermodynamic functions calculated from the pyridine assignment are found to be in good agreement with published experimental values.
Vibrational spectra and conformations of alkyl substituted three‐membered ring compounds: Ethylcyclopropane, isopropylcyclopropane and ethyloxirane
Authors: Nease A. B. , Wurrey C. J. 
Published: May 2005

AbstractThe infrared spectra (from 4000 to 200 cm−1) and Raman spectra of ethylcyclopropane, isopropylcyclopropane and ethyloxirane have been recorded in solid, liquid and vapor phases. From the spectral data, ethylcyclopropane has been shown to exist solely in the gauche conformation in all three states of matter. Likewise, isopropylcyclopropane exists solely in a bisected conformation having a mirror plane of symmetry. On the other hand, however, in the gas phase ethyloxirane exists as an equilibrium mixture of the two nonequivalent gauche rotameric forms. In all cases, steric repulsions between methyl hydrogens and β‐ring hydrogens preclude the existence of possible conformers where a methyl group is situtated over (cis) the three‐membered ring. Tentative vibrational assignments have been proposed for major spectral bands of all three molecules.
Raman band intensities of some local group modes of α‐Glycine, L‐alanine and DL‐alanine crystals
Authors: Machida Katsunosuke , Mori Michiyo , Kagayama Akira 
Published: May 2005

AbstractBand intensities in the polarized Raman spectra have been measured for the CO2− stretching, the CH2 stretching and the CH2 bending modes of α‐glycine crystal and the CO2− stretching and the CH3 symmetric deformation modes of L‐ and DL‐alanine crystals. Variations in the relative band intensities on the change of the scattering geometry have been elucidated by applying the oriented gas model to the local groups, –CH2, –CH3 and –CO2−, of these amino acid crystals. The calculated values of the components of the derived polarizability tensors are consistent with the geometry of the groups. The depolarization ratios estimated from the calculated anisotropy of the polarizability tensors have been compared with those observed for aqueous solutions.
A study of some vibrational band intensities in the pre‐resonance Raman spectra of naphthalene, phenazine, pyrazine, cinnoline and quinazoline
Authors: Aminzadeh A. , Fawcett V. , Long D. A. 
Published: May 2005

AbstractExperimental studies of the variation of intensity with excitation wavenumber of various vibrational bands in the Stokes Raman spectra of the following molecules are reported: naphthalene, pyrazine, phenazine, cinnoline and quinazoline. The results are discussed in terms of the Albrecht–Hutley theory of pre‐resonance Raman intensities and the electronic states involved in the pre‐resonance enhancement identified.
Etude par Spectroscopie et Microscopie Raman de Phases Oxyde de Molybdène Déposé sur Alumines
Authors: Sombret B. , Dhamelincourt P. , Wallart F. , Muller A. C. , Bouquet M. , Grosmangin J. 
Published: May 2005

AbstractRaman spectroscopy and microscopy have been used to study some catalysts: Mo supported on alumina. Different Mo species were found, depending upon the amount of molybdenum deposited on the carrier. At low coverages (4% wt MoO3) distorted molybdate tetrahedra were observed. Increasing the surface coverage resulted in the formation of a polymolybdate phase with octahedrally surrounded molybdenum. Additionally, ‘bulk MoO3’ appeared when amounts were above 16% wt MoO3. When the supports were washed during their preparation with aqueous NH4OH and HNO3 solutions, preferential formation of polymolybdate phase was observed. In case of washing with alkaline solution ‘free MoO3’ was also detected. Finally using the Raman microprobe MOLE, a map giving the distribution of the different species at the surface of support was obtained.
On the tautomerism of the thymine anion in the solid state: A Raman and infrared study
Authors: Lippert Bernhard 
Published: May 2005

AbstractSolid state infrared and Raman spectra of thymine, thymine monohydrate, three types of chloro(thyminato‐N1)ethylenediamineplatinum(II) complexes and three types of potassium thyminate (trihydrate, monohydrate, anhydrous compound) are reported and compared. The effects of hydrogen bonding, intermolecular coupling, crystal symmetry and tautomerism are discussed. For the anhydrous potassium thyminate a tautomeric structure, different from that found in the tri‐ and monohydrate, is postulated.
Vibrational spectra and structure of cyclopropyl isothiocyanate
Authors: Wurrey C. J. , Krishnamoorthi R. , Nease A. B. 
Published: May 2005

AbstractFor cyclopropyl isothiocyanate, the infrared (4000–200 cm−1) spectra in all three phases and the Raman spectra of the liquid and solid phases have been recorded. From Raman depolarization data and infrared gas phase band contours it has been concluded that cyclopropyl isothiocyanate exists in the cis conformation. No evidence for the existence of other conformations was found in the spectra. An assignment for 24 of the 27 fundamental vibrational modes has been proposed and this assignment has been shown to be in excellent agreement with vibrational assignments for other monosubstituted cyclopropanes and a number of isothiocyanate compounds.
Benzisoxazoles ‐1,2 et ‐2,1: Analyse vibrationnelle infrarouge et Raman
Authors: Mille G. , Guiliano M. , Angelelli J. M. , Chouteau J. 
Published: May 2005

AbstractRaman (3200–100 cm−1; liquid state) and infrared spectra (4000–200 cm−1; vapour, liquid state, and dissolved in inert and proton acceptor solvents) of −1,2 and −2,1 benzisoxazoles have been recorded. Their experimental analysis have allowed a complete attribution of the fundamental vibrations and of some overtone and combination vibrations of these heterocycles.
Etude de la Dispersion Angulaire des Modes Polaires d'un Monocristal de Phosphite de Lithium LiH2PO3
Authors: Beys Louis , Hillaire Paul 
Published: May 2005

AbstractThe angular dispersion of polar phonons with wave vectors k(k » (ω/c)) rotating in the planes of symmetry of the orthorhombic LiH2PO3 single crystal has been observed with Raman scattering experiments at T = 293 K in the regions 250–600 cm−1 and 850–1350 cm−1. The agreement of the experimental data with the existing theories of angular dispersion is very satisfying.
Interference effects in the high Resolution CARS spectra of gases
Authors: Laane J. , Kiefer W. 
Published: May 2005

AbstractThe CARS spectra of gas‐phase molecules have contributions from both real and imaginary components of the third‐order non‐linear susceptibility. When the spectral lines are closely spaced as in the high‐resolution CARS spectra (e.g. ˜ 0.03 cm−1) of the Q‐branches of diatomic molecules, considerable interference between the lines occurs for the contribution of the real part of the susceptibility, which causes asymmetry in the band profiles. The magnitude of the interference is dependent on the bandwidths Γ which are themselves primarily due to pressure broadening at high and medium pressures and due to Doppler broadening at low pressure. In this work the CARS spectra of two individual lines and of the diatomic molecules O2, N2 and NO have been calculated for a number of different linewidths. The effects of interference wereshown to result in substantial spectral differences for the various values of Γ.
Solid state vibrational spectroscopy. 9—A kinetic study, using Raman spectroscopy, of the solid state thermal decompositions of alkali metal peroxydisulphates
Authors: Cleaver Kevin D. , Davies J. Eric D. 
Published: May 2005

AbstractThe kinetic behaviour of the solid state thermal decomposition of peroxydisulphate to pyrosulphate, M2[S2O8] → M2[S2O7], M = Na, K, Rb, Cs, has been studied by following the temporal decrease in the intensity of the Raman band arising from the vs(SO3) mode of [S2O8]2−. The data are best analysed using a conventional kinetic approach rather than the Avrami–Erofeev treatment normally applied to solid state reactions. Although the salts display different kinetic orders, 1.5, 2.0, 1.0 and 1.0 for the Na, K, Rb and Cs salts respectively, the lack of crystallographic data does not allow us to rationalize these differences.
Activité Raman du m‐Chloronitrobenzène, Cristal Piézo‐électrique
Authors: Pigenet Claude , Le Calvé Nicole , Pasquier Bernadette 
Published: May 2005

AbstractThe piezo‐electric crystal m‐C6H4ClNO2 was studied by Raman scattering. TO–LO splitting of 1–7 cm−1 was observed for some internal modes and correlated to the infrared intensities. The observed Raman lines corresponding to the vsNO2 mode are interpreted through an analysis using G0(k,–k) subgroups of the factor group G0(0). The effective dynamical charges were calculated. The polaritons corresponding to the vs(NO2)A1 mode and skeletal mode at 1123 cm−1 were observed.
Time‐resolved Raman spectra of photoexcited semiconductor plasma
Authors: Luzzi Roberto , Vasconcellos Áurea R. 
Published: May 2005

AbstractA theoretical study of time‐resolved Raman scattering by a highly photoexcited semiconductor plasma is developed. The scattering cross‐section is calculated using the Zubarev non‐equilibrium ensemble method to describe the macroscopic evolution of the far from equilibrium plasma. Numerical results appropriate for GaAs are presented as an illustration.
Resonance‐Raman and electronic absorption spectra of O ions in γ‐irradiated Cd(ClO3)2
Authors: Campelo L. C. , Melo F. E. A. , Mendes Filho J. , Katiyar R. S. , Vargas H. 
Published: May 2005

AbstractResonant vibrational Raman measurements of the O ion modes in γ‐irradiated Cd(ClO3)2 single crystals are reported. It is concluded that the O ions occupy only one non‐equivalent site in the host lattice, in accordance with the ESR measurements previously reported. Resonance enhancement of the fundamental mode and its overtones as a function of the exciting wavelength is also investigated. The activation energy is determined by a simple direct calculation.
Theory of the electronic Raman effect in intermediate valence compounds
Authors: Foglio Mario E. 
Published: May 2005

AbstractWe present an approximate expression for the electronic Raman scattering intensity of localized impurities, and we employ this result in a simple model of intermediate valence compound with a hybridization term of the Anderson type. We have calculated the relevant time correlation functions using a Green's function technique. Using the published estimates of p, the probability of finding a Sm ion as Sm3+, determined from the lattice parameters, we were able to compare our expression for the Raman linewidth with published measurements of the linewidth in Sm1–xYxS. The theoretical dependence of the linewidth with x at 300 K gives only qualitative agreement with experiment. Out theory reproduces fairly well the independence of the line shape when samples with 0.15 < x < 0.3 underwent the temperature‐induced black to gold transition.
Resonance in the Raman scattering of CaF2, SrF2, BaF2 and diamond
Authors: Grimsditch M. , Cardona M. , Calleja J. M. , Meseguer F. 
Published: May 2005

AbstractThe dependence of the first order Raman scattering efficiency of CaF2, SrF2, BaF2 and diamond on photon energy ωL has been measured with different techniques. We find that in the visible these cross‐sections increase with ωL much faster than ω. This result has important implications as CaF2, for instance, is usually used as a standard scatterer in resonant Raman experiments, with the assumption that its efficiency is excatly proportional to ω. The possible sources of these anomalies are discussed.