bluuebunny/crossref_metadata_2025 huggingface dataset:
Low frequency depolarized light scattering from aqueous solutions of alkali halides
Authors: James David W. , Irmer Raimund
Published: May 2005

The depolarized scattering spectrum from 3 cm−1 to 300 cm−1 has been recorded for a range of aqueous solutions of alkali halides over a wide concentration range. The profile has been analysed in terms of two elastic bands which are essentially Lorentzian in shape and two inelastic bands at ∼60 cm−1 and ∼180 cm−1 which are described by a Lorentzian‐Gaussian product function. The relationship of the inelastic features to those previously obtained by band convolution is examined. It is shown that there is coupling between the broader elastic mode and that at 60 cm−1. This has the effect of strongly damping the motion responsible for the 60 cm−1 band. Variations in band width and intensity with change in concentration, cation and anion are discussed.
Analyse Vibrationnelle des Acides Cyclobutanedicarboxyliques‐1,3 cis et Trans en Solution Aqueuse: 1—l' Acide Cyclobutanedicarboxylique‐1,3 Cis et Ses Sels de Potassium
Authors: Fabrégue Eliane , Cassanas Geneviève , Bardet Lucette , Escale Roger , Chapat Jean‐Pierre , de Montgolfier J.
Published: May 2005

Une étude par RMN montre que, en solution aqueuse, l'acide cyclobutanedicarboxylique‐1,3‐cis a une conformation gauche diéquatoriale, tandis que l'isomère trans a une conformation gauche axiale‐équatoriale. L'analyse des spectres de polarisation Raman permet de retenir la symétrie C2 pour l'acide 1,3‐cis; le monoanion et le dianion ont la symétrie Cs, les plans des deux substituants étant orthogonaux. Une attribution des fréquences de vibrations fondamentales est proposée pour chaque composé.
Low‐temperature phase transition in 1,7‐dicarbaclosododecaborane (meta‐carborane) found by Raman and NMR methods
Authors: Bukalov S. S. , Leites L. A. , Blumenfeld A. L. , Fedin E. I.
Published: May 2005

A second phase transition in solid 1,7‐dicarbaclosododecaborane (meta‐carborane) in the vicinity of 165 K has been found by Raman and NMR T1 studies. All three isomers of carborane are shown to exist in the solid in three crystal modifications, two of them plastic and the low temperature one ordered.
Raman spectra of Cl and Br at 12 K produced from the reaction of HCl or HBr with NO2
Authors: Chen L.‐H. , Nour E. M. , Laane J.
Published: May 2005

The products of the reactions of HCl or HBr with nitrogen dioxide at 12 K have been examined using Raman spectroscopy. For the NO2+HCl reaction spectroscopic evidence for Cl, asym‐N2O2, N2O3, N2O4, ClNO2, ClNO3, NO, NO, and sym‐N2O2 was found. For the reaction with HBr only Br, was detected due to resonance Raman enhancement effects. These results are consistent with the previously proposed gas‐phase reaction scheme for HCl+NO2. However, the reaction proceeds further at low temperatures to produce Cl (or Br). The Raman frequencies for Cl were observed at 515(ν3), 462(ν1), and 236 cm−1(ν2). The Br resonance Raman spectra, which represent the first well documented spectra for this species, show strong fundamental bands at 281(ν1) and 227 and 238 cm−1 (doublet for ν2) as well as an overtone doublet at 471 and 487 cm−1.
Vibrational, resonance Raman and electronic spectra of the μ‐oxo‐bis[pentacyanomanganate (III)] ion
Authors: Jubert A. H. , Espindola J. A. , Varetti E. L. , Aymonino P. J.
Published: May 2005

The resonance Raman spectra of the polycrystalline substance as well as the polarized infrared spectrum of an ordered array of small monocrystals were obtained for K7[Mn2O(CN)10]CN. Several of the bands observed in these spectra as well as in the electronic spectrum of the complex ion are assigned to expected transitions.
Effect of pressure on the Raman spectra of solids: 1—KC103
Authors: Heyns A. M. , Clark J. B.
Published: May 2005

The Raman spectra of KClO3 are reported at room temperature up to pressures of 60 kbar in a diamond‐anvil cell. The phase transition between phases I and II occurs at approximately 7 kbar, is sluggish and the spectra show that the two phases coexist over a pressure range of approximately 5 kbar. The Raman spectra of phases I and II differ appreciably in the ClO stretching region and the spectra of KClO3 II can be interpreted in terms of the predicted unimolecular rhombohedral cell which has no inversion centre. Mode Grüneisen parameters have been calculated for most of the modes observed and are used in an attempt to assign some of the lattice vibrations.
Vibrational spectrum and normal coordinate calculations of the salicylic acid molecule
Authors: Volovšek V. , Colombo L. , Furić K.
Published: May 2005

Normal coordinate calculations for the salicylic acid molecule have been performed and the assignment of the observed Raman and IR spectra is proposed. The anomalous splittings observed for CO stretching modes are accounted for by specific interactions due to the symmetry characteristics and by possible conformational changes in the solution.
Aspects of resonance Raman spectroscopy for the case of a double‐well potential
Authors: Leclercq J. M. , Sandorfy C.
Published: May 2005

The resonance Raman effect is examined in the case of a Raman active harmonic vibrational mode coupled with a mode governed by a double‐well potential. It is shown that in such a case the nature of the potential surface in the resonating electronic excited state is the determining factor governing the appearance of the bands in the spectrum. In certain cases, when both wells are significantly populated, the only observed band may be characteristic of the less populated well in the ground state.
Lattice vibrations of crystalline l‐cocaine hydrochloride
Authors: Vergoten G. , Fleury G. , Gamot A. P.
Published: May 2005

Low‐frequency Raman spectra of crystalline l‐cocaine hydrochloride were recorded at room temperature and 9 K. Polarization of Raman bands was obtained on single crystals. The observed frequencies of the lattice modes are compared with those calculated using semi‐empirical intermolecular atom‐atom potentials. Eigenvectors of the lattice modes are given.
Derivative Raman spectroscopy applied to biomembrane systems
Authors: van de Ven M. , Meijer J. , Verwer W. , Levine Y. K. , Sheridan J. P.
Published: May 2005

Derivative Stokes‐Raman spectroscopy has been applied to biomembrane systems containing the fluorescent antibiotic amphotericin B. The membranes studied included weakly scattering solutions of dimyristoylphosphatidylcholine (DMPC) and multilamellar liposomes composed of DMPC and cholesterol. In this techqnique, the wavelength of an Ar ion‐laser pumped, tunable CW Rhodamine 6G dye laser was sinusoidally modulated with an electro‐optic birefringent tuner. The wavelength‐modulated Raman signal becomes amplitude‐modulated at the exit slit of a scanning monochromator. The signal, demodulated by a phase‐sensitive detector, was proportional to the first derivative of the Raman spectrum under appropriate conditions. The results indicate that this modulation technique can offer improvements in Raman signal‐to‐noise ratios of up to a factor of two for the conformationally sensitive phospholipid acyl‐chain vibrations of the biomembranes.
The effect of stacking on a low‐frequency vibrational band in an aqueous solution of adenylyl‐3′,5′‐cytidine (ApC)
Authors: Nielsen O. Faurskov , Christensen D. H. , Aubard J. , Dodin G.
Published: May 2005

Low‐frequency Raman spectra from 20 to 400 cm−1 of a 0.1 M aqueous solution of adenylyl‐3′,5′‐cytidine (ApC) ammonium salt were studied. An aqueous solution of ammonium chloride was used as reference. Experimental data were transformed to the R(ν) representation described previously. Spectra were obtained at temperatures between 0 and 70 °C. A broad band with a maximum below 100 cm−1 was assigned to water/base associate. This result corroborates previous assignments for nucleosides and nucleotides.
Raman scattering in resonance with short‐ and long‐lived vibronic states
Authors: Tubino R. , Mulazzis E. , Birman J. L.
Published: May 2005

Depending on the nature of the electronic absorption spectrum, that is, whether there are resolved vibronic transitions or broad and structureless bands, the scattering time associated with the Raman process can be long (10−8–10−12 s) or short (<10−12 s). In the first case the resonance Raman spectrum is characterized by a strong and non‐systematic dependence of first and higher order processes on the exciting wavelenghth; In the latter case the resonance Raman spectrum exhibits a strong, but systematic, frequency dependence of the intensities, which also show a regular decrease with the order of the process. These effects have been interpreted in terms of the Fourier transform of the correlator function which describes the time dependence of the secondary emission, evaluated for intermediate and long times and for the short time limit, respectively, Calculations for the gaseous I2 molecule using a simplified model Hamiltonian are reported and compared with the experimental data.
Resonance Raman and UV/visible absorption studies of protonated retinal schiff base phototransformations by irradiation with various laser lines
Authors: Delatour T. , Baron M. H. , Belloc J. , Favrot J. , de Loze C.
Published: May 2005

Binary mixtures of all‐trans‐N‐retinylidene‐n‐butylamine (NRB) in hexafluoroisopropanol (HFIP) were irradiated by various laser lines. The laser lines served both as sources of photoconversion and for Raman excitation. The photoproducts were studied by clectronic and resonacnce Raman Spectroscopy. The high specificity of resonance Raman spectroscopy was used to characterize different photoproducts at concentrations of the order uf 10−5 m, present simultaneously in the same mixture. The results show that a partial break in conjugation occurs during the phototransformation. The electronic spectra of the photoproducts were compared with the electronic spectra of modified chromophores or pigments.
Surface‐enhanced Raman spectroscopy of ruthenium‐pyridyl complexes at copper electrodes
Authors: Chambers Jeffrey A. , Buck Richard P.
Published: May 2005

Surface‐enhanced Raman spectra of 2,2′‐bipyridine, Ru(bpy)(py)4(CIO4)2, Ru(py)6(BF4)2 and Ru(bpy)‐(PVP)(CIO4)2 at the surface of a copper electrode are presented [bpy = 2,2′‐bipyridine; py=pyridine; and PVP =poly(4‐vinylpyridine)]. The dependence of the spectra on potential is demonstrated through presentation of complete spectra at applied potentials from −0.2 to −1 V, as well as in plots of SER intensity vs electrode potential. The effect of excitation wavelength on the spectra is discussed. Significant differences between the potential dependences of these compounds at copper and silver electrode surfaces are shown. SER spectra from the surface‐enhanced resonance Raman active ruthenium complexes could be obtained only with an excitation wavelength longer than 514.5 nm.
The vibrational spectrum and the normal coordinate analysis of KOX (X  H or D)
Authors: Kanesaka Isao , Kawahara Hisakazu , Kawai Kiyoyasu
Published: May 2005

The Raman spectra of KOX (X  H or D) at 77 K and room temperature are reported. The observed frequencies are assigned on the basis of a normal coordinate analysis by use of the valence force field. The KO stretching force constants are consistent with those expected from bond distances or related compounds. Dispersion relations are derived and some bands are assigned to a combination band at critical points.
The individual CH bond as a Raman spectroscopic probe to the internal rotation of the CHCl2 Group in C6H5CHCl2
Authors: Ribeiro‐Claro P. J. A. , Teixeira‐Dias J. J. C.
Published: May 2005

Evidence is provided concerning the internal rotation of the CHCl2 group in the C6H5CHCl2 molecule in the condensed phase using mainly the Raman spectra of the alkylic carbon‐hydrogen stretching vibration of C6H5CHCl2 and its deuteriated analogues. Comparison of the Raman bands observed in the region of the CH stretching vibrations for the hydrogenated compound with its deuteriated derivatives allows the assingnment of two Raman bands to the CH vibrator of the CHCl2 group. The dependence of the profiles of these bands on temperature and dilution in a series of solvents suggests a conformational equilibrium. Comparision of two different theoretical treatments of the isolated molecule enables us to reconize the importance of non‐boarded interactions operating during the internal rotation of the dichloromethyl group. The experimental results, used together woth the theoretical studies, lead to the evidence for two probable rotational isomers, designated CH⊥ and CH‖ which are responsible for the two observed Raman bands.
Fermi resonance in Raman spectra of crystalline 5‐aminotetrazole monohydrate
Authors: Bigotto Adriano , Castellani Gianna
Published: May 2005

New experimental IR and Raman data have been obtained for 5‐aminotetrazole in the solid state and in aqueous solution. The band pattern observed between 1100 and 1000 cm−1 in the Raman spectrum of the hydrated crystals has been interpreted in terms of Fermi resonance of a state associated with the tetrazole ring breathing mode and a two‐phonon state associated with the first overtone of a water libration.
Concentration dependence of Raman linewidth of isopropanol in aqueous solution
Authors: Tanabe Kazutoshi
Published: May 2005

The isotropic Raman linewidth of isopropanol at 818 cm−1 assigned to the CO stretching vibrational mode has been measured at a variety of concentrations in aqueous solution and in nonpolar tetrachloroethylene solution. On the basis of the concentration dependence of the linewidths observed in tetrachloroethylene solution, the isotropic Raman linewidth of the observed line is found to reflect the molarity of the hydrogen bonds of isopropanol. The unusual concentration dependence of the linewidths observed in aqueous solution, which shows a prominent maximum at a low concentration of isopropanol, has been examined in the light of these considerations. As a result, it is concluded that the concentration dependence of the linewidth is well explained in terms of the change in the partial molar volume of isopropanol, reflecting the change in the hydration structure in aqueous solution, and that the isotropic Raman linewidth of isopropanol is determined essentially by hydrogen bonding as an inhomogeneous broadening mechanism, other factors such as the vibrational dephasing being of less significance.
Potential of time‐resolved picosecond interferometry for Raman‐fluorescence discrimination
Authors: Delhaye M. , Deffontaine A. , Chapput A. , Bridoux M.
Published: May 2005

Preliminary experiments using Perot‐Fabry interferometers demonstrated the possibility of filtering selectively the fluorescence background from Rayleigh scattering excited by 25 ps pulses. Experiments aimed at extending the technique to spontaneous, Raman scattering are in progress. This technique is compatible with either single‐channel or multi‐channel detection of Raman spectra excited by mode‐locked ion, dye or solid‐state lasers.
Raman lineshape study of the A1 skeletal modes in tert‐butyl chloride
Authors: Friedman B. Ri. , Schwartz M.
Published: May 2005

The polarized and depolarized Raman spectra of the ν6 (CC3 stretch), ν7 (CCl stretch) and ν8 (CC3 bend) modes of tert‐butyl chloride have been studied as a function of temperature in the liquid phase. Isotropic correlation times for the bending mode were found to be 3–4 times longer than values obtained for the two stretching vibrations. An analysis of the isotropic correlation functions using the Kubo lineshape formalism revealed that the less efficient vibrational relaxation of the deformation arises primarily from the lower second monents of this mode. Reorientational times calculated from the two stretching vibrations were almost three times shorter than the earlier reported dipolar relaxation time, indicating that the tumbling motion of tert‐ butyl chloride is close to the small‐step diffusion limit.
Structural study of surface tungstate in WO3Al2O3: Effects of Hydration and 18O Exchange
Authors: Stencel John M. , Makovsky Leo E. , Diehl J. Rodney , Sarkus Tom A.
Published: May 2005

The Raman spectra of a series of WO3AI2O3 catalysts containing 1‐30 wt‐% of WO3 were investigated with respect to the effect of O2 calcination and H2OD2O exposure. These studies showed that the frequencies of bands due to surface tungstate species can be shifted reversibly by as much as 6% of their values during alternate O2 calcination and H2O exposure cycles. The exchange of 18O for l6O in the surface tungstate was also investigated with Raman spectroscopy and ion‐scattering spectrometry. The results were used to assign Raman bands to fundamental vibrations of the surface tungstate and to propose a mechanism of interaction between H2O and the surface tungstate that hitherto has not been addressed for WO3AI2O3.
Vibrational spectra and normal coordinate calculations for some dimethyl sulfide complexes of gold(I) and gold(III)
Authors: Butler Ian S. , Neppel Anton , Plowman Keith R. , Shaw C. Frank
Published: May 2005

Infrared and Raman spectra have been recorded at various temperatures for the solld gold (I) and gold (III) coordination compounds (CH3)2 SAuX (X = Cl, Br), (CH3)2 SAuCl3 and their perdeuteriated derlvatives. Vibrational assignments are proposed for the observed bands on the basis of modified Urey‐Bradley force field calculations. The primary force constants, K(Au‐X) and K(Au‐S), are essentially independent of the oxidation state of the gold atom. The data also show that (CH3)2S and (CH3)3P have similar trans‐directing influences in the ground state. The signs of the interaction constants in the square‐planar species, together with the slightly larger trans‐to‐sulfur Au‐Cl stretching force constant in comparison with the corresponding cis value, suggest that the trans‐to‐sulfur Au‐Cl bond is stabilized relative to the cis Au‐Cl bonds by the presence of the (CH3)2S ligand.
Resonance Raman spectra and excitation profiles of tetradesmethyl‐β‐Carotene
Authors: Okamoto Hiromi , Saito Shigeki , Hamaguchi Hiro‐O , Tasumi Mitsuo , Eugster Conrad H.
Published: May 2005

Resonance Raman spectra of tetradesmethyl‐β‐carotene were recorded using nine laser lines in the visible region. In a KBr disk at 77 K, two strong fundamental bands (1523 and 1133 cm−1) and their overtone and combination bands were observed to the fifth overtone region. Excitation profiles of nine Raman bands, including overtone and combination bands, were measured in isopentane solutions at 185 K. These were simulated by a simple two‐dimensional model based on Albrecht's A‐term, and a reliable set of parameters corresponding to the structure differences between the excited and ground electronic states was determined. The agreement between the observed and calculated excitation profiles was excellent, showing the adequacy of the model adopted.
Brillouin study of the hexagonal—orthorhombic phase transition in LiKSO4
Authors: Young P. W. , Katiyar R. S. , Scott J. F.
Published: May 2005

Brillouin spectra of lithium potassium sulfate have been obtained in its hexagonal phase from room temperature to the orthorhombic phase transition temperature at 435°C. The ν11 longitudinal sound velocity corresponding to the C11 elastic coefficient undergoes a smooth decrease with increasing temperature; the maximum decrease is 6.0% at T0=435°C and the temperature dependence of ν11 satisfies an expression of form

with B=(1.13±0.04) × 10−4K−1, C = (0.9±0.1) K and Tc = (467±6)°C=(740±6)K.
Raman spectra of Pb2MoO5 single crystal
Authors: Li‐ji Liao , Qi‐nian Zhang , Peng‐xiang Zhang , Yu‐lung Liu , An Tu
Published: May 2005

In accordance with the crystal structure proposed by Binnie, the principal vibrations of a Pb2MoO5 crystal have been analysed. The symmetry types of all characteristic modes were calculated and the symmetry types of the internal and external vibration modes of the MoO42− and other ions were further calculated by means of factor group analysis. The experimental results are compared with those of the group‐theoretical calculations, and with the Raman lines of PbMoO4 and other Scheelite‐type crystals. The distribution of the spectral lines and their symmetry show the effect of the internal vibrations of the MoO42− ion in a Pb2MoO5 crystal.
Fermi resonance and Raman intensities of carbon disulphide
Authors: Montero S. , Domingo C. , Wetzel F. , Finsterhölzl H. , Schrötter H. W.
Published: May 2005

The gas‐phase Raman spectrum of CS2 has been recorded and analysed in the region of the ν1 : 2ν2 Fermi resonance. The absolute differential Raman scattering cross‐sections and depolarization ratios of the observed vibrational transitions are satisfactorily interpreted in terms of three bond polarizability parameters and the cubic force constant k122.
Raman spectra and vibrational assignments of the molecular adducts PhnPH3–n GaCl3 (n = 1–3)
Authors: Taylor Michael J. , Bohle D. Scott , Riethmiller Stephen
Published: May 2005

The title compounds were prepared and their Raman spectra were measured, assigned and compared with that of PH3GaCl3. The frequencies of the pyramidal GaCl3 unit are sensitive to the basicity of the phosphine ligand. Modes ν(Gap), appreciably coupled to Ph‐P stretching vibrations, are located at 316, 260 and 182 cm−1 as medium to weak bands in the spectra of PhPH2GaCl3, Ph2 PHGaCl3 and Ph3PGaCl3, respectively. The PH stretching and bending modes give rise to medium to strong Raman bands, and these frequencies increase on coordination.
An adaptive detection system for Raman spectral peaks at low signal‐to‐noise ratios
Authors: Dyer Stephen A. , Hardin David S. , Bradley Eugene B.
Published: May 2005

Raman spectroscopic techniques have made it possible to study adsorbed species on single metal crystals at submonolayer coverages. However, as the amount of coverage decreases, the signal‐to‐noise ratio (SNR) deteriorates. This paper describes an adaptive peak detector (APD), a data analysis system capable of detecting peaks at low SNRs. The basic APD consists of anadaptive linear predictor (ALP) followed by a variance estimator. This detector is robust in that its performance does not rely on a priori knowledge of the exact signal and noise statistics. An experiment was performed in which single Lorentzian peaks embedded in white Gaussian noise at low SNRs were presented to the APD. A dramatic improvement in the detectability of the peaks is demonstrated; the experimental results indicate that the APD is useful at SNRs as low as 0.3. ALP convergence is shown to be a function of the input variance and the length of the predictor. Practical APD implementation considerations are given, and implications for future studies of adsorbed species are discussed.
Raman and infrared spectra of crystalline methyl iodide
Authors: Binbrek O. S. , Anderson A. , Andrews B. , Torrie B. H.
Published: May 2005

Raman and infrared spectra of polycrystalline samples of CH3I and CD3I were recorded at temperatures between 20 K and the melting point, 209 K. No evidence for a solid‐state phase transition was found. New splittings of the internal modes and more complete lattice spectra were observed at lower temperatures. An assignment of all principal bands is proposed, based on the known molecular and crystal structures.
Electronic and vibrational spectra of N‐heterocyclic molecules of biological interest and effect of solvents
Authors: Goel R. K. , Gupta (Km.) C.
Published: May 2005

The infrared and Raman spectra of liquid 2, 4‐dimethoxypyrimidine and solid 6‐chloro‐2,4‐dimethoxypyrimidine and the near ultraviolet spectra of their vapours are reported. An assignment of fundamentals is proposed. Spectra in polar solvents in the UV region are also reported and the effect of solvents is discussed.
Effect of dimerization on Raman intensities: An SCF ab initio study of (HCl)2
Authors: Silvi B. , Allavena M.
Published: May 2005

The intensities of the Raman lines corresponding to the intramolecular stretching modes of (HCl)2 have been calculated from an SCF wavefunction. It is found that the derivatives of the mean polarizability and of the polarizability anisotropy of the proton donor unit are enhanced, while the corresponding properties of the proton acceptor unit remain unaffected. The theoretical intensity ratio is calculated to be 1.69 in qualitative agreement with experiment.
Raman study of the symmetric ν1 vibrational mode of N3− and NO3− in aqueous solutions
Authors: Dean K. J. , Wilkinson G. R.
Published: May 2005

The totally symmetric ν1 vibrational modes of the anions N3− and NO3− have been studied in aqueous solution with very high precision. The effect of different alkali metal cations (Li+, Na+, K+, Rb+ and Cs+) has been systematically recorded as a function of the solution concentration. The experimental results show that the anion ν1 mode frequencies are dependent on both the cation present and on the solution concentration. Extrapolation of the experimental data yielded precise values of the anion ν1 frequencies in the limit of infinite dilution. These frequencies are 1342.7 ± 0.1 cm−1 for N3− and 1047.4 ± 0.1 cm−1 for NO3−. When Li+ or Na+ was present in solution with the azide anion, the ν1 frequency was shifted to a higher value than the infinite dilution frequency, with both cations having approximately the same effect, whereas when K+, Rb+ or Cs+ was present the ν1 frequency was decreased, the largest decrease being caused by Cs+, followed by Rb+, with the smallest decrease being caused by K+. In the case of the nitrate anion, the cations Na+, K+, Li+ and Rb+ were all responsible for an increase in the NO3− ν1 frequency with respect to the infinite dilution value, with the magnitude of the perturbation decreasing from Na+ to Rb+. When Cs+ was present the NO3− ν1 frequency was observed to decrease by a very small amount. It is suggested that for the vibrationally excited azide anion, the cation perturbation occurs through a form of polarizability interaction. However, the cation‐nitrate anion interaction is thought to occur through the effect that the hydrated cation has on the vibrationally excited nitrate anion cosphere of hydration.
Analysis of the resonance Raman spectra of 13C‐and 2H‐substituted carotenoids
Authors: Hayashi Hidenori , Saito Shigeki , Tasumi Mitsuo
Published: May 2005

The resonance Raman spectra of 13C‐ and 2H‐substituted carotenoids were observed from photosynthetic bacteria cultured in 13C‐and 2H‐substituted media, respectively. The observed Raman bands of 13C‐ and 2H‐substituted carotenoids could be reasonably assigned on the basis of the normal coordinate analysis of a model molecule. This gave substantial support to the previous assignments of the Raman and infrared bands of β‐carotene.
Etude par Microspectrometrie Raman de Composes Graphitiques Inseres Par SO3
Authors: Ladjadj M. , Dhamelincourt M. C. , Dhamelincourt P. , Vast P.
Published: May 2005

Graphite intercalation compounds are of considerable scientific interest for both applied and fundametal reasons (structural ordering). Micro Raman spectroscopy has been used to investigate graphites intercalated with sulphur trioxide. In these compounds, the E2g2 vibrational layer mode of the graphite lattice shows the known linear frequency dependence with the inverse of the step as observed for many acceptor‐type intercalates. The frequency behaviour of this mode is also indicative of a difference between intercalated graphites prepared with either liquid or gaseous SO3. A study of the Raman spectra as a function of time allowed information on the intercalation kinetics and the ageing of these materials to be obtained.
Infrared, Raman and inelastic neutron scattering study of phase transitions in trimethyloxosulphonium iodide, (CH3)3SOI
Authors: Sourisseau C. , Bee M. , Dworkin A. , Jobic H.
Published: May 2005

Calorimetric (DTA), infrared, Raman and inelastic neutron scattering (INS) measurements have been performed for the trimethyloxosulphonium iodide compounds (CH3)3SOI and (CD3)SOI over the range 10–450 K. Two solid‐solid phase transitions were found at about 200 and 250 K and the vibrational study showed that only the low‐temperature crystalline form (III) is completely ordered. From a temperature dependence study of the optical and INS spectra it is concluded that methyl group reorintations are mainly involved in the phase (III)⟷phase (II) transition, while the whole molecule reorientations about the three‐fold axis, partly involved in the phase (II)⟷phase (I) transformation, must be much slower than and decoupled from methyl motions. Finally, the potential barrier height against methyl rotations has been estimated to 13.3 kJ mol−1 from the observed torsional frequencies and compares favourably with the activation energies derived from previous NMR experiments (10.9 kJ mol−1) and from quasi‐elastic neutron scattering results (10.6 kJ mol−1).
Raman and infrared spectra of tetramethylcyclobutane‐1, 3‐dithione and the fully deuteriated derivative
Authors: Shurvell H. F. , Gordon R. D. , Girling R. B.
Published: May 2005

Raman and infrared spectra of tetramethylcyclobutane‐1, 3‐dithione (TMCBDT) and the fully deuteriated derivative (TMCBDT‐d12) have been recorded. A reasonably complete set of vibrational frequencies and assignments are presented for the two molecules. The symmetric CS stretching mode was observed at 1328 cm−1 for TMCBDT and at 1352 cm−1 for TMCBDT‐d12. The antisymmetric CS stretching mode occurs at lower frequencies of 1167 cm−1 for TMCBDT and 1158 cm−1 for the deuteriated molecule. This is consistent with previous observations for tetramethylcyclobutanedione. Ground‐state vibrational frequencies of several modes involved in progressions in the n→ π* electronic absorption spectra have been located.
Raman polarizabilities of the ν2, ν5 bands of CD3Cl
Authors: Escribano R. , García Hernández M. , Mejías M. , Brodersen S.
Published: May 2005

The Raman spectrum of the Coriolis interacting ν2, ν5 bands of CD3Cl was recorded with a resolution of ca 0.6 cm−1. Using the vibrational‐rotational parameters of Yamada and Hirota, a computer simulation of the Raman contour was performed, yielding relative values of Raman polarizability derivatives for these bands. By comparison with the absolute intensity measurement of Orza et al., absolute values of the Raman polarizabilities were obtained. The sign of the Raman intensity perturbation was found to be negative.
Electronic, Infrared, Raman and Resonance Raman Spectra of some Hexahalodi(aquo)dimolybdate(II) Anions, Mo2X6(H2O)22−, with Quadruple Molybdenum‐Molybdenum Bonds
Authors: Ceylan V. K. , Sourisseau C. , Brencic J. V.
Published: May 2005

The electronic (800‐400 nm), infrared, ordinary Raman (400‐20 cm−1) and resonance Raman spectra (3000‐20 cm−1) of several hexahalodi(aquo)dimolybdate(II)anions, Mo2X6(H2O)22−, with X = Cl, Br, I, containing quadruple metalmetal bonds were investigated. The electronic spectra of the solid compounds at various temperatures (25, 100 and 300 K) show intense and sometimes structured bands in the visible region (510‐580 nm) assigned to the expected δ → δ* transitions; energy values of the 0 → 0 transition, of the excited‐state metal‐metal stretching vibrational frequency and of the damping factors were thus determined. From the infrared and Raman spectra, the skeletal stretching modes in these binuclear anions have been localized, and from resonance Raman results the ground‐state harmonic frequencies, anharmonic constants, force constants and dissociation energies of the Mo‐Mo bonds have been estimated.

Finally, within the Franck‐Condon model for resonance Raman scattering, theoretical and experimental excitation profiles of the metal‐metal fundamental and its first overtone have been compared in order to obtain accurate values of the displacement parameters (Ble ≈︁ 2.78‐2.53) and of the shift in equilibrium positions (Δr1 = 0.13‐0.12 Å); these magnitudes are consistent with other observations and these data represent one of the first quantitative estimates in such systems.
Structure Moléculaire des Dérivés Nitres Aromatiques 5–Spectres de Vibration et Analyse par Coordonnées Normales du 1,3,5‐Triamino‐2,4,6‐trinitrobenzène
Authors: Vergoten G. , Fleury G. , Blain M. , Odiot S.
Published: May 2005

Les spectres IR et Raman de 1,3,5‐triamino‐2,4,6‐trinitrobenzène ont été mesurés sur toute la gamme spectrale (10 à 4000 cm−1). Une analyse par coordonnées normales utilisant un champ de force Urey‐Bradley modifié et tenant compte des redondances cycliques permet l'attribution. Les seuls modes purs sont: la torsion CNO2 à 101 cm−1, la torsion CNH2 à 606 cm−1, la déformation angulaire hors du plan NH2 à 1030 cm−1, la déformation angulaire dans le plan NH2 à 1212 cm−1 et les deux déformations de valence NH2 à 3208 et 3308 cm−1.
Phase transition in manganese and zinc fluorotitanate hexahydrate and hexadeuterate systems observed by Raman spectroscopy
Authors: Choudhury P. , Ghosh B. , Patel M. B. , Bist H. D.
Published: May 2005

Raman spectra of MnTiF6·6H2O, MnTiF6·6D2O, ZnTiF6·6H2O and ZnTiF6·6D2O single crystals were studied in different polarizations between 300 and 77 K and the observed bands were assigned to the various modes of vibrations of these systems. Phase transition in these systems was observed by studying the intensity of νs(TiF6) mode and νs(H2O/D2O) mode with temperature. The mechanism of the phase transition is discussed.
Orientation of Ru(pyridine)6(BF4)2 at silver electrodes
Authors: Chambers Jeffrey A. , Buck Richard P.
Published: May 2005

Comparison of Raman spectra of octahedral Ru(pyridine)6(BF4)2 with those of Ru(bipyridine)(pyridine)4(ClO4)2 provides an opportunity to analyse the orientation of Ru(pyridine)6 at silver over a wide potential range. At the more positive potentials, the Ru(pyridine)6 appears to be bonded through two pyridine ligands, while at more negative potentials, the orientation is probably C4ν, indicating bonding through one pyridine. Previously reported potential dependences of Raman scattering intensities show mobility of the complex on the electrode surface and probable conversion between these two orientations. Possibilities for further orientation changes at more positive and more negative potentials are obscured by electrode oxidation and complex desorption, respectively.
Raman and far infrared spectra of solid methyl fluoride, CH3F and CD3F
Authors: Binbrek O. S. , Anderson A. , Torrie B. H.
Published: May 2005

Far infrared and Raman spectra of solid CH3F and CD3F have been recorded at 80 and 20 K. The lattice spectra of CD3F and the lattice Raman spectrum of CH3F are reported for the first time. Additional peaks have also been observed in the far infrared spectrum of solid CH3F. New splittings for the internal mode fundamentals for ν3, ν5 and ν6 are reported for both compounds, and also for ν2 (CH3F) and ν4 (CD3F). An assignment of the observed bands is proposed. The crystal structure has not been determined directly, but the spectroscopic evidence suggests that it is centrosymmetric with at least eight molecules in the primitive unit cell.
Surface‐Enhanced Raman scattering spectra of aqueous silver borohydride sols of pyridine and deuterium‐containing pyridines
Authors: Stidham Howard D. , Harris Scott M.
Published: May 2005

Surface‐enhanced Raman scattering spectra of aqueous silver horohydride sols of pyridine, pyridine‐4‐d, pyridine‐2,6‐d2 and pyridine‐3,5‐d2 are reported. Depolarization ratios are given as a function of pyridine concentration for a number of pyridine bands over a substantial range of concentrations. Evidence is presented of multiple site adsorption and a new interpretation of these Raman spectra is proposed. The evidence indicates that the surface enhancement derives essentially from the presence of long linear segments of chains of silver spheres in the aggregating sols. The concentration dependence of the depolarization ratios and of the average silver sol particle size show that the depolarization ratio characterizes the extent of dendritic growth of sol aggregates and is thus the same for every Raman band in a given preparation at the same time in the history of its evolution, independent of the rotational characteristics of the sol particles or of the adsorbed pyridine molecules.
Resonance Raman scattering in dyes derived from azobenzene
Authors: Cataliotti R. S. , Murgia S. M. , Paliani G. , Poletti A. , Zgierski M. Z.
Published: May 2005

Resonance Raman spectra and excitation profiles are reported for six azo dyes in CCl4 solutions through the visible absorption spectrum region. The excitation profiles observed for the five most intense fundamentals in each dye indicate interference between two overlapping electronic manifolds.
Raman spectra of copper(I), silver(I) and gold(I) cyanides in aqueous solutions of sodium thiosulphate
Authors: El‐Hinnawi Mahmoud A. , Peter Lyle , Meyer B.
Published: May 2005

Systems of copper(I), silver(I) and gold(I) cyanides dissolved in aqueous solutions of sodium thiosulphate in different molar ratios have been studied by Raman Spectroscopy. CuCN dissolves completely in aqueous thiosulphate solution in a 1:3 CuCN to S2O32− ratio, forming only mixed cyanothiosulphate species. No evidence was found for the formation of Cu (CN)2−, Cu(CN)32− or Cu(CN)43−. The mixed cyano copper complex was isolated as a white solid insoluble in water and most other solvents. The solid probably consists of a polymeric structure with bridging cyanide and thiosulphate. AgCN dissolves completely in aqueous thiosulphate solution in a 1:1 AgCN to S2O32− ratio, resulting in the formation of Ag(CN)2− and Ag(S2O3)23− species. As the concentration of thiosulphate increases Ag(CN)2(S2O3)3− and Ag(CN)2(S2O3)25− are formed. There is strong evidence for the existence of bridging silver thiosulphate complex in solutions of low S2O32− concentration. AuCN dissolves completely in aqueous thiosulphate solution in a 1:2 AuCN to S2O32− ratio, forming Au(CN)2−, Au(CN) (S2O3)2− and Au(S2O3)23−. No evidence was found for the formation of species of higher coordination number on increasing the concentration of S2O32−, which indicates that the linear two‐coordinate gold complexes are the most stable.
Measurement of the intensity of resonance Raman bands of aromatic compounds in the solid state by the divided‐disc method
Authors: Tsukamoto Ikuko , Lee Hohi , Uchida Hiroko , Machida Katsunosuke
Published: May 2005

Relative intensities of the resonance Raman bands of four azo and two phthalein dyes and two colourless aromatic compounds in the solid state have been evaluated by recording the addition Raman spectra using the divided KBr disc method. The 984 cm−1 band of potassium sulphate was used as the intensity standard. From the relationship between the relative intensity and the sample concentration, the scattering coefficients for representative resonance Raman bands and the sum of the absorption coefficients at the wavelengths of the excitation and the Raman lines were estimated simultaneously for each dye.
Forward and partially reflected backward scattering measurement of resonance Raman intensities by the divided‐disc method
Authors: Tsukamoto Ikuko , Machida Katsunosuke
Published: May 2005

An experimental device for measuring the forward scattering intensities of resonance Raman bands of powdered dyes was investigated by using a new transmission‐type sample spinner and divided KBr discs. The backward scattering intensities of the same samples for partially reflected incident radiation were measured by inserting a small mirror behind the disc attached to the usual reflection‐type sample spinner. Applying a Schrader‐Bergmann version of the Kubelka‐Munk theory of diffuse reflection to the combined data from these measurements, we were able to evaluate the absorption coefficients at the wavelength of the incident and the scattered radiations and the relative values of the Raman scattering coefficients simultaneously.
Analyse vibrationnelle et structurale en série aliphatique saturée. 7—spectres de vibration de l'Acide hydroxymalonique et de ses sels alcalins en solution aqueuse
Authors: Delarbre Jean Louis , Maury Luc , Bardet Lucette
Published: May 2005

Les spectres Raman et infrarouges de l'acide hydroxymalonique et de ses sels alcalins en solution aqueuse (H2O et D2O) ont été enregistrés entre 100 et 4000 cm−1. L'analyse du facteur de dépolarisation nous a permis de conclure que l'acide hydroxymalonique et le sel neutre appartiennent au groupe de symétrie Cs alors que le sel acide appartient au groupe C1. Une attribution des vibrations fondamentales est proposée.
‘Extra’ resonances in non‐linear Raman spectroscopy
Authors: Kircheva P. P. , Simeonov S. D.
Published: May 2005

In the treatment of absorption spectra and Raman excitation profiles of polyatomic molecules, relaxation constants appear as ‘soft’ parameters. It is shown that the spectra of non‐linear Raman scattering under resonance pumping conditions are sensitive to variations in the relaxation constants and the number of active vibrations, especially when ‘extra’ resonances are included. This is demonstrated by calculations of coherent Stokes Raman scattering spectra carried out using the density of states model and displaced independent harmonic oscillators. The use of non‐linear Raman spectra for checking the reliability of the model descriptions of S0–S1 transitions is proposed.
Raman spectra and oxygen‐related absorption bands in pure silica core fibres
Authors: Carvalho W. , Dumas P. , Corset J. , Neuman V.
Published: May 2005

The Raman spectra of pure silica core fibres revealed the presence of molecular oxygen, which may be responsible for two absorption bands, one at 0.76 and the other at 1.27 μm.
Internal rotational potential in α,α‐dichlorotoluene
Authors: Schaefert Ted , Penner Glenn H.
Published: May 2005

Whereas carbon‐hydrogen stretching frequencies and some CNDO/2 and molecular mechanics calculations suggest a double minimum potential for the rotation about the sp2‐sp3 carbon‐carbon bond in α,α‐dichlorotoluene, an extensively geometry optimized STO 3G MO computation implies a two‐fold (single minimum) potential of 11.6±0.1 kJ mol−1 and that in the conformer of low energy the CH bond in the side‐chain prefers the benzene plane. Fully relaxed molecular mechanics procedures also indicate a two‐fold barrier. A value of 9.2±1.3 kJ mol−1 had been derived from long‐range spin‐spin coupling constants. There is a need for an independent determination of the shape of the internal potential.
Hyper Rayleigh and hyper Raman scattering from ammonium chloride and ammonium bromide
Authors: French M. J. , Hall R. J. B. , Long D. A. , Al‐Rubaiey F. M. F.
Published: May 2005

The hyper Rayleigh and hyper Raman (0–1600 cm−1 wavenumber shift) spectra of oriented single crystals of ammonium chloride and ammonium bromide are reported. It is demonstrated that hyper Rayleigh scattering is a very sensitive measure of the presence of a centre of symmetry within a crystal structure and this property is used to investigate the residual ordering within an ammonium chloride crystal at 55 K above the order‐disorder phase transition. The hyper Raman wavenumber shifts associated with the transverse (TO) and longitudinal (LO) components of the optic mode, the librational mode which is infrared and Raman inactive, and the H–N–H internal mode were observed for both crystals. A basis for the interpretation of the relative hyper Raman intensities of the LO and TO modes is provided by an extension of the Poulet treatment of the relative intensities in the Raman spectrum.
Vibrational and electronic spectroscopic study of lanthanides and effect of sodium on the aromatic system of benzoic acid
Authors: Lewandowski Włodzimierz , Barańska Halina
Published: May 2005

Raman spectra of benzoic acid, sodium benzoate and complexes of lanthanides with benzoic acid, of general formula Ln(Obz)3 (Ln = lanthanum, neodymium, terbium, dysprosium or lutetium; OBz = benzoic acid radical) were recorded. The Raman bands of lanthanide benzoates were interpreted on the basis of the Raman and IR spectra. Analysis of benzene ring vibrations, active in the Raman and IR spectra, and electronic transitions in the UV and visible spectra provided information on the effect of metal coordination on the aromatic system of benzoic acid.
Vapour‐phase Raman spectra of benzoic acid
Authors: Furić K. , Colombo L.
Published: May 2005

The medium‐resolution Raman spectrum of benzoic acid vapour has been recorded. Comparison of the high‐frequency spectrum with the internal spectra of substituted and similar molecules indicates that previous assignments of the spectra should be revised. Three possible explanations are proposed for the broad feature observed at very low frequencies. Two of them lead to the conclusion that there is a very low barrier for hindered rotation around the CC bond connecting the carboxylic group with the phenyl ring.
Inter‐ and intra‐molecular coupling and Fermi resonance in the Raman spectra of liquid water
Authors: Sokołowska Anna , Kęcki Zbigniew
Published: May 2005

The region of OH and OD stretching vibrations in the Raman spectrum of liquid H2O and D2O was investigated by analysing the isotropic and anisotropic components of the bands. The constants for inter‐ and intra‐molecular and Fermi coupling were estimated and the positions of all components calculated. The intermolecular coupling appears to be stronger than intramolecular coupling in liquid water.
Pure rotational Raman spectra of deuteriated ethylenes: Molecular polarizability parameters
Authors: Mompeán F. J. , Escribano R. , Montero S. , Martín J.
Published: May 2005

The rotational Raman spectra of C2D4, C2HD3 and CH2CD2 are presented with a resolution of ca 0.3 cm−1. A computer simulation has been carried out to reproduce the observed contours from literature values of the rotational constants. The molecular polarizability parameters are determined with ca 10% uncertainty by transfer of the C2H4 literature values. The assignment of the J sub‐band heads is shown.
Reflectivity and transmissivity of a slab caused by the stimulated Raman effect
Authors: Merten L. , Schulz V.
Published: May 2005

It is shown that as a result of anharmonic coupling of the polariton waves, Stokes and anti‐Stokes waves by a pump wave, an irradiated second wave (two‐beam method) generates new waves from a slab. The frequency of the irradiated wave can be chosen from the Stokes and anti‐Stokes visible region or from the polariton in the infrared region.

First numerical results are given for GaP for reflectivity in the polariton and in the Stokes visible region. The spectra show strong amplification of the irradiated wave.
Raman spectroscopic results for order–disorder transitions of K2Ba(NO2)4
Authors: Unruh H.‐G.
Published: May 2005

The temperature dependence of internal NO2 modes has been investigated by polarized Raman scattering from potassium barium nitrite single crystals. The frequencies of the symmetric stretching and bending modes are determined for the three non‐equivalent NO2 sites present at room temperature. The structural implications associated with the phase transition at about 200 K are derived from line splittings and relative intensities. The experimental results are consistent with an order–disorder transition and no soft lattice mode has been found.