bluuebunny/crossref_metadata_2025_split huggingface dataset:
The vibrational spectrum, normal coordinate analysis and conformational equilibrium of 3‐chloro‐2‐methylpropene
Authors: Compton D. A. C. , Hsi S. C. , Mantsch H. H. , Murphy W. F. 
Published: May 2005

AbstractThe infrared spectra of gaseous and liquid 3‐chloro‐2‐methylpropene and the Raman spectra of the compound as gas, liquid and frozen solid have been recorded. Several bands present in the Raman spectrum of the liquid were found to be absent or greatly reduced in intensity in the spectrum of the solid phase, thus indicating the presence of a conformational equilibrium. The Raman polarization data show that the gauche conformer of this compound is the more stable. A study of the temperature dependence of the relative intensities of two Raman bands due to different conformers led to values of ΔHθ of 2.5±0.5 kJ mol−1 and ΔSθ of −4.8±2.0 JK−1 mol−1 for the conformational equilibrium in the liquid phase. These results are consistent with a conformational equilibrium of the type gauche⇌s‐cis, as found for a number of related molecules. A complete vibrational assignment has been proposed for the spectral data, except for the unobserved methyl torsion, aided by a normal coordinate treatment.
The analysis of unresolved Raman excitation profiles. 1—Totally symmetric vibrations with applications to ruthenium red and zirconium trisulfide
Authors: Siebrand Willem , Zgierski Marek Z. 
Published: May 2005

AbstractThe problems involved in the analysis of unresolved Raman excitation profiles are studied theoretically. The aim of such an analysis is to identify vibrational parameters of the resonant state and possibly other states involved in the scattering. For totally symmetric modes, discussed in this paper, the most important of these parameters are the displacements of the equilibrium positions, the problem being to separate these parameters from vibronic line broadening. It is shown how this can be done for systems of several modes and several interfering electronically excited states by model calculations based on a multimode approach. The effect of coupling with solvent modes on vibronic lineshapes is considered explicitly. Some reported analyses based on the independent‐oscillator approach are criticized for their lack of internal consistency or their use of unacceptable parameter values. It is demonstrated that these analyses can be improved by taking multimode effects into account. For cases where the full N‐mode problem is too difficult to handle directly, a method based on interrelated n<N‐mode calculations is developed. Two examples are treated in detail, namely ruthenium red and ZrS3. For both, sets of displacement parameters are derived from the unresolved profiles. A condition for the feasibility of such an analysis is the availability of excitation profiles for all Raman active fundamentals and one or more overtones or combination bands.
New Raman spectroscopic results on the orientational disorder of nitrite anions in sodium nitrite
Authors: von der Lieth Claus Wilhelm , Eysel Hans Hermann 
Published: May 2005

AbstractRaman spectra of oriented sodium nitrite single crystals are reported. Half‐widths, peak frequencies and band shapes change when the temperature is varied from 30 to 513 K. Resolution of the Raman bands of the symmetric NO vibrations into contributions from ordered and disordered positions yield a temperature‐ dependent order parameter. On the basis of a double minimum potential for the ferroelectric phase, ΔH = 3.5 kJ mol−1 and ΔU = 11.5 kJ mol−1 are calculated from the Raman data.
Raman study of three polytypes of PbI2
Authors: Khilji M. Y. , Sherman W. F. , Wilkinson G. R. 
Published: May 2005

AbstractRaman spectra of three polytypes of lead iodide (2H, 4H and 6H) have been investigated as a function of temperature at ambient pressure. The band assignments have been carried out on the basis of folding of 2HPbI2 phonon dispersion curves in the Brillouin zone. The temperature induced changes in the Raman spectra are interpreted in terms of an interpolytypic phase transformation (at 415 K) and photodecomposition at 470 K.
Raman spectra of disordered Hg(NH3)2Cl2 and Hg(NH3)2Br2
Authors: Ebisuzaki Y. , Hobbs C. C. , Richard P. D. 
Published: May 2005

AbstractThe Raman spectra of disordered Hg(NH3)2Cl2, Hg(ND3)2Cl2 and Hg(NH3)2Br2 are reported. The spectra consist of the internal vibrations of the mercuric complex with no lattice phonons being observed. The bending and the symmetric stretching mode for the complex (Hg(NH3)) occur at 110 cm−1 and 413 cm−1 in the chloride and at 85 cm−1 and 381 cm−1 in the bromide.
Bond polarizability calculations of the Raman optical activity of (R)‐(+)‐3‐Methylcyclohexanone
Authors: Barron L. D. , Clark B. P. 
Published: May 2005

AbstractThe bond polarizability theory of Raman optical activity is used to calculate the complete Raman optical activity spectrum of (R)‐(+)‐3‐methylcyclohexanone. The results are compared with the observed depolarized Raman circular intensity difference spectrum in the region 50‐1800 cm−1. The predictions are better in the upper half of this range probably because at lower frequency the calculated normal coordinates are less reliable and the contributions from carbonyl deformations increase.
Dispersion curves of an infinite polyene chain (Erratum)
Authors: Tasumi M. 
Published: May 2005

AbstractThis Erratum corrects a mistake relating to the definition of force constants which appeared in the following paper: F. Inagaki, M. Tasumi and T. Miyazawa, Vibrational analysis of Polyene Chains, J. Raman Spectrosc. 3,335 (1975).
Raman spectra of the rare earth trimetaphosphates
Authors: Begun G. M. , Bamberger C. E. 
Published: May 2005

AbstractRaman spectra of anhydrous crystalline powders of all the lanthanide trimetaphosphates (with the exception of Pm(PO3)3) and of yttrium trimetaphosphate have been obtained. These data have been interpreted in a systematic manner based on the known structures of these compounds. Variations of the vibrational band frequencies with atomic number are much less than with the orthophosphates.
Raman spectra of pyridine N‐oxide complexes with Co(II) and Ni(II) perchlorates
Authors: Arenas J. F. , Marcos J. I. , Otero J. C. 
Published: May 2005

AbstractThe complexes [(PyO)6Co](ClO4)2 and [(PyO)6Ni](ClO4)2 have been synthesized and their Raman spectra recorded from a microcrystalline powder. The experimental data agree with those previously calculated for the low frequency vibrations. General assignments of both spectra have been proposed on the basis of a group factor S6 for both the cation and the anion.
In vivo studies of nucleic acid by ultraviolet resonance Raman spectroscopy on eucaryotic living cells
Authors: Nocentini S. , Chinsky L. 
Published: May 2005

AbstractWe observe for the first time spectra of nucleic acids of living cells, obtained by resonance Raman spectroscopy excited in the u.v. range (257 nm). This wavelength which is close to that of the maximum of absorption of the main components of nucleic acids allows the resonance Raman effect to be obtained and the fluorescent contribution of aromatic amino acids present in proteins to be avoided.
Vibrational spectra of bromocyclopropane
Authors: Wurrey C. J. , Berry R. J. , Yeh Y. Y. , Little T. S. , Kalasinsky V. F. 
Published: May 2005

AbstractFourier transform infrared spectra of bromocyclopropane at a resolution of 0.5 cm−1 have been recorded as well as liquid phase infrared spectra of this molecule from 4000–400 cm−1. For the first time, gas phase Raman spectra and solid phase infrared spectra of bromocyclopropane have been obtained. By combining all of the spectral data available it has been possible to assign all 21 normal modes of vibration of bromocyclopropane (as well as several overtones and combination bands) with a high degree of confidence. This proposed assignment is in excellent agreement with assignments for similar molecules and with anticipated cyclopropyl group frequencies.
Raman and infrared spectra of solid carbon diselenide
Authors: Torrie B. H. , Andrews B. , Anderson A. , Powell B. M. 
Published: May 2005

AbstractRaman and infrared spectra of polycrystalline samples of CSe2 have been recorded at temperatures from 20–205 K. A comparison with previous results for CS2 shows that the spectra are consistent with the two substances having the same centrosymmetric orthorhombic structure. The observed spectra for CSe2, in both the lattice and molecular regions, are in good agreement with group theoretical predictions based on this structure. There is only one solid phase over the range of temperatures examined.
The Raman spectra of manganese and zinc fluorotitanate hexahydrate systems
Authors: Choudhury P. , Ghosh B. , Raghuvanshi G. S. , Bist H. D. 
Published: May 2005

AbstractRaman spectra of ZnTiF6, 6H2O and MnTiF6, 6H2O single crystals have been observed in different polarizations. The various mode frequencies have been identified by studying the spectra in solution and comparing our data with those on similar systems.
Raman spectra of 1‐organosilatranes
Authors: Imbenotte M. , Palavit G. , Legrand P. 
Published: May 2005

AbstractThe Raman spectra of five organosilatranes (R = H, CH3, (CH2)3NH2, OC2H5 and F) are reported. The normal modes of the cage are presented and the assignment of the Si‐N stretching mode is discussed on the basis of C3ν symmetry for the silatrane skeleton.
Vibrational spectroscopic studies of a new class of oligophosphate glasses of biological interest: Part 2
Authors: Bertoluzza A. , Battaglia M. A. , Simoni R. , Long D. A. 
Published: May 2005

AbstractExamples of a class of glassy biomaterials with chemical composition similar to that of bone have been prepared by heating mixtures of calcium metaphosphate and hydroxylapatite. The Raman and infrared spectra of these materials are reported and discussed in relation to glass structure, which is of the linear polymeric type with chain length depending on the molar ratio R=[CaO]/[P2O5]. The products of the thermal decomposition of hydroxylapatite have also been characterized spectroscopically.
Low frequency depolarized light scattering from aqueous solutions of alkali halides
Authors: James David W. , Irmer Raimund 
Published: May 2005

AbstractThe 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

AbstractUne 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

AbstractA 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractNormal 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

AbstractThe 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

AbstractLow‐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

AbstractDerivative 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

AbstractLow‐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

AbstractDepending 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

AbstractBinary 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

AbstractSurface‐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

AbstractThe 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

AbstractEvidence 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

AbstractNew 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.