bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractSystems 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

AbstractRelative 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

AbstractAn 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

AbstractLes 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

AbstractIn 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

AbstractThe 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

AbstractWhereas 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

AbstractThe 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

AbstractRaman 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractIt 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

AbstractThe 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.
Raman scattering study of the pressure‐ and temperature‐induced phase transitions in the chain compounds (CH3)4NMnCl3 and (CH3)4NCdCl3
Authors: Couzi M. , Mlik Y. 
Published: May 2005

AbstractThe Raman spectra of (CH3)4NMnCl3 (TMMC) and (CH3)4NCdCl3 (TMCC) single crystals have been studied at different pressures between 0 and 6 kbar and at temperatures ranging from 80 to 300 K. The P, T phase diagrams of TMMC and TMCC have been determined, and a generalized phase diagram for these systems is proposed. This diagram includes four different structural modificiations whose structures are discussed on the basis of the present Raman results and of previously published structural data. Phase I is hexagonal (P63/m, Z = 2 space group) and exhibits orientational disorder of the (CH3)4N+ groups; phases II, III and IV are monoclinic and apparently ordered. Phase III (P21/m, Z = 2) exhibits a re‐entrant character. The Raman spectra of phase II are consistent with the P21/a, Z = 4 space group induced by anti‐phase translations of the octahedra chains, but do not reveal any feature that could be related to an incommensurability. It is concluded that the structure of phase IV is very complex (for instance P21/m, Z = 8 or P21/a, Z = 12). The order‐disorder processes and their possible coupling with other lattice dynamic properties are considered, to explain the I ↔ II and I ↔ III transitions; additional structural information is needed in order to choose between the different models examined.
Raman spectrum of the solid electrolytes LiI · H2O and LiI · D2O
Authors: Poulsen F. W. 
Published: May 2005

AbstractThe Raman spectra of cubic LiI · H2O and LiI · D2O have been revised. The spectra reveal only internal and librational modes of H2O (D2O). The isotopic ratios, νH/νD, are in the range 1.33–1.78.
Recording Raman spectra from plant cell walls
Authors: Atalla R. H. , Agarwal U. P. 
Published: May 2005

AbstractA Raman microprobe system has been successfully utillized to obtain luminescence‐free spectra from sections of woody tissue. The procedures for optimizing the microprobe and the sample mounting techniques are described. Spectra from the secondary wall of black spruce (Picea mariana) indicate that both lignin and cellulose can be studied in their native state.
Interpretation of the vibrational modes of uracil and its 18O‐substituted and thio derivatives studied by resonance Raman spectroscopy
Authors: Ghomi M. , Letellier R. , Taillandier E. , Chinsky L. , Laigle A. , Turpin P. Y. 
Published: May 2005

AbstractOn the basis of a valence force field, the frequencies of the vibrational modes of uracil and its 18O derivatives substituted in the 2‐, the 4‐ and the 2, 4‐positions, have been calculated. The frequencies are compared with those available from the ultraviolet resonance Raman spectra. The resonance Raman bands observed experimentally in the spectra of the uracil 2‐, 4‐ and 2, 4‐dithio derivatives have been calculated with an equivalent extended force field, and a tentative assignment of these lines is proposed.
Infrared and Raman spectroscopic study of molecular reorientation of mesitylene in the neat liquid
Authors: Lee H. I. , Kim M. S. 
Published: May 2005

AbstractReorientation of mesitylene in the neat liquid has been investigated using a combination of IR and Raman techniques. Assuming that the vibrational contribution to line broadening is the same for the IR and Raman spectra and that the rotational diffusion model is a good description for the reorientation of this molecule, rotational diffusion constants have been determined experimentally. The temperature dependences of both the tumbling and the spinning of mesitylene are explained on the basis of the hydrodynamic models for reorientational motion.
The nature of the ‘free’ OH groups in water
Authors: Giguère Paul A. , Pigeon‐Gosselin Marie 
Published: May 2005

AbstractThe shoulder at the high‐frequency edge of the O‐H stretching bands in the Raman spectra of liquid water is suppressed by addition of about 12 mol% of hydrogen peroxide. This is further evidence for ‘free’ OH groups, i.e. non‐hydrogen‐bonded (NHB), in water, in contrast with liquid hydrogen peroxide. According to a new model, water contains two kinds of hydrogen bonds: the linear bonds (LHB), as in ice, and the bifurcated bonds (BHB) between three molecules. This upsets the ideal 1:1 ratio of proton donor to proton acceptor sites, creating a slight excess of the former, hence the ‘free’ OH groups. Their concentration at room temperature is only of the order of 1–2% from comparison with the spectra of the OH− ion in aqueous solutions. There are no ‘free’ H2O molecules in liquid water.
Raman spectra of thin TCNQ films deposited on silver films
Authors: Yoshikawa M. , Nakashima S. , Mitsuishi A. 
Published: May 2005

AbstractRaman spectra of thin TCNQ films deposited on Ag films were measured as a function of TCNQ thickness. For these thin TCNQ films, several modes which are different from those in TCNQ films deposited on glass substrates were observed. A comparison with the Raman spectra of an oxidation product of TCNQ2− (DCTC−) indicates that the thin TCNQ layers (ca 20 Å) near the underlying Ag films are converted into DCTC− layers.
Surface‐enhanced Raman scattering (SERS) of nucleic acid components in silver sol: Adenine series
Authors: Kim Sang Kyu , Joo Tai Ha , Suh Se Won , Kim Myung Soo 
Published: May 2005

AbstractSurface‐enhanced Raman scattering (SERS) of adenine, adenosine, 2′‐deoxyadenosine, 5′‐dAMP, 5′‐rAMP, 5′‐rADP and 5′‐rATP adsorbed on aqueous Ag sol has been investigated. A shift of the adenine ring breathing mode from 746 to 735 cm−1 with increasing adenine concentration is interpreted as reflecting the reorientation of adenine on the Ag surface. Such a shift is not observed for adenosine, 2′‐deoxyadenosine and 5′‐dAMP. SERS spectra of 5′‐rAMP, 5′‐rADP and 5′‐rATP can be obtained either at neutral pH in the presence of pyridine or by lowering the pH of the Ag sol. The pH effect is discussed in terms of surface plasmon resonance theory.
Vibrational spectra and phase transitions in columnar M[M′III(SO4)3] compounds
Authors: Bremard Claude , Laureyns Jacky , Abraham Francis 
Published: May 2005

AbstractCompounds of general formula M[M′III(SO4)3] exhibit a columnar structure and, at room temperature, belong to the C, C and C symmetry space groups with, respectively, M1T1, M′III In; MIT1, M′IIIFe; and MI Cs, M′III Fe.The Raman spectra of powder samples have been recorded in the temperature range 77–600 K. These vibrational studies indicate the role played by the SO4 groups and MI cations in the phase transitions. All the compounds follow a space group phase sequence in accordance with the general point group relationship 2/m → 3 → 3m → 3m.
Vibrational spectra and structure of halogen‐substituted cyclopropanes. IV–cis‐ and trans‐ 1,2‐dibromocyclopropane
Authors: Schrumpf G. , Dunker H. 
Published: May 2005

AbstractThe infrared and Raman spectra of cis‐ and trans‐ 1,2‐dibromocyclopropane have been measured in the liquid phase from 4000 to 50 cm−1. An assignment of all fundamentals of the two isomers is proposed which is in accord with all the well established assignment of all fundamentals of the two isomers is proposed which is in accord with all the well established assignments of simple bromocyclopropanes and disubstituted halocyclopropanes. Evidence has been obtained for an attractive interaction between the two bromine substituents in the ecliptic position as encountered in the cis isomer.
The conformational equilibria and the IR and Raman spectra of 2‐(choromethyl)‐2‐methyl‐1,3‐dichloropropane
Authors: Martinsen K. , Powell D. L. , Nielsen C. J. , Klaeboe P. 
Published: May 2005

AbstractThe infrared spectra of 2‐chloromethyl‐2‐methyl‐1,3‐dichloropropane in several phases, including the pure liquid, as a solute and as an amorphous and crystalline solid at 80 K and under pressure (2–30 kbar), have been recorded. Raman spectra of the neat liquid and of the plastic and anisotropic crystalline phases were obtained at various temperatures.A large number of IR and Raman bands present in the neat liquid, in solution and in the plastic crystalline phase vanished in the low‐temperature and in the high‐pressure crystal spectra. Among seven possible conformers, three (having symmetries C1, C8 and C3) have no 1,3‐parallel CCI bonds and are present in the liquid, in solution and in the plastic phase. In the anisotropic crystal, only the C1 conformer was present. A phase transition between the plastic and anisotropic crystal occurred at 253 K. ΔH0 values between the most stable conformers Cs and C1 were 5±1 and 3±1 kJ mol−1 K−1 in the plastic phase and in the liquid phase, respectively.A force constant calculation for the C1, Cs and C3 conformers and for various conformers of other halogenated neopentanes (a total of 11 conformer molecules) was carried out with the overlay technique. A 41‐parameter force field was adjusted to more than 280 observed frequencies, giving very satisfactory agreement.The spectra were interpreted in terms of conformers of C1, Cs and C3 symmetry.
Resonance Raman and far‐infrared studies of charge‐transfer complexes of iodine
Authors: Nour E. M. , Chen L. H. , Laane J. 
Published: May 2005

AbstractThe reactions of I2 with phenazine (PH), acridine (AC) and hexamethylenetetramine (HMTA) have been investigated by resonance Raman and far‐infrared spectroscopy. The results indicate that the species (PH)2I+I3−, (AC)2I+I3− and (HMTA)2I+I3− are formed. However, the 1:1 adduct I2. PH is also produced and this can be obtained in relatively pure form by recrystallization.
Conformational enthalpy and volume changes in chlorocyclohexane determined by Raman spectroscopy
Authors: Gardiner Derek J. , Littleton C. John , Walker Nicholas A. 
Published: May 2005

AbstractThe Raman spectrum of chlorocyclohexane has been recorded as a function of temperature from −40 to +110 °C and the conformational enthalpy for the equatorial to axial equilibrium was determined as 1.10±0.13 kJ mol−1 for ΔH. Changes in the Raman spectrum as a function of pressure up to 5.6 kbar have been interpreted in terms of a shift in the conformational equilibrium to favour the axial form at high pressure. The associated conformational volume change has been calculated as 2.33±0.27 cm3 mol−1.
Stimulated Raman gain measurements in liquids using thermal lens detection
Authors: Bailey R. T. , Cruickshank F. R. , Pugh D. , Guthrie S. , Nelson C. H. 
Published: May 2005

AbstractThe vibrational energy deposited in a liquid by stimulated Raman gain was detected using the thermal lens scheme. The technique was demonstrated using benzene and toluene, with a frequency doubled Q‐switched Nd–YAG laser and a tunable dye laser. The rise time of the thermal lens signal was recorded with the object of obtaining information on vibrational to translational energy transfer processes.
Vibrational study of the complexation of methylmercury by glutathione
Authors: Alex Serge , Savoie Rodrigue 
Published: May 2005

AbstractThe Raman spectra of aqueous mixtures of glutathione (GSH) and methylmercury(II) were obtained at various [GSH]/[CH3Hg(II)] ratios and pH conditions. The results show that the favored step in the complexation of these species is through the substitution of the proton on the thiol group of GSH by a CH3Hg+ ion. Coordination of a second methylmercury ion on to the sulfur atom is also believed to occur extensively in acidic solutions, giving the charged complex GS(HgCH3)2+. The decrease in the concentration of this species with increasing pH is partly compensated for by complexation through substitution of a proton on the protonated amino group of GSH, a process which is favored in basic solutions. A factor analysis, based on Raman spectra of various mixtures studied under different pH conditions, has shown that these three types of complexation accounts for nearly all of the interactions which take place between glutathione and methylmercury.
Raman scattering tensor elements for some ag modes of anthracene
Authors: Bree A. , Zwarich R. 
Published: May 2005

AbstractThe intensities of the Raman lines of anthracene in solution and in the pure crystal at room temperature have been measured using several excitation frequencies (ν0) in the pre‐resonance region. The data were used to derive molecular scattering elements αii at each νo for a number of ag fundamentals. While the values of αxx and αyy are constant over the restricted range of excitation used, αzz shows an enhancement as νo moves towards resonance with the first absorption system (I). Overlap factors were determined from the fluorescence spectrum of anthracene in a biphenyl matrix, and these values were used to calculate the contribution αzz(I) due to scattering off the first excited electronic state. Working beyond the oriented‐gas assumption improved the fit between calculated and observed enhancement. There is a measurable background contribution to αzz due to scattering off higher excited states and this has an opposite algebraic sign from αzz(I) for all ag fundamentals except possibly for the 394 cm−1 mode.