bluuebunny/crossref_metadata_2025 huggingface dataset:
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

The 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

The 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

A 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

On 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

Reorientation 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

The 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

Raman 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

Surface‐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

Compounds 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

The 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

The 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

The 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

The 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

The 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

The 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

The 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.
Raman spectra of halogen‐substituted methanes in the liquid state. 3—Temperature effects
Authors: Fukushi Kohji , Fukuda Takuya , Kimura Masao
Published: May 2005

The effect of temperature on the peak positions, the isotropic and reorientational band widths and the depolarization ratios of the Raman bands for the totally symmetric vibrations of CHCl3, CH2Cl2, CH2Br2, CH3Br, CH3I and CD3I has been measured in the liquid state. The isotropic band width for a CX stretching vibration decreases with increasing temperature for molecule with only one CX bond, whereas it increases for a molecule with two or three equivalent CX bonds. The isotropic band width for the deformation vibrations decreases with increase in temperature. For all the bands, the depolarization ratios depend only slightly on temperature.
Raman and Fourier transform infrared study of yeast alcohol dehydrogenase
Authors: Hall William H. , Jagodzinski Paul W.
Published: May 2005

Raman spectra of yeast alcohol dehydrogenase in buffered, aqueous solutions and in D2O, and FTIR spectra of aqueous solutions and thin films have been collected and analyzed. No significant differences between the Raman spectra in the pH range 6.00–7.50 and between the infrared spectra of the solution and film have been observed. The tyrosine doublet strongly favors exposed hydroxyl groups and the Raman spectra indicate multiple conformations for the disulfide moieties. Analysis of Raman intensities favors significant α‐helix and random coil contents. The secondary structure of yeast alcohol dehydrogenase based on Raman data is compared with the better characterized secondary structure of equine liver alcohol dehydrogenase.
Etude du Polypropylègne Isotactique par Effet Raman‐Laser: Déformation par Etirage Uniaxial
Authors: Cambon L. D. , Ramonja J. L. , Luu D. V.
Published: May 2005

L'étude par effet Raman‐laser d'échantillons de polypropylène isotactique, étirés soit à température ambiante, soit à 135°C par la méthode d'extrusion‐soufflage, nous permet de suivre l'évolution des phases au cours de la déformation. Nos résultats montrent d'une part, que la phase amorphe se déforme en premier, entraǐnant l'orientation de la phase cristalline dans la direction de l'axe d'etirage, d'autre part que cette měme phase amorphe a tendance à se concentrer dans le plan perpendiculaire à l'axe d'étirage.
Raman spectra of intraocular lenses before and after implantation in relation to their biocompatibility
Authors: Bertoluzza A. , Fagnano C. , Monti P. , Semerano G. , Garcia‐Ramos J. V. , Caramazza R. , Cellini M.
Published: May 2005

Raman spectra of seven commercial poly(methyl methacrylate) intraocular lenses (IOLs) before and after implantation in the anterior chamber of rabbit eyes are reported and discussed in order to assess their biocompatibility.

The material does not seem to change its structure on implantation; in particular the level of residual monomer, which is the main factor responsible for the biological intolerance of the lenses, remains constant.

Providing a non‐destructive structural probe, Raman spectroscopy is a suitable method for monitoring the biocompatibility of ophthalmological materials.
Raman optical activity of some azo dyes induced by inclusion in cyclodextrins
Authors: Hattori T. , Higuchi S. , Tanaka S.
Published: May 2005

The Raman optical activity (ROA) spectra of some azo dyes binding to cyclodextrins have been measured. This appears to be the first successful attempt to measure the ROA induced in achiral molecules by intermolecular interaction with chiral molecules. There was no relationship between the ROA signals and the Raman shifts accompanying inclusion phenomenon. From comparison of the ROA spectra of methyl orange with α‐cyclodextrin and congo red with γ‐cyclodextrin, it seems that the ROA spectra reflect the difference in the positions of the SO3− groups in the guest molecules.
Etude par Spectrometrie Raman de Monocristaux de CdMo6Cl14 et CdMo6Br14
Authors: Mancour S. Mancour , Caillet P. , Jouan M. , Dao Nguyen Quy
Published: May 2005

Raman spectra of single crystals of CdMo6Cl14 and CdMo6Br14 were recorded with several directions of polarization. It is shown that the spectra must be interpreted from one [Mo6X8i]X6a cluster, slightly distorted apart cubic ideal symmetry. All the vibrational modes are identified and their frequencies determined. This work is the first Raman study of ‘cube‐octahedral’ cluster Mo6X8 in the solid state.
Resonance Raman spectra of 2‐(2‐pyridylazo)‐5‐diethylaminophenol and its complex at various pH values
Authors: Kawai Kiyoyasu , Masago Harue , Kanamori Kan , Kanesaka Isao , Kasahara Issei , Goto Katsumi
Published: May 2005

The structure of 2‐(2‐pyridylazo)‐5‐diethylaminophenol (PADAP) and its complex at various pH values was studied by resonance Raman spectroscopy. The spectral features are sensitive to the pH and the solvent, which can be explained in terms of azo–hydrazone tautomers. Two types of quinonoid structures are found under neutral conditions: a hydrazone structure in chloroform solution and a pyridone‐like structure with an NH bond in the pyridine ring in aqueous solution. The quinoid structure is found at both pH 0.1 and 2.3. The relationship between the structure and the absorption spectrum under neutral conditions is discussed on the basis of CNDO/2 calculations.
Characterization of the flavin–protein interaction in L‐Lactate oxidase and old yellow enzyme by resonance inverse Raman spectroscopy
Authors: Bienstock Rachelle J. , Schopfer Lawrence M. , Morris Michael D.
Published: May 2005

Resonance inverse Raman spectroscopy was used to examine the interactions between the flavin and surounding protein in L‐lactate oxidase (from Mycobacterium smegmatis) and Old Yellow Enzyme (from brewer's bottom yeast). Spectra were taken of the enzymes both free and bound to various ligands. For L‐lactate oxidase, the ligands consisted of substrate analogs (acetate, propionate) and inorganic anions (phosphate, sulfate and nitrate). For the inorganic anions, the expected attenuation with detuning was not observed for several bands which are associated with flavin rings II and III. This effect appears to be due to a disruption of ring stacking between the uracil–pyrazine end of the flavin moiety and an aromatic amino acid. A shift in the 1232 cm−1 band and changes in the bandwidths of bands in the 1450–1600 cm−1 region indicate minor reorganization of the hydrogen bonding structure around the isoalloxazine on ligand binding.

For Old Yellow Enzyme, the ligand was chloride. Chloride caused a slight change to the Raman spectrum, indicative of decreased hydrogen bonding to the flavin.
Le Système Gazeux Gallium–Chlore: Etude par Spectrométrie Raman. 2–Analyse Quantitative
Authors: Hillel R. , Aǐt‐Hou A. , Berthet M. P. , Bouix J.
Published: May 2005

Procedures for the quantitative treatment of Raman spectra are proposed for the investigation of gallium–chlorine gaseous mixtures. They are based on correlations between pressures and Raman band intensities and require a knowledge of reliable entropy and heat capacity data for the main gaseous species. For the ratio Cl/Ga=3 and between 590 and 690 K, the pressure determinations from the band intensity evolution corresponding to the symmetric vibrational modes ‘ν1’ of Ga2Cl6 and GaCl3 confirm the starting consideration of the single equilibrium Ga2Cl6(g)⇌2GaCl3(g). They lead to an enthalpy of dissociation of Ga2Cl6 very close to the literature data. For Cl/Ga3 and between 800 and 950 K, the treatment of the Raman spectra is performed by computation of the GaCl spectrum in order to discriminate between the GaCl3 ‘ν1’ band intensity and the GaCl ‘νs’ branch intensity. This intensity difference and the GaCl ‘νQ’ branch intensity are used for pressure determinations. The results are consistent with the proposed equilibrium 2Ga(l)+GaCl3(g)⇌3GaCl(g). They lead to a calculated reaction enthalpy that allow one to select a reliable value for the enthalpy of formation of GaCl.
UV resonance Raman excitation profiles of l‐cystine
Authors: Johnson Craig R. , Asher Sanford A.
Published: May 2005

The UV Raman excitation profiles of l‐cystine have been measured between 220 and 514.5 nm. No enhancement is observed from the lowest energy electronic transition (λmax = 245 nm). The excitation profiles for the SS, CS and CO stretching vibrations are each satisfactorily modeled by standard Albrecht A‐term pre‐resonance expressions which indicate that the Raman intensities derive from a state(s) at ca 170 nm which is probably σ → σ* in character. Selective enhancement of disulfide stretching vibrations in proteins will require excitation in the vacuum UV spectral region.
Fourier transform infrared and laser Raman microprobe spectra of uridine
Authors: Xu Zhen H. , Butler Ian S.
Published: May 2005

Vibrational assignments are proposed for the room‐temperature FTIR and laser Raman microprobe spectra of solid uridine. These assignments are based chiefly on comparisons of the vibrational data observed for uracil, D‐ribose and a 1:1 mixture of these two compounds with those for the uridine nucleoside itself.
Raman spectral studies of single crystal CH3ND3NO3
Authors: Mylrajan M. , Srinivasan T. K. K.
Published: May 2005

Raman spectra of single crystal N‐deuterated methylammonium nitrate (CH3ND3NO3) were studied in the temperature range 77–400 K. A systematic temperature dependence study of the internal and external modes was carried out. The results show the preseuce of three structural phases. Raman spectra of phase II in the internal and lattice region were interpreted on the basis of a D space group and relative polarization data. A thermal hysteresis characteristic of a first‐order transition was observed in the
equation image

The spectral features of phase I indicate this to be a plastic phase, in which cations and anions exhibit isotropic reorientational motion. The spectral changes that occur in the
equation image
transition suggest a freezing out of the thermal motion and reveal that only minor changes are involved in this transition.
Application of transform theory to resonance cars excitation profiles of a cyanine dye
Authors: Watanabe Nobuhisa , Shimizu Masaaki , Tanaka Jiro
Published: May 2005

The transform method has been used to investigate the CARS excitation profiles (CEPs) of a highly fluorescent cyanine dye including linear non‐Condon sources of scattering. It is demonstrated that the calculated predictions of the CEPs are in good agreement with the experimental data of the CARS excitation profile of the dye. The observed values of the linear non‐Condon activity parameters, Ca, of three vibrational modes of 3,3′‐diethylthiacar‐bocyanine bromide were as large as 0.3. This suggests that linear non‐Condon electronic transition moments are important in the investigation of CEPs of cyanine dyes.
Surface‐enhanced raman spectroscopy of acrylamide and polyacrylamide adsorbed on silver colloid surfaces: Polymerization of acrylamide on silver
Authors: Suh J. S. , Michaelian K. H.
Published: May 2005

The SERS spectra of acrylamide and polyacrylamide adsorbed on the surface of silver colloid particles are reported. The SERS spectrum of acrylamide is interpreted as indicating that polymerization takes place on silver colloid surfaces. Evidence supporting this conclusion includes the fact that the CH2 stretching vibrations of acrylamide adsorbed on the silver colloid surfaces are at 2926 and 2972 cm−1, which correspond exactly to those of polyacrylamide, and are greatly different from those at 3050 and 3115 cm−1 observed for acrylamide in aqueous solution. Another possible indication of polymerization is the band at 1164 cm−1, which can be assigned to a polymer skeletal vibration.

Although acrylamide is polymerized on the silver colloid surfaces, the SERS spectra of polyacrylamide polymerized before adsorption and acrylamide polymerized on the colloid surface are very different from each other. This observation is attributed to the different surface geometry of these two polymers, and the possible contibution of non‐polymerized species in the SERS spectrum of acrylamide.
Resonance Raman spectra of the N,N ‐ dihydro‐4,4′‐bipyridinium radical cation
Authors: Barker David J. , Cooney Ralph P. , Summers Lindsay A.
Published: May 2005

The Raman spectrum of diprotonated 4,4′‐bipyridine in the solid state as the dibromide salt is reported. The resonance Raman spectrum of the radical cation derived by one‐electron reduction of the dication is also reported. Viscous glycerol was employed as a solvent in order to protect the radical by inhibiting oxygen diffusion. The spectra are interpreted on the basis of a comparison with those of related compounds. A large shift in frequency (+70 cm−1) of the inter‐ring stretching vibration between the parent dication and radical monocation is observed. This has been interpreted in terms of a major contribution to the delocalized radical structure of a quinoid‐type form.
Spectres Raman de l'Ethylene‐d0 et de l'Ethylene‐d4 en phase Gazeuse. 1–Etude des Contours des Bandes ν6 et ν8 et Evaluation de la Constante de Coriolis, ζ,8
Authors: Barbès H.
Published: May 2005

Les structures rotationnelles des bandes Raman ν6 et ν8 de l'éthylène‐d0 et de l'éthylène‐d4 à l'état gazeux ont été enregistrées. Le contour de chaque bande perturbée ν8 a été analysé en simulant les bandes du rotateur asymétrique, ce qui a permis de mettre en évidence les effects d'une interaction de Coriolis de type a. La constante de Coriolis, ζ,8 a été déduite pour chaque molécule.
Raman spectra of single‐crystal Cd(BrO3)2 · 2H2O and polycrystalline Cd(BrO3)2 · 2D2O
Authors: Devananthan T. , Srinivasan T. K. K.
Published: May 2005

Raman spectra of single‐crystal Cd(BrO3)2 · 2H2O and polycrystalline hydrate, deuterate and partially deuterated samples at 90 and 298 K were investigated in detail. Polycrystalline hydrate, deuterate and partially deuterated samples were examined at 90 and 298 K in the OH and OD internal region by infrared spectroscopy in order to explore the structural environment of water of hydration. Vibrations in the OH stretching region were attributed to (H2O)I and (H2O)II type molecules. Single‐crystal Raman spectra were analysed and most of the normal modes were assigned.
Measurement of Raman scattered intensities in media with natural or field‐induced optical activity
Authors: Slobodyanyuk A. V. , Schaack G.
Published: May 2005

The intensity of Raman scattered light has been calculated for gyrotropic media, i.e. for media with a natural optical activity or a gyrotropy induced by a magnetic field. It is shown that anomalies in the scattered intensity are in general due to interference effects between the two orthogonally polarized normal modes of electromagnetic radiation propagating in the anisotropic crystal either in the incident or in the scattered beam or in both. Only when the state of polarization of the incident and the scattered waves agrees with one of these normal modes are clear results obtained which are simply to interpret. Hence the intensity anomalies sometimes observed in these media find an interpretation in the frame of the generally accepted theory. No breakdown of selection rules will occur in such media.

The calculated results are compared with experimental findings in α‐quartz and in ZnP2 and also in paramagnetic TmVO4 and in CeF3 in external magnetic fields.
Spectra and structure of small ring compounds. XLIX—Raman and infrared spectra, conformational analysis and vibrational assignment of methylcyclobutane and methyl‐d3‐cyclobutane
Authors: Kalasinsky V. F. , Harris W. C. , Holtzclaw P. W. , Little T. S. , Geyer T. J. , Durig J. R.
Published: May 2005

The Raman (3500–20 cm−1) and infrared (3500–50 cm−1) spectra of gaseous and solid methylcyclobutane and methyl‐d3‐cyclobutane have been recorded. Additionally, the Raman spectra of the pure liquids have been recorded and qualitative depolarization values have been obtained. The spectra have been interpreted on the basis that both the axial and equatorial conformers are present in the fluid phases and that the equatorial form is thermodynamically preferred and the only form present in the annealed solid. All 39 of the normal vibrational modes have been assigned for both the d0 and d3 compounds. An abundance of spectral evidence is presented which indicates extensive coupling between the vibrations associated with the ring and those of the methyl group. The CH3 internal torsional mode has been observed in the Raman spectrum of the solid at 232 cm−1 and utilizing this frequency the periodic threefold barrier to internal rotation has been calculated to be 1190 cm−1 (3.40 kcal mol−1). The fundamental ring puckering mode has been assigned from the Raman spectra of the gases to weak features observed at 161 and 154 cm−1 for the d0 and d3 compounds, respectively. All of these results are compared with the corresponding quantities for some similar molecules.
Vibrational spectroscopy at very high pressures. 47—Raman scattering study of K3Cu(CN)4: A trigonally distorted species
Authors: Adams David M. , Hatton Peter D.
Published: May 2005

K3Cu(CN)4 displays a high‐pressure phase transition at 14 kbar and another at ca 100 kbar (as estimated visually using an ungasketted diamond anvil cell). No Raman spectra could be obtained for phase III but the Raman spectra of phase II show that the trigonal distortion evident at ambient pressures is retained. The suggested space group of phase II is C, a maximal zellengleich descent of the ambient structure, C. As with K2M(CN)4 (M = Zn, Cd or Hg), a trigonal distortion appears favoured under external pressure.
Calculation of the Raman line broadening on carbonation in synthetic hydroxyapatite
Authors: de Mul F. F. M. , Otto C. , Greve J. , Arends J. , Ten Bosch J. J.
Published: May 2005

The position and broadening of the Raman band associated with the phosphate symmetric stretching vibration in hydroxyapatite are simulated using a simple inter‐ and intra‐ionic potential. The results are compared with experimental values. This comparison was made as a function of the incorporation of carbonate ions in the lattice for a number of substitution models. The line width of the phosphate symmetric stretching vibration is shown both theoretically and experimentally to be dependent on the carbonate content. Good agreement between calculations and experiment is obtained. The results of the calculations offer some support to the suggestions in the literature that the dielectric constant has to be considered as a function of the distance in the lattice, increasing beyond the first environmental layer.
A test reaction for rapid‐mixing, rapid‐flow Raman cells
Authors: Cartier L. R. Sans , Storer A. C. , Carey P. R.
Published: May 2005

The design and construction of a four‐jet rapid‐mixing, rapid‐flow Raman cell, suitable for following chemical or biochemical reaction events 20 ms and longer after mixing, is described. A suitable test reaction, the base‐catalysed hydrolysis of 2,4‐dinitrophenyl acetate in 10% methanol, has been characterized by a stopped‐flow kinetic analysis. When this reaction is carried out in the rapid‐mixing, rapid‐flow Raman cell a resonance Raman peak of the 2,4‐dinitrophenolate product, measured against a methanol peak as an internal standard, permits the calculation of the extent of product formation. Using the rate constant determined from the stopped‐flow kinetic analysis, the dead time (the time after mixing) in the Raman flow cell can be calculated for the flow‐rate employed. When the flow system is operating correctly, this dead time is in close agreement with that calculated from the known flow‐rate and the combined volume of the mixing and flow cell. Since the reaction is monitored using the commonly available 457.9 nm Ar+ line, it can be used to test the operational efficiency of rapid‐mixing, rapid‐flow systems built in most Raman laboratories.
Phase transitions in non‐ionic surfactant–water systems as studied by Raman spectrometry. II—A new methodology
Authors: Gaufrès R. , Bribes J.‐L. , Sportouch S. , Ammour J. , Maillols J.
Published: May 2005

In order to compare the molecular Raman spectra between an optically isotropic phase and an anisotropic phase, a method is proposed having especially in view the study of transitions in lyotropic surfactant systems. Its application to the transition between the isotropic and hexagonal phases in the water‐α‐octyl‐ω‐hydroxypentakis (oxyethylene) system shows that there is no significant molecular structure change at transition. This result suggests that all the micelles in the L1 phase in equilibrium with the hexagonal phase have a cylindrical shape.
Solid‐state vibrational spectroscopy of disordered crystals. II—Phonon spectra and structure of crystalline thioanisole
Authors: Cataliotti Rosario Sergio , Paliani Giulio , Santini Sergio
Published: May 2005

The phonon spectra of thioanisole have been measured in a temperature range from the freezing point to 77 K, in order to ascertain if disordered crystalline phases are obtained as in other sulphur‐containing molecular crystals studied. All the Davidov splitting components have been assigned on the basis of a correlation diagram which has been constructed assuming a unit cell isomorphous with a Cmc21 orthorhombic crystal.
High‐pressure Raman study of liquid and solid thiophene up to 100 kbar at 300 K
Authors: Shimizu H. , Matsunami N.
Published: May 2005

High‐pressure Raman spectra of liquid and solid thiophene C4H4S have been measured up to 100 kbar at 300 K in a gasketed diamond anvil cell. The pressure dependence of intramolecular and intermolecular vibrational modes revealed a solidification point at 6 kbar and a pressure‐induced phase transition at 40 kbar. This solid‐solid phase transition was identified as the III→IV phase transition by comparison with the intermolecular Raman spectra of the low‐temperature solids at atmospheric pressure. The appearance of a dark‐red modification of C4H4S, which is irreversibly formed at pressures above 80 kbar with laser irradiation, is discussed.
Resonance Raman studies of the structures and vibrational assignments of photochromic S‐alkyldithizones
Authors: Takahashi Hiroaki , Yamada Osamu , Isaka Hiroaki , Igarashi Takashi , Kaneko Norio
Published: May 2005

The resonance Raman spectra of S‐methyldithizone (MeHDz), S‐ethyldithizone (EtHDz) and S‐isopropyldithizone (iPrHDz) have been measured in the solid state and in solution. It is shown that the red and yellow isomers of these S‐alkyldithizones adopt in solution the trans‐syn‐s‐trans and trans‐anti‐s‐trans configurations, respectively, with respect to the NN, CN and CN bonds of the formazan skeleton. It is also demonstrated that for EtHDz the red and yellow isomers can be isolated as different crystal forms. Vibrational assignments are given for both red and yellow isomers of MeHDz based on the frequency shifts of five kinds of isotopically substituted species.
Raman spectra of single crystals of α‐P4S3
Authors: Burns Gary R. , Rollo Joanne R. , Syme Roderick W. G.
Published: May 2005

Polarization data for the Raman‐active k = 0 phonons of single crystals of α‐P4S3 have been measured at 10 K and at high resolution. Of the 24 external and 60 internal phonons expected for the D2h factor group of α‐P4S3 we have observed 16 external and 38 internal phonons. The effect of the layer lattice has been proposed to explain the absence of some expected phonon structure. The present work together with an earlier study of the pressure and temperature dependence of the Raman‐active phonons have enabled the 4A1, A2 and 5E internal molecular modes to be assigned. The resulting normal coordinates give good fits for the Raman‐active bands of the heavy isotope P4 32S2 34S and for the mixed chalcogen species P4S3 − xSex.
Halogen‐substituted amides. VI—vibrational spectra of some fluoro‐ and iodo‐substituted acetamides
Authors: Murthy E. Krishna , Rao G. Ramana
Published: May 2005

The Raman spectra of 2‐fluoroacetamide, trifluoroacetamide and 2‐iodoacetamide were recorded and their infrared spectra as mulls were measured in the range 4000–200 cm−1. The Fourier transform far‐infrared spectra of the same samples, in the region 500–50 cm−1, were also obtained. The frequencies were assigned to various fundamental modes of the molecules on the basis of qualitative considerations.
Raman and infrared studies on (5‐dimethyl‐aminopenta‐2,4‐dienylidene)dimethylammonium perchlorate
Authors: Sano Norimichi , Shimizu Masaaki , Tanaka Jiro , Tasumi Mitsuo
Published: May 2005

Pre‐resonance Raman and infrared spectra of (5‐dimethylaminopenta‐2, 4‐dienylidene)dimethylammonium per‐chlorate have been measured in various environments. Unusual intensity changes of some particular peaks in the Raman spectra are observed for two crystalline polymorphs and solutions of the dye. Most of the Raman and infrared bands in solution are assigned to normal modes. This analysis allows the major difference between the spectra of two polymorphs to be explained.
Phonon spectra and unit cell analysis of 2‐cyanothiophene
Authors: Cataliotti Rosario Sergio , Antolini Francesco , Morresi Assuntina , Santinelli Fabio , Santini Sergio
Published: May 2005

Vibrational spectra of 2‐cyanothiophene in the solid state reveal that the crystals are ordered below the freezing point and have an orthorhombic C2v unit cell. Intermolecular forces between the two molecules occupying the Bravais unit are not strong enough to promote the separation of all the Davidov doublets of the phonon states.
Halogen‐substituted amides. VIII—normal coordinate analysis of trifluoroacetamide
Authors: Murthy E. Krishna , Rao G. Ramana
Published: May 2005

A 23‐parameter modified valence force field has been employed for a normal coordinate analysis of trifluoroacetamide. A least‐squares technique was used to refine the force constants. The potential energy distributions were also calculated. The nature of the absorption bands is discussed in relation to the mixing of vibrational frequencies.
Resonance Raman spectra of the complex pentacyano‐4‐cyanopyridineferrate(II) and its 4‐cyanopyridine‐bridged binuclear complex with a ruthenium(II) pentaamine unit
Authors: Della Védova C. O.
Published: May 2005

Comparative resonance Raman effect (RRE) studies of both the 4‐cyanopyridine complex with the pentacyanoferrate(II) anion, the first [Fe(CN)5L]3− anion studied by RRE, and a binuclear complex formed by this anion with 4‐cyanopyridine as bridging ligand and a pentaamineruthenium(II) moiety are reported. The RR spectra obtained show differences in the number of enhanced modes in each case. The spectroscopic data suggest coordination of the Fe(CN)5 unit through the pyridine nitrogen of 4‐cyanopyridine in both the mononuclear and the binuclear complex. Assignment of the electronic spectra as being due to metal to ligand charge transfer (MLCT) (FeII → pyridine‐N, 4‐cyanopyridine) is proposed for the bands at 476 nm (aqueous solution) and 470 nm (solid dispersion in KBr) in both the mononuclear and the binuclear complex, respectively, and MLCT (RuII → nitrile, 4‐cyanopyridine) for the band at 418 nm (solid) observed in the binuclear complex only.

Excitation profiles of the 1600 cm−1 bands in the mononuclear complex (in acetonitrile‐methanol solution) and of the 1607, 1207 and 1020 cm−1 bands in the binuclear complex (as solid) were obtained and are interpreted.
Line widths in the pure rotational Raman spectra of nitrogen, oxygen and hydrogen broadened by foreign gases
Authors: Edwards H. G. M. , Long D. A. , Webb S. W.
Published: May 2005

Broadening coefficients, σp, have been determined for the pure rotational Raman lines of nitrogen and oxygen, perturbed by hydrogen, helium and methane, and of hydrogen broadened by helium, argon, nitrogen and carbon monoxide, over the pressure range 2–100 bar with a host gas partial pressure of 1 bar. The results are summarized below:

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The broadening coefficients are discussed in relation to the dipole, quadrupole and octopole moments and the polarizabilities of the perturbing species.
Vibrational dephasing of arsine in the liquid and plastic crystalline states
Authors: Wilde Richard E.
Published: May 2005

Raman spectra of the ν1 bands of AsH3 have been obtained for the liquid state and for phase I of the solid state. It is shown that phase I is a plastic crystalline phase. A modeling procedure applied to the vibrational autocorrelation function shows that the modulation of the vibrational frequency is fast and that the vibrational dephasing is probably caused by the rotations. Evidence for a ν1‐ν3 Coriolis‐coupling effect is also presented.
Spectra and structure of small ring compounds. LII—Raman and far‐infrared spectra of solid 1,1‐dicyanocyclopropane and ab initio calculations of cyclopropane, cyanocyclopropane and 1,1‐dicyanocyclopropane
Authors: Little T. S. , Zhao Wenyun , Durig J. R.
Published: May 2005

The Raman (3500–10 cm−1) and far‐infrared (400–70 cm−1) spectra of solid 1,1‐dicyanocyclopropane have been recorded. The molecular structure of cyclopropane, cyanocyclopropane and 1,1‐dicyanocyclopropane have been calculated by ab initio methods at the 4‐31G basis set level. The harmonic force fields for cyanocyclopropane and 1,1‐dicyanocyclopropane have also been calculated using the same basis set. By the combination of experimental data and normal coordinate calculations with scaled ab initio force constants, the vibrational assignments for these two molecules have been revised. Discrepancies between the previously reported and present assignments are discussed. The molecular structures of cyanocyclopropane and 1,1‐dicyanocyclopropane obtained in this work are compared with the molecular structure of cyclopropane.
Study of factors responsible for the half‐width of the NH3 Raman torsional band in crystalline sulphamic acid
Authors: Bocquet J. F. , Abello L. , Muthusubramanian P. , Lucazeau G.
Published: May 2005

Raman spectra of single crystals of NH3SO3 were recorded for the B1g and B3g polarization in the range 10–500 cm−1 for the temperature range 10–360 K and for zz, zy and zχ polarizations in the range 2500–3300 cm−1 at 77 and 300 K. Neutron diffraction data on the polycrystalline sample at 4 and 77 K were obtained in order to study the structural variation with temperature. Potential energy calculations made using atom‐atom potentials show that torsional mode broadening is not caused by hot‐band transitions. The ful width at half maximum intensity of the torsional mode was accounted for in terms of the reorientational motion of the NH3 rotor and the pure vibrational dephasing (PVD). At 300 K the reorientational motion contributes about 2 cm−1. The PVD broadening was calculated on the basis of cubic coupling between the torsional and hydrogen bond stretching modes following a semi‐classical model. Its contribution at 300 K was estimated to be 25 cm−1.
Raman and infrared study of reorientational dynamics in trifluorobenzene
Authors: Yuan P. , Chen A. F. T. , Schwartz M.
Published: May 2005

The Raman spectral bandwidths of two A1′ vibrations of 1,3,5‐trifluorobenzene (TFB) were measured in the neat liquid as a function of temperature and in the solvents CH2Cl2 and CS2. The Raman and IR linewidths of two E′ modes were also measured in solution. Derived values of the two rotational diffusion constants, D⊥ and D∥, were compared with the predictions of several current theories. It was observed that the Hynes–Kapral‐Weinberg (HKW) theory is superior to both the microviscosity–free rotor and Hu–Zwanzig ‘slip’ models of reorientational diffusion. Calculated values of D⊥ and D∥ for TFB in solution using the HKW model are in excellent agreement with the experimentally measured diffusion constants.
Fourier transform Raman spectra of deeply coloured inorganic species. I–The permanganate ion
Authors: Hendra P. J. , Le Barazer P. , Crookell A.
Published: May 2005

The literature contains only very poor Raman spectra on several deeply coloured ions. In this paper, new spectra of high quality are given for the permanganate ion, obtained using Fourier transform Raman techniques and nearinfrared excitation. Several other tetraoxo compounds have also been studied by these techniques as a comparison.
Analyse Vibrationnelle et Structurale en Série Aliphatique Saturée. IX—Spectres de Vibration de l'Acide Pimelique et de ses Sels Alcalins en Solution Aqueuse
Authors: Delarbre J. L. , Fabrègue E. , Maury L. , Bardet L.
Published: May 2005

The Raman and infrared spectra of pimelic acid, (CH2)5[COOH (D)]2, and its potassium salts in aqueous solution were recorded from 4000 to 200 cm−1. The two salts belong to the Cs symmetry point group whereas the acid has C1 symmetry. These results are similar to those found previously for lower alkanedloic acids with an odd number of carbon atoms, namely glutaric acid, (CH2)3(COOH)2, and malonic acid, CH2(COOH)2.
Vibrations of the tetrahedral AlCl4− ion in crystals: An estimation of crystal environmental effects on the spectra of the chloroaluminate ion in crystals
Authors: Narayanan V. Anantha
Published: May 2005

Force constans for AlCl4− in a series of alkali metal compound crystals were calculated using an orbital valence force field. The calculated force constants were utilized to estimate, by empirical methods, the spreads in AlCl bond lengths and ClAlCl angles caused by crystalline environmental effects. They are of the order of few hundredths of an ångstrom and a few degrees, respectively. These variations are compared and correlated with the structure details available in the literature for these ions in crystals.