bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface chemistry of MoO3γ‐Al2O3 catalysts studied by laser Raman spectroscopy: Hydration and dehydration reactions and generalization to other supported systems
Authors: Payen E. , Kasztelan S. , Grimblot J. , Bonnelle J. P.
Published: May 2005

The Raman spectra of supported molybdena‐alumina catalysts are reversibly modified by changing the laser power falling on the sample, which was examined in air. O2 calcination or evacuation at 500–700°C produces the same modification if in situ characterization is performed. Subsequent contact with the ambient atmosphere restores the original spectra. The shift from 950 to 1000 cm−1 of the main Raman line assigned to the MoO (t) stretch is interpreted as a reversible dehydration of the supported molybdate. Dehydration of the catalysts appears to be easier when a promoter is present. In agreement with Iiterature observations, this hydration phenomenon can be generalized to other supported systems such as WO3γ‐Al2O3 and V2O5γ‐Al2O3. The OH groups present on the supported polymolybdate or polytungstate have a Brönsted acidity as shown by pyridine chemisorption.
Darstellung, Schwingungsspektrum und Normalkoordinatenanalyse des Gold‐ortho‐Thiophosphates, AuPS4
Authors: Pätzmann U. , Brockner W. , Cyvin B. N. , Cyvin S. J.
Published: May 2005

AuPS4 has been prepared and characterized by vibrational spectroscopy, differential thermal analysis and chemical analysis. The frequencies are tentatively assigned. A polymer chain structure is proposed. Normal coordinate analyses have been carried out for different fragments of the AuPS4 chain. PED calculations show strong v(AuS) and δ(SPS) couplings and remarkably high AuS frequencies.
Resonance Raman spectrum of the 4, 4′‐bipyridine radical anion
Authors: Kihara Hayato , Gondo Yasuhiko
Published: May 2005

Resonance Raman, ESR and visible absorption spectra have been observed at room temperature for the 4, 4′‐bipyridine radical anion in tetrahydrofuran and for 4, 4′‐bipyridine adsorbed on metallic potassium. Based on the quinoid structure of the radical anion, as predicted by the MO theory, a normal coordinate analysis has been carried out. The relative Raman intensities have also been calculated satisfactorily for the totally symmetric modes of the radical anion. Thus, the main Raman bands are interpreted in terms of the molecular structure change caused by the resonant electronic transition in the visible region. The results are compared with those of the biphenyl radical anion, 2,2′‐bipyridine radical anion and the methylviolegen radical cation reported in the literature.
Intensity measurement of resonance Raman spectra of dye solutions with the divided Raman cell
Authors: Tsukamoto Ikuko , Nagai Hisako , Machida Katsunosuke
Published: May 2005

The resonance Raman intensities of methyl orange and brilliant blue FCF in aqueous solutions were measured by using a rotating divided Raman cell which provides an external intensity standard. The logarithms of the apparent intensities of the sample bands revealed a good linear dependence on the light path length. The relative Raman scattering coefficients of the samples with respect to a common reference band were determined from the intercepts. The effects of the excitation wavelength and the presence of surfactant on the apparent Raman intensities and the relative Raman scattering coefficients are discussed.
Vibrational spectra of cyclopropyl cyanide and cyclopropyl cyanide‐α‐d1
Authors: Green P. M. , Wurrey C. J. , Krishnamoorthi R. , Yeh Y. Y.
Published: May 2005

Raman spectra of cyclopropyl cyanide‐α‐d1 (CPCN‐d) in its condensed phases have been recorded for the first time, along with the solid‐phase Raman spectrum of the parent compound, cyclopropyl cyanide (CPCN). In addition, liquid‐ and solid‐phase infrared spectra were obtained for the isotopic derivative, and gas‐phase Fourier transform infrared spectra were obtained for both compounds. The data for CPCN‐d, combined with information deduced from gas‐phase infrared band contours and Raman depolarization ratios, enable vibrational assignments to be proposed for 47 of the 48 normal modes of these two molecules. Strong mixing of several modes in CPCN is revealed by the deuterium labeling, and evidenc for self‐association in the condensed phases is discussed. The vibrational frequencies and assignments are compared with similar results for other cyanide‐ and halogen‐substituted cyclopropanes.
Characterization of some derivatives of ferrocene and (η6‐benzene)tricarbonylchromium(0) by micro‐Raman spectroscopy
Authors: Butler Ian S. , Harvey Pierre D. , Allen Geoffrey C.
Published: May 2005

The micro‐Raman spectra of eight ferrocene derivatives [CpFeCp′; Cp; Cp = η5−C5H5, Cp′= η5−C5H4R where R = C(O)Me, C(O)Ph, C(O)CH2Ph, etc.] and three (η6‐C6H5R)Cr(CO)3 complexes have been recorded for the solids at room temperature in order to demonstrate the applicability of this new spectroscopic technique to organometallic complexes. Much lower laser powers than are normally used for Raman measurements have proved possible (0.5–3 mW at the samples) because of the high collection efficiency of the microscope optics and the multiscanning capability of the spectrometer. Raman spectra can now be obtained for materials earlier thought to be too unstable to survive the long periods of continuous laser irradiation necessary. Some vibrational assignments are proposed for the organometallic complexes examined.
Spectra and structure of phosphorus–boron compounds. XXIII–Raman and infrared spectra, vibrational assignment and normal coordinate analysis of methyldifluorophosphineborane
Authors: Odom J. D. , Stanley A. E. , Cheng Mei‐Shiow , Durig J. R.
Published: May 2005

The Raman (3500−10 cm−1) and infrared (3500−20 cm−1) spectra of CH3PF2BH3 and CH3PF2BD3 were recorded for the gaseous and solid states. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were measured. All the fundamental modes except the two internal rotations were assigned utilizing band contours, depolarization values, isotopic shifts and group frequencies. A normal coordinate calculation was carried out utilizing a modified valence force field to calculate the frequencies and the potential energy distributions. The observation of five Raman lines in the spectrum of the solid, and the observation of the doubling of several of the intramolecular fundamentals, indicate that there are at least two molecules per primitive cell. These results are compared with similar quantities in some corresponding molecules.
Raman tensors for the 1614 and 633 cm−1 modes of bis(2‐hydroxyethyl) terephthalate
Authors: Lewis E. L. V. , Bower D. I.
Published: May 2005

Raman spectroscopy has been used extensively over the last 12 years in the study of molecular orientation in polymers and liquid crystals. It has become increasingly clear that fundamental information about the anisotropy of the Raman scattering from molecules is needed, including its dependence on internal field effects. This paper reports the results of a study of the Raman scattering due to two benzene ring modes in a single crystal of a model compound for poly(ethylene terephthalate) (PET). The ratios of the observed scattered intensities for various scattering geometries and polarizations have been corrected in several alternative ways for internal field effects, before being used to evaluate the ratios of the Raman tensor components. It was not possible, however, to decide which of the internal field corrections considered was the most appropriate and the results were in some cases significantly different for different corrections. Several alternative assumptions were also made about the orientations of the principal axes of the Raman tensor with respect to the symmetry axes of the para‐disubstituted benzene rings. Even when complete freedom of the axes was allowed, the greatest departure of any principal axis from the corresponding symmetry axis of the ring was found to be only 9±4° for the 1614 cm−1 mode whereas the greatest departure for the 633 cm−1 mode was 13±5°, supporting other evidence that the latter mode is less localized to the benzene ring than the former. The implications of the results for the use of Raman spectroscopy in studying molecular orientation in PET are discussed.
Molecular interactions between electrophiles and nucleic acids. II—Raman and infrared spectra of adenine, adenine hydrochloride and the corresponding 1‐methyl derivatives in relation to tautomerism and mutagenic phenomena of bases of nucleic acids
Authors: Bertoluzza A. , Fagnano C. , Tosi R. , Morelli M. A. , Long D. A.
Published: May 2005

The Raman and IR spectra of adenine (AH3) and of its derivatives adenine hydrochloride (AH4Cl), 1‐methyladenine (1MeAH2) and 1‐methyladenine hydrochloride (1MeAH3Cl) are discussed in relation to the mutagenic and carcinogenic activities that they display.

The spectra give evidence for a shift of tautomeric stability from the aminic form, which is favoured in AH3, toward the iminic, or iminic‐derived form, in the derivatives AH4Cl, 1MeAH2 and 1MeAH3Cl.

The different biological activities of this series of compounds, in particular the mutagenic and carcinogenic effects, can be interpreted in terms of different reactivites associated with the π electronic systems, and of a hydrogen‐bond coupling different from the canonical Watson–Crick type.
Raman and far‐infrared spectra of crystalline methylene bromide
Authors: Anderson A. , Torrie B. H. , Danagher D. J. , Laurin D. G. , White J. K. , Zung W. W. E.
Published: May 2005

Lattice vibrations of polycrystalline CH2Br2 and CD2Br2, obtained by Raman and far‐infrared spectroscopy, are reported. The observed peaks are compared with the predictions of a group theoretical analysis based on the known structure of the stable phase. Assignments are proposed on the basis of isotopic shifts and intensities. Evidence of a metastable phase is presented, but attempts to isolate this phase at low temperatures were unsuccessful.
Micro‐Raman study of barium sulphate coprecipitated with potassium ions
Authors: Haley L. V. , Mattioli T. A. , Wiles D. R.
Published: May 2005

Results of a micro‐Raman spectral investigation of K+‐doped BaSO4 crystals prepared by a previously described radiochemical coprecipitation procedure are reported. Changes in the spectral bands of the ν1, ν2, ν3 and ν4 modes of the sulphate ion as a function of K+ concentration in the BaSO4 crystals reflect changes in the local environment of the SO42− ion indicating mixed‐crystal formation. These preliminary results show that Raman spectroscopy can be used to characterize changes in the BaSO4 lattice due to coprecipitated impurities.
Intensités Raman et Attribution des Modes dans le Poly(Fluorure de Vinylidène) en Phase β
Authors: Armengaud Alain , Ramonja Jean‐Louis , Abenoza Michel
Published: May 2005

La comparaison des intensités théoriques et des intensités expérimentales, réalisée sur la forme β du poly(fluorure de vinylidéne) orientée monoaxialement nous a permis d'attribuer les raies Raman observées aux différents modes de vibration de la chaǐne. Nous précisons plus particulièrement l'attribution des raies de fréquences 1278, 882 et 840 cm−1 (raies qui subissent une profonde modification lors de la transition ferro–paraélectrique des copolymères contenant du PVF2β) aux mouvements νs(CC), ρ(CH2) et νs(CF2), respectivement. Enfin, nos résultats vérifient que les groupements CH2 et CF2 conservent une bonne individualité dans la chaǐne du polymère.
Bond polarizability anisotropy: Resolution of the sign ambiguity
Authors: Armstrong Robert S. , Aroney Manuel J. , Clark Robin J. H.
Published: May 2005

An internally consistent “valence–optical” scheme of additive bond and group polarizabilities, obtained from analysis of electric birefringence, refractivity and Raman intensity data, is shown to apply to a series of compounds of Group IVB elements. For all M‐halogen bonds considered (M = Si, Ge or Sn; halogen = C1, Br or I), only the positive option for ±γ, the bond anisotropy from Raman intensities, is compatible with the scheme. The negative alternatives for γ lead to results which are anomalous and in some instances not physically meaningful. This procedure permits a definitive resolution of the problem of the sign ambiguity in ±γM‐halogen.
Crystal growth and Raman spectra of CaHCl and CaDCl
Authors: Ayadi Mohamed , Sieskind Manuel
Published: May 2005

The Raman spectra of CaHCl and CaDCl were measured at room temperature. The symmetries of the modes were determined by means of polarized Raman scattering from oriented single crystals and by deuterium substitution of the hydrogen atoms.
Ultraviolet (239 nm) resonance Raman spectroscopy of an enzyme–substrate intermediate of papain
Authors: Bajdor K. , Peticolas W. L. , Wharton C. W. , Hester R. E.
Published: May 2005

A new technique is described for the study of intermediates formed in enzyme–substrate complexes by resonance Raman spectroscopy. This technique uses an ultraviolet line from a YAG laser which is obtained by frequency doubling to 266 nm and then shifting by means of stimulated anti‐Stokes Raman scattering to 239 nm. The advantage of this line is that it falls in an absorption minimum for the aromatic residues, tyrosine and tryptophan, which permits the observation of resonance Raman spectrum of enzyme‐substrate intermediates whose absorption maxima fall within the range 225–245 nm. In order not to decompose the sample and yet conserve it, a slow flow technique has been devised which avoids the use of a quartz window. The method is illustrated with the complex formed from a simple oligopeptide and the enzyme papain. Excellent ultraviolet resonance Raman spectra are obtained from the enzyme, the substrate and the complex. By computer subtraction of the component spectra from the spectra of the complex, the presence of a new band at 1680 cm−1 is seen, which is ascribed to the carbonyl band of the acyl group bound at the active site.
Semibullvalène: Spectres de Vibration et Leur Analyse
Authors: Tabacik Vlado , Blaise Paul
Published: May 2005

Le tricyclo[3.3.0.02,8]octadiène‐3,6 (semibullvalène; C8H8) siège d'un réarrangement de Cope intramoléculaire, présente un potentiel à double minimum. Sont enregistrés ses spectres Raman (1) et infra‐rouge (1 et g). 41 fondamentales parmis 42 ont été identifiées et leur attribution proposée. Cette attribution est basée sur la détermination des facteurs de dépolarisation ρp et sur I'analyses des contours rotationnels des bandes en absorption infra‐rouge. Une attention particulière est accordée aux doublets présents dans les spectres.
Crystal standard/metal disc method for the measurement of low‐temperature resonance Raman spectra in the solid state
Authors: Bartholomew C. R. , McConnell A. A. , Smith W. E.
Published: May 2005

Mounting a sodium nitrate crystal on the surface of a disc made by compacting silver powder and the material to be studied enables Raman spectra of compounds such as zinc and nickel phthalocyanine to be measured in such a way that relative peak inteasities in any one disc can be quantified using the nitrate as a standard. It is a good method for the measurement of low‐temperature spectra of resonant compounds and for the measurement of temperature dependence.
A new multichannel Raman optical activity instrument
Authors: Barron L. D. , Torrance J. F. , Cutler D. J.
Published: May 2005

A fully computer‐controlled Raman optical activity spectrometer equipped with an intensified diode array detector is described. Despite using a conventional single‐lens light collection system for simplicity, both polarized and depolarized Raman optical activity spectra can be obtained rapidly and routinely. A novel double grating spectrograph design permits good spectra to be obtained down to 50 cm−1 in liquids. Natural spectra of the chiral samples (–)‐α‐pinene and (+)‐methylcyclohexanone and magnetic spectra of iridium (IV) hexachloride are presented.
Correlation of the Raman ν1 bands of aquated divalent metal ions with the cation–hydrated water distance
Authors: Kanno H.
Published: May 2005

The frequencies of the symmetric stretching ν1 Raman bands have been measured for aquated Be2+, Mg2+, Ca2+, Mn2+, Fe2+, Ni2+, Zn2+, Cd2+, Hg2+ and Pb2+ ions in aqueous solutions. There is a linear relationship between the frequency of the band and 1/rMO, where rMO is the distance between a metal cation and its hydrated water molecules. It is concluded that the electrostatic theory for ionic hydration can explain most of the hydrations of divalent metal ions in aqueous electrolyte solutions.
Programme d'Identification Moléculaire Informatisée à Partir de Spectres Raman. Exemples d'Inclusions Fluides dans les Minéraux
Authors: Benosman A. , Vergoten G. , Moschetto Y. , Fleury G.
Published: May 2005

A l'image des interpréteurs PAIRS (spectroscopie infrarouge) et PARS (spectroscopie Raman) pour des fonctions organiques, un troisième interpréteur PARSM a été élaboré. Cet interpréteur sert à la reconnaissance de fonctions chimiques et minéralogiques souvent rencontrées dans I'étude des inclusions fluides. Après une petit aperçu sur l'importance de la spectroscopie Raman pour l'étude des inclusions fluides, nous décrivons la démarche utilisée pour la mise au point de PARSM.
Raman scattering temperature measurements for water vapor in non‐equilibrium dispersed two‐phase flow
Authors: Neti S. , Anastasia C. M. , Smith W. R. , Chen J. C.
Published: May 2005

Laser Raman spectroscopy has been demonstrated to be a useful technique for making temperature measurements in single‐phase water vapor at atomospheric pressure over the temperature range 393–593 K. It has also been demonstrated that laser Raman spectroscopy can measure water vapor temperatures in non‐equilibrium dispersed two‐phase flow over the temperature range 393‐353 K in spite of large Rayleigh and Mie scattering from droplets. Estimated temperature uncertainties are ±15 K for single‐phase and ±22 K for two‐phase flows.
FT‐IR, photoacoustic and micro‐Raman spectra of the dodecacarbonyltriruthenium (O) complexes Ru3(13CO)12 and Ru3(CO)12
Authors: Butler Ian S. , Xu Zhen H. , Darensbourg Donald J. , Pala Magdalena
Published: May 2005

Room‐temperature FT‐IR, photoacoustic and micro‐Raman spectra are reported for the fundamental and binary ν(CO) overtone and combination regions of solid Ru3(13CO)12(13C‐enriched 99.98%) and Ru3(CO)12. These results, together with solution FT‐IR data, have enabled some vibrational assignments to be made.
Computer‐controlled system for the accurate measurement of depolarization ratios
Authors: Steele D. , Stevens Josephine A. , Gerrard D. L. , Maddams W. F.
Published: May 2005

A computer‐controlled switching device for a Pockel cell is described. Depolarization ratios of Raman bands are measured accurately as the intensities of alternate polarizations are recorded at a time separation equal to that for a single point measurement. Measurements on liquid chloroform agree to within experimental reproducibility with literature values.
Raman spectro‐electrochemistry. I. In situ raman spectroscopic studies of the electrochemical reduction of CO2 at lead‐impregnated PTFE‐bonded carbon gas diffusion electrodes
Authors: Masheder D. , Williams K. P. J.
Published: May 2005

In situ Raman spectroscopic studies of the electrochemical reduction of carbon dioxide at lead‐impregnated PTFE‐bonded carbon gas diffusion electrodes are reported. Polarization of the electrode surface resulted in the appearance of two weak bands at 2824 and 2915 cm−1. These do not correspond to the wavenumber shifts expected for free formic acid, but they are thought to arise from the presence of a ‘free’ formate ion and the formic acid perturbed at the electrode surface, respectively. Spectral changes observed at lower wavenumber shifts on polarization of the electrodes are interpreted in terms of the reduction of lead oxide to lead.
Raman study of molecular motions in relation to phase transitions in [Ni(NH3)6](NO3)2
Authors: Janik J. M. , Janik J. A. , Pick R. M. , Le Postollec M.
Published: May 2005

A Raman band at 710 cm−1 has been used for the study of the NO3− ion reorientation and of the phase transitions in [Ni(NH3)6](NO3)2. The strong temperature dependence of the width of this band in phase I is evidence for the NO3− reorientation in this phase. The reorientations stops in phase II. The same band was used for studying the phase II/phase III transition. The large thermal hysteresis of this transition has been confirmed.
Reorientation of methylbenzene molecules in the liquid phase: A comparative Raman band shape analysis
Authors: Ribeiro‐Claro P. J. A. , Da Costa A. M. Amorim , Teixerira‐Dias J. J. C.
Published: May 2005

A comparative Raman band shape study of the reorientation of monosubstituted benzene molecules (C6H5X, X = CH3, CH2Cl, CHCl2, CCl3 and CCCH3) in the liquid phase has been performed. Reorientational correlation functions appear to be less sensitive to molecular reorientation about the major axis (Z axis) than to rotation of the axis itself, approaching a symmetric top case. Molecular motion anisotropy is found to increase in the order C6H5CH3 < C6H5CH2Cl < C6H5CHCl2 < C6H5CCl3 < C6H5CCCH3 as the rotation about the Z axis becomes increasingly preferred. These results are in agreement with NMR spin–lattice relaxation data.

As expected for liquids with imporatant intermolecular interactions, both the free rotor and Kubo's model fail to fit the experimental correlation functions.
Spectres Raman de l'Ethylene‐d0 et de l'Ethylene‐d4 en Phase Gazeuse. 2—Spectres Raman de Rotation Pure. Evolution du Rapport R = αb/αa en Fonction de la Deutération de l'Ethylène
Authors: Barbès H.
Published: May 2005

Les spectres de rotation pure de C2H4 et de C2D4 ont été enregistrés. La reproduction des contours expérimentaux par des spectres simulés permet d'évaluer le rapport R égal à 0.21 pour C2H4 et 0.23 pour C2D4. Les valeurs des polarisabilités optiques principales, et les relations de αzz, αyy, αxx et R en fonction des polarisabilités de liaison de l'éthylène permettent de montrer l'évolution croissante de R avec la deutération.
Coexistence of intermolecular couplings and Fermi resonance in the liquid phase
Authors: Sokolowska Anna
Published: May 2005

The positions of polarized Roman bands resulting from simultaneous Fermi resonance and intermolecular couplings were calculated by a perturbation method. It was found that four bands should be observed, two in the isotropic and two in the anisotropic component. The dependence of the band positions on the positions of the unperturbed bands and on the intermolecular coupling constants and also the dependence of band intensity rations on the intermolecular coupling constant were investigated. The intermolecular coupling constants, the Fermi resonance coupling constants and the unperturbed band positions of ethylene carbonate were calculated from the derived equations and the experimental data.
Electronic Raman and fluorescence spectroscopic studies of Eu3+‐doped A2SO4 · χH2O sulphates
Authors: Ram Shanker
Published: May 2005

IR, Raman (100–6000 cm−1), visible absorption and fluorescence spectra of Eu2(SO4)3 · 8H2O and that doped in A2SO4 · χH2O (with A = Li, Na, K, Rb or Cs) have been studied. The bands observed are analysed in terms of the internal and external vibration modes due to the SO and H2O groups and the Eu3+ electronic Raman transitions. Particular attention is given to the electronic Raman transitions for all the 7F0 → 7FJ′ (J′=1–6) levels in an Eu3+ (4f6) configuration. In this regard, several spectra at different temperatures (77–500 K for solids and 77–360 K for solutions) and concentrations (for solutions) were measured with different lines of an Ar+ laser. This automatically isolates and thus helps in the identification of the bands with different vibrational/electronic Raman, fluorescence or vibronic origins. The bands of H2O are also confirmed by deuteriation. The electronic Raman bands are too weak and in general are masked in the fluorescence. Addition of a few drops of KI in an aqueous solution has been found to depress the intensity for the fluorescence and as a result it facilitates the observation of the electronic Raman effect. The transition energies as observed for the various 7F0 → 7FJ′ Raman bands are consistent with those deduced by the 5D0.1 → 7FJ′ fluorescence and 7F0 → 7FJ′ IR absorptions. The transitions in the Raman and fluorescence processes seem to be inter‐related. The specimens containing the alkali metal cations or the deuteriated salts reveal very intense fluorescence, and only a few and weak Raman bands. The interstate coupling and vibronic decay of the Eu3+ ions through the several radiative and non‐radiative processes operative are generally responsible for these features.
Polarized Raman and IR spectra of lattice vibrations in the non‐centrosymmetric m‐aminophenol crystal
Authors: Giermanska J. , Szostak M. M. , Girard A. , Sanquer M.
Published: May 2005

Polarized Raman and IR spectra of lattice vibrations (10–260 cm−1) in the m‐aminophenol crystal have been recorded at various temperatures in the range 20–300 K. LO–TO splittings of about 2 cm−1 have been observed for two modes of A1 symmetry. Lattice dynamic calculations of frequencies and calculations of Raman intensities based on the generalized oriented gas model have been performed. A discussion of the influence of hydrogen bonding on the lattice dynamics is presented.
Raman resonance excitation profile of the μ‐oxobis[pentacyanomanganate (III)] ion
Authors: Jubert A. H. , Varetti E. L. , Nakamoto K. , Sala O. , Aymonino P. J.
Published: May 2005

The resonance Raman spectra of potassium μ‐oxobis[pentacyanomanganate(III)] cyanide, K7[Mn2O(CN)10]CN, were measured using exciting lines at 356.4, 406.7, 530.9, 568.2, 603.5, 647.1 and 676.4 nm. By combining these data with those obtained previously (excitations at 457.9, 476.5, 488.0, 496.5, 514.5 and 608.6 nm), the excitation profiles were plotted for three totally symmetric vibrations at 1880 (CNax strech), 527 (MnCax stretch) and 259 cm−1 (MnOMn stretch). It was found that the equation derived by Mingardi et al. can adequately express these excitation profiles and that the previous assignment of the electronic transition at 509 nm needs revision.
Investigation of SnCl2AlCl3 mixtures by Raman spectroscopy
Authors: Gilbert B. P. , Taulelle F. , Trémillon B.
Published: May 2005

Raman spectra of the liquid and gas phases are reported for various molten mixtures of SnCl2 and AlCl3. As in other chloroaluminate melts, AlCl4− and Al2Cl7− are the main species present in the liquid phase. However, the spectra indicate the presence of Al2Cl6; in addition, the splitting of the ν3 band and the location of the ν1 band (341 cm−1) observed for AlCl4−, are in favour of a strong Sn2+‐AlCl4− interaction. A quantitative study of the main ν1 band ratios in the liquid allows an estimation of the equilibria between the three above‐mentioned species and, consequently, the calculation of the activity of Al2Cl6. By following the intnsity of the ν2 Al2Cl6 band in the gas phase, a method for measuring the Al2Cl6 pressure has been developed. Because a phase separation occurs around 87% of Alcl3, Raoult's law has been reformulated and the Al2Cl6 activities measured from the liquid and gas phases are in very good agreement. A comparison of the acidity level with other chloroaluminate melts is also made.
Raman spectra of some indo‐, thia‐ and selena‐carbocyanine dyes
Authors: Sato Hiroyasu , Kawasaki Masahiro , Kasatani Kazuo , Katsumata Masa‐aki
Published: May 2005

Raman spectra of some indo‐, thia‐ and selena‐carbocyanine dyes have been measured. The bands are assigned to the modes associated with the methine chain, end chromophore and methyl/ethyl group based on a comparison of the positions of the bands for a series of dyes with similar structures and those for 1,2,3,3–tetramethylindoleniumiodide and 2–methyl–3–ethylbenzothiazolium iodide, compounds related to the end chromophore of indo‐ and thia‐carbocyanine dyes, respectively.
UV resonance Raman study of the DNA–β‐propiolactone interaction
Authors: Jollès Béatrice , Chinsky Laurent , Laigle Alain
Published: May 2005

The interaction between DNA and a carcinogenic molecule, β‐propiolactone (BPL), has been followed by UV resonance Raman spectroscopy. The excitation wavelength, 257 nm, is such that the information obtained concerns the changes in the nucleic bases. At the same time as the spontaneous pH decrease caused by the hydrolysis of some BPL molecules, alkylation at N‐7 of guanine is shown to occur. More sites of interaction are found after the enzymatic hydrolysis of DNA modified by BPL at neutral pH. Guanine is shown to be modified at several sites: N‐7, N‐2 and N‐1. Alterations of adenine are also found, in N‐1 and after a reorganization of the structure concerning the N‐1 and N‐6 positions.
High‐pressure Raman study of ammonium halides
Authors: Jeon Seung‐Joon , Porter Richard F. , Ruoff Arthur L.
Published: May 2005

Raman spectra of NH4X (X = Cl, Br, I) in the range 2800–3200 cm−1 have been obtained at pressures up to 40 GPa at room temperature. The pressure dependences of the n̈1 and n̈3 modes are discussed in relation to hydrogen bonding effects in the crystals. The Raman spectra of ammonium halides show that the n̈3 mode merges to the v1 mode at pressures above 22.5 GPa in NH4Cl, 33.5 GPa in NH4Br and 35 GPa in NH4I.
Spectroscopic and molecular orbital studies of ethyl chloroactate and ethyl bromoacetate
Authors: Dube N. , Porwal P. , Prasad R.
Published: May 2005

Infrared spectra of ethyl chloroacetate and ethyl bromoacetate in the region 4000‐600 cm−1 have been recorded, together with laser Raman spectra of the molecules in the region 4000–100 cm−1. These spectra, in conjunction with CNDO 2 computations, were employed to study the conformational behaviour of the molecules. A normal coordinate analysis was carried out for the cis‐trans isomers of these molecules and supported the frequency assignments fairly well.
UV resonance Raman study of platinum binding to guanine in mono‐ and di‐nucleotides
Authors: Perno Joseph R. , Park Young D. , Reedijk Jan , Spiro Thomas G.
Published: May 2005

Ultraviolet resonance Raman UVRR spectra, with 240 and 218 nm excitation, are reported for complexes of cis‐NH32Pt2+ with dGMP 2‐deoxyguanosine 5′‐monophosphate having H or D at C‐8. Previously reported UVRR effects of Pt binding to G are confirmed and extended. Excitation profiles recorded throughout the UV region are reported, together with cross‐sections for the perchlorate ion, used as an internal standard. The excitation profiles show strong losses in enhancement associated with Pt binding for most of the guanine G UVRR bands in resonance with the UV electronic transitions of G. Hypochromic effects are involved, associated with diminished transition dipole moments due to the N‐7‐bound Pt, as are changes in Franck‐Condon products. A new, weak resonance is seen in the excitation profiles at ca 220 nm, and is attributed to a Pt → G metal‐ligand chargetransfer transition. Because bands showing large frequency shifts on Pt binding are selectively enhanced by this transition, 218 nm is the best wavelength for monitoring Pt binding to G in UVRR spectra. Even at this wavelength, Raman contributions from uncomplexed G and also A tend to obscure the Pt‐bound G spectrum, as shown by the spectra of the dinucleotides d(GpG) and d(ApG) complexed with Pt(dien)2+ (dien = diethylenetriamine), although a marker for Pt‐bound G can still be detected. The 218 nm‐excited spectrum of cis‐Pt[d(GpG)N‐7(1), N‐7(2)] shows clear evidence of both N(C‐3′‐endo) and S(C‐2′‐endo) sugar conformations, and also intensity alterations which may be associated with the ‘head‐to‐head’ arrangement of the Pt‐bound G residues.
Polarized Raman spectrum and normal coordinate analysis of α‐MnMoO4
Authors: Kanesaka Isao , Hashiba Hideto , Matsuura Ikuya
Published: May 2005

The poarized Raman spectum of α‐MnMoO4 and the infrared spectrum of the poycrystalline material are reported. The observed bands were assigned on the basis of a normal coordinate analysis using a valences force field. Force constants of molybdate ions were examined in detail. Lattic vibrations are explained mainly in terms of MnO streching force constants. Coupling between MoO stretchings on MoO bonds of differents lengths is slight and in general a v2‐like mode is higher in frequesncy than a v4‐like mode. The position of oxygen atoms substituted after an oxidation reaction of an olefin by using an 18O tracer is identified.
Symmetries of SF6 and CO2 in liquid and high‐pressure gaseous states
Authors: Bhattacharjee R.
Published: May 2005

The theory of distortion‐induced activity (DIA) of IR and Raman forbidden modes has been applied to SF6 and CO2 in the liquid and high‐pressure gaseous states. It is concluded that these molecules attain polar types of distortions in these states.
Etude par Spectrométrie Infrarouge et Raman des Phases Cristallines Basses Temperatures de (NH4)3H(SO4)2
Authors: Kamoun M. , Lautié A. , Romain F. , Novak A.
Published: May 2005

The Raman and infrared spectra of (NH4)3H(SO4)2 crystal were investigated in the range 20–300 K. An assignment of bands due to internal and external vibrations is given. The crystalline phases designated II, III, V and VII were identified and characterized spectroscopically. Hydrogen bonding, the nature and degree of structural (dis)order and the mechanisms of the phase transitions are discussed. The NH4+ ions show an important orientational disorder and become fully ordered in phase VII only. They are involved in all transitions and seem the main cause of the ferroelectricity at low temperature.
Determination of potential curve parameters of excited electronic states of polyatomic molecules by resonance CARS
Authors: Lau A. , Pfeiffer M. , Werncke W. , Weigmann H.‐J. , Lenz K.
Published: May 2005

Resonance CARS line‐shape analysis has been applied to determine the parameters of the excited electronic state potential curves of a cyanine dye and its short‐lived photoisomers during the process of photoisomerization. For this very complicated situation other methods for the estimation of these values would fail. The origin shift parameters determined are very small and the homogeneous line width is smaller than the line width of the absorption band.
Spectroscopic and calorimetric studies of phospholipid–polyamine molecular interactions
Authors: Bertoluzza A. , Bonora S. , Fini G. , Morelli M. A.
Published: May 2005

The effect of polyamines (putrescine, spermine and spermidine) on the physical properties of liposomes of phospholipids with different amount of charge on the bilayer was studied. The measured effect depends both on the charge of the lipid and on the charge of the polyamine, which under physiological conditions can be considered as a polycation. No interaction was observed with a neutral phospholipid for all the polyamines considered. With charged phospholipids, polyamines modify the surface charge and, as a consequence, the inner structure of the core of the bilayer also changes. The polyamine with the highest positive charge and the phospholipid with the highest content of negative groups showed the strongest interaction.
Infrared and single‐crystal Raman spectra of (NH4)3H(SO4)2
Authors: Rajagopal P. , Aruldhas G.
Published: May 2005

Infrared and polarized Raman spectra of (NH4)3H(SO4)2 have been recorded and analysed. Multiple bands are observed for the vibrational modes of SO and NH groups. HSO and SO ions are found to coexist with vibrational interaction between them. NH ion is not rotating freely in the lattice.
Calculation of the vibration–rotation line intensities in the Raman spectra of gases
Authors: Cheglokov A. E. , Ulenikov O. N. , Cherepanov V. N. , Makushkin Yu. S.
Published: May 2005

The method of irreducible tensorial sets is used for deriving general formulae describing the intensities of vibration‐rotation Raman lines of molecules of different symmetries. Using this method, generalization of the parameters characterizing isotropic, antisymmetric scattering, taking into account vibration‐rotation interactions, has been carried out. The effect of vibration‐rotation interactions on the Raman scattering cross‐section is considered.
SERS of α, β‐unsaturated ketones on colloidal silver
Authors: Clavijo R. E. , Mutus B. , Aroca R. , Dimmock J. R. , Phillips O. A.
Published: May 2005

Raman and infrared spectra of four α,β‐unsaturated ketones were studied. Surface‐enhanced Raman spectra were obtained on colloidal silver with two laser lines (514.5 and 647.1 nm). Evidence of strong chemisorption on the silver surface was supported by the observation of the metal‐ligand stretching vibrations. Molecular orientation of the substrate is discussed using the electromagnetic interpretation of observed intensities.
Vibroelectronic transitions in a geological fluorapatite (Esparraguina)
Authors: Martin F. , Prieto A. C. , Martin I. , Rull F.
Published: May 2005

A Raman study of a geological fluorapatite with significant substitutions of Ca2+ by Sr2+ and Ce3+ and some other minor impurities is reported. The spectra were measured at 10 K and at room temperature using excitation wavelengths of 488, 514.5 and 647.1 nm. Strong vibroelectronic transitions were observed and are explained in terms of the role played by the impurities.
Resonance Raman spectra of a Langmuir–Blodgett film of substituted copper phthalocyanine on n‐type silicon
Authors: McConnell A. A. , Smith W. E.
Published: May 2005

Resonance Raman excitation profiles for a substituted phthalocyanine dispersed as a polycrystalline powder in a silver disc were compared with those for a Langmuir–Blodgett (LB) multilayer of the same material on a silicon surface. There is a strong angular dependence of the efficiency of the scattering process. The LB profiles are strongly influenced by the electronic fields from the smooth semiconducting silicon surface, which gives rise to increased π‐π* energy separation and comparatively efficient scattering from upper vibronic states.
Concentration (D2O in H2O) and temperature Raman study of the molecular interactions in the OD stretching spectra of D2O and D2O/H2O mixtures using the fourier deconvolution technique
Authors: Zhelyaskov V. , Georgiev G. , Nickolov Zh. , Miteva M.
Published: May 2005

The OD stretching spectra of D2O for temperatures from 5 to 90°C and for concentrations (D2O in H2O) from 100 to 10 mol‐% were studied. These spectra were treated by means of the Fourier deconvolution technique for the first time.

Using the positions of the resolved components the coupling constants for intra‐ and inter‐molecular and Fermi resonance interactions and all parameters according to the presented model, for all investigated temperatures, were evaluated. A gradual decrease in all interactions was observed in the concentration study, in accordance with expectations and in agreement with the results for dilute solutions of H2O in D2O.

The temperature behaviour of the coupling constants and other parameters were in accordance with the corresponding data for H2O. The only exception is the temperature behaviour of the intramolecular coupling constant. The greater mass of the D atom is one of the probable reasons that lead to the smaller sensitivity of OD frequency to the hydrogen bond fluctuations.

All the results verify the assignments and assumptions made according to the model presented and support the continuous model for the water structure.
Raman spectroscopic study of chain complexes of bis(hydrazine) zine and manganese halides
Authors: Personette William , Szczepanski Jan , KuBulat Kulim , Vala Martin
Published: May 2005

The Raman spectra of polycrystalline Zn (N2H4)2X2 (X  Cl or Br) and Mn(N2H4)2Cl2 were run over the range 90–3590 cm−1. The bands observed in the higher frequency region (400–3590 cm−1) were assigned to perturbed hydrazine vibrations and generally agree well with previously reported infrared studies. A normal coordinate analysis was performed on the core of the complexes, metal · N4X2, and used to assign the observed metalnitrogen and metal–halide bands in the lower frequency range (90–400 cm−1).
Etude Raman des Verres 0.2Na2O(0.8x)SiO2xB2O3 (0<x⩽0.7)
Authors: Assih Toyi , Beys Louis , Hillaire Paul , Phalippou Jean
Published: May 2005

L'étude Raman des verres de la série 0.2Na2O(0.8 − x)SiO2xB2O3 a été réalisée pour des pourcentages molaires x en B2O3 tels que 0 < x ⩽ 0.7. Le choix des échatillons est tel que la droite leurs points figuratifs dans le diagramme du ternaire, coupe celle qui délimite les zones relatives aux oxygénes pontants et non pontants, permettant ainsi d'observer: les modifications des bandes Raman caractéristiques des 4. Dans les spectres de basses fréquences, l'étude de la diffusion de la lumiére par les vibrations acoutiques, pondérée par l'effet de température, nous a permis en utilisant la théoprie de Martin et Brenig de déduire une ‘longueur de corrélation’ caractéristique de l'ordre à courte‐distance.
Etude par Microscopie Raman de la Couche Liquide Situee au Contact d'un Cristal de NaNO3 en Cours de Dissolution dans sa Solution Mère
Authors: Koussinsa F. , Bertin F. , Bouix J.
Published: May 2005

The efficiency of Raman microscopy coupled with multichannel acquisition of data was tested for studying the dissolution layer of a mineral salt in its undersaturated mother solution. Experimental work was carried out on sodium nitrate solutions at concentrations ranging between 0.05 and 7.8 M. At lower concentrations the existence of three main species, free aquated ions, solvent‐separated ion pairs and contact ion pairs, was confirmed spectroscopically, in addition to a small amount of aggregates (NO3− · Na+)n which occur only at high concentrations ([NO3−]>2 M). Gaussian‐Lorentzian parameters of each ν1(A′1) band characteristic of such individual species were calculated and were found to vary considerably depending on whether the Raman spectra were recorded with a standard scanning system or with a multichannel detector. When the laser beam was focused at the interface between a dissolving NaNO3 crystal and the sodium nitrate solution ([NO3−]=4.68 M), the micro‐Raman spectra showed that the concentration of aggregates was considerably increased compared with that determined in the same way in the bulk of the nitrate solution. The technique used to obtain reliable spectra of the dissolution layer is discussed in detail.
Vibrational spectra and conformations of chloro‐ and bromo‐cyclobutane
Authors: Gatial A. , Klaeboe P. , Nielsen C. J. , Powell D. L. , Sülzle D. , Kondow A. J.
Published: May 2005

The Raman and IR spectra of chloro‐ and bromo‐cyclobutane as vapours, liquids and as amorphous and crystalline solids were recorded at various temperatures. Additional IR spectra of the high‐pressure crystalline phases were obtained at ca 25 kbar pressure. IR matrix isolation spectra were recorded at 14 K, using the hot nozzle technique.

Evidence is presented to show that chloro‐ and bromo‐cyclobutane have a second (axial) conformer existing in amounts less than 10% for chloro‐ and 3% for bromo‐cyclobutane at ambient temperature, in addition to the dominant (equatorial) conformer. From the study of the Raman spectra of the liquid and vapour as a function of temperature, enthalpy differences between the two conformers were calculated. The axial conformers could not be trapped at 17 K, revealing the barrier to ring conversion to be smaller than 5 kJ mol−1.

New vibrational assignments, supported by normal coordinate analyses are presented for both compounds.
Normal coordinate analysis of p‐nitrobenzaldehyde and assignments of infrared and Raman bands
Authors: Mohan S. , Prabakaran A. R.
Published: May 2005

The infrared and Raman spectra of p‐nitrobenzaldehyde were recorded on a Perkin‐Elmer IR 983 double‐beam grating spectrophotometer and on a Cary Model 82 grating spectrophotometer, respectively. The observed frequencies were assigned to various modes of vibrations on the basis of normal coordinate calculations.
Raman intensities of cyclohexane in the gas phase
Authors: Lorenzo C. F. , Alcántara R. , Martin J.
Published: May 2005

An experimental study of the Raman intensities of cyclohexane in the gas phase is presented. The absolute scattering coefficients and depolarization ratios corresponding to clearly differentiated spectral regions (containing one or more normal modes) were measured. The absoulute intensity of the 802 cm−1 Raman line was used as an external intensity standard. The value of S obtained for this band is 12.24 × 10−81 C2V−2 m4.
Surface‐enhanced resonance Raman spectroscopy of sulphonated copper phthalocyanine at a silver electrode
Authors: McConnell A. A. , Nimmo J. A. , Smith W. E.
Published: May 2005

The Raman spectrum of sulphonated copper phthalocyanine on a silver electrode surface is reported for four excitation wavelengths in the Q‐band region at voltages between +0.6 and −0.6 V (vs SCE). SERS activity is observed and the bonding and orientation of the surface species are voltage dependent and are inferred from a vibrational analysis. Maximum scattering intensity is observed at −0.2 V (vs SCE) and is attributed to molecules bonded edge‐on to the surface through SO3− groups.
Fourier transform infrared and Raman microprobe spectra of some silylated ribonucleosides
Authors: Butler Ian S. , Xu Zhen H. , Ogilvie Kelvin K.
Published: May 2005

The FT‐IR and laser micro‐Raman spectra of ten silylated nucleoside derivatives of uridine and their synthetic precursors, tert‐butyldimethylsilyl chloride and monomethoxytrityl chloride, were measured at room temperature. Some spectral differences are clearly evident for the 2′‐ and 3′ ‐silylated isomers; such distinctions are difficult to observe by other spectroscopic methods (e.g. 1H NMR spectroscopy). The differences in the positions of the CO stretching vibrations for the uracil base in uridine and the silylated derivatives are due chiefly to variations in the extent of hydrogen bonding in the solids. In addition, several bands attributable to SiO modes in the silylated compounds have been assigned.
Raman spectra and phase transitions of (5‐dimethylaminopenta‐2, 4‐dienylidene)‐dimethylammonium perchlorate
Authors: Sano Norimichi , Shimizu Masaaki , Tanaka Jiro
Published: May 2005

Lattice vibrational Raman spectra of (5‐dimethylaminopenta‐2, 4‐dienylidene)dimethylammonium perchlorate were measured for two crystal modifications at various temperatures. The phonon frequencies below 200 cm−1 were different for the two crystal forms. A phase transition was found by means of Raman spectra and differential scanning calorimetry (DSC). With increase in temperature of the crystal, the orange form is converted to the yellow form at ca. 370 K, and this transition is irreversible. Near the transition temperature, the Raman bands of both forms were observed simultaneously. This observation and an endothermic peak in the DSC curve show that two forms are correlated by a first‐order phase transition.
Raman and optical rotatory dispersion study of amylose in water–ethanol mixtures
Authors: Maciejewska Wanda , Kaczmarski Marceli
Published: May 2005

Raman spectroscopy and optical rotatory dispersion techniques were used to investigate the transitions of the coil–helix and helix–helix forms and the conformation of functional groups in amylose in water–ethanol mixtures. The conditions of the transitions of a random coil form to the left‐ and right‐handed helix of V‐amylose under the influence of ethanol were determined. The Raman measurements also provided information on different trans and gauche conformations of CH2OH groups. The correlation between the process of adopting the right‐handed helix of V‐amylose and the (g, g) conformation of CH2OH groups is discussed.