bluuebunny/crossref_metadata_2025 huggingface dataset:
Resonance Raman studies of transition metal peroxo complexes: 5—The oxygen carrier cobalt(II)‐salen and its μ‐peroxo complexes, [(L)(salen)Co]2O2; L = DMSO, py, DMF, pyO and no L
Authors: Hester R. E. , Nour E. M.
Published: May 2005

Resonance Raman spectra of the species [Co(salen)], [Co(salen)]2 and [Co(salen)(py)] were obtained both from the solids and from CHCl3 solutions. These spectra show a large number of bands in the 100–1750 cm−1 region which are assigned to vibrational modes of the salen ring. Oxygenated complexes having the general form μ‐peroxo‐[Co(salen)(L)]2O2, with ligand L being DMSO, py, DMF, pyO or no L and occupying the axial position trans to the dioxygen, gave resonance Raman spectra with many bands throughout the region 100–1750 cm−1. The ν(CoO) and ν (OO) wavenumbers in these complexes have been assigned by means of oxygen‐18 substitution. Force constants for the OO and COO bonds in the DMF complex have the values 380 and 247 N m−1, respectively. The effect of changing the ligand L on the observed wave numbers is interpreted in terms of both σ and π‐donor effects through the metal. Band intensity excitation profiles demonstrate that the O22− → Co3+ CT transition occurs at ˜370±10 nm for the complexes containing ligands L and at 580 nm for the complex with no L. Resonance function plots of Raman band intensities are interpreted in terms of the relative values of the OO bond orders which are shown to vary with the ligand L as follows: py>pyO>DMF>DMSO. This order is, however, at variance with that based on the ν (OO) wavenumbers.
Variable temperature and pressure study of the Raman spectrum of five phases of HgI2
Authors: Khilji M. Y. , Sherman W. F. , Stadtmuller A. , Wilkinson G. R.
Published: May 2005

Raman spectra of red and yellow forms of HgI2 have been recorded as a function of temperature and pressure. Temperatures between 77 and 570 K and pressures up to 14 khar have been used to investigate the vibrational modes of four (and possibly five) phases of this material. No evidence could be found from the Raman spectrum to support the suggestion that a thermal anomaly within the stability range of the red form indicates a III to IV transition. Clear differentiation between the yellow high temperature and high pressure phases has been shown, and the phase boundary (YHP→YHT) located. A previously unreported Raman spectrum of an orange phase is shown, and a modified phase diagram is presented.
Laser Raman spectroscopy of biomolecules: 15—Conformational study of partially reduced, fully reduced and cyanogen bromide treated ribonuclease a
Authors: Lord Richard C. , Relyea Noël M.
Published: May 2005

Reduction of one disulfide bond in bovine pancreatic ribonuclease A, which leaves the enzyme with nearly unimpaired biological activity, makes barely perceptible changes in the aqueous Raman spectrum. Reduction of all four disulfide bonds, which inactivates the enzyme, produces serious conformational changes. The spectrum shows a substantial decrease in α‐helical content and conversion of all tyrosines to a weakly hydrogen‐bonded form. Cleavage of the peptide chain by cyanogen bromide at the three sites of methionine residues (13, 29–30 and 79) makes little alteration in the α‐helical content but reduces the proportion of the β‐pleated sheet. This structural change is attributed mainly to the chain breaking at residue 79, which occurs in the center of the β‐network.
The radial transition of tetrahydrofuran
Authors: Sont W. N. , Wieser H.
Published: May 2005

A weak sequence of lines in the Raman spectrum of tetrahydrofuran vapour around 270 cm−1 has been observed for the first time and is assigned to combination transitions between the pseudorotational‐radial states of the five‐membered ring. With the aid of these lines an interpretation for the complex infrared band in the same region is suggested. A suitable Hamiltonian is applied to the pseudorotation energy levels in the ground and the first excited radial state.
Resonance Raman spectra of transient free radicals using stopped flow multichannel and rapid scan methods
Authors: Merlin J. C. , Lorriaux J.‐L. , Hester R. E.
Published: May 2005

Chemical oxidations of 1,4‐dimethoxybenzene (DMOB) and diazabicyclooctane (DABCO) in solution result in the generation of short‐lived free radical cations which have strong visible absorptions. These have been used for the excitation of resonance‐enhanced Raman spectra. The DMOB+˙ radicals were produced in a stopped‐flow apparatus linked with an optical multichannel Raman instrument. The DABCO+˙ species was produced by rapid mixing and its spectrum determined by rapid scanning of a conventional spectrometer. Both kinetic data and vibrational spectra are produced by these methods.
Spectra and structure of organogermanes: 21—Infrared and Raman spectra, and vibrational assignment of (CH3)3GeNNN and Normal coordinate calculations of (CH3)3GeNNN, (CH3)3GeNCO and (CH3)3GeNCS
Authors: Durig J. R. , Jalilian M. R. , Sullivan J. F. , Turner J. B.
Published: May 2005

The Raman spectra of gaseous, liquid and solid trimethylgermylazide, (CH3)3GeNNN, and the infrared spectra of the gas and solid have been recorded (20–3200 cm−1). Assignment of the fundamentals, based on their depolarization values and group frequencies, is given and discussed. A normal coordinate calculation has been carried out utilizing a modified simple valence force field. The extent of vibrational coupling has been determined. It is believed that the main force constants should be transferable to other substituted trimethylgermanium compounds and, thus, transferability is demonstrated by some normal coordinate calculations for trimethylgermylisocyanate and trimethylgermylisothiocyanate. The bonding in these pseudohalogens is discussed and it is shown that the appropriate resonance structures can account for the linearity of the GeNCS moiety and the non‐linearity of the GeNCO and GeNNN moieties.
Raman spectroscopic investigations of the acid‐base forms of dithizone
Authors: Pemberton Jeanne E. , Buck Richard P.
Published: May 2005

Raman spectra of three forms of dithizone are presented. Significant structural changes are indicated in the Raman spectra when a proton is added or lost from neutral dithizone (H2Dz) to form the corresponding conjugate acid of dithizone (H3Dz+) and the dithizone anion (HDz−), respectively. These spectral changes are correlated with the structures previously proposed for these species.
Isotopic hydrogen exchange in the dinucleoside monophosphate IpI
Authors: Thomas G. J. , Ferreira S. A.
Published: May 2005

Each of the hypoxauthine residues of the dinucleoside monophosphate, inosylyl(3′→5′)inosine (IpI), manifests the same rate of deuterium exchange of the proton at the 8‐C ring position, as measured by Raman spectrophotometry. In the temperature interval 30–80°C and at neutral pD, the exchange rate constants yield Arrhenius parameters (Ea = 22.4±0.6 kcal mol−1; A = 2.13 × 1013 h−1) that are identical to values obtained on inosine‐3′:5′‐monophosphate (cIMP), but different from those of inosine‐5′‐monophosphate (5′‐IMP) which exchanges more slowly. The results confirm that nucleotides containing the monovalent phosphate anion, exchange more rapidly than those containing the divalent phosphate anion, and suggest further that base stacking in IpI does not greatly retard the speed of 8‐CH exchange of either of the hypoxanthine rings.
Laser‐Raman spectroscopy of biomolecules 16‐temperature dependence of the conformation of crystalline ribonuclease a from x‐ray diffraction and Raman spectroscopy
Authors: Gilbert William A. , Lord Richard C. , Petsko Gregory A. , Thamann Thomas J.
Published: May 2005

X‐ray diffraction and Raman spectra have been studied for crystalline ribonuclease A as a function of temperature, up to 50°C for diffraction and 70°C for the spectra. Changes in the geometry of hydrogen‐bonded tyrosines, disulfide groups and methionine side chains have been followed by means of the x‐ray diffraction results, and the corresponding effects on the Raman spectra have been ascertained. The temperature trend of the Raman spectra of the crystalline enzyme corresponds surprisingly closely to that observed by Chen and Lord for the aqueous enzyme. It appears that intermolecular forces in the crystal are less important to the temperature stability of the enzyme than intramolecular forces. The close correspondence of the crystalline and aqueous temperature trends enables conformational changes in the crystal which affect the Raman spectrum to be identified with corresponding changes in aqueous conformation as shown by the aqueous Raman spectrum.
Measurement of weak depolarization ratios of the Rayleigh scattering of gases using Raman spectroscopy
Authors: Monan Max , Bribes Jean‐Luc , Gaufrès Robert
Published: May 2005

Using a spectroscopic method suggested by Murphy, the depolarization ratios for the Rayleigh scattering of several gases have been measured, lying in the range of 10−2 to 5*10−5. The values obtained are generally lower than those found by previous authors who used the classical method, especially in the case of extremely small depolarization ratios. For hydrogen and deuterium sulphides, which present the smallest depolarization ratios ever observed, a difference is found between the isotopomers although this at the limit of the experimental error.
Resonance Raman spectra of phenoxy and monosubstituted phenoxy radicals
Authors: Shindo Hitoshi , Hiraishi Jiro
Published: May 2005

The resonance Raman spectra of the phenoxy radical and its deuterated species have been observed. The characteristic features of the spectra have been interpreted on the basis of a large contribution from a quinonoid type resonance structure. The assignment of each band is discussed. The effects of ortho and para substitution on the Raman spectra are also discussed.
Linear solid state array detectors in Raman spectroscopy
Authors: Hug W. , Surbeck H.
Published: May 2005

We demonstrate the rapid recording of liquid phase anti‐Stokes vibrational and gas phase rotational spectra with an unintensified solid state detector. The ratio of the Stokes and anti‐Stokes intensities of the 522 cm−1 vibration of toluene (Wilson 6a) does not appear to agree with theoretical predictions, in contrast to nearby lines. This possibility of a direct comparison accentuates the advantage of the simultaneous multichannel recording without drift. We also discuss the signal‐to‐noise performance of unintensified detectors and point out the limits where intensification is preferable.
Raman and infrared studies on new anticancer inorganic ring systems. 2—Pentaziridinocyclodiphosphathiazene (NPAz2)2NSOAz, Az = (NC2H4)
Authors: Manfait Michel , Alix Alain J. P. , Lahana Roger , Labarre Jean‐François
Published: May 2005

A Raman and infrared investigation of SOAz 2, one of the two allotropic varieties of a new anticancer agent, SOAz, has been made in order to have a better understanding of its interactions with DNA. A third allotropic variety, named SOAz 3, was found to be produced when heating SOAz 2. The SOAz 3 → SOAz 2 transformation is also described. SOAz 3 appears to be the conformation of SOAz in aqueous solution and consequently seems to be the moiety which is responsible for its anticancer effectiveness.
On two different approaches to the theory of the resonant Raman effect
Authors: Dellepiane G. , Piseri L. , Tubino R. , Mulazzi E.
Published: May 2005

Two widely used theoretical approaches to the resonant Raman intensities are discussed briefly and compared. It is shown that the final expressions for the scattering cross‐section are identical, when the same approximations are used.
Raman and infrared spectra, vibrational assignments and barriers to internal rotation of cis‐ and trans‐1‐chloropropene
Authors: Durig J. R. , Guirgis G. A.
Published: May 2005

The Raman spectra of both cis‐ and trans‐1‐chloropropene were obtained between 3500 and 20 cm−1 for the vapor, liquid and solid states and the polarization data were obtained for the fluid phases. The infrared spectra were recorded between 3500 and 50 cm−1 for both compounds in the vapor and solid states. Complete vibrational assignments based on depolarization data, infrared band contours and group frequencies are presented for both molecules on the basis of Cs symmetry. The methyl torsion for trans‐1‐chloropropene was observed in the infrared spectrum of the vapor as a series of transitions with the 1 ← 0 fundamental having a frequency of 208 cm−1; from this fundamental frequency a periodic barrier to internal rotation was calculated to be 844±16 cm−1 (2413±46 cal mol−1). Although the methyl torsion was not observed directly for cis‐1‐chloropropene, the first overtone was tentatively assigned in the Raman spectrum of the vapor at 205 cm−1. Many of the fundamentals for both the cis and trans molecule appear as doublets in the spectra of the solids which indicates that there are at least two molecules per primitive cell for each solid. These results are compared to corresponding quantities in some similar molecules.
Raman optical activity in carbonyl deformations
Authors: Barron L. D. , Torrance J. F. , Vrbancich J.
Published: May 2005

The contribution of carbonyl deformation co‐ordinates to normal modes is discussed in the context of the Raman optical activity of chiral molecules containing a carbonyl group attached to a cyclic system. A comparison of the Raman optical activity spectra of 3‐methylcyclohexanone and 3‐methyl methylenecyclohexane provides convincing evidence for the dominant role of carbonyl deformations in the generation of the large couplet at about 500 cm−1 in 3‐methyl cyclohexanone. The spectra of nopinone, β‐pinene and 5‐methylcyclohex‐2‐ene‐1‐one are also discussed. Finally, a model bond polarizability theory of Raman optical activity in carbonyl deformations is presented.
Fermi resonance in Raman and infrared spectra of Ni(CH3COO)2·4H2O and its deuterated analogue
Authors: Raghuvanshi G. S. , Pal Mahendra , Bist H. D.
Published: May 2005

The doublet at 962–906 cm−1 observed in the room temperature spectra of Ni(CH3COO)2. 4H2O is attributed to the ν4 state of the acetate group undergoing strong Fermi‐type anharmonic interaction with a two‐phonon hybrid state associated with a water libration exhibiting characteristic hypsochromic shift and hyperchromic effect with decreasing temperature. In the deuterated analogue another doublet at 706–666 cm−1 is associated with the v5 state of the acetate group and another two‐phonon hybrid state, also associated with a D2O libration, exhibiting hypsochromic shift but the hypochromic effect. The Fermi interaction enhances in the hydrate and diminishes in the deuterate as the temperature is lowered.
Structure in nitrate glasses: Multiple anion sites or random continuum?
Authors: Leong Wah Hing , James David W. , Carrick Malcolm T.
Published: May 2005

The Raman spectra have been studied of tertiary glasses formed by the progressive replacement of Ca(II) by Mg(II) in an equimolar Ca(NO3)2:KNO3 mixture. The Raman bands of the three internal modes of the nitrate ion show progressive growth of a new set of components as the Mg(II) concentration increases. The changes are interpreted in the light of previous experimental and theoretical studies. A case is made for the existence of discrete anion sites in which the field perturbing the anion is dominated by one species of cation. Even in the case of the (Ca/K)NO3 glass, there is evidence for discrete sites rather than a continuum of anion environments.
Vibrational spectra and assignments of ethylene‐diamine and its deuterated derivatives
Authors: Giorgini Maria Grazia , Pelletti Maria Rosaria , Paliani Giulio , Cataliotti Rosario Sergio
Published: May 2005

The infrared and Raman spectra of ethylenediamine and its deuterated derivatives have been studied in both the liquid and solid states. An assignment of the fundamental vibrational modes for the four molecules is proposed assuming for the liquids a gauche configuration (C2 symmetry); the assignment is based on depolarization values, isotopic shifts and classic group frequencies correlations.
Determination of A0 and Dk for CD3I from the ν4 Raman and IR bands
Authors: Poulsen Carsten , Brodersen Svend
Published: May 2005

The ν4 Raman band of CD3I has been recorded at a resolution of 0.28 cm−1. A weighted least‐squares analysis, including data from the ν4 infrared band recorded by Peterson and Edwards, gave A0 = 2.59608±0.00010 cm−1 and DK = (1.98±0.10)x10−5 cm−1 in addition to values for ν, (Aζ)4, ΔA and ΔB The ν4 state is essentially unperturbed. Using literature values for the αA constants, Ae was calculated as 2.6200±0.0008 cm−1, indicating a value of re = 1.03192±0.00015 Å for the distance of the deuterium atoms from the figure axis.
Time‐resolved resonance Raman study of transient benzooxazolinic merocyanines
Authors: Albert J. L. , Aubard J. , Dubois J. E.
Published: May 2005

The time‐resolved resonance Raman spectrum (excitation: 532 nm, 30 ns laser pulse; optical multichannel detection) of the short‐lived species generated by UV flash irradiation of a benzooxazolinic spiropyran in toluene or benzene, has been obtained. The CW resonance Raman spectrum of a related permanent benzooxazolinic merocyanine closely resembles the spectrum of the transient species. A tentative assignment of the Raman bands is proposed in order to characterize the bonds directly involved in the π‐electron delocalization of the merocyanines.
Temperature dependence of the low frequency Raman scattering spectra in tetramethylammonium tetrachlorozincate
Authors: Henocque J. , Sauvajol J. L. , Lefebvre J. , Marion G.
Published: May 2005

The behaviour of some lattice modes in the Raman spectra (wavenumber shift range 0–50 cm−1) has been investigated for (N(CD3)4)2 ZnCl4 and (N(CH3)4)2 ZnCl4 over the temperature range 183–523 K.
Vibrational spectroscopy at high pressures: 44—thallous carbonate
Authors: Adams D. M. , Hatton P. D. , Taylor I. D.
Published: May 2005

Raman spectra of thallous carbonate have been studied to c. 52 kbar and mid‐IR spectra to 36 kbar. Details of the assignment have also been established using single‐crystal IR reflectance and Raman spectroscopy. Phase transitions were found near 13 and 38 kbar on the basis of the Raman evidence, thus supporting the earlier conclusions of Meisalo and Kalliomaki based on x‐ray powder and optical results. Analysis of possible space group relations between phases III (ambient) and IV showed that IV must be orthorhombic and adopt one of the D groups, where n = 17, 19, 21, 25 or 28. Structural relationships between the phases are discussed.
Soft mode in diamantane, C14H20
Authors: Jenkins T. E.
Published: May 2005

Diamantane (C14H20) is a molecular solid which has a second order phase transition at 35K driven by a Raman‐active soft‐mode. There has been some controversy regarding the symmetry of soft‐mode and it is shown that this must be triply degenerate. Possible space groups of the low temperature phase are presented.
Temperature dependence of the Raman active B3g torsional mode of sulphamic acid
Authors: Ratcliffe C. I. , Sherman W. F. , Wilkinson G. R.
Published: May 2005

The Raman active B3g torsional mode of a single crystal of sulphamic acid has been observed as a function of temperature from liquid nitrogen to room temperature. The frequency decrease and markedly asymmetric broadening with increasing temperature have been characterized and are discussed.
Diode array versus photomultiplier for measuring the UV‐excited resonance Raman spectra of enzyme‐substrate transients
Authors: Carey P. R. , Sans Cartier L. R.
Published: May 2005

The construction of a multiplex system for recording the resonance Raman (RR) spectra of enzyme‐substrate complexes in the near‐UV region is described. The instrument is based on commercially available components consisting of a 2 W UV krypton ion laser, a triple spectrograph (in which the first two monochromators act as a zero dispersion, variable bandpass filter) and an intensified diode array. The performance of this system is compared with that of a double monochromator with a photomultiplier as a detector. The enzyme‐substrate systems chosen as examples for the comparison offer a difficult experimental challenge because they evolve rapidly and have poor optical homogeneity. In addition, a simple apparatus is described for recording the RR spectra of enzyme‐substrate complexes in cryosolvents at temperatures as low as −50 °C.
Correction of measured resonance intensity profiles using a monochromator‐photomultiplier response function
Authors: Chinsky Laurent , Peticolas Warner L. , Turpin Pierre‐Yves
Published: May 2005

The ultraviolet transmission response function of a double monochromator Raman spectrometer has been obtained in the 28 000–40 000 cm−1 range, using a very simple method, assuming that the two halves of the double monochromator are rigorously identical in the transmission of light. The measured transmission response function of a commercially available double monochromator has been found to vary sharply in the region of 33 000 cm−1. Such a substantial variation in transmission must be taken into account when Raman intensities are measured as a function of the excitation wavelength, even when an internal standard is used, as the absolute frequency of the Raman standard is different from the absolute frequencies of the Raman lines of the sample. This is particularly the case when overtone and combination band intensities are measured relative to a fundamental of the internal standard, since the overtone frequencies are often displaced by more than 1000 wavenumbers from the fundamentals. Failure to make such corrections can lead to substantial errors in a measured resonant Raman excitation profile.
Spectroscopic and electrochemical studies of transition metal tetrasulfonated phthalocyanines: 2—resonant raman spectra of aqueous solutions of cobalt and iron tetrasulfonated phthalocyanines
Authors: Simic‐Glavaski B. , Zecevic S. , Yeager E. B.
Published: May 2005

Raman spectra of the polarized and depolarized light scattered from cobalt and iron tetrasulfonated phthalocyanines in aqueous media at various pH values are discussed and correlated with previously obtained data. The Raman vibrational modes from pyrrole and benzene were used for a tentative band assignment in the frequency range from 200 to 1700 cm−1.
Low‐frequency depolarized light scattering from aqueous solutions of halogen acids and their sodium salts
Authors: James David W. , Irmer Raimund
Published: May 2005

The depolarized light scattering from 3 to 300 cm−1 has been studied for aqueous solutions of the halogen acids over a wide range of concentrations. The scattering profiles are interpreted on the basis of a four band component model in which two of the bands are centred on the exciting line and there are two shifted frequencies of ∼60 and ∼180 cm−1. The width of the bands is found not to give a measure of the cooperative rotational relaxation but is related to the decrease in dynamic coupling of oscillators in the network because of the presence of foreign ions. The intensity variations are dominated by polarizability fluctuations from both polarizable anions and the hydrated proton. The influence of the proton is similar to that of the iodide ion. There is also evidence for a reinforcement of local order at low electrolyte concentration.
Spectroscopic analysis of the 1:1 tetracyanoquinodimethane‐9,9′‐bifluorenylidene charge‐transfer complex: Infrared, UV‐visible and resonance Raman spectra
Authors: Angeloni L. , Sbrana G.
Published: May 2005

The 1:1 TCNQ‐9,9′‐bifluorenylidene π‐complex (TCNQ=tetracyanoquinodimethane) was investigated by infrared, UV‐visible and Raman spectroscopy. Resonance Raman spectra of the solid were measured and from the analysis of the excitation profiles the lower energy electronic levels of TCNQ and 9,9′‐bifluorenylidene in the complex were identified. A blue shift of the low‐lying electronie levels of the interacting molecules was observed. The mechanisms responsible for the Raman intensity of TCNQ in the complex and in solution are discussed.
Spectroscopic studies of explosives: 1—detection of nitro compounds on silica gel and carbon by non‐resonant Raman spectroscopy
Authors: Carver F. W. S. , Sinclair T. J.
Published: May 2005

Raman spectra have been obtained from trace amounts of propanetriol trinitrate, tetramethoxymethane tetranitrate, 1,3,5‐trinitro‐1,3,5‐triazacyclohexane and 2,4,6‐trinitro‐1‐methylbenzene adsorbed on silica gel and on activated charcoal. Detection limits for these nitro compounds lay between 1 and 10 μg on silica gel and between 20 and 40 ng on activated charcoal.
Analyse Vibrationnelle et Structurale en Série Aliphatique Saturée: 5—Spectres de Vibration de l'Acide Ethylmalonique et de ses Sels Alcalins en Solution Aqueuse
Authors: Delarbre J. L. , Maury L. , Bardet L.
Published: May 2005

Les spectres Raman et infrarouge de l'acide éthylmalonique [C2H5CH(COOH)2, C2H5CD(COOD)2] et de ses sels alcalins [C2H5CH(COOH)(COOK), C2H5CD(COOD)(COOK) et C2H5CH(COOK)2, C2H5CD(COOK)2] en solution aqueuse ont été enregistrés de 3500 à 200 cm−1. L'analyse du facteur de dépolarisation nous a permis de conclure que l'acide et le dianion appartiennent au groupe de symétrie Cs le sel acide appartenant au groupe C1. Une attribution des vibrations fondamentales est proposée.
Raman spectra of CdSb
Authors: Houde D. , Jandl S. , Carlone C. , Arushanov E.
Published: May 2005

Raman spectra of CdSb at 100 K are presented. Twenty‐two out of the twenty‐four predicted phonons are detected. Frequencies of different modes are low, implying motions associated with large reduced masses. Their values are comparable to those obtained from infrared measurements.
Resonance Raman spectra and excitation profiles of some rifamycins
Authors: Angeloni L. , Marzocchi M. P. , Smulevich G.
Published: May 2005

The resonance Raman Spectra of rifamycin SV, its sodium salt and rifampicin have been investigated under various physical conditions. The excitation profiles of the strongest Raman bands have been measured using an Ar+ laser for excitation. The proposed vibrational assignment indicates that the magnified image group is the main portion of the chromophore for both rifamycin SV Na salt and rifampicin molecules. Excitation profile studies of the δ(CO−) and ν(COH) vibrations indicate the presence of a single electronic transition in the visible region. In addition these two modes derive their intensities from 0–1 vibronic transitions whereas no evidence for the contribution due to the 0–0 term is found. This is explained in terms of coupling with the other totally symmetric modes and broadening due to phonon‐electron interactions.
Raman scattering study of CsH2PO4
Authors: Aoki Magane , Kasahara Masaru , Tatsuzaki Itaru
Published: May 2005

Raman spectra of CsH2PO4 have been observed at 295 and 83 K in the frequency shift region 40–1200 cm−1. According to factor group analysis, Raman active vibrational modes at k = 0 are classified as follows; 13Ag + 8Bg in the paraelectric phase and 23A + 22B except for acoustic modes in the ferroelectric phase. No soft modes were observed in the A class modes. The frequency and the line width of one of the internal modes of the HPO ions were measured as a function of temperature in the scattering geometries b(cc)a* and c(bb)a*, where a* is perpendicular to the bc plane. Remarkable anisotropy was found in the temperature dependence of both the frequency and the line width. The results are discussed by considering that the phase transition is of an order‐disorder type and the relaxation time of the polarization fluctuation is very long compared with the inverse of the associated phonon frequencies.
Anharmonic effects in Raman‐active modes of PbCl2
Authors: Melo F. E. A. , Filho J. Mendes , Moreira J. E. , Lemos V. , Cerdeira F.
Published: May 2005

The behaviour of representative lines in the room temperature Raman spectrum of PbCl2 under the influence of a high hydrostatic pressure (up to 80 kbar) is reported. Pressure derivatives and mode Grüneisen parameters are calculated for 13 of the 18 Raman‐active modes. Combining these results with previous data for the temperature dependence of these phono frequencies, the implicit (thermal expansion) and explicit (vibrational amplitude‐driven) contributions are separated from ωj(T). This separation shows that anharmonic effects are stronger for vibrations involving motion of chlorine ions than for those involving only lead atoms.
Molecular reorientation and vibrational relaxation in dibromomethane
Authors: Chen S. J. H. , Schwartz M.
Published: May 2005

The polarized and depolarized Raman spectra of the ν2 (CH2 bend) and ν3 (CBr stretch) vibrations in dibromomethane have been studied as a function of temperature throughout the liquid range. Reorientational correlation times derived from the two modes were simllar in both magnitude and dependence on temperature. This result, together with other structural data, suggests that the rotational dynamics of this molecule in the liquid phase are quasi symmetric‐top in character. Vibrational dephasing times calculated from the two lineshapes were also of the same magnitude. However, modulation times determined via the Kubo lineshpae formalism varied markedly between the vibrations. This provides evidence that vibrational dephasing of the bending and stretching modes are influenced by different intermolecular forces in the liquid.
Raman spectra of fully deuteriated syndiotactic and isotactic poly(methyl methacrylate)
Authors: Neppel Anton , Butler Ian S.
Published: May 2005

The Raman spectra of solid fully deuteriated syndiotactic (D8s‐PMMA, 55%) and undeuteriated isotactic (H8i‐PMMA, 92%) poly(methyl methacrylate) have been recorded in the 3500–200 cm−1 range at ambient temperature. Vibrational assignments are proposed for most of the observed bands and, in the case of D8s‐PMMA, the data have resolved some of the inconsistencies in the spectra of the undeuteriated polymer.
Micro‐Raman spectroscopy of chromosomes
Authors: de Mul F. F. M. , van Welie A. G. M. , Otto C. , Mud J. , Greve J.
Published: May 2005

Raman spectra of intact chromosomes (Chinese hamster), recorded with a microspectrometer, are reported. The spectra could be assigned to protein and DNA contributions. Protein and DNA conformations and the ratio of base pairs in DNA were determined.
Inverse Raman spectroscopy of bilirubin and its ditauride
Authors: Hillig Kathy J. Dien , Morris Michael D.
Published: May 2005

The inverse Raman spectrum of bilirubin and bilirubin ditauride were measured under pre‐resonant conditions. Spectra in chloroform and dimethyl sulfoxide were assigned by comparison with model compounds and on the basis of the known effects of the solvents on the internal hydrogen bonding in bilirubin. The band assignments were used to interpret the spectra of bilirubin ditauride in aqueous solution. Evidence is presented for strong hydrogen bonding to the pyrrole NH bonds and to the lactam rings. It is proposed that hydrogen bonding to water is facilitated by photoactivation and, in turn, stabilizes photohiliruhin.
Experimental observation of the Raman spectrum of 1‐Methylsilatrane hydrochloride
Authors: Imbenotte M. , Palavit G. , Legrand P.
Published: May 2005

The Raman spectrum of 1‐methylsilatrane hydrochloride has been recorded. The disappearance of the 354 cm−1 band, found in the spectrum of 1‐methylsilatrane, is in agreement with the assignment of this vibration to the SiN stretching mode on the basis of a previous a priori normal coordinate treatment.
Surface‐enhanced resonance Raman spectroscopy of highly fluorescent complexes
Authors: Chambers Jeffrey A. , Buck Richard P.
Published: May 2005

Surface‐enhanced resonance Raman (SERR) spectra of a series of highly fluorescent complexes of ruthenium(II), 2,2′‐bipyridine and 1,10‐phenanthroline are presented. The effect of applied potential on the SERR spectra is discussed. SERR spectra of mixed ligand complexes can be predicted from weighted averages of spectral features for the tris complexes.
Pressure dependence of the Raman spectra of LiNbO3 and LiTaO3
Authors: Mendes‐Filho J. , Lemos V. , Cerdelra F.
Published: May 2005

The pressure dependence of the room‐temperature Raman spectrum of LiNbO3 and LiTaO3 in the range 1 bar‐80 kbar is reported. The studies were confined to the transverse optical modes, since these are the modes which could be involved in the ferroelectric‐paraelectric phase transition occurring in both materials at high temperatures. All mode frequencies increase linearly as the pressure increases and no distinctive behaviour is observed in the lowest frequency A1 (TO) modes, identified by some workers as soft modes.
Raman and infrared spectra and normal coordinate analysis of the molecular adducts H3NGaX3 and H3PGaX3 (X = Cl or Br)
Authors: Taylor Michael J. , Riethmiller Steven
Published: May 2005

The preparation of 1 : 1 molecular adducts H3NGaX3 and H3PGaX3 (X = Cl or Br) is described. The IR (40–4000 cm−1) and Raman (50–3500 cm−1) spectra of these compounds have been recorded and 11 of the 12 fundamental vibrations are assigned on the basis of C3ν molecular symmetry. A force field of seven valence force constants and three or four interaction constants is utilized in calculating the frequencies and potential energy distributions. Changes in NH3 and PH3 frequencies and force constants are consistent with structural changes upon coordination. Modes of GaN stretching, 480–500 cm−1, and GaP stretching, 280–305 cm−1, are assigned and force constants k(GaN) = 1.85−2.0 mdyn Å−1 and k(GaP) = 1.0–1.2 mdyn Å−1 are obtained. Normal modes of vibration of the ammonia adducts are nearly pure but some coupling is found between gallium‐phosphorus and gallium‐halogen stretches in the case of the phosphine adducts.
Analyse Vibrationnelle et Structurale des Acides Cyclobutanedicarboxyliques‐1,2‐cis et ‐trans et de Leurs Sels de Potassium en Solution Aqueuse
Authors: Fabrégue Eliane , Cassanas Geneviève , Bardet Lucette
Published: May 2005

Les spectres Raman et infrarouge des acides cyclobutanedicarboxyliques‐1,2‐cis et ‐trans en solution aqueuse et de leurs sels de potassium ont été analysés. L'absence de symétrie est en faveur d'une conformation plissée pour tous les composés. Une attribution des fréquences de vibration est proposée.
Carbon association of surface‐enhanced Raman scattering (SERS) by pyridine on gold electrodes: A Raman and Auger spectroscopic study
Authors: Mernagh Terrence P. , Cooney Ralph P. , Spink John A.
Published: May 2005

Surface‐enhanced Raman scattering (SERS) by pyridine on gold electrode surfaces to arise from the adsorption of pyridine in or on surface carbon present after the oxidation‐reduction cycle (ORC). Similar Raman ring‐breathing mode spectra for both gold and silver electrodes and sols indicate a common intensely scattering phase which is independent of the metal substrate. The common phase proposed is [carbon‐pyridine]. Auger electron spectroscopy indicates that the SERS spectrum arises from a surface microzone having a C to Au ratio of ca 7. Cathodic elimination of microzone carbon results in the elimination of pyridine SERS. Carbon‐enriched (sputtered) gold surfaces exhibit the same ring‐breathing mode pattern as for the conventional SERS surface. Laser carbonization effects are suggested by differences in the SERS intensities observed for the presence and absence of laser flux during the ORC. Laser decarbonization appears to be the origin of the characteristic decay of SERS from gold electrodes. It is proposed that the decay is instantaneous for 514.5 nm Ar+ excitation and slower for 647.1 nm Kr+. Differences in pyridine SERS intensities from silver and gold electrodes are attributed to differences detected by Auger spectroscopy in the extent of laser microzone carbonization. On the basis of these findings Au/pyridine SERS has been classified as Type I.
Resonance CARS spectrum of the short‐lived dimethyl terephthalate Anion radical
Authors: Werncke W. , Weigmann H.‐J. , Lau A. , Tschol Tschö Jong , Dat T. P.
Published: May 2005

Resonance coherent anti‐Stokes Raman scattering was used to obtain vibrational spectra of the short‐lived dimethyl terephthalate anion radical. Changes in the double bond character of the carbonyl group were clearly observed in the CARS spectrum.
Raman studies of orientational disorder in crystals: The hexamethylethane plastic phase, T> Tc=152 K
Authors: Gharbi H. , Sauvajol J. L. , Fontaine H. , More M.
Published: May 2005

Raman spectra of some bands in the plastic phase of hexamethylethane have been recorded as a function of temperature. Interesting features related to the molecular reorientations and librations have been derived from the band shape analysis of F2g and Eg low‐frequency spectra. A novel temperature dependence of the libration width has been observed. The analysis of the internal modes' bandwidths at ν1 = 878 cm−1 and ν2 = 475 cm−1 provides consistent results for the monomolecular reorientational dynamics.
Extended measurement and assignment of isotropic Raman transitions in the ν1 region of 12CD4
Authors: Lolck Jens‐Erik , Owyoung Adelbert , Esherick Peter
Published: May 2005

The isotropic Raman spectrum of 12CD4 is presented in the range from 2101 to 2113 cm−1, thus covering the ν1(A1) Q‐branch and part of the ν2 + ν4(F1 + F2) Q‐branch. Experimental results for the 2101‐2108 cm−1 range were obtained using the ‘inverse Raman spectroscopy’ technique and have been published previously. New measurements in the 2108 cm−1‐2113 cm−1 range were obtained using the very similar ‘stimulated Raman gain spectroscopy’ technique. In both spectra the resolution is limited by the Doppler width of the lines. Formally, only transitions to the upper state of the ν1 band are allowed in isotropic Raman scattering, but strong resonances enhance transitions to the upper state of ν2 + ν4. An effective Hamiltonian which takes these resonances into account was used to interpret the spectra and led to the assignment of all significant lines. In all, 165 Raman transitions were assigned, and these transitions are fitted by the model Hamiltonian with a standard deviation of 0.008 cm−1.
Infrared and Raman spectra of trichloromethanesulphenyl bromide and its reactions with some inorganic halides
Authors: Mazzieri M. R. , Della Védova C. O. , Cutín E. H. , Varetti E. L. , Aymonino P. J.
Published: May 2005

The infrared and Raman spectra of liquid and the infrared spectrum of solid CCl3SBr have been obtained. It was observed that CCl3SBr reacts both with infrared windows made of CsI and with powdered KI, producing CSCl2, and that it also reacts with AgCl windows giving CCl3SCl as a gaseous product.
Vibrational spectrum and normal coordinate analysis of CX3CO2NX4(X=H or D)
Authors: Kanesakar Isao , Tanbo Hironori , Kawahara Hisakazu , Kawai Kiyoyasu
Published: May 2005

The vibrational spectrum of ammonium acetate at room temperature and 77 K is reported. The observed factor group splitting between four acetate ions is slight in each internal mode. The normal coordinate analysis is carried out under the assumption of neglect of hydrogen atoms. Good agreement between observed and calculated frequencies is obtained for the lattice vibrations. It is clarified that the hydrogen bond has considerable strength and a very strong Raman band at 58 cm−1 in CH3CO2NH4 is a libration of the acetate ion about an axis perpendicular to the molecular plane. The strong IR band at 260 cm−1 in CH3CO2NH4 is discussed.
Effect of electrolytes on the Raman bands of dimethylformamide and acetone
Authors: Thyagarajan G. , Gurunadham G. , Dhamejani R.
Published: May 2005

The CO stretching Raman bands of dimethylformamide and acetone have been studied for the pure liquids and for solutions of alkali metal halides and perchlorates in these liquids. An enormous reduction in the intensity of these bands was found in the presence of the perchlorate ions, especially in the case of dimethylformamide. In each case a new band appears in the CI–O stretching region of the perchlorate. The results indicate the formation of stable complexes between the organic molecule and perchlorate ion through the CO bond.
Vibrational spectra and symmetry of 3,3,6,6‐tetramethylcyclohexa‐1,4‐diene
Authors: Sjøgren Carl E. , Kloster‐Jensen Else , Nielsen Claus J.
Published: May 2005

The vibrational spectra of 3,3,6,6‐tetramethylcyclohexa‐1,4‐diene as a vapour, a liquid, a crystalline solid and isolated in argon and nitrogen matrices at 13K have been recorded and interpreted in terms of a planar ring structure (D2h). The fundamental modes of vibration have been assigned with the aid of a normal coordinate calculation and by comparison with the spectra of cyclohexa‐1,4‐diene.
Scattering and propagation of light: A historical difficulty of Bohr's theory
Authors: Mathieu J. P.
Published: May 2005

The classical theory of radiation was able to explain satisfactorily the relationship between the dispersion of refraction and coherent light scattering. However, in the 1920s the old quantum theory encountered difficulties in explaining these phenomena and these were only fully overcome 20 years later.
Surface enhanced resonance Raman study on fluorescein dyes
Authors: Hildebrandt Peter , Stockburger Manfred
Published: May 2005

Fluorescein and its derivatives fluoresceinamine and diiodofluoresceiniodoacetamide have been studied by surface enhanced resonance Raman spectroscopy (SERRS). Adsorption of the dyes at the silver/electrolyte interface requires attractive interactions between polar side groups (such as NH2, OH and COOH) with the metal as a prerequisite for Raman enhancement and fluorescence quenching. It was possible to characterize two prototropic forms of fluorescein and fluoresceinamine by their SERR spectra. Only vibrations of the chromophoric part (xanthene) of the molecule contribute to the measured spectra. Substituents in the phenyl ring influence only the ability of adsorption and the structure of the adsorbed molecules.
Raman scattering by polaritons in Ti:LiNbO3 waveguides
Authors: Langbein U. , Lederer F. , Ponath H.‐E. , Trutschel U.
Published: May 2005

A general theory of Raman scattering in piezoelectric slab waveguides is presented. If the anisotropy of the uniaxial waveguide material is sufficiently large, incident slab‐guided waves can be scattered by polaritons of the upper branch of the polariton dispersion curve. The angular dependence ω2(θ) of the scattered‐wave frequency has been calculated in detail, for both y‐ and z‐cut Ti:LiNbO3 waveguides in the polariton frequency range ωp=900–5160 cm−1 (pump wavelength 4880 Å). The detection of weak proton vibrations within the strong polariton Raman spectrum of proton‐exchanged Ti:LiNbO3 waveguides is discussed.
Raman spectroscopic and X‐ray diffraction study of Na2Se·9(H, D)2O and comparison between OH(D)…︁Se and OH(D)…︁S hydrogen bonds
Authors: Derkosch J. , Mikenda W. , Baumgartner O. , Mereiter K. , Preisinger A.
Published: May 2005

Raman spectroscopic (75 K) and X‐ray crystal structure (135 K) data for Na2Se·9(H, D)2O and Na2S·9(H, D)2O are compared, paying particular attention to the hydrogen bond networks in the two isostructural compounds. The crystal structures differ essentially only with respect to the hydrogen bond lengths of corresponding OH…︁Se and OH…︁S bonds, those to Se being uniformly larger by about 0.1 Å than those to S. The uncoupled νOD frequencies of isotopically dilute HOD molecules are very similar in both compounds, being larger only by about 10 cm−1 on average for the selenide than for the sulphide. It can therefore be claimed that the hydrogen‐bond capabilities of the selenide and the sulphide ions are almost equal.
Pulse shapes of Raman and Rayleigh scattering
Authors: Morozov V. A. , Shorygin P. P.
Published: May 2005

The expressions for the pulse shapes of secondary radiation in the frequency range of Rayleigh scattering and resonance fluorescence and in the range of Raman scattering and shifted resonance fluorescence are obtained on the basis of the quantum treatment of transformation of light pulses, the resonance conditions for Raman and Rayleigh scattering being considerably different. The characteristic cases of different pulse shapes of Raman and Rayleigh scattering are considered for the condition when the molecules are irradiated by light pulses which are shorter then the lifetime of the excited state of the molecule and are weak enough not to result in saturation.
New results in incommensurate crystals: Kink diffusion and long‐period lock‐in phases
Authors: Scott J. F.
Published: May 2005

Two new results for incommensurate phases of crystals are discussed: the experimental observation of a q2 dependence of the inverse relaxation time observed in the hypersonic regime via near‐forward Brillouin scattering experiments, tentatively interpreted as kink diffusion, and the theoretical demonstration that long‐period lock‐in phases observed in crystals which are simultaneously ferroelectric in their incommensurate phases are stabilized by the spontaneous polarization field. This theory explains the observed limits of incommensurate wave vector in BaMnF4 as a function of temperature: 2a*/5 = 0.399a*–0.389a* = 5a*/13, where the 2/5 value is the low‐temperature limit and the 5/13 value is the high‐temperature limit. It also explains one mechanism for stabilizing the 2/5 phase at lower temperatures than are permitted in the ANNNI (axial next‐nearest neighbour Ising) model of Yamada and Hamaya in the absence of a spontaneous polarization field.
OH torsion of some chlorophenols
Authors: González‐Díaz P. F. , Sigüenza C.
Published: May 2005

The νt(OH) and νt(OD) torsional modes in some chloro‐substituted derivatives of phenol were assigned from their Raman spectra in CS2 solution. The corresponding rotation barriers were then calculated by means of a rigorous optimization method. Some theoretical calculations have allowed an extension of the discussion to the vapour phase.
Étude Raman des Verres xB2O3(1–x)GeO2 avec 0<x<1
Authors: Beys Louis , Hillaire Paul , Assih Toyi , Phalippou J.
Published: May 2005

L'étude Raman des verres de la série xB2O3(1–x)GeO2 obtenus par fusion a été rélisée pour des poucentages molaires en B2O3 compris entre x = 0.2 et 0.9. L'apparition de raies, inexistantes dans les spectres des deux constituants purs, est la principlae catactéristique des spectres enregistrés. En particulier, les bandes de fréquences 720 et 1060 cm−1 sont attribuées à des liaisons GeOB. La premiére, apparaissant en měme temps que la raie 808 cm−1 caractéristique des groupements boroxols, correspond à une liaison GeOB dans laquelle B appartient à un groupement boroxol; la seconde à une liaison de měme type dans laquelle B est à I'intérieur d'un groupement triangulaire BO3. La variation d'intensité de ces raies en fonction de x permet de suivre l'évolution des proportious relatives de triangles et de groupements boroxols.
Laser Raman study of phase transformation in single crystals of cadmium fluorotitanate hexahydrate
Authors: Thakur Ganesh , Verma A. L.
Published: May 2005

A detailed temperature‐dependent Raman study of oriented single crystals of CdTiF6·6H2O down to 10 K was carried out in the regions of internal vibrations and lattice modes. The line width, frequency shift and intensities of the modes associated with the [Cd(H2O)6]2+ and [TiF6]2− octahedra show abrupt changes at temperatures around 200 and 80 K, respectively, and many doubly degenerate modes split into two components. These studies suggest that this system undergoes two structural phase transitions at 200 and 80 K. A mechanism for these phase transitions is suggested.