bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vibrational spectra of SrNa2P4O12 · 6H2O and CaNa2P4O12 · 5.5H2O
Authors: Santha N. , Nayar V. U. 
Published: May 2005

AbstractIR and Raman spectra of CaNa2P4O12 · 5.5H2O and SrNa2P4O12 · 6H2O were recorded and analysed. The bands corresponding to the P4O groups and water molecules are assigned. The symmetry of the P4O ion is S4 in CaNa2P4O12 · 5.5H2O and C2h in SrNa2P4O12 · 6H2O. Three crystalloraphically independent water molecules exist in these compounds. Water II and water III form strong hydrogen bonds, in contrast to water I.
Secondary structure of the double‐stranded DNA genome of bacteriophage T7 in packaged, underpackaged and unpackaged states
Authors: Thomas George J. , Serwer Philip 
Published: May 2005

AbstractDouble‐stranded DNA exhibits prominent Raman bands in the spectral region 600–900 cm−1, authenticated by x‐ray crystallography as diagnostic of the macromolecular secondary structure. Since the DNA Raman fingerprint can be measured in the presence of protein, Raman spectroscopy was employed to investigate the secondary structure of dsDNA packaged within the protein coat of bacteriophage T7. Comparison of the Raman spectrum of deproteinized DNA with that of wild‐type T7 phage (52% DNA, 48% protein) reveals a packaging‐associated shift of the principal BDNA Raman marker (the band of the 825–840 cm−1 interval which is a sensitive indicator of phosphodiester geometry), without shifts of other conformation sensitive Raman markers (the bands of the 600–780 cm−1 interval which indicate sugar puckers and glycosyl torsions). The Raman marker for the protein‐free state occurs at 836 cm−1, typical of B‐form DNA of heterogeneous sequence; the marker for the packaged state occurs at 825 cm−1, characteristic of a modified B‐form DNA observed previously for specific sequences. These findings indicate different B‐form variants for dsDNA in packaged and protein‐free states. The modified B‐form secondary structure of packaged DNA is maintained when the virion is thermally burst to release the genome without removal of proteins.Comparison of the Raman spectrum of the wild‐type T7 virion with that of a deletion mutant packaging 8.4% less DNA than wild‐type (underpackaged T7), reveals the same packaging‐associated shift of the principal B‐form marker (825 cm−1) vis‐à‐vis protein‐free DNA (836 cm−1), and additional evidence of small but significant differences between phosphodiester geometries in packaged and underpackaged states. These differences are explained by a marginally (<5%) greater proportion of non‐B backbone geometry in wild‐type T7. Both wild‐type and mutant T7 exhibit Raman markers of the C2′‐endo/anti nucleoside conformations exclusively. The results are interpreted in terms of the formation of increasing amounts of non B‐form phosphodiester geometry with increasing density of DNA packaging. The data are consistent with an excess of <5% A‐type phosphodiester geometry in packaged versus underpackaged states, and 10 ± 4% excess A‐type phosphodiester geometry in packaged versus protein‐free states. Based on Raman amide I and amide III markers, the protein structures and protein‐DNA interactions in wild‐type T7 are indistinguishable from those in the T7 deletion mutant.
Phonons and phase transitions in zirconia
Authors: Perry C. H. , Lu F. , Liu D. W. , Alzyab B. 
Published: May 2005

AbstractThe martensitic‐austenitic phase transition in zirconia was investigated as a function of temperature and pressure using Raman and IR spectroscopy. The frequencies and symmetries of the phonon modes corresponding to the monoclinic (M),C(4 molecules per unit cell) structure were identified at 300 K and 1 atm. The temperatureinduced transition to the tetragonal (TI),Dstructure (2 molecules per unit cell) showed thermal hysteresis (1225 ↔ 1425 K). The corresponding pressure‐induced transition at room temperature showed a pressure hysteresis (3.4 ↔ 3.95 GPa). However, the structural transition was to a different tetragonal modification (TII) withD2horC4vsymmetry with 4 molecules per unit cell.
Raman spectra, vibrational assignment, structural parameters and ab initio calculations for ethyl nitrat
Authors: Durig J. R. , Sheehan T. G. 
Published: May 2005

AbstractRaman spectra (4000–10 cm−1) of gas, liquid and solid ethyl nitrate were recorded. The qualitative depolarization values were obtained from the spectrum of the liquid. A vibrational assignment for the normal modes is proposed based on depolarization values, group frequencies and normal coordinate calculations. The structures for the trans and gauche conformers have been determined from ab initio Hartree‐Fock gradient calculations using the Gaussian‐82 program with both the 3–21G and 6–31G* basis sets. From this calculation at the 6–31G* level, the energy difference between the more stable trans conformer and the higher energy gauche conformers was found to be 474 cm−1 (1.36 kcal mol−1) with a gauche dihedral angle (CCON) of 79°. The trans to gauche and gauche to gauche barriers are 990 cm−1 (2.83 kcal mol−1) and 3152 cm−1 (9.01 kcal mol−1), respectively. Barriers to internal rotation for the CH3 and NO2 groups were also obtained from ab initio calculations. For the trans conformer the values are 1304 cm−1 (3.73 kcal mol−1) and 2702 cm−1 (7.73 kcal mol−1) and for the gauche conformer they are 1161 cm−1 (3.32 kcal mol−1) and 2758 (7.89 kcal mol−1) for the CH3 and NO2 barriers, respectively. Normal coordinate calculations were also performed for both conformers utilizing force fields calculated from the 3–21G basis set which support the vibrational assignments. The results of this investigation are compared with similar data on some corresponding molecules.
Theoretical investigations of continuum resonance Raman scattering in HD+
Authors: Datta Banani , Saha Samir , Bhattacharyya S. S. 
Published: May 2005

AbstractContinuum resonance Raman scattering from the heteronuclear molecular ion HD+ in the wavelength range 700–2500 Å has been treated theoretically using second‐order perturbation theory together with the Racah algebra technique. Effects of interference between the intermediate 1s σg, 2p σu and 2p πu states on the scattered intensities and depolarization ratios have been invesatigated. The intensities of the Raman lines for O‐, Q‐ and S‐branches have been calculated using the non‐thermal Franck–Condon factors for vibrational and thermal Boltzmann factors for the rotational population of HD+ and a thermal rovibrational distribution corresponding to 600 K for selected transitions. The calculated cross‐sections are found to be larger than the exprimental values for neutral diatoms.
Polarisabilités Molecularires et Polarisabilités de Liaison dans H2S et D2S
Authors: Barbès H. 
Published: May 2005

AbstractLa simulation des contours expérimentaux des spectres Raman de rotation pure permet d'évaluer le rapport R = αb/αa pour H2S et D2S. Les valeurs de R, des polarisabilitiés moléculaires et des polarisabilités de liaison évoluent avec la deutériation.
Raman scattering from soft modes in barium‐doped lead germanate
Authors: Hosea T. J. C. 
Published: May 2005

AbstractThe Raman spectrum of the soft mode and adjacent low‐frequency A TO modes in pure and barium‐doped lead germanate was measured as a function of temperature, T, through the ferroelectric‐paraelectric phase transition. The barium concentrations studied varied from 2.3 to 6.6%. The Raman spectra were analysed for all the temperatures and dopings by least‐squares fitting of a model response function. In general, the phonon line widths increase with the amount of barium doping whereas the soft frequency decreases. Both the soft optic frequency and the mode strength display Curie‐Weiss behaviour close to the Curie temperature, Tc. When they are plotted as a function of T c‐T, the various fitted soft‐mode parameters generally behave in a qualitatively similar fashion for the different specimens. However, on a quantitative basis, the agreement is less good, showing that the behaviour of the soft mode does not scale simply as Tc‐T. This may indicate that the influence of the different polarizabilities of the barium defects is important in lead germanate.
Shell model description of hyper‐Raman scattering from alkali metal halides
Authors: Vogt H. 
Published: May 2005

AbstractHyper‐Raman scattering by the zone‐centre optical phonons of alkali metal halides is described in terms of an anharmonic shell model. In order to reproduce the measured relative values of the hyper‐Raman tensor elements, three types of fourth‐order coupling parameters, representing intra‐ionic, inter‐ionic and Coulomb anharmonicities have to be taken into account. Deducing the non‐linear force constants of the short‐range inter‐ionic interactions from a Born‐Mayer potential and supplementing them by exact expressions of their Coulomb Counterparts, it is possible to determine all parameters contributing to hyper‐Raman scattering. The model also predicts the third‐harmonic generation coefficients in satisfactory agreement with experimental data.
Multiplex pure rotational coherent anti‐stokes Raman spectroscopy in a molecular beam
Authors: Bloembergen Nicolaas , Chen Kuei‐Hsien , Lü Cheng‐Zai , Mazur Eric 
Published: May 2005

AbstractPure rotational coherent anti‐Stokes Raman spectroscopy using a single broad‐band dye laser was applied to study the rotational energy distribution of molecules in a pulsed supersonic beam. The multiplex BOXCARS configuration allows the accurate determination of rotational constants and rotational temperatures, and offers many advantages over other methods. The technique was applied to calibrate the cooling effect of a pulsed molecular beam of nitrogen and to study the rotational energy distributions of infrared multiphoton‐excited ethylene.
Raman spectra and normal coordinate analysis of thirteen selectively deuterated tetramethylsilanes
Authors: Fischer D. , Klostermann K. , Oehme K.‐L. 
Published: May 2005

AbstractThe Raman spectra of liquid (CH3)4‐mSi(CD3)m (m = 0‐4), (CH2D)4‐nSi(CH3)n and (CHD2)4‐nSi(CD3)n (n = 0‐3) were recorded from 3200 to 50 cm−1. Normal coordinate analyses were made using both a unique internal valence force field (IVFF 1) for all 13 isotopomers and 13 slightly modified IVFF 2s for each isotopomer, including torsional modes in each case. Vibrational assignments were made using the potential energy distributions and eigenvectors in addition to the depolarization ratios, the IR spectra and the Teller‐Redlich product rule.
Effect of isotope dilution on the Fermi resonance in water
Authors: Sokołowska Anna 
Published: May 2005

AbstractThe additivity of the contributions of HOD, H2O and D2O to the contours of the OH and OD stretching bands was studied in a 1:1 H2O‐D2O mixture. The observed non‐additivity of contours was explained in terms of Fermi resonance changes caused by the variations in resonance intermolecular coupling parameters due to isotope dilution. The integral intensities of OH and OD bands in the mixture were additive.
Vibrational spectra of para‐disubstituted benzophenones
Authors: Volovšek Vesna , Baranović Goran , Colombo Lidija , Durig James R. 
Published: May 2005

AbstractRaman (3500‐20 cm−1) and IR (4000‐80 cm−1) spectra of benzophenone and a series of its para‐disubstituted derivatives (substituents F, Cl, Br and CH3) as melts and in solution were recorded. A complete empirical assignment of the measured spectra was made and the influence of para substitution on the normal modes was investigated.
High‐pressure Raman study of CsVO3 and pressure‐induced phase transitions
Authors: Kourouklis G. A. , Jayaraman A. , Espinosa G. P. , Cooper A. S. 
Published: May 2005

AbstractThe pressure dependence of the Raman frequencies of cesium vanadate (CsVO3) was studied using a diamond anvil cell up to 15 GPa. From the abrupt changes in the Raman specta three pressure‐induced phase transitions are inferred at 10, 11.5 and 13 GPa. The first phase transition, at 10 GPa, is subtle but affects the VO bond length. It is believed that this transition is of the same nature as that observed in postassium and rubidium vanadates. The much higher transformation pressure in CsVO3 is attributed to the anomalous compressibility of the Cs+ ion. The second phase transition involves more drastic changes in the high‐frequency region. This is attributed to the rotations and distortions in the VO4 tetrahedra which lower the symmetry of the lattice. In the third phase transition, the appearance of broader Raman peaks and the disappearance of the chain deformation modes suggest a partial disorder in the chain structure.
Raman spectroscopy of sulphur‐containing amino acids and their derivatives adsorbed on silver
Authors: Lee Heewon , Kim Myung Soo , Suh Se Won 
Published: May 2005

AbstractSurface‐enhanced Raman scattering (SERS) of sulphur‐containing amino acids and peptides (L‐cysteine, L‐cystine, L‐methionine, L‐methionylglycine and glycyl‐L‐methionine) in silver sol was investigated. The Raman signal was enhanced by a factor of about 105. In the pH range 5–11, L‐cysteine was found to absorb on the silver surface through the sulphur atom and also the carboxylate and amino groups. The changes in the SER spectrum of L‐cysteine observed on lowering the pH of the sol solution below 5 suggested that the amino group was desorbed from the surface on protonation. The SER spectrum of L‐cystine was similar to that of L‐cysteine, indicating cleavage of the SS bond on adsorption on the silver surface. L‐Methionine, L‐methionylglycine and glycyl‐L‐methionine also seemed to adsorb via the sulphur atom and also the carboxylate and amino groups in the pH range 5–9. The SER spectra of these compounds showed no concentration dependence in the ranges investigated.
Resonance Raman spectroscopy of the acid–base indicator neutral red
Authors: Bisset Alison , Dines Trevor J. 
Published: May 2005

AbstractResonance Raman spectra of the acid–base indicator neutral red and its monoprotonated and diprotonated derivatives, excited in the region of the lowest energy electronic absorption bands, are reported. The bands are assigned to vibrations of the phenazine ring system and the substituents. Measurements of the band intensities have permitted an evaluation of the geometric changes attendant upon excitation to the resonant excited state.
Relationship between resonant Raman scattering in Ag–C2H4 complexes and SERS
Authors: Brings R. , Mrozek I. , Otto A. 
Published: May 2005

AbstractConcentrations less than 10−2 of silver dispersed in C2H4 matrices (ratio of Ag atoms and C2H4 molecules in the matrix) induce an absorption band in the visible range by electron transfer excitation and (with the exception of the C–H stretch vibrations) shifted Raman bands, assigned to resonant enhancement by two orders of magnitude by electron transfer in Ag–C2H4 complexes. Both phenomena are absent for Ag dispersed in C2H6. These results are analogous to the chemical specific and vibrational selective surface‐enhanced Raman scattering (SERS) of C2H4 and C2H6. The loss of the electron transfer excitation by mixing oxygen into the Ag–C2H4 matrix (as measured by Ozin et al.) corresponds to the quenching of SERS by oxygen.
Raman studies of cation–surfactant interactions in alkylpolyoxyethylene surfactant aqueous solutions
Authors: Siew Diana C. W. , Cooney Ralph P. , Taylor Michael J. 
Published: May 2005

AbstractRaman studies are reported of conformational change in an alkyl polyoxyethylene non‐ionic surfactant associated with coordination to alkali and alkaline earth metal cations. This surfactant has a simpler mix of conformers (with TTT relatively unimportant) compared with non‐ionic surfactants incorporating an aromatic ring in the hydrophobic head‐group. This relatively simple conformational pattern facilitates the interpretation of the 868 cm−1 band assigned to a TGTTḠT (T, trans; G, gauche; Ḡ, gauche minus) for the OCH2CH2OCH2CH2O polyoxyethylene sequence associated with surfactant‐cation complexes. Counter anions such as halides appeared to have a negligible effect on complex formation.
Resonance Raman scattering in the case of a strong dynamic Jahn–Teller effect
Authors: Tehver I. 
Published: May 2005

AbstractA method is proposed for calculating the resonance Raman excitation profiles in the case of degenerate excited electronic levels strongly coupled to non‐totally symmetric degenerate vibrations, based on the semi‐classical approach. General equations have been obtained and model calculations with the Monte Carlo method for systems of cubic symmetry have been carried out. There is a simple transform relationship between the absorption spectrum and the Raman amplitude of the non‐totally symmetric mode which prevails. All the equations obtained can also be used for pre‐resonance Raman scattering regardless of the strength of the vibronic coupling.
IR and Raman spectra of MgMoO4 · nH2O (n = 1, 5)
Authors: Isaac Mary , Santha N. , Nayar V. U. 
Published: May 2005

AbstractThe IR and Raman spectra of two hydrated molybdates, MgMoO4 · H2O and MgMoO4 · 5H2O, were recorded and analysed. In both the compounds, bands indicating MoO octahedral coordination are observed. Three crystallographically different water molecules exist in MgMoO4 · 5H2O. MgMoO4 · H2O exhibits weak hydrogen bonds and MgMoO4 · 5H2O hydrogen bonds of medium strength.
Raman spectroscopy of BeO at low temperatures
Authors: Devanarayanan S. , Morell G. , Katiyar R. S. 
Published: May 2005

AbstractPolarized first‐order Raman spectra of BeO crystal were recorded at various temperatures to study the variations in frequencies and intensities associated with some of the phonons. At 35 K five modes were assigned to be fundamentals at 338.1 682.6, 726.7 and 1085.8 cm−1. The different scattering geometries were utilized to study the directional dependence of the dipolar phonons. Two peaks at 703.6 and 1093.7 cm−1. were the quasi‐TO and LO modes, respectively. Both the frequency and the intensity of the phonons increase with decreasing temperature. The mode at 682.6 cm−1 was examined in more detail at several temperatures.
Resonance Raman spectra of dioxygen adducts of manganese(II) porphyrins in dioxygen matrices
Authors: Weselucha‐Birczynska A. , Proniewicz L. M. , Bajdor K. , Nakamoto K. 
Published: May 2005

AbstractThe resonance Raman spectra of side‐on type dioxygen adducts of Mn(TMP), Mn(TPP) and Mn(OEP), where TMP, TPP and OEP denote the dianions of tetramesityl‐, tetraphenyl‐ and octaethyl‐porphines, respectively, were measured in O2‐Ar(1 : 30) matrices at ca. 15 K. The bands near 990, 710 and 430 cm−1 were assigned to ν(O2), νs(MnO) and νa(MnO), respectively, based on 16O2/18O2 isotopic shifts and normal coordinate calculations on an isosceles MnO2 moiety. Vibrational coupling between the νs (MnO) and porphyrin modes obscured the location of the former mode in the spectra of Mn(TPP)O2 and Mn(OEP)O2. The bands near 825 cm−1 which appear in all three porphyrins are shifted 34–36 cm−1 on 16O2/18O2 substitution. Evidence is presented to show that this band is due to the ν(MnO) of oxomanganese(IV) porphyrin, which was produced by photo‐cleavage of the OO bond of the dioxygen adduct. These ν(MnO) are ca. 70 cm−1 higher than those observed in acetonitrile solution. This has been attributed to the difference in the spin state; the oxomanganese(IV) porphyrins in acetonitrile solution are of high spin whereas those produced in O2‐Ar matrices are of low spin.
Surface‐enhanced Raman analysis of vitamin B complex: Quantitative detection of p‐aminobenzoic acid
Authors: Narayanan V. Anantha , Bello Job M. , Stokes David L. , Vo‐Dinh Tuan 
Published: May 2005

AbstractSurface‐enhanced Raman scattering (SERS) spectra of vitamin B complex extracted in ethanol were analyzed using a silver‐coated alumina substrate. The SERS effect appears to enhance selectively the spectrum of p‐aminobenzoic acid (PABA) from among the complex constituents of the vitamin B complex tablet. A calibration graph of SERS signal intensity versus concentration of PABA was constructed for quantitative analysis. With such a graph it is possible to detect PABA down to low parts per million levels. The potential of the SERS technique in other analytical and biomedical areas is discussed.
Demonstration of low‐frequency performance and microanalysis capability of multi‐channel Raman spectroscopy with near‐infrared excitation. I
Authors: Barbillat J. , Da Silva E. , Roussel B. 
Published: May 2005

AbstractThe use of a liquid nitrogen‐cooled unintensified charge‐coupled device (CCD) multi‐channel array detector combined with a continuous‐wave Nd: YAG laser operating at 1064 nm and a triple grating spectrograph to obtain Raman data in the low‐frequency range down to 25 cm−1 is reported. The capabilities of near‐infrared multichannel Raman microanalysis, which permits the acquisition, with a conventional optical microscope attachment, of Raman spectra with a spatial resolution of better than a few micrometres, is also illustrated.
Comparative study of the structure of TvNPV polyhedrin and TvNPV virion protein by Raman spectroscopy
Authors: Bao Peidi , Liu Xinming , Huang Tianquan , Wu Tieqiao 
Published: May 2005

AbstractRaman spectra were obtained and analysed for polyhedrin and virion protein of Trabala vishnou nuclear polyhedrosis virus (TvNPV‐P and TvNPV‐VP, respectively). It was found that the secondary structures of the protein of the two samples differ: the protein of TvNPV‐P has predominantly an α‐helical and β‐sheet structure whereas that of TvNPV‐P contains predominantly a β‐sheet content, with an α‐helix content and a lower random‐coil or β‐turn content. All tyrosyl residues in the protein of TvNPV‐P are exposed, whereas 80% of the tyrosyl residues are exposed and 20% are buried in the protein of TvNPV‐VP. The majority of the tryptophan residues in the protein of TvNPV‐VP are in a hydrophobic environment. The TvNPV‐VP has a trans‐gauche‐trans configuration of the CCSSCC linkage.
Surface‐enhanced Raman spectroscopy of pyridine and thiophenol on non‐aqueous colloidal copper
Authors: Pate J. , Leiden A. , Bozlee B. J. , Garrell R. L. 
Published: May 2005

AbstractSurface‐enhanced Raman (SER) spectra of pyridine and thiophenol on a copper colloid prepared in isopropanol were obtained. Aggregation of the colloid, which occurs only slowly in the presence of adsorbates, was found to be essential to the detection of SER spectral features with excitation at 660 nm. As with aqueous copper sols, thiophenol was found to adsorb more strongly than pyridine to the copper surface. However, both adsorbates required greater concentrations in the bulk solution than for aqueous systems in order for SER features to be observed.
Fourier transform and surface‐enhanced Raman spectra of barbituric acid and of its anion
Authors: De Oliveira L. F. C. , Santos P. S. , Rubim J. C. 
Published: May 2005

AbstractFourier transform Raman spectra in the near‐IR region and surface‐enhanced Raman (SER) spectra were used to obtain the vibrational spectra of barbituric acid and its anion, since their ordinary Raman spectra cannot be obtained owing to a strong fluorescence emission. Based on the present data and literature IR data, a tentative vibrational assignment is proposed for the two species. In addition, the SER spectra of barbiturate anion adsorbed on a silver electrode in borate buffer (pH 8.4) were used to infer the geometry of adsorption, which probably involves the participation of at least one of the carbonyl groups, although a more precise definition of the geometry of adsorption depends on additional data.