bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman spectroscopic investigation of polybromide‐containing functional polymers
Authors: Schnittke A. , Stegemann H. , Füllbier H. , Gabrusenoks J. 
Published: May 2005

AbstractSolid polybromide‐containing functional polymers were obtained from basic anion‐exchange resins. The chloride or hydroxide anions of the commercial resins were exchanged by bromide, then dried under anaerobic conditions and allowed to react with a gaseous bromine phase. The formation of linear, slightly asymmetric tribromides was proved by Raman and far‐IR spectroscopy. The tribromide spectra are characterized by the symmetrical stretching vibration ν1 at about 160 cm−1 and the antisymmetric stretching vibration ν3 at about 200 cm−1. If the Br2: Br− molar ratio is greater than 1 an additional band could be observed at about 255 cm−1. This band is assigned to the stretching vibration of coordinated bromine. It is shifted in the direction of free bromine at about 300 cm−1 with increasing bromine content in the functional polymers. According to the spectroscopic results, the anion structure in amorphous polybromide‐containing functional polymers can be explained by tribromide ions and bromine molecules interacting with the tribromide. The thermal instability of higher polybromides was also proved spectroscopically.
Raman and infrared spectra of solid dichlorofluoromethane
Authors: Lefebvre J. H. , Anderson A. 
Published: May 2005

AbstractRaman and infrared spectra of solid dichlorofluoromethane were recorded in both the internal and lattice mode regions at 20 and 80 K. The lattice spectra are consistent with a non‐centrosymmetric unit cell containing at least four molecules. All nine internal modes are observed, and their multiple components are interpreted in terms of crystal field effects and isotopic splittings.
Theoretical investigations of discrete resonance Raman scattering in H2 via intermediate B, C states
Authors: Banerjee Sima , Bhattacharyya S. S. , Saha Samir 
Published: May 2005

AbstractDiscrete resonance Raman scattering (DRRS) from the ground X1Σg+(νg = 0, Jg = 0‐2) state of H2 via excited intermediate states B1Σu+(νi = 0‐3, Ji = 0‐3) and C1Πu(νi = 0‐3, Ji = 1‐3) was studied theoretically, applying the reduced density operator formalism. The Raman Spectra for the pure rotational, fundamental and higher overtones are presented. The intensities of the Raman lines for O, Q and S branches were calculated using thermal Boltzmann factors for vibrational‐rotational distribution at room temperature (300 K). The calculated DRRS cross‐sections are found to be many orders of magnitude larger than normal (non‐resonance) Raman cross‐sections for H2 or continuum resonance Raman cross‐sections for molecular ions such as HD+.
Solution‐phase vibrational relaxation studies in N,N‐dimethylacetamide
Authors: Purkayastha Anusree , Kumar Kamal 
Published: May 2005

AbstractVibrational relaxation studies in N,N‐dimethylacetamide revealed that the hydrodynamic and dispersion forces play a significant role in the line broadening of the CO stretching vibrational band. The non‐coincidence effect was also examined in the light of dielectric screening due to different environmental conditions.
Absolute Raman pair cross‐section for the πu mode in supercritical carbon dioxide
Authors: Baglin F. G. , Hacura A. , Yoon J. H. 
Published: May 2005

AbstractThe absolute Raman cross‐section was measured for the πu mode of supercritical carbon dioxide at 50 and 75°C over five densities. These measurements clearly show that a dimeric species is responsible for the quadrupole induced dipole (QPID) Raman spectral activity of the πu(ν2) transition in carbon dioxide. This result is in accord with earlier predictions by Amos et al.
Raman scattering and scanning electron tunnelling studies of metal liquid‐like films produced from silver and gold sols
Authors: Bell Steven E. J. , McGarvey John J. , Rigby Stephanie J. , Walmsley D. G. 
Published: May 2005

AbstractSurface‐enhanced Raman scattering (SERS) excited at several visible wavelengths and recorded using a cooled charged‐coupled device detector is reported from the mobile, interfacial, liquid‐like metal films (MELLFs) formed when solutions of metal complexes or pyridine in chlorocarbon solvents are mixed with aqueous sols of silver or gold. MELLF formation has not previously been reported for gold sols or for pyridine as stabilizer. Comparison of the spectra for the MELLFs formed from individual metal complexes and from 50:50 mixtures show that the spectral patterns observed for the latter are distinctive and are not generally equivalent to the sum of the spectra associated with the individual complexes, in contrast to the situation observed for sols where the individual spectra do appear to be additive. Raman scattering from both gold and silver MELLFs is readily observed at excitation wavelengths in the red, around 750 nm, but at 514 nm only that from silver films is detectable. These findings are considered in terms of particle size and absorption band intensities. A preliminary study of the film surface topography and particle size was carried out by scanning tunnelling electron microscopy (STM) of Ag MELLFs deposited on gold‐coated mica substrates. Computer‐processed images of the STM data show the presence on the film surface of finger‐like bars, 200–400 nm long with approximately square cross‐section, 40–60 nm side, together with other smaller cuboid features. The implications of these findings in relation to SERS are briefly considered.
Surface‐enhanced resonance Raman scattering of a NO2‐bisphthalocyanine adduct in Langmuir‐Blodgett monolayers
Authors: Souto J. , Aroca R. , Desaja J. A. 
Published: May 2005

AbstractLangmuir‐Blodgett (LB) monolayers of dysprosium and holmium bisphthalocyanine complexes (DyPc2 and HoPc2) were prepared at 10°C and transferred to glass slides coated with gold island films. Surface‐enhanced resonance Raman scattering (SERRS), and visible absorption spectrometry were used to monitor the interaction between the LB monolayer and NOx (NO2‐N2O4) gas. It is shown that the absorption and inelastic scattering spectra of LB are sensitive tools to monitor the interaction between the MPc2 molecule and the NO2, allowing the spectral properties of the adduct formed by chemisroption to be determined.
SERS and Fourier transform SERS studies of the hexacyanoferrate(III)‐hexacyanoferrate(II) couple on gold electrode surfaces
Authors: Lowry R. B. 
Published: May 2005

AbstractSurface‐enhanced Raman spectroscopy (SERS) and its Fourier transform (FT) variant were used to study the hexacyanoferrate(III)‐hexacyanoferrate(II) couple at the surface of gold electrodes. The effects of potential, Fe(CN) concentration and base electrolyte (KCl) concentration were measured, and point to distortion of the Fe(CN) ion on the surface of the electrode. The Fe(CN) ion was found not to be strongly adsorbed when a base electrolyte concentration of > 10 mM was used, but the strong adsorption of the Fe(CN) ion was demonstrated. The increased resolution that is possible when using the FT‐SERS technique allows for the partial resolution of bands in the CN stretching region, and thus the construction of a model for the hexacyanoferrate(III) system.
Raman and far‐infrared spectra, conformational stability, barriers to internal rotation, vibrational assignment and ab initio calculations of 2,3‐dicholoropropene
Authors: Durig D. T. , Guirgis G. A. , Durig J. R. 
Published: May 2005

AbstractThe far‐infrared spectrum (375 to 30 cm−1) of gaseous 2,3‐dichloropropene, CH2C(CH2Cl)Cl, was recorded at a resolution of 0.06 cm−1. The fundamental asymmetric torsional mode is observed at 91.9 cm−1 with eight excited states falling to low frequency for the s‐cis (chlorine atom eclipsing the double bond) conformer. For the higher energy gauche conformer, the asymmetric torsion is estimated to be near 85 cm−1. Utilizing the s‐cis torsional frequency, the gauche dihedral angle and the enthalpy difference between conformers, the potential function governing the interconversion of the rotamers was calculated. The determined potential function coefficients are V1 = 1047 ± 96, V2 = −619 ± 68, V3 = 1216 ± 50 and V4 = 26 ± 22 cm−1, with an enthalpy difference between the more stable s‐cis and gauche conformers of 245 ± 30 cm−1 (0.70 ± 0.09 kcal mol−1). This function gives values of 1035 ± 10 cm−1 (2.96 ± 0.03 kcal mol−1), 2015 ± 150 cm−1 (5.76 ± 0.43 kcal mol−1) and 787 ± 10 cm−1 (2.25 ± 0.03 kcal mol−1) for the s‐cis to gauche, gauche to gauche and gauche to s‐cis barriers, respectively. From the relative intensities of the Raman lines of the liquid at 1633 cm−1 (gauche) and 1649 cm−1 (s‐cis) as a function of temperature, the enthalpy difference is found to be 334 ± 39 cm−1 (0.95 ± 0.11 kcal mol−1), but now with the gauche conformer more stable. Also, the more polar gauche conformer remains in the crystalline solid. The Raman spectrum of the gas was recorded from 3500 to 70 cm−1 and, utilizing these data and the previously reported infrared data, a complete vibrational analysis is proposed for both conformers. The conformational stability, barriers to internal rotation, fundamental vibrational frequencies and structural parameters which were determined experimentally are compared to those obtained from ab initio Hartree—Fock gradient calculations employing both the 3‐21G* and 6‐31G* basis sets and to the corresponding quantities for some similar molecules.
Raman and infrared spectra of solid hydrogen selenide
Authors: Paldus B. A. , Schlueter S. A. , Anderson A. 
Published: May 2005

AbstractRaman and infrared spectra of solid H2Se at temperatures between 85 and 20 K are reported and interpreted. The broad peaks observed in the spectra of phase II are characteristic of an orientationally disordered crystal, whereas the multiple components of the internal modes and rich lattice spectra found for phase III are indicative of an ordered structure. The unit cell for this phase is probably centrosymmetric and contains at least four molecules. Plausible assignments for all observed spectroscopic features are proposed.
Spectra and structure of organophosphorus compounds. XLVIII—Raman and infrared spectra, conformational stability, vibrational assignments and ab initio calculations of dimethyl(methylthio)phosphine
Authors: Durig J. R. , Smith David F. , Barron D. A. , Harlan R. J. , Phan H. V. 
Published: May 2005

AbstractThe Raman spectra (3200–10 cm−1) and infrared spectra (3200–50 cm−1) of dimethyl(methylthio)phosphine, CH3SP(CH3)2, and dimethyl(methyl‐d3‐thio)phosphine, CD3SP(CH3)2, in the gas and solid forms were recorded. Additionally, the Raman spectra of the liquids were recorded and qualitative depolarization ratios measured. All 36 of the normal modes were assigned and the asymmetric torsion was observed in the far‐infrared spectrum of gaseous CH3SP(CH3)2 at 75 cm−1. From a comparison of the vibrational spectra obtained for the fluid phases with those obtained for the amorphous and annealed solids, it is concluded that the molecule exists as a mixture of the cis and trans conformers in the fluid phases with the trans conformer being the more stable form in the liquid and the only one present in the spectra of the annealed solid. However, for the vapor state the cis conformer is the more stable form. The enthalpy difference between the cis and the trans conformers was determined from a variable‐temperature study of the Raman spectrum of the liquid to be 199 ± 8 cm−1 (569 ± 23 cal mol−1). A complete vibrational assignment is proposed which is supported by a normal coordinate calculation obtained from the force fields calculated with the ab initio RHF/3–21G* basis set. Full geometry optimizations were carried out with the 3–21G* and 6–31G* basis sets for the transition state to determine the barriers to internal rotation about the CH3SP bond. All of these results are compared with corresponding data for several other organophosphorus compounds.
Vibrational spectrum of Zn2 VO(PO4)2
Authors: Baran Enrique J. , Lii Kwang‐Hwa 
Published: May 2005

AbstractThe infrared and laser Raman spectra of Zn2 VO(PO4)2 were recorded and are briefly discussed with the aid of a factor group analysis. Some interesting aspects related to the strongly condensed nature of the phosphate groups and to the characteristics of the VO bonds in this structure are also considered.
Vibrational spectra, thermodynamic functions and barriers to internal rotation for isomeric trifluoromethylbenzoyl chlorides
Authors: Shanker R. , Yadav R. A. , Singh I. S. , Singh O. N. 
Published: May 2005

AbstractThe polarized Raman spectra (50–4000 cm−1) and IR spectra (180–4000 cm−1) of o‐, m‐ and p‐ trifluoromethylbenzoyl chlorides were recorded and all the 45 (30a′ + 15a") normal modes of vibration were assigned assuming Cs symmetry. Consistent assignments for the internal modes of the COCl and CF3 groups are proposed. Thermodynamic functions were computed and barriers to internal rotations for the COCl and CF3 tops were determined, using the assigned vibrational frequencies and assumed structural parameters for the three isomers.
Raman and infrared study of structural phase transitions in (NH4)3H(SeO4)2 and (ND4)3D(SeO4)2
Authors: Raimbault G. , Romain F. , Lautié A. 
Published: May 2005

AbstractThe Raman and infrared spectra of (NH4)3H(SeO4)2 and (ND4)3D(SeO4)2 were investigated between 20 and 400 K in the 4000–10 cm−1 frequency range. Five crystalline phases were characterized spectroscopically and structural information was obtained by comparison with results previously obtained on sulphate analogues. Phase III at room temperature is strongly disordered, mainly as regards the ammonium ions, and a decrease in temperature leads to a progressive ordering; however, parent and deuterated compounds show different phase sequences. Only the ferroelectric phase V shows the spectra characteristic of a fully ordered crystal. The mechanism of phase transitions, involving motions of NH4+ and selenate entities, and the behaviour of the strong OH…︁O hydrogen bond, present in the asymmetric (SeO4HSeO4)3− dimers, are discussed.
Vibrational spectra and conformation of 1‐chloro‐4‐fluorobut‐2‐yne and ab initio calculations on 1,4‐dihalobut‐2‐ynes
Authors: Karlsson A. , Klaeboe P. , Nielsen C. J. 
Published: May 2005

AbstractRaman spectra were recorded in the 3200‐5 cm−1 range for 1‐chloro‐4‐fluorobut‐2‐yne as a liquid at various temperatures and as amorphous and different crystalline solids at low temperature. In the liquid, the Raman spectra showed broad, asymmetrical band shapes as previously reported for other 1,4‐dihalobut‐2‐ynes. Additional IR and far‐IR spectra were obtained of the liquid, vapour, amorphous and crystalline solids at low temperature, and of the compound isolated in argon and nitrogen matrices at 13 K. The vapour and liquid spectra were interpreted in terms of a low barrier to internal rotation and the crystal spectra of a single conformer, gauche. The unusual band shapes in the low‐frequency Raman spectra of the 1,4‐dihalobut‐2‐ynes are discussed and are reproduced fairly well by a simple model of a molecule exhibiting nearly free internal rotation. The agreement between the observed and calculated spectra is good for all the molecules studied when ab initio potentials are applied in the model calculations. Temperature effects in the Raman spectra of liquid 1‐chloro‐4‐fluorobut‐2‐yne can also be derived from the model. Internal rotation in 1,4‐difluoro‐, 1,4‐dichloro‐, 1‐chloro‐4‐fluoro‐, 1,4‐dibromo‐ and 1,4‐diiodobut‐2‐yne was studied with the aid of ab initio calculations. The barriers were found to be low and decreasing through the series from 1,4‐difluoro‐ to 1,4‐diiodobut‐2‐yne accompanied by an increase in the equilibrium dihedral angle, XCCCCY, from 101° in 1,4‐difluorobut‐2‐yne to 180° in 1,4‐diiodobut‐2‐yne. The systematic variations through the series were correlated with the local dipole moments of the halomethyl groups and the electronegativities of the halogen substituents.
Vibrational spectra of LiNH3OHSO4 and LiND3ODSO4
Authors: Pillai V. P. Mahadevan , Pradeep T. , Suresh G. , Nayar V. U. 
Published: May 2005

AbstractInfrared and Raman spectra of LiNH3OHSO4 and LiND3ODSO4 were recorded and analysed. Bands were assigned on the basis of SO4, NH3 and OH vibrations. The symmetric stretching mode in the deuterated compound is found to be at higher frequencies, indicating the existence of strong hydrogen bonds in LiNH3OHSO4. The SO4 ion is distorted in the crystal. A, B and C bands are observed in the OH stretching region, also showing the formation of strong hydrogen bonds.
Resonance Raman enhancement of the oxo‐bridged dinuclear iron center: Vibrational modes in iron(III) physiological‐type porphyrin complexes
Authors: Brémard C. , Kowalewski P. , Merlin J. C. , Moreau S. 
Published: May 2005

AbstractOxo‐bridged dinuclear iron(III) complexes of two physiological‐type prophyrins, (DPDEFe)2O and (PPDEFe)2O (where DPDE = deuteroporphyrin dimethyl ester and PPDE = protoporphyrin dimethyl ester), were investigated using resonance Raman and infrared spectroscopy. The assignment of the porphyrin vibrational modes was performed using polarization measurements and previous studies concerning the corresponding mononuclear iron(III) complexes, (DPDEFe)Cl, (PPDEFe)Cl, and related compounds. The assignment of the FeOFe axial bridge vibrational modes of the two μ‐oxo complexes investigated and the synthetic analogue (TPPFe)2O (where TPP = tetraphenylporphyrin) was made with the help of 18O substitution. The dependence of the frequencies vs and va on the FeOFe angle for (TPPFe)2O is in good agreement with the angle value previously determined by x‐ray diffraction data. The values of the FeOFe angle in (DPDEFe)2O and (PPDEFe)2O were estimated to be close to 160° and 170°, respectively. The excitation profiles (351.1–647.1 nm) of the porphyrin core marker bands for all the μ‐oxo complexes studied are in good agreement with the expected general trends of the resonance enhancement with moderate vibronic coupling. However, for the μ‐oxo physiological‐type porphyrin complexes, the v4 marker band exhibits and unexpected strong enhancement maximum near the maximum found in the excitation profile of the va and vs (FeOFe) modes. These enhancement maxima tend to correspond to a minor oxo → Fe(III) charge‐transfer band in the electronic absorption spectra. A mixing of several electronic levels under low symmetry may be responsible for this enhancement phenomenon.
Surface‐enhanced Raman spectroscopic study of amsacrine and amsacrine–DNA interactions
Authors: Barton Thomas F. , Cooney Ralph P. , Denny William A. 
Published: May 2005

AbstractSurface‐enhanced Raman scattering (SERS) spectroscopy has been employed to study the interaction of intercalating ligands with DNA. SERS was used to obtain spectra of acridine, aminoacridine, the 9‐anilinoacridine amsacrine and related compounds at associated solution concentrations down to 1 μM. A major advantage of SERS was the near absence of fluorescence normally inherent in solution spectra of these compounds. SERS spectra of amsacrine–DNA complexes at various ligand/base pair ratios showed free ligand concentrations consistent with those calculated from the binding constant, and showed that the less strongly interacting acridine was largely unbound even at high ligand/base pair ratios.
Far‐infrared reflectivity and Raman study in the ferroelectric–ferroelastic crystal of tris(dimethylammonium) nonabromodiantimonate
Authors: Marqueton Y. , Miniewicz A. , Jakubas R. 
Published: May 2005

AbstractA study of far‐infrared (5–400 cm−1) polarized reflectivity spectra and preliminary Raman measurements of the ferroelectric crystal of DMABA, [NH2(CH3)2]3Sb2Br9, were made in the temperature range 80–300 K. The paraelectric–ferroelectric phase transition occurring at Tc = 164 K in this crystal has an impact on low‐frequency phonons. Oscillator strengths, induced dipole moments and mode dampings were determined as a function of temperature. Low‐frequency dielectric parameters were estimated from infrared reflectivity spectra of DMABA.
Continuum resonance Raman scattering in isotopically pure 127I79Br
Authors: Vogt P. , Deckert V. , Kiefer W. 
Published: May 2005

AbstractHigh‐resolution Stokes and anti‐Stokes Raman spectra of isotopically pure 127I79Br were recorded with excitation by argon ion laser radiation using CCD camera detection and a scanning multi‐channel technique. The observed spectra show a complex rotational–vibrational structure, which can be explained in terms of Q branches, S band heads, unresolved O branches and corresponding hot band transitions. The spectral band shapes of the fundamental vibrational transitions and of several overtones were studied as a function of laser power and excitation wavelength. A symmetry principle between Stokes and anti‐Stokes spectra is also demonstrated. In addition, hyperfine structure in the electronic Raman spectra of atomic 127I and 79Br was observed under high resolution.
Raman spectroscopy of PH3 and PH2 at high temperature and simulation of PH3 Raman spectrum
Authors: Abraham P. , Bekkaoui A. , Bouix J. , Monteil Y. 
Published: May 2005

AbstractExperimental Raman spectra of the symmetric stretching vibration band v1 and of the degenerate stretching vibration band v3 of PH3 were obtained for temperatures ranging from 293 to 903 K. These spectra also show a band of a new gaseous species, which is a pyrolysis product of PH3. This band can be unambiguously attributed to PH2. To extract the Raman spectrum of PH2 from the overall spectrum, the PH3 Raman spectra of the v1 and v3 bands were calculated. The way in which these bands were calculated is explained and a comparison is made between the experimental and simulated spectra at different temperatures. These comparisons clearly identify the PH2 v1 band. By the subtraction of the simulated spectrum from the experimental spectrum, the origin of the PH2 v1 band is estimated to be 2310.3 ± 2 cm−1.
Raman optical activity instrument for biochemical studies
Authors: Hecht L. , Barron L. D. , Gargaro A. R. , Wen Z. Q. , Hug W. 
Published: May 2005

AbstractA simple and fully computer‐controlled backscattering incident circular polarization Raman optical activity (ICP ROA) instrument suitable for chioptic studies of biologically significant molecules in aqueous solution is described. It consists of a fast single‐stage monochromator equipped with a holographic edge filter, a highly efficient holographic difiaction grating and a thinned back illuminated thermoelectrically cooled charge‐coupled device detector as the key spectral elements. A longitudinal electro‐optic modulator is employed to switch between orthogonal circular polarization states in the incident laser radiation within a backscattering geometry. A thick Lyot depolarizer is used for the depolarization of the backscattered Raman radiation. High‐quality backscattering ICP ROA spectra of (1S)‐( − )‐trans‐pinane, (1R)‐( + )‐trans‐pinane, L‐alanine, L‐alanyl‐L‐alanine, lysozyme, D‐glucose, α‐D‐cyclodextrin and 2′‐deoxycytidine are presented as typical examples of the excellent performance characteristics.
Comment: Vibrational spectra and conformational stability of n‐butane
Authors: Murphy W. F. 
Published: May 2005

AbstractA study of the vibrational spectrum of gaseous n‐butane was recently presented in this journal [J. R. Durig et al., J. Raman Spectrosc. 22, 683 (1991)]. From the temperature dependence of the Raman spectrum, the enthalpy difference between the trans and gauche conformers was found to be ca 375 cm−1 (1072 cal mol−1). In a recent absolute intensity study of gaseous n‐butane [W. F. Murphy et al., J. Phys. Chem. 95, 1124 (1991)], a relative conformer abundance was determined which corresponds to an energy difference of 690 cal mol−1 (241 cm−1). The latter result confirms several other recent determinations of this quantity. Concerns regarding the validity of the temperature dependence method are presented, and the preference for the lower value of the enthalpy difference is defended.