bluuebunny/crossref_metadata_2025 huggingface dataset:
Raman and infrared rotation‐vibration spectra of the ν1 Band of D14N3
Authors: Bendtsen Jørgen
Published: May 2005

The rotational structure of the ν1 band of D14N3 in the wavenumber region 2200–2600 cm−1 has been measured by means of Raman spectroscopy with a resolution of 0.3 cm−1. Both components of the hybrid band were observed. In addition, an infrared spectrum of the same wavenumber region was recorded with a resolution of 0.07 cm−1. In the infrared experiment mainly the parallel component was observed. The molecular parameters determined from the observed wavenumbers in the Raman spectrum are (ν0)1=2478.32 (1) cm−1, A1 = −11.096 (1) cm−1,½(B1 + C1)=0.37187 (4) cm−1, (DK)1 = 2.85 (2) × 10−3cm−1 and (HK)0 = 2.7 (4) × 10−6 cm−1. From the infrared spectrum the following values were obtained: (ν0)1 = 2478.451 (3) cm−1, A1 = 11.0902 (4) cm−1, B1 = 0.378186 (9) cm−1, C1 = 0.365032 (9) cm−1, (DK)1 = 2.69 (2) × 10−3 cm−1 in addition to values for (D1)1 and (DJK)1. The discrepancy between the values for (ν0)1 obtained from the two experiments is mainly due to uncertainties in the absolute calibration and to differences in the intensity distributions of the unresolved Q‐branch lines in the two types of experiments.
Raman spectroscopic evidence for β‐turn conformation
Authors: Lagant P. , Vergoten G. , Fleury G. , Loucheux‐Lefebvre M. H.
Published: May 2005

A correlation connecting the well known amide III band frequency of the peptide bond with the torsional angle ψ is proposed.
Raman spectra of NaLa(MoO4)2 single crystal
Authors: Ramakrishnan V. , Dhas G. Arul , Narayanan P. S.
Published: May 2005

The Raman spectra of NaLa(MoO4)2 single crystal have been recorded and interpreted on the basis of C4h symmetry. The observed fundamentals (internal and external) have been assigned unambiguously with the help of polarization data. All the group theoretically predicted Raman active fundamentals have been observed.
Raman and far‐infrared spectra of crystalline methylene chloride
Authors: Anderson A. , Torrie B. H. , Danagher D. J. , Laurin D. G. , White J. K. , Zung W. W. E.
Published: May 2005

The lattice vibrations of crystalline CH2Cl2 and CD2Cl2 have been observed by Raman and far‐infrared spectroscopic techniques. The results are compared with the predictions of group theory, and peaks are assigned on the basis of frequency shifts on deuteration and considerations of intensities, molecular inertia factors and crystal structure.
H2 Raman‐shifted YAG laser ultraviolet Raman spectrometer operating at wavelengths down to 184 nm
Authors: Fodor Stephen P. A. , Rava Richard P. , Copeland Robert A. , Spiro Thomas G.
Published: May 2005

Apparatus is described for the acquisition of Raman spectra with excitation at wavelengths as short as 184 nm. The H2 Raman‐shifted output of an Nd:YAG laser is directed on to a free‐flowing sample, and the Raman photons are collected and dispersed by a scanning 1.26 m single monochromator equipped with a 2400 groove holographic grating and a solar blind phototube with integrating electronics, or by a 0.5 m spectrograph with an 1800 groove holographic grating and a reticon multi‐channel detector. Data for air‐sensitive samples are obtained by enclosing the sample jet in an inert gas purged shroud equipped with a UV‐transparent optical window. Raman spectra are reported for phenylalanine at a series of excitation wavelengths down to 184 nm. They show a sharp transition between 200 and 192 nm from vibronic to Franck–Condon scattering. At 200 nm, the intensities of the vibronically induced ν8a and ν8b modes, at 1606 and 1586 cm−1, are nearly the same as that of the 1000 cm−1 ν1 ring breathing mode, whereas at 192 nm the relative intensities of the former bands are dramatically dimished. In contrast, the ν8a and ν8b modes of tyrosine continue to show enhancement comparable to the ring breathing modes at 192 nm, the maximum of the strong 1Bα, b tyrosine absorption. The spectrum of insulin at 192 nm shows comparable contributions from tyrosine, phenylalanine and amide vibrations, whereas at 200 and 218 nm excitation the aromatic contributions are dominant.
Enhancement of resonance Raman scattering from crystal violet deposited on island silver films
Authors: Chou Y. C. , Liang N. T. , Tse W. S.
Published: May 2005

The observed thickness dependence and excitation profiles of the surface‐enhanced resonance Raman scattering (SERRS) from crystal violet (CV) on silver films demonstrated the importance of surface roughness and chemical effects. Using different normalization schemes in studying the excitation profile of SERRS we were able to identify that there are three multiplicative contributions to the observed overall enhancement, viz. the electromagnetic effect, the molecular resonance effect and the charge‐transfer effect originating from the strong electronic interactions between CV and the metal islands.
Photoisomerization studies of pinacyanol using nanosecond time‐resolved resonance cars
Authors: Werncke W. , Tschol Tscho Jong , Weigmann H.‐J. , Pfeiffer M. , Lau A. , Rentsch S. , Graness A.
Published: May 2005

Resonance CARS spectra of the short‐lived photoisomer of pinacyanol were obtained. From the CARS line frequencies, intensities, line shapes and depolarization ratios it can be concluded that a cis‐isomer rather than a twisted configuration is observed.
Raman spectra of gases. XXVI—Trifluoroacetaldehyde
Authors: Durig J. R. , Guirgis G. A. , Van Der Veken B. J.
Published: May 2005

The Raman spectra from 3500 to 10 cm−1 of gaseous, liquid and solid trifluoroacetaldehyde (fluoral), CF3CHO, have been recorded and qualitative depolarization values were obtained for the fluid phases. Two of the bending fundamentals have been reassigned. The infrared gas‐phase band contours have been calculated and compared with the observed values. From the far‐infrared spectrum of the gas, the fundamental (66.2 cm−1) and overtone (128.6 cm−1) of the internal rotation have been identified. The barrier to internal rotation has been calculated to be 298±10 cm−1 (852±29cal mol−1). The spectrum of the solid is consistent with at least two molecules per primitive cell. These results are compared with earlier results and with similar parameters for some corresponding molecules.
Raman and infrared spectra and fundamental frequencies of 1,2,4,5‐tetrabromobenzene
Authors: Yadav R. A. , Shanker R.
Published: May 2005

The Raman spectrum of 1,2,4,5‐tetrabromobenzene has been recorded in powder form in the region 100–4000 cm−1 and the IR spectra in nujol mull and a CsI pellet in the region 200–4000 cm−1. Tentative vibrational assignments have been proposed assuming D2h point group symmetry. Observation of a number of overtone and combination bands enabled the inactive fundamentals and those fundamentals which were not observed experimentally to be estimated.
Depolarization dispersion curves of some Raman fundamentals in ferrocytochrome c and oxyhaemoglobin
Authors: Zgierski Marek Z.
Published: May 2005

Depolarization dispersion curves and Raman excitation profiles of three fundamentals in ferrocytochrome c (1585, 1312 and 1363 cm−1) and oxyhaemoglobin (1583, 1376 and 1638 cm−1) are calculated togther with the corresponding absorption spectra in the region of 16000‐23000 cm−1. A four‐orbital model with two‐electron interaction term and vibronic coupling terms for the a1g, a2g, b1g and b2g vibrations is used in two‐mode calculations. It is shown that the observed depolarization dispersion curves indicate the presence of symmetry‐breaking A2g and B1g electronic perturbations in ferrocytochrome c and of a B2g off‐diagonal electronic perturbation in oxyhaemoglobin. These electronic perturbations lower the D4h symmetry of the porphyrin ring. It is also demonstrated that smaller vibronic perturbations become active in these molecules at lower symmetry. These vibronic perturbations result mainly from the symmetry‐forbidden (D4h group) linear dependence of the nuclear potential energy in the Q and B states and of the two‐electron interaction term on non‐totally symmetric vibrational coordinates.
Raman spectra of some complexes containing methyl‐, dimethyl‐ and trimethyl‐halophosphonium cations
Authors: Finch Arthur , Gates Peter N. , Muir Alan S.
Published: May 2005

Vibrational assignments for the skeletal modes of the solid‐state species (CH3)nPX5−n (X  Cl, Br; 1 ⩽ n ⩽ 3) have been made on the basis of their Raman Spectra. The results are consistent with ionic formulations (CH3)nPX4−n +X− and are compared with any previously available data. Two modifications of (CH3)2PCl2 +Cl− have been observed for the first time and their relative stabilities investigated. Raman spectra of the mixed halogen cationic compounds CH3PCl2Br+X−, CH3PClBr2 +X− and (CH3)2PClBr +X− are also reported and Lewis acid complexes of all the phosphonium cations show characteristic high‐frequency shifts in the PX stretching modes [relative to those in (CH3) RPX4−n +X−] which are rationalized in terms of anion‐cation interactions. CH3PCl4 has been observed in a molecular form and the transition to the ionic modification (at ca 160 K) has been monitored by variable temperature Raman spectroscopy.
Misassignment of the strong Raman band near 1000 cm−1 in some substituted benzenes, and the Herzberg versus Wilson convention for numbering the vibrations of benzene
Authors: Miller Foil A.
Published: May 2005

Mono, 1,3, 5‐substituted benzenes (and only these) have a very strong, highly poarized Raman band at 1000±10 cm−1. It is often misassigned as the symmetrical ring breathing, whereas in fact it is derived from the benzene trigonal ring deformation v6. In the current literature the vibrations of benzene are numbered according to either the Herzberg or the Wilson scheme. A plea is made for using only one convention, and reasons are gigen for choosing Herzberg's.
Raman intensities of liquids: Potential secondary standards for Raman shifts greater than 1000 cm−1
Authors: Eysel Hans H.
Published: May 2005

Relative integrated Raman intensities of selection of bands of liquid of liquid C6H6, C6H6, C6H12, CH3CN, CH2Cl2 and 1,1‐dichloroethene (C2H2Cl2) have been measured using the external standard method and a bivided spinning cell. Absoulte scattering activities were computed from these relative intensities based on the scattering activity of cyclohexane (7680 × 10‐9 cm4 g‐1 per moleculey) integrated over the sum of CH stretch vibrations.
Vibrational spectroscopy at high pressures. Part 50. A Raman scattering study of MSCN (M = K, Rb, Cs, NH4) at high pressures
Authors: Adams David M. , Pogson Mark
Published: May 2005

The phase behaviour of the title compounds was studied at high pressures using Raman spectroscopy. The isostructural materials KSCN and RbSCN show two phase changes (12.5 and 45.5 kbar; 10.5 and 37.5 kbar, respectively) which appear to be second order in type. Structures and transition mechanisms are proposed for each phase. CsSCN has a different orthorhombic structure and shows only one phase change in the range studied, at 23.5 ± 1.5 kbar, which also seems to be second order. The known phase transition in NH4SCN at 2 kbar has been confirmed, and a new one found at 10 kbar. A monoclinic cell is proposed for the new phase.
Investigation of the photoisomerization process of bisdimethylaminoheptamethine by means of time‐resolved CARS
Authors: Lau A. , Werncke W. , Pfeiffer M. , Weigmann H.‐J. , Bok Kim Man
Published: May 2005

Resonance CARS measurements of the photoisomeriztion process of bisdimethylaminoheptamethine under different resonance and excitation conditions are presented and compared with model calculations. A Six‐level model—a Rulliere‐type model extended by one level—is suggested.
Raman scattering in lithium ammonium sulphate
Authors: Lemos V. , Gomes P. A. P. , Melo F. E. A. , Filho J. Mendes , Moreira J. E.
Published: May 2005

Polarized Raman spectra of single crystals of lithium ammonium sulphate (LiNH4SO4) have been obtained. Detailed assignments of symmetry were made using selective scattering geometries. Separation of TO and LO components were either observed experimentally or calculated using oblique phonon frequency measurements.
Raman spectra of L(+)‐glutamic acid and related compounds
Authors: Shurvell H. F. , Bergin F. J.
Published: May 2005

Raman spectra of aqueous solutions of L(+)‐glutamic acid were studied in the pH range 0.5–12.5. Various ionic species were identified from the spectra and the pH ranges in which they predominate were established. Solid‐state Raman spectra of L(+)‐glutamic acid and the hydrochloride and monosodium salt were recorded and the spectra assigned and correlated with the structures of the three molecules. Near‐infrared Fourier transform Raman spectra of the three solid compounds were recorded and are compared with the spectra obtained using dispersive instruments.
Raman spectroscopy of low‐temperature phases of RbAg4I5
Authors: Shawabkeh A. , Scott J. F.
Published: May 2005

Raman spectra were obtained of single crystals of RbAg4I5 in an effort to confirm independently the far‐infrared results of Volkov and co‐workers that structural phase transitions occur at 44 and 30 K. The present results, that a strong ‘extra’ line occurs below 44 K at 12 cm−1, is in agreement with their measured value, confirming that the phase just below 44 K is non‐centrosymmetric, in agreement with their proposed C3 point group.
Origin of Raman spectral difference between spinning cell and flow cell measurements for bacteriorhodopsin photointermediates
Authors: Nakagawa M. , Maeda A. , Ogura T. , Kitagawa T.
Published: May 2005

Previous resonance Raman studies with the spinning cell technique indicated that the L550 intermediate gave a doublet at 1552 and 1539 cm−1 for the CC stretching mode whereas the results from the flow cell technique suggested that the two bands arise from different intermediates on the basis of different kinetic behaviour. This study has explored the origin of the discrepancy by applying both the double‐beam flow apparatus and the spinning cell to an identically prepared sample for observing transient resonance Raman spectra. It was found that the presence of a very small amount of dark adapted species caused the apparent differences in the kinetic behaviour of these two bands.
Raman and far‐infrared study of the lattice vibrations of solid nitromethane
Authors: Prystupa D. A. , Anderson A. , Torrie B. H.
Published: May 2005

The Raman and far‐infrared spectra of crystalline nitromethane and its fully deuterated analogue were recorded over the frequency range 20–400 cm−1 and at temperatures between 20 and 150 K. In the spectra of CH3NO2, 15 of the 21 Raman‐ and 13 of the 15 infrared‐active lattice modes predicted by group theory were observed. The corresponding numbers for CD3NO2 were 17 and 14, respectively. Isotopic frequency shifts together with inertia and intensity arguments were used to assign the peaks. Frequency coincidences in the two types of spectra are indicative of a non‐centrosymmetric cell. Several features are attributed to the torsional mode or interactions with this mode.
Temperature dependence of the Raman spectrum of fully deuterated acetanilide
Authors: Sauvajol J. L. , Almairac R. , Moret J. , Barthes M. , Ribet J. L.
Published: May 2005

The temperature dependence of the Raman scattering from a single crystal of acetanilide (ACN‐H) and fully deuterated acetanilide (ACN‐D) in the low‐frequency (phonon) and CO stretching regions was studied. The observed normal behaviour of the frequency shift of the CO stretching modes in ACN‐D, raises questions concerning several theoretical models previously proposed to explain the peculiar behaviour with temperature of the A1g stretching modes observed in ACN‐H. The forms of the low‐frequency Raman spectra for ACN‐H and ACN‐D are very similar, except in the frequency range 70‐120 cm−1, where an additional mode (denoted D′) is seen in the Raman spectrum of ACN‐D. A strong temperature dependence of the frequency of this band is observed. The origin of this mode is still undecided.
Resonance Raman investigation of meisenheimer complexes derived from 1,3,5‐trinitrobenzene
Authors: Santos P. S. , Gonçalves N. S.
Published: May 2005

The Raman spectra of Meisenheimer complexes derived from 1,3,5‐trinitrobenzene and proline, tryptophan, albumin and pyrrolidine were obtained. The spectra excited in and out of resonance with the electronic transition at ca. 460 nm show an outstanding enhancement of modes involving mainly the symmetric stretching and deformation of the NO2 groups. The results also indicate a marked reduction in the symmetric and asymmetric stretching frequencies, in addition to suggesting a decrease in symmetry on going from the parent nitro aromatic to the Meisenheimer complexes.
Surface‐enhanced resonance Raman scattering (SERRS) of ruthenium(II) heteroleptic complexes with 2,2′‐bipyridine and 1,4,5,8,9,12‐hexaazatriphenylene adsorbed on silver sols
Authors: Vanhecke F. , Heremans K. , Mesmaeker A. Kirsch‐De , Jacquet L. , Masschelein A.
Published: May 2005

The surface‐enhanced resonance Raman (SERR) spectra of several monometallic and polymetallic complexes of Ru(II) with 2.2′‐bipyridine (bpy) and the trichelating 1,4,5,8,9,12‐hexaazatriphenylene (HAT) on silver sols are reported. The SERR technique allows a vibrational study of these compounds, which is not always possible in solution because of their strong luminescence. Geometric and spectroscopic factors determine the features of the SERR spectra. It is suggested that the wavelength dependence of the SERR spectra is determined by selection rules similar to those proposed for surface‐enhanced Raman scattering.
Comparative study of aclacinomycin versus adriamycin by means of resonance Raman spectroscopy
Authors: Nonaka Yasuomi , Tsuboi Masamichi , Nakamoto Kazuo
Published: May 2005

Resonance Raman spectra of adriamycin and aclacinomycin A were examined in their H2O and D2O solutions. These spectra appear totally different from each other, but the differences are found to be similar to those between 1,4‐ and 1,8‐dihydroxyanthraquinone, which are considered to be model chromophores of adriamycin and aclacinomycin, respectively. Surface‐enhanced resonance Raman spectra of these two drugs were also compared by the use of silver sols. The effects of DNA binding on the resonance Raman spectra are also significantly different for these two drugs. Adriamycin was found to be intercalated in the CpG (or GpC) site of the DNA duplex, but aclacinomycin in the TpA (or ApT) site. Most of the differences in the spectra and sequence specificity are explained in terms of the molecular structures of their chromophores, i.e. in the adriamycin chromophore (1,4‐dihydroxyanthraquinone) two OH groups are hydrogen bonded to different CO groups, whereas in the aclacinomycin chromophore (1,8‐dihydroxyanthraquinone) two OH groups form hydrogen bonds with the same CO group, leaving the other CO group free from any intramolecular hydrogen bonding.
Application of Raman spectroscopy in recognition of the two crystalline forms of terephthalic acid
Authors: Colombo L. , Volovšek V. , Furić K. , Durig J. R.
Published: May 2005

Solid terephthalic acid exists in two polymorphic forms with both structures being triclinic. Raman spectroscopic studies have been made in order to recognize the presence of form I and/or form II in the sample.
Raman bands of N‐deuterated histidinium as markers of conformation and hydrogen bonding
Authors: Takeuchi Hideo , Kimura Yukiko , Koitabashi Ikuyo , Harada Issei
Published: May 2005

Raman spectra were measured for five crystals containing N‐deuterated histidinium and their C2‐deuterated analogues. The spectra showed strong bands assignable to the C4C5 stretching mode, ν(C4C5), and the NτC2Nπ symmetric stretching mode, ν(NτC2Nπ), characteristic of the N‐deuterated imidazolium ring. By comparison with the crystal structures, the ν(C4C5) and ν(NτC2Nπ) frequencies are found to increase linearly with increase of the absolute value of the CαCβC4C5 torsional angle (χ2, 1), which determines the ring orientation relative to the amino acid backbone. Exceptionally, the ν(NτC2Nπ) frequency of the C2‐deuterated imidazolium ring does not depend on the conformation but shows a correlation with the ND stretching frequency of the ring, indicating that ν(NτC2Nπ) becomes a marker of hydrogen‐bonding strength when the imidazolium ring is deuterated at C2. These marker bands may be useful in studying the conformation and hydrogen‐bonding states of histidine residues in proteins and peptides.
Use of Q‐switched lasers in near‐infrared fourier transform Raman spectroscopy. I
Authors: Cutler David J. , Mould Henry M. , Bennett Bob , Turner Andrew J.
Published: May 2005

It is demonstrated that the use of pulsed lasers in near‐infrared Fourier transform Raman spectroscopy can give a significant increase in signal‐to‐noise ratios over continuous‐wave measurements made using the same average laser power. It is also shown that when a thermal (or other relatively long‐lived) background is present, the use of pulsed excitation can greatly reduce its effect and, under certain circumstances, can allow it to be subtracted completely.
Raman and infrared spectra of NiI2 · 6H2O
Authors: Cariati F. , Bruni S. , Martini M. , Spinolo G.
Published: May 2005

The polarized Raman spectra and infrared absorption spectra of NiI2 · 6H2O were measured in the 50–4000 cm−1 region at low temperatures. Deuterated samples were also studied and gave results which were useful for interpretation purposes. Satisfactory assignments of water internal and external modes and lattice vibrations were made. The vibrational analysis, on the basis of which the assignments were made, was related to the D34 factor group; however, the symmetry of the Raman‐active bands, as deduced from polarized spectra, suggests that for water librations the C2h factor group provides a better basis for interpretation.
Raman spectrum of CuSO4 · 5H2O single crystal
Authors: Liu D. , Ullman F. G.
Published: May 2005

The Raman spectrum of a CuSO4 · 5H2O single crystal was measured at 95 K. The assignment of the internal modes of the molecular complex Cu2+ (H2O)4 and of differently bonded water molecules is discussed.
Raman spectra of polymorphs of isotactic polypropylene
Authors: Chalmers J. M. , Edwards H. G. M. , Lees J. S. , Long D. A. , Mackenzie M. W. , Willis H. A.
Published: May 2005

Raman spectra of the α‐, β‐, γ‐ and smectic polymorphs of isotactic polypropylene were recorded at 298 and 16.5 K. At 298 K the spectra of the polymorphs were very similar except in the antisymmetric CH stretching region. However, at 16 K the Raman spectra of the polymorphs show different features in several wavenumber shift regions. Comparisons are made with infrared spectra recorded at 298 and 100 K and interpretations are made on the basis of non‐equivalent sites in the monoclinic unit cells.
Application of surface‐enhanced Raman spectroscopy to biological systems
Authors: Cotton Therese M. , Kim Jae‐Ho , Chumanov George D.
Published: May 2005

This review summarizes the literature relating to the application of surface‐enhanced Raman scattering (SERS) and surface‐enhanced resonance Raman scattering (SERRS) techniques to the study of biological molecules. The emphasis is on publications that have appeared during the period from 1985 to 1991. The review is divided into six major parts. First, a brief overview of the current understanding of the mechanistic aspects of SERS/SERRS is given, with an emphasis on the relationship between theoretical predictions and experimental results. The most common experimental systems (colloids, metal island films, and electrodes) are described. Studies of biological systems are described in the second (small molecules), third (DNA and proteins) and fourth (membranes proteins and membrane preparations) sections. In the fifth or conclusion section, the potential use of SERS or SERRS as a method for obtaining spectra of native biological molecules is evaluated. Finally, the sixth section describes advances in Raman instrumentation in terms of their possible impact on future applications of SERS/SERRS techniques to biological molecules.
Vibrational study of (CH3NH3)2ZnCl4 and (CH3 NH3)2ZnBr4
Authors: Srinivasan T. K. K. , Mylrajan M. , Rao J. B. Srinivasa
Published: May 2005

Raman and infrared spectral studies of (CH3NH3)2ZnCl4 and (CH3NH3)2ZnBr4 were carried out at 90, 300 and 443 K. The vibrational spectra were analysed on the basis of the C space group. Assignments were also made by comparison with the spectra of the N‐deuterated analogues. The non‐degenerate CN stretching mode showed splitting due to non‐equivalent cations in the lattice as opposed to layer type of perovskites. Above 426 K, these splittings are absent, indicating the removal of non‐equivalence. The cation bands are broad above 426 K, indicating the reorientational motion of the cations.
SERS of cytosine and its methylated derivatives on metal colloids
Authors: Śanchez‐Cortés S. , Garcia‐Ramos J. V.
Published: May 2005

SERS spectra of cytosine, 1‐methylcytosine, 5‐methylcytosine and 1,5‐dimethylcytosine on silver and on copper colloids are reported. A study of the influence of pH on the normal Raman spectra of these compounds was made in order to understand better the behaviour of these molecules on metal surfaces. The results obtained indicate remarkable changes in the type of adsorbate—metal interactions depending on the metal used as the SERS support. These interactions are also influenced by the presence of methyl groups in the cytosine molecule.
Effect of temperature on the local structure in liquid benzene. I—Raman spectra of the depolarized Rayleigh wing
Authors: Pinan‐Lucarre J. P. , Loisel J. , Berreby L. , Dayan E. , Dervil E.
Published: May 2005

The behaviour of (i) the Raman integrated intensity of the v16 (405 cm−1) vibrational band and (ii) the depolarized Rayleigh wing of benzene over its whole liquid range as a function of temperature was examined. In case (i) the variation obtained seems to be monotonic, but in case (ii) a change in the intensity variation is observed around 37–40°C. This change may be attributed to a modification of symmetry in the local molecular environment of a given benzene molecule.
Characterization of porous titania glass: Raman, x‐ray diffraction and x‐ray photoelectron spectroscopic studies
Authors: Chee Yee Hong , Cooney R. P. , Howe R. F. , van der Heide P. A. W.
Published: May 2005

Porous titania glass (PTG) was characterized by laser Raman spectroscopy, x‐ray diffraction, ultraviolet‐visible spectroscopy, photoelectron spectroscopy and transmission electron microscopy. PTG after annealing at 573 K contains amorphous titania and anatase. Heating in air above 693 K causes transformation into the rutile phase. The low transition temperature is attributed to the highly defective nature of PTG.
Solid‐state infrared and Raman spectra of carbonyl‐tert‐butyl isocyanide complexes of chromium(0), molybdenum(0) and tungsten(0), M(CO)6−n(CNBu‐t)n (n = 1–3)
Authors: Li Hongqi , Butler Ian S. , Uhm Haewon L.
Published: May 2005

Vibrational assignments are reported for the room‐temperature IR and Raman spectra of three series of solid group 6B metal(0) carbonyl‐tert‐butyl isocyanide complexes of the general formula M(CO)6‐n(CNBu‐t)n, where M = Cr, Mo, W and n = 1–3. Sequential replacement of the CO groups by CNBu‐t leads to gradual shifts of the ν(CN) bands to higher energies, while the ν(CO) bands shift to lower energies. These results provide good evidence for the stronger σ‐donor and weaker π‐acceptor capacities of the CNBu‐t ligand compared with those of CO.
Investigation of haem—protein coupling and structural heterogenity in myoglobin and haemoglobin by resonance Raman spectroscopy
Authors: Schweitzer‐Stenner Reinhard , Dreybrodt Wolfgang
Published: May 2005

To probe distortions of the haem group in myoglobin and haemoglobin resulting from ligand—haem and protein—haem interactions, the dispersion of the depolarization ratio and the resonance excitation profiles of the Raman line ν4 were analysed in terms of parameters describing intra‐ and intermanifold vibronic coupling between the Q and B states of the porphyrin macrocycle. These parameters depend linearly on symmetry classified normal distortions of the haem group. It is shown by group theoretical arguments that perturbations at the pyrrole nitrogens N(I) and N(III) of the haem cause B1g‐type distortions which increase with increasing tilt and bend angles of the proximal imidazole and the distal O2 ligand, respectively. Moreover, antisymmetric A2g‐type distortions are imposed via perturbations at the Cα atoms of pyrrole I and III when one of the ligands moves away from a position in which it eclipses the N(I)Fe2+N(III) line of the porphyrin. It is found that the influence of the proximal and distal ligand on the haem symmetry is different in myoglobin and haemoglobin. In oxymyoglobin the O2—haem interaction is responsible for the comparatively large B1g distortion at N(III). B1g distortions in oxyhaemoglobin and its isolated subunits are smaller then in oxymyoglobin. They are mainly caused by repulsive interactions between haem and proximal imidazole. A2g distortions at Cα(I) and Cα(III) are negligible in oxymyoglobin and small in deoxymyoglobin and deoxyhaemoglobin. They are comparatively strong, however, in oxyhaemoglobin and its isolated subunits, owing to the proximity and the large azimuthal angle of the proximal imidazole. In the isolated β‐chains of oxyhaemoglobin haem—protein coupling is more effective and causes larger B1g and A2g distortions than in the α‐chains. While the haem distortions investigated are independent of pH in the isolated α‐chain, they depend significantly on pH in the isolated β‐chain. This is caused by protonation of three titrable groups with pK = 5.8, 6.6 and 7.8, which were earlier assigned to His Eβ, His HC3β and His FG4β, respectively. In intact oxyHbA the allosteric coupling between these titrable groups and haem are modified by strengthening that of His HC3β and reducing that of His FG4β. Coupling between the former group and the haem is probably caused by the hydrogen bond between the penultimate Tyr HC2β and Val FG5β and steric interactions between Tyr HC2β and Cys F9β. Consequently, it is completely absent in the modified oxyhaemoglobin bis(maleimidomethyl) ether, in which the hydrogen bond between the penultimate Tyr HC2β and Val FG5β is ruptured.
Antibody—antigen interactions studied by means of Raman spectroscopy
Authors: Fagnano C. , Fini G.
Published: May 2005

The percentages of secondary structure of rabbit IgG and anti‐IgG in the lyophilized solid and aqueous solution state were obtained from the Raman spectra. The Raman spectrum of the lyophilized IgG—anti‐IgG complex was also recorded. The vibrational results indicate that the percentages of secondary structure of IgG do not change when lyophilized IgG is dissolved in water. Moreover, the secondary structure of IgG and of anti‐IgG changes only very slightly as a consequence of the complex formation. However, the Raman spectra in the SS stretching region suggest that some changes in the molecular geometry around the SS bridges take place as a consequence of the IgG—anti‐IgG complex formation.
Basic experiments in thin‐layer chromatography–fourier transform Raman spectrometry
Authors: Rau Axel
Published: May 2005

In some basic experiments, the feasibility is demonstrated of obtaining artifact‐ and fluorescence‐free spectra by in situ (Fourier transform (FT)) Raman spectrometry of TLC spots. In addition, the high sensitivity enhancement by using TLC–FT‐SERS of silver colloid‐activated chromatographic spots is shown.
Resonance Raman and time‐resolved resonance Raman studies of 3MLCT‐state populations in the series of ruthenium(II) complexes with bipyridine and tetramethylbipyridine
Authors: Danzer Gerald D. , Bajdor Krzystof , Kincaid James R.
Published: May 2005

The resonance Raman (RR) and time‐resolved resonance Raman (TR3) spectra of the complexes of ruthenium(II) with the ligands 2,2′‐bipyridine (bpy) and 4,4′,5,5′‐tetramethyl‐2,2′‐bipyridine (tmb) are reported. The RR spectra of the ground‐state species show no anomalous behaivor and are consistent with vibrationally isolated chelate ligands. The TR3 spectra provide definitive evidence that the 3MLCT excited‐state electron density is localized on the bpy ligand in the three complexes containing this ligand.
Investigation of the adsorption of 2‐phenyl‐1‐ethanethiol on silver by Raman spectroscopy
Authors: Mi Lee Hwa , Kim Kwan , Kim Myung Soo
Published: May 2005

Surface‐enhanced Raman scattering (SERS) of 2‐phenyl‐1‐ethanethiol was investigated in a silver sol. The molecule was found to be chemisorbed dissociatively on the silver surface by rupture of its SH bond. Although both the trans and gauche conformers around the C‐1C‐2 axis could exist on the surface with submonolayer coverage, the trans conformer seemed to be dominant as the bulk concentration of the molecule was sufficient for full monolayer coverage. In the submonolayer coverage limit, a gradual trans‐to‐gauche transition was found to occur on the surface with increase in borohydride concentration in the sol solution. The vibrational assignment of the molecule in the liquid phase was also refined by using the SERS data.
Surface‐enhanced Raman scattering of pyridine in silver colloids excited in the near‐infrared region
Authors: Liang E. J. , Engert C. , Kiefer W.
Published: May 2005

A scanning Raman spectrometer and an Nd: YAG laser operating at 1.06 μm were used to observe the surfaceenhanced Raman scattering (SERS) of pyridine in yellow silver colloids. Enhancement factors for the triangle ring breathing vibration mode at 1006 cm−1 and for the totally symmetric breathing mode at 1036 cm−1 are about 16.5 and 21 times larger, respectively, than those found for excitation at 514.5 nm. The large enhancement factors for excitation in the near‐infrared region suggest that further refinement of the theories currently proposed to explain the SERS effect is necessary.
Raman and infrared spectra, conformational stability, barriers to internal rotation, ab initio calculations and vibrational assignment of cyanomethyl methyl ether
Authors: Durig J. R. , Tang Qun , Phan H. V.
Published: May 2005

The Raman spectra (3400–10 cm−1) of gaseous, liquid and solid and the infrared spectra (3500–35 cm−1) of gaseous and solid cyanomethyl methyl ether (methoxyacetonitrile), (CN)CH2OCH3, were recorded. The farinfrared spectrum of the gas was recorded at a resolution of 0.10 cm−1 in the region from 370 to 30 cm−1. The fundamental asymmetric torsions of the gauche and trans conformations were observed at 112.5 and 104.6 cm−1, respectively, with the gauche form having two excited‐state transitions falling to lower wavenumber. From these data, along with the enthalpy difference and gauche dihedral angle, the asymmetric torsional potential function was calculated with the following coefficients: V1 = 153 ± 9, V2 = −619 ± 8, V3 = 1000 ± 2 and V4 = −100 ± 2 cm−1. From this potential function, the trans to gauche, gauche to gauche and gauche to trans barriers were determined as 512, 1592 and 951 cm−1, respectively, with an enthalpy difference of 439 ± 19 cm−1 (1255 ± 54 cal mol−1) and the gauche conformer the more stable form in the gas phase. The enthalpy difference was also determined experimentally from variable‐temperature studies of the Raman spectrum and a value of 337 ± 44 cm−1 (964 ± 126 cal mol−1) was obtained for the liquid with the gauche form more stable. Additionally, the symmetric methyl torsions of both gauche and trans forms were observed at 170.4 and 217.6 cm−1, respectively. On the basis of a one‐dimensional model, the barrier to internal rotation of the methyl moiety was determined as 839 cm−1 (2.40 kcal mol−1) for the guache conformer and 947 cm−1 (2.71 kcal mol−1) for the trans form. A complete vibrational assignment is proposed for a gauche‐trans equilibrium in the gas and liquid phases from the Raman (3200–10 cm−1) and infrared (3200–35 cm−1) spectra, but in the solid state only the gauche conformer remains. The structural parameters, conformational stability, barriers to internal rotation and fundamental vibrational frequencies which were determined experimentally were compared with those obtained from ab initio calculations employing the RHF/4–31G*, RHF/6–31G* and MP2/6–31 + + G** basis sets. These results were compared with the corresponding quantities obtained for some similar molecules.
Polarized Raman spectra and factor group analysis of methylammoniummercury trichloride crystals
Authors: Hossain M. Abul , Sattar Abdus , Srivastava J. P. , Bist H. D.
Published: May 2005

Polarized Raman spectra of methylammoniummercury trichloride crystals were measured at room temperature. Factor group analysis involving the correlation method was applied. The observed spectra were interpreted in terms of internal and external oscillations of the constituent molecular ions, CH3NH3+ and HgCl3−.
Raman and infrared spectra, conformational stability, barriers to internal rotation and ab initio calculations of fluorocarbonyl isocyanate
Authors: Durig J. R. , Guirgis G. A. , Krutules K. A. , Phan H. , Stidham H. D.
Published: May 2005

The Raman (3100–10 cm−1) and infrared (3100–30 cm−1) spectra of fluorocarbonyl isocyanate, FC(O)NCO, were recorded for the gas and solid. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were obtained. The observed bands are assigned on the basis of the more stable cis conformer (isocyanate group cis to the carbonyl bond) in the fluid states but only the trans conformer remains in the annealed solid. From temperature dependence studies of the Raman spectra of the gas and liquid, two pairs of conformer peaks were used to determine Δ H values of 258 ± 47 cm−1 (738 ± 134 cal mol−l) and 140 ± 29 cm−1 (400 ± 83 cat mol−1), respectively, with the cis conformer the more stable rotamer in both phases. Additionally, variable‐temperature studies of the infrared spectrum of the sample dissolved in liquified Kr gave ΔH = 150 ± 28 cm−1 (429 ± 80 cal mol−1), which should closely represent the ΔH value for the gas. A complete vibrational assignment is proposed for both conformers based on infrared bard contours, Raman depolarization data, group frequencies, relative intensities and normal coordinate calculations. The experimental conformational stability, barriers to internal rotation, structural parameters and fundamental vibrational wavenumbers were compared with those obtained from ab initio gradient calculations employing the RHF/3–21G, RHF/6‐31G* and /or MP2/6‐31G* basis sets and to the corresponding quantities obtained for some similar molecules.
Non‐linear Raman spectroscopy of liquid crystals: Polarization measurements and relaxation processes in 4‐cyano‐4′‐heptylbiphenyl (7CB)
Authors: Davies A. N. , Jeremy Jones W. , Price Alun H.
Published: May 2005

The non‐linear Raman spectrum of 4‐cyano‐4′‐heptylbiphenyl is reported. Measurements of depolarization ratios of the vibrational bands at 2224 cm−1 (CN stretching), 1606 cm−1 (aromatic ring stretching) and 1185 cm−1 (CH aromatic in‐plane deformation) are used to evaluate the order parameters (〈P2〉 and 〈P4〉) using a ‘line model’ for the molecules. The results are internally consistent and also show the same general features (including some discrepancies in 〈P4〉) reported by other workers. Nevertheless, the results demonstrate that the technique is capable of wide application to the study of the anisotropic properties of liquid crystals and provides a valuable probe into the study of the biaxial nature of these sytems.
Picosecond time–resolved Raman spectroscopy of S1p‐terphenyl and p‐terphenyl d14 in solution: Time‐dependent changes of Raman band shapes
Authors: Iwata Koichi , Hamaguchi Hiro‐o
Published: May 2005

The picosecond time‐resolved Raman spectra of p‐erphenyl and its deuterated analogue (dl4) in the first excited singlet (S1) electronic state were observed in heptane and acetonirile solutions. The most intense band in the S1, p‐erphenyl at 750 cm−1 is assigned to an in‐plane ring vibration based on the shift on the deuteration. The peak position and the bandwidth of the 750 cm−1 band change as the time delay between the pump and probe pulses changes. The initial changes in the position and width appear between 0 and 5 ps, which can be attributed to the strong electric fields of the pump and probe light pulses. After the initial changes are over, the position and the width of the 750 cm−1 band change gradually to their stationary values until about 30 ps. These changes are probably due to the cooling of the solute–solvent system. Similar changes are recorded for two other Raman bands at 993 and 1018 cm−1.
Comparative Raman, infrared and optical spectroscopic studies of thin films of an axially substituted phthalocyanine compound
Authors: Wijekoon W. M. K. P. , Kama S. P.
Published: May 2005

A series of thin films of an axially substituted silicon phthalocyanine, PcSi(OsiCH3C6H5OH)2, were made by spin coating and vacuum evaporation techniques. Electronics spectra of these films exhibit a bathochromic shift of the Q band compared with that of a chloroform solution. This bathochromic shift is ascribed to the formation of aggregates in films as seen by the scanning electron micrographs of them. Neither electronic nor vibrational spectra provide evidence for the formation of cofacial dimers which are usually found in evaporated films of axially substituted silicon phthalocyanines. The evaporated films that are redissolved in chloroform exhibit the same electronic and proton NMR spectra as the fresh solutions. The Raman and infrared spectra suggest that both evaporated and spin‐coated films possess similar molecular structures.
Raman characterization of an operating InAlAs—InGaAs—InP high electronic mobility transistor
Authors: Matrullo N. , Constant M. , Sagon G. , Fauquembergue R. , Leroy A.
Published: May 2005

Raman scattering was used to probe electronic properties in In‐based structures. First, Raman signatures of undoped and doped InAlAs and InGaAs bulk materials and Raman spectra of InAlAs—InGaAs heterostructures were recorded. Raman scattering by coupled longitudinal optic phonons and two‐dimensional electron gas provides a powerful probe of electronic properties in this structure. More precisely, Raman results allowed information to be obtained on the two‐dimensional gas electron carrier concentration. Then, a specific advantage of the micro‐Raman method was demonstrated by the observation of the carrier concentration the vicinity of the gate of an operating high electronic mobility transistor (HEMT). Qualitative variations of carrier concentration in the two‐dimensional electron gas were observed and compared successfully with carrier concentration calculations using Monte Carlo simulations.
Spectra and structures of silicon‐containing compounds. XX—Raman and infrared spectra, conformational stability, vibrational assignment and ab Initio calculations of methylvinyldifluorosilane
Authors: Durig J. R. , Guirgis Gamil A. , Qtaitat Mohammad A.
Published: May 2005

The Raman (3100—10 cm−1) and infrared (3100—40 cm−1) spectra of methylvinyldifluorosilane, CH2CHSiF2CH3, were recorded for the gas and solid. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were obtained. The observed bands in the fluid states are assigned on the basis of the more stable gauche (antiperiplanar) conformer where one of the fluorine atoms is eclipsing the double bond and the less stable cis (synplanar) conformer. However, in the annealed crystalline solid, only the cis conformer remains. A complete vibrational assignment is proposed for both conformers based on infrared band contours, Raman depolarization data, group wavenumbers and normal coordinate calculations. The experimental stability, barriers to internal rotation, and fundamental vibrational wavenumbers are compared with those obtained from the ab initio calculations employing the RHF/3‐21G*, RHF/6‐31G* and MP2/6‐31G* basis sets and to the corresponding quantities obtained for some similar molecules.
Probing the effects of electrolytes on intermolecular interactions in solution by optical‐heterodyne detected Raman‐induced kerr effect spectroscopy (OHD‐RIKESH)
Authors: Deuel Hans P. , Cong Peijun , Simon John D.
Published: May 2005

Time‐domain experimental femtosecond OHD‐RIKES results for electrolyte solutions (NaI and LiCIO4 in acetonitrile and ethyl acetate) are presented and discussed within the context of the molecular polarizability ellipsoid of the solvent. It is concluded that the anisotropic part of the liquid intermolecular potential is not significatly influenced by the addition of electrolytes, even at concentrations up to the saturation limit.
In situ resonance Raman spectra of carotenoids in bird's feathers
Authors: Veronelli M. , Zerbi G. , Stradi R.
Published: May 2005

Micro resonance Raman spectra of a series of synthetic carotenoids and of a large number of bird's feathers which contain various kinds of carotenoids were analysed on the basis of the effective conjugation coordinate (ECC) theory. The data obtained on parrots provide the first structural data on the chemical nature of the pigments embedded in their feathers, and show that these pigments are unmethylated polyene molecules. Data on the molecular orientation of the carotenoids and on the presence of different pigments in the same feather are presented and discussed.
Raman non‐coincidence effect of the carbonyl stretching mode in confined polar liquids
Authors: Wallen S. L. , Nikiel L. , Lee Y.‐T. , Jonas J.
Published: May 2005

The Raman non‐coincidence effect of the symmetric C=O stretching band was measured in liquid acetone and N,N‐dimethylformamide confined to porous silica glasses prepared by the sol—gel process. The experiments were carried out both on bulk liquids and liquids confined to glasses with pore radii from 17—76 Å at 293 K. The value of the non‐coincidence was decreased with decreasing pore radius (R) and scaled approximately as 1/R. Additional information about the role of pore surface effects was obtained by measurements on the polar liquids confined to surface‐modified glasses when the surface hydroxyl groups were replaced by OSi(CH3)3 groups. The experimental data show that the non‐coincidence effect is independent of the pore size in surface‐modified glasses.
Association of newly synthesized major fl coat protein with infected host cell inner membrane
Authors: Smilowitz Henry , Carson John , Robbins Phillips W.
Published: May 2005

The bacteriophage fl major coat protein becomes associated with the host cell inner membrane very shortly after it is synthesized. Pulse‐chase experiments suggest that the virus is never stably associated with the host cell outer membrane; we propose that it passes directly from the inner membrane to the growth medium.
Recombination in yeast mitochondrial DNA
Authors: Shannon Charles , Rao Ayyagari , Douglass Stephen , Criddle R. S.
Published: May 2005

When haploid yeast strains containing mitochondrial DNAs (mtDNAs) of different buoyant densities are mated, the resulting zygotes contain a mixed population of mitochondria and mitochondrial DNAs. During vegetative growth of diploid cells formed from such a cross between a petite strain with mtDNA of density 1.677 g cm−3 and a respiratory competent strain with mtDNA of density 1.684 g cm−3, mtDNAs with intermediate buoyant densities are obtained. Virtually all newly synthesized mtDNA in diploid ρ− progeny has the intermediate buoyant density. Therefore, within 2 generations of growth of the diploid cells, the intermediate buoyant density species predominate. In crosses between a respiratory competent strain and other petite strains with different values of genetic suppressiveness, it was found that the amount of recombination yielding mtDNAs of intermediate buoyant densities roughly parallels the degree of suppressiveness. Individual clones of respiratory deficient cells from such crosses were also isolated to confirm that stable mtDNAs with intermediate buoyant densities were obtained. Thus, it is apparent that some form of recombination takes place within the mtDNAs of yeast cells that results in stable mtDNA species.