bluuebunny/crossref_metadata_2025 huggingface dataset:
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

A 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

High‐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

Experimental 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

A 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

A 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.
Detection of conserved structural elements in ferredoxins and cupredoxins by resonance Raman spectroscopy
Authors: Loehr Thomas M.
Published: May 2005

Iron‐sulfur proteins and cupredoxins are electron‐transfer proteins containing metal—cysteinate ligation. Both classes of proteins have intense (Cys)S → Mox charge‐transfer bands that are effective for resonance enhancement of Raman‐active modes of vibration of the metal ion chromophores. Resonance Raman (RR) spectroscopy provides a sensitive and powerful method for the investigation of the structural details of the metal clusters. The abundance of normal modes in plant ferredoxins and high‐potential iron proteins has been shown to arise from coupling of the FeS stretching modes with an SCC deformation mode that is at a maximum when the FeSCC dihedral angle is ∼ 180°. X‐ray crystallographic results support these findings. For cupredoxins, the complexity of the RR spectra has been considerably more difficult to understand. However, the availability of several high‐resolution crystal structures of plant and bacterial cupredoxins has shown that the conformation of the cysteinate ligand is highly conserved, and that the five‐atom chain consisting of CuSγCβCαN is coplanar. This coplanarity provides a mechanism for coupling ν(CuS) with δ(CuSC), δ(SCC) and δ(CCN) deformation modes. Experiments with Cu, N and H isotopes have extended these assignments by revealing the extent of the coupled modes of vibrations. Modern molecular biology techniques are now providing site‐specific ligand mutations that are revolutionizing the study of the metal clusters in these electron‐transfer proteins.
Time‐resolved resonance Raman studies of bacteriorhodopsin and its intermediates K590 and L550: Biological implications
Authors: Lohrmann R. , Stockburger M.
Published: May 2005

Experiments with a spinning cell and a single continuous‐wave laser beam (514 nm) in reflection geometry were performed to obtain the resonance Raman (RR) spectra of the intermediate K590 of the retinal chromophore of bacteriorhodopsin (bR). Samples of diluted aqueous suspensions of ‘purple membranes’ from Halobacterium halobium were used, which entail bR as an integral protein. K590 is formed photochemically in ca. 5 ps from the parent chromophore BR570 and in H2O decays into the product L550 with a time constant of ca. 1.2 μs (21°C). Using a flow velocity of ca. 20 m s−1 and a beam waist of 40 μm, the integrated relative concentrations of BR570, K590 and L550 in the beam were 58:33:10, respectively. By this method the ‘late’ K intermediate which is accumulated on a time scale of ca. 1 μs was probed. The spectra of the mixture were recorded with a spectral step width of 0.2 cm−1 and a band width of 4 cm−1. Up to 100 scans were accumulated to obtain the high quality which is required for subtraction and band‐fitting procedures. The contributions of BR570 and L550, whose spectra were obtained in separate experiments, were subtracted leaving the pure spectra of K590. Experiments were performed in H2O and D2O suspensions. Structural changes of the chromophore during the transition from K590 to L550 were inferred from the RP spectra in the hydrogen out‐of‐plane, the fingerprint and the CC/CN stretching regions. It was concluded that in this transition the chromophore relaxes from a distorted to a planar conformation and at the same time a positive charge of the protein envelope approaches the β‐ionone ring of retinal. It is proposed that this electrostatic interaction is important for the biological function of bR.
Theoretical analysis of the resonance CARS spectra of diacetylene single crystals
Authors: Materny A. , Kiefer W.
Published: May 2005

A theoretical model is presented which describes the excitation and line profiles of resonance CARS spectra obtained from diacetylene single crystals containing few short polymer chains. The model is based on a crude Born‐Oppenheimer approximation. The electronic wavefunctions are calculated by means of an LCAO MO (linear combination of atomic molecular orbital) method in the Hückel approach. The Franck—Condon integrals are calculated under the assumption of harmonic potential functions. The model includes a distribution of polymer chain lengths and inhomogeneous broadening due to distortions of the monomer host lattice. The simulations of the CARS excitation and line profiles taken from FBS and TS/FBS diacetylene crystals are based on results of former calculations of absorption and linear resonance Raman spectra of these materials. Fairly good agreement between model and experimental CARS spectra is obtained. Strong resonance behaviour can be seen by varying the frequency of the pump laser. Interference effects occur for neighbouring lines, which can also be simulated by the theoretical model. Possibilities for applications of diacetylene polymers as non‐linear optical devices are discussed.
High‐pressure Raman study of K and T forms of the octachloro cyclic phosphazene tetramer P4 N4 CI8
Authors: Muthu D. Victor S. , Chandrabhas N. , Sood A. K. , Venkatesan K. , Venugopalan P. , Jayaraman A.
Published: May 2005

The octachloro cyclic phosphazene tetramer P4N4Cl8 was studied by high‐pressure Raman spectroscopy up to 10 GPa in the K form (boat‐shaped molecule) and in the T form (chair‐shaped molecule). There are pressure‐induced phase transitions in the crystal with the K‐form molecules. There is a conformation change from the T to the K form under a non‐hydrostatic pressure of less than 0.7 GPa.
Fourier transform Raman and infrared vibrational study of human skin: Assignment of spectral bands
Authors: Barry B. W. , Edwards H. G. M. , Williams A. C.
Published: May 2005

Fourier transform (FT) Raman and infrared spectra of the outermost layer of human skin, the stratum corneum, were recorded. Assignments consistent with the FT Raman vibrations were made for the first time and compared with assignments from the FTIR spectrum. The results demonstrate that FT Raman spectroscopy holds several advantages over FTIR in studies of human skin. The molecular and conformational nature of human skin, and modifications induced by drug or chemical treatments, may be assessed by FT Raman spectroscopy.
Low‐temperature Raman spectrum of phase V ammonium nitrate
Authors: Park Y. S. , Reid J. K. , Brown R. J. C. , Shurvell H. F. , Norrby L. J.
Published: May 2005

Raman spectra of polycrystalline normal and three 15N isotopic ammonium nitrates (15NH4NO3, NH4 15NO3 and 15NH4 15NO3) were recorded at various temperatures between 10 and 300 K. Isotopic shifts of both internal and external modes of the ammonium ion relative to isotopic normal NH4NO3 were observed. Various components of the hetero‐ionic coupled internal mode (ν3 of the nitrate ion with ν4′ of the ammonium ion) were assigned with more certainty on the basis of the 15N isotopic shifts. Detailed studies of the temperature dependence of one internal mode (ν1) of the NO3 ‐ ion and several external modes were made. The frequency and half band width versus temperature plots for both the internal mode and the external modes of 15NH4NO3 indicate only one crystal structure (phase V) between 10 and 257 K. Comparison of the frequency shifts between various isotopic compounds in the external mode region permitted a more precise assignment of the lattice modes associated with the NH4+ and NO3− ions to be made.
Normal coordinate analysis and MNDO calculations: Assignment of the vibrational spectrum of acridine
Authors: Butler Catherine A. , Cooney Ralph P.
Published: May 2005

A combination of normal coordinate analysis (based on a Urey–Bradley–Kekulé force field) (UBFF) and modified neglect of diatomic overlap (MNDO) calculations were employed to determine a qualitative working assignment of the vibrational spectrum of acridine. This assignment was employed in resonance Raman studies of the chromophoric acridine‐based anti‐tumour drug amsacrine. The assignments emerge from the potential energy distribution (PED) calculations in the normal coordinate analysis and from the potential energy minima and optimized geometry in the MNDO calculations. The MNDO frequency parameters were calibrated using the carbon–hydrogen stretching modes.
Skeletal vibrational spectra of LAuCl3 complexes with heterocyclic nitrogen donors
Authors: Shamir J. , Givan A. , Canovese L. , Cattalini L. , Uguagliati P. , Tobe M. L.
Published: May 2005

The low‐frequency Raman and infrared spectra of a series of gold(III) chloride complexes of the type of LAuCl3 (where L is thiazole, oxazole and their derivatives) were studied. The skeletal gold–chlorine and the gold–ligand vibrations were assigned.
RAMPAC: a program for analysis of complicated Raman spectra
Authors: de Mul F. F. M. , Greve J.
Published: May 2005

A computer program for the analysis of complicated (e.g. multi‐line) Raman spectra is described. The program includes automatic peak search, various procedures for background determination, peak fit and spectrum deconvolution and extensive spectrum handling procedures.
Raman and infrared spectra, conformational stability, vibrational assignment, barriers to internal rotation and ab initio calculations of but‐2‐enoyl chloride
Authors: Durig J. R. , Groner Christian U. , Costner T. G. , Wang Aiying
Published: May 2005

The Raman (3500–10 cm−1) and infrared (3200–50 cm−1) spectra were recorded for the fluid and solid phases of but‐2‐enoyl chloride (crotonyl chloride), trans‐CH3CHCHCClO, where the methyl group is trans to the CClO group, and a complete vibrational assignment is proposed. These data were interpreted on the basis that the s‐trans (anti) form (two double bonds oriented trans to one another) is the most stable form in the fluid phases and the only conformer remaining in the solid state. The asymmetric torsional fundamental of the more stable s‐trans and the higher energy s‐cis (syn) form were observed at 97.5 and 86.9 cm−1, respectively. From these data the asymmetric potential function governing the internal rotation about the CC bond was determined. The potential coefficients are V1 = −111 ± 2, V2 = 1860 ± 48, V3 = 6 ± 2, V4, = −43 ± 24 and V6 = −22 ± 6. The s‐trans to s‐cis and s‐cis to s‐trans barriers were determined to be 1890 and 1785 cm−1, respectively, with an enthalpy difference between the conformers of 105 ± 52 cm−1 [300 ± 149 cal mol−1 (1 cal = 4.184 J)]. Similarly, the barrier governing internal rotation of the CH3 group for the s‐trans conformer was also determined to be 912 ± 30 (2.61 ± 0.09 kcal mol−1) from the torsional fundamental observed in the far‐infared spectrum of the gas. All these data were compared with the corresponding quantities obtained from ab initio Hartree–Fock gradient calculations employing the RHF/3–21G*, RHF/6–31G* and/or MP2/6–31G* basis sets. These results were compared with the corresponding quantities for some similar molecules.
Resonance polarization and phase‐mismatched CARS of pheophytinbexcited in theQyband
Authors: De Boeij W. P. , Lucassen G. W. , Otto C. , Greve J.
Published: May 2005

Resonance polarization and phase‐mismatched coherent anti‐Stokes Raman scattering (CARS) measurements were performed on pheophytinbdissolved in acetone excited in theQyabsorption band, where strong broad fluorescence makes spontaneous Raman spectroscopy impossible. The phase‐mismatching technique was applied to suppress solvent background and used in combination with the polarization‐sensitive CARS technique to measure directly the\documentclass{article}\pagestyle{empty}\begin{document}$ \chi \mathop {1111}\limits^{(3)} $\end{document}and\documentclass{article}\pagestyle{empty}\begin{document}$ \chi \mathop {1221}\limits^{(3)} $\end{document}components to estimate depolarization ratios. The spectra were fitted by a non‐linear least‐squares procedure yielding vibrational band parameters. Some CARS dispersion information on the vibrational amplitudes was obtained by varying the pump wavelength. CARS excitation profiles based on transform theory were calculated and partly explain the observed amplitude dispersion. The application of the combined phase‐mismatched polarization CARS technique may be useful in many other cases of highly fluorescing molecules when resonantly excited.
Femtosecond three‐colour CARS of liquids with magic polarization conditions
Authors: Purucker H.‐G. , Tunkin V. , Laubereau A.
Published: May 2005

It was shown recently that three scattering mechanisms with different time behaviours can be separated in time‐domain CARS simply by varying the polarization of the detected anti‐Stokes signal. In an extension of this work, the magic angle 49.1° for the elimination of the resonant‐anisotropic contribution was verified experimentally. It was also found that the residual non‐resonant scattering component observed at −60° with suppression of the common CARS interaction represents a six‐wave mixing process involving the optical Kerr effect. Using the novel polarization techniques the vibrational dynamics of neat dimethyl sulphoxide was studied in the CH stretching region. Evidence is reported for homogeneous broadening of the symmetric mode at 2913 cm−1 and for a doublet splitting of the asymmetric Raman band of the liquid at 2996 cm−1 not resolved in spontaneous Raman spectroscopy.
Applications of Raman spectroscopy to the study of polymers and polymerization processes
Authors: Edwards H. G. M. , Johnson A. F. , Lewis I. R.
Published: May 2005

The application of Raman spectroscopy to polymers and polymerization processes is surveyed and the advent of recent advances in instrumental techniques to polymer analysis is highlighted. Some of the problems of the more widely‐used infrared spectroscopic methods, for example in microstructural analysis of polydienes and copolymers, are discussed and the advantages of the Raman spectroscopic technique are explained. The use of near‐infrared excitation and Fourier‐transform Raman instrumentation for process monitoring and polymer composite studies is discussed. Raman microscopic and waveguide spectroscopic studies of small samples and polymer coatings on substrates are considered. Other applications are mentioned in the areas of polymer orientation, surface‐enhanced Raman scattering, conducting polymers, biopolymers and time‐resolved studies.
Waveguide Raman spectroscopy of polymers and polymer laminates
Authors: Tait Jonathan K. F. , Dixon N. Michael , Everall Neil , Davies Gerald , McIntyre Robert , Yarwood Jack
Published: May 2005

The Raman waveguide spectra of a series of polymer laminates obtained using a simple optical waveguide coupling device are reported. The optical properties of these polymer films were obtained by measuring the waveguide coupling angles and the resulting electric field calculations were shown to predict (semiquantitatively) the observed spectra as a function of waveguide mode number. A discussion of the practical difficulties encountered with available polymer samples emphasizes why such measurements are not yet to be regarded as ‘routine’. No unequivocal evidence could be found for interfacial effects at the polymer/polymer interface.
Polytypic structure and low‐frequency Raman spectra of long‐chain compounds: Stearic acid E form
Authors: Kaneko Fumitoshi , Kobayashi Masamichi , Sakashita Hirotoshi
Published: May 2005

Polarized Raman spectra in the low‐frequency region were measured for single‐layered (Mon) and double‐layered (Orth II) polytypes of stearic acid, E form. In E(Mon) three intense bands due to the longitudinal acoustic modes (LAM) were observed in both the (cc) and (bc) polarizations (which is consistent with the crystal structure), whereas in E(Orth II) the (cc) and (bc) components split at different frequencies. The LAM modes were analysed using a simple coupled oscillator model involving an interaction between the terminal methyls. The LAM modes vibrating in‐phase between successive bimolecular layers appear at higher frequencies than the antiphase modes, because the interlayer interaction acts only on the former modes. The half‐widths of the higher order harmonics of LAM bands are about twice that of the fundamental.
Theory of dispersion of raman scattering by molecules containing two identical chromophores
Authors: Morozov V. A.
Published: May 2005

It is shown that the interaction between identical chromophores of freely orienting rigid bichromophoric molecule described by the non‐diagonal elements of the molecular damping matrix may lead to unusual dispersion of the depolarization ratios of Raman bands. The forms of the predicted dispersion curves depend on the mechanism for the occurrence of a Raman band and on the mutual orientation of the chromophores. The dispersion curves have anomalous extrema at the frequency of the pure electronic transition of the molecule, i.e. at the maxima of the excitation profiles of Raman lines in an examined frequency field, in contrast to known dispersion curves of the depolarization ratio, the extrema of which are often found to coincide with minima rather than maxima in the excitation profile. This circumstance favours the experimental observation of the predicted curves. Also presented is an excitation profile of the vibrational Raman optical activity signal for such randomly oriented molecules with optically inactive chromophores. This profile has one sign only, unlike the double‐signed spectrum of circular dichroism for such molecules. This makes the recording of this profile under conditions of inhomogeneous broadening of spectral lines more convenient than recording the circular dichroism spectrum.
Fourier transform IR, matrix fourier transform IR, Raman, 13C NMR, 1H NMR and mass spectroscopic study of acetyl isocyanate
Authors: Védova C. O. Della , Mack H.‐G. , Altabef A. Ben
Published: May 2005

Infrared data for vapour and matrix‐isolated acetyl isocyanate, CH3C(O)NCO, in argon at low temperature, together with the Raman spectrum of the liquid, suggest the existence at room temperature of only one conformer with Cs symmetry and cis with respect to the double bonds. The study was completed with characterization of the compound by mass, 13C NMR and 1H NMR spectra.
Relative intensities in surface‐enhanced Raman spectra of 9‐methoxy‐2‐N‐methylellipticinium chloride studied by potential energy distribution of the vibrational modes
Authors: Aubard J. , Bernard S. , Levi G. , Grosroyat H. , Christensen D. H. , Sorensen G. O. , Nielsen O. Faurskov
Published: May 2005

Near‐infrared Fourier transform (NIR‐FT) Raman and surface‐enhanced Raman spectroscopic (SERS) techniques were used in studies of the vibrational spectrum of 9‐methoxy‐2‐N‐methylellipticinium chloride. NIR‐FT‐Raman spectra were obtained on the powder and SER spectra were measured in silver colloids using dilute aqueous solutions of the drug (2 × 10−6 M, pH 7.5). Some Raman bands in the SER spectrum show increased relative intensities compared with the corresponding bands in the NIR‐FT‐Raman spectrum, whereas other bands show decreased relative intensities. A general valence force field was used in the calculation of the potential energy distribution of the vibrational modes. This calculation reveals that bands from the indole moiety of the molecule show intensity enhancements, whereas bands arising from modes localized in the isoquinolinium part of the molecule show decreasing intensities in the SER spectra. These results strongly indicate that the indole part of the molecule is close to or attached to the silver surface.
Combined Raman and 51V NMR spectroscopic study of vanadium (V) oligomerization in aqueous alkaline solutions
Authors: Amado Ana Margarida , Aureliano M. , Riberio‐Claro Paulo J. A. , Teixeira‐Dias J. J. C.
Published: May 2005

The Raman spectra of aqueous vanadium (V) solutions at different pH values, ranging from 13.1 to 7.0, are presented. The dominant bands in the range 700–1100 cm−1 are assigned to the VO symmetrical stretching of the different oligomers, using additional information from 51V NMR spectra and empirical models. The effects of pH, concentration and ionic strength on the oligomerization equilibria are discussed. The ionic strength is found to affect significantly the oligomer composition of vanadate solutions, which is of interest in biochemical and biological studies.
Experimental verification of backscattering CARS spectroscopy on opaque media
Authors: Weippert A. , Funk J.‐M. , Materny A. , Kiefer W.
Published: May 2005

The applicability of a recently suggested coherent anti‐Stokes Raman spectroscopic (CARS) reflection technique to investigations of strongly absorbing materials was tested. Teh underlying principle is that the CARS signal generated in the surface layers of the sample is detected as a beam which is backscattered from the surface of an opaque medium rather than in transmission. A special experimental arrangement was used which allowed CARS spectra to be obtained with reasonable signal strenth. As an example, experimental results for a TS6 (hexa‐2,4‐diynylene di‐p‐toluenesulphonate)polydiacetylene single crystal are presented. Spectra obtained at different angles of incidence are discussed.
Micro Raman study of dislocations in n‐type doped GaAs
Authors: Paetzold O. , Irmer G. , Monecke J. , Griehl S. , Oettel O.
Published: May 2005

Micro Raman spectroscopy was used in order to clarify dislocation‐related effects in a GaAs sample Bridgeman‐grown from a slightly As‐rich melt and doped with Si to achieve a free electron concentration of about 1018 cm−3. The specific advantage of the Raman method is demonstrated by the direct observation of an increase in the carrier concentration in the vicinity of dislocations and by the detection of both crystalline and amorphous As in the dislocation core. A defect model is proposed, which is in a agreement with results obtained by other methods such as high spatial resolution photoluminescence. The possibility of determining internal lattice distortions by means of Raman spectroscopy is discussed, but further systematic investigations are necessary to obtain reliable results.
Infrared and Raman studies on calcium, zinc and cadmium hydroxide halides Ca{O(H,D)}Cl, Cd{O(H,D)}Cl, Zn{O(H,D)}F and β‐Zn{O(H,D)}Cl
Authors: Lutz H. D. , Schmidt M. , Weckler B.
Published: May 2005

IR and Raman spectra of Zn(OH)F, β‐Zn(OH)Cl and isostructural Ca(OH)Cl and Cd(OH)Cl and of deuterated specimens recorded at ambient and liquid nitrogen temperature are presented and assigned to OH(OD) stretching, librational and translational modes. The spectra obtained are discussed on the basis of the layered crystal structures of these hydroxide halides. The main results are (i) detection and proof of the presence of very weak hydrogen bonds in the case of M(OH)Cl (M = Ca, Cd) and for OH(2) of Zn(OH)F [in addition to ordinary hydrogen bonds in the case of β‐Zn(OH)Cl and OH(1) of Zn(OH)F] with OH stretching wavenumbers of the corresponding hydroxide ions partially greater than that of free, gaseous OH− ions, (ii) a less symmetrical structure of Ca(OH)Cl and Cd(OH)Cl compared with that obtained from the heavy atoms alone and (iii) proof of the presence of two different kinds of hydroxide ions in nearly equal amounts in Zn(OH)F containing two lattice sites each occupied by F− and OH−. The high‐energy shift of the OH modes mentioned above is attributed to the synergetic effect.
Property tensors and tensorial covariants of classical point groups. Applications to Raman effects of higher order and other problems
Authors: Brandmüller J. , Illig D.
Published: May 2005

Polar and axial tensorial covariants without intrinsic symmetries have been calculated using the method of representation theory up to rank 4 for the 32 crystallographic, the 5 pentagonal, the 2 icosahedral, the 7 decagonal and the 5 continuous one‐parametric classical point groups (Curie limiting point groups). The full results have been published as tables by the Fachinformationszentrum Karlsruhe. This paper reviews the general method of calculation, which is based on representation theory using an extension of Neumann's principle. The results are compared critically with various complications of special cases in the literature and a number of errors and inconsistencies are pointed out.
Applications of Raman and surface‐enhanced Raman scattering spectroscopy in medicine
Authors: Nabiev Igor , Chourpa Igor , Manfait Michel
Published: May 2005

The first part of this review is devoted to medical applications of Raman spectroscopy as a diagnostic or analytical tool. Studies of human arteries, ocular lenses, living cells and chromosomes are reviewed, in addition to recent advantages in cancer diagnostics using Raman spectroscopy. The second and major part is devoted to a relatively new field, surface‐enhanced Raman scattering (SERS) spectroscopy of biomedical species. The SERS effect is accompanied by strong quenching of fluorescence and so enabes the range of species that can be investigated by Raman technique to be extended. The ultra‐high sensitivity of SERS enables spectra to be obtained at concentrations down to 10−10 M. A wide range of experiments designed to probe the structure, topology and composition of biomedical species using SERS spectroscopy can be envisioned. Some of these currently being studied are: the determination of the distribution of drugs within a living cell and on the cellular membrane, the selective study of cell membrane components, the analysis of crude biomedical mixtures and extracts and new techniques, based on SERS spectroscopy, Fourier transform SERS spectroscopy and the SERS microprobe method.
Measurement of poly(aryl ether ether ketone) crystallinity in isotropic and uniaxial samples using Fourier transform‐Raman spectrocopy: A comparison of univariate and partial least‐squares calibrations
Authors: Everall N. J. , Chalmers J. M. , Ferwerda R. , van der Maas J. H. , Hendra P. J.
Published: May 2005

A range of thermally annealed isotropic and uniaxially drawn PEEK films were examined using polarized Fourier transform Raman spectroscopy in an attempt to obtain useful quantitative correlations with crystallinity. Both univariate (carbonyl stretching wavenumber measurement) and multivariate (partial least‐squares) calibrations were found to give good correlations, in the latter case yielding a standard error of prediction of ca. 2.4% crystallinity. Both approaches show potential for measurement of crystallinity in both isotropic and oriented samples using just one correlation model. A previously suggested crystallinity index (the ratio of the 1600 and 1610 cm−1 band intensities) failed to give a satisfactory correlation for either sample set. It was also shown that the ratio of the 1146 cm−1 band intensities measured with the laser polarized perpendicular and parallel to the draw direction correlates with the sample birefringence.
Examples of analysis of pigments from fine art objects by Raman microscopy
Authors: Davey R. , Gardiner D. J. , Singer B. W. , Spokes M.
Published: May 2005

Raman microscopy has several advantages over other methods of analysis used to identify pigments from fine art objects. Examples are given of the use of this technique for the analysis of pigments taken from water‐colours, a lithograph and oil paintings.
Fourier transform Raman spectroscopic and scanning electron microscopic studies of chemical vapor deposited diamond‐like carbon films
Authors: Bist H. D. , Bhargava S. , Little T. S. , Gardner J. K. , Durig J. R. , Sahli S. , Aslam M.
Published: May 2005

A combined study based on scanning electron microscopy and Fourier transform Raman spectroscopy is presented for different kinds of diamond films. These films were obtained by the hot filament chemical vapor deposition (HFCVD) technique with both silica (SiO2) and silicon (Si) being used as substrates. CVD diamond films, having crystallite dimensions larger than about 1 μm (the wavelength for Raman excitation being 1.06 μm with an Nd:Yag CW laser), show tetrahedral chemical bonding and single‐crystal structural features being characterized by the appearance of the sharp first‐order 1330 cm−1 Raman line characteristic of natural or high‐pressure synthetic diamonds. Films having crystalline dimensions < 0.1 μm still exhibit tetrahedral (sp3) bonding. For such small crystals, the wavevector conservation rule for Raman spectroscopy of single crystals of diamond breaks down and only broad features, with the most intense Raman lines falling in the range 1260–1100 cm−1, are observed. This broad feature is characterized by some additional superimposed sharp lines, the maxima of which vary from sample to sample, showing the effect of overlap of spectra from various domain sizes of the crystallites, edge effects and contribution from other forms of non‐diamond carbon. The crystalline diamond peak observed at 1330 cm−1 indicates that the diamond structure, at the temperature of synthesis, is retained in these films, and the large width of the Raman peak is probably due to the presence of defects. The main low‐wavenumber peaks observed in all spectra obtained with 1.06 μm excitation are interpreted as arising from the amorphous disordered sp3‐bonded carbons, which are formed as precursors to the crystalline diamond grown by the HFCVD technique.
Raman and infrared study of solid benzyl alcohol
Authors: Prystupa D. A. , Anderson A. , Torrie B. H.
Published: May 2005

Raman and infrared spectra of solid benzyl alcohol and two partially deuterated homologues are reported for the first time. The internal vibrational modes and lattice modes of benzyl alcohol are assigned on the basis of isotopic wavenumber shifts. The spectra of solid benzyl alcohol at low temperatures are shown to be consistent with an ordered non‐centrosymmetric structure, with at least four molecules in the unit cell.
Micro‐Raman study of laser ablated YBa2Cu3O7–δ thin film deposited on inconel with a tin buffer layer
Authors: Soni R. N. , Sathaiah S. , Joshi H. C. , Bist H. D. , Raghuvanshi G. S. , Kumar Ashok , Narayan J.
Published: May 2005

The Raman spectra of YBa2 Cu3 O7–δ superconducting thin film deposited on Inconel with a TiN buffer layer by a laser ablation technique are reported. The results indicate that the film is fully oxygenated, homogeneous and polycrystalline and has a preferred orientation along the c‐axis. No evidence of interdiffusion between the film and the substrate was found. Unusual photoinduced changes in the Raman spectra were observed by varying the incident cw Ar+ (514.5 nm) laser power densities between 50 to 250 ± 5 W mm−2. The increase in the intensity ratios of the out‐of‐phase and in‐phase c‐axis bending vibrations of O(2)—O(3) oxygen atoms to that of the axial symmetric stretching vibration of bridging oxygen O(4) (i.e. I337/I503 and /I445/I503) and the decrease in the full‐width at half‐maximum intensity (FWHM) of the out‐of‐phase, c‐axis bending vibration (337 cm−1) can be attributed to the improvement in the crystallinity of the film due to oxygen ordering in the CuO2 planes induced by laser irradiation.
Transient resonance CARS and CSRS of diphenylbutadiene‐d4 in the S0, S1T1 and photoinduced radical ion states
Authors: Kamisuki Toshio , Hirose Chiaki
Published: May 2005

The Raman, resonance CARS (coherent anti‐Stokes Raman scattering) and CSRS (coherent Stokes Raman scattering) spectra of α, α′, β, β′‐deuterated trans, trans‐1,4‐diphenylbuta‐1,3‐diene (DPB‐d4) in the So, S1, T1, radical cation and radical anion states were studied. The radical ions were produced transiently by ns‐pulsed UV irradiation in a solution containing electron donors ar acceptors. A comparative study of the observed Raman frequencies with those of DPB‐d0 permitted vibrational assignment of the transient species of DPB. Features relating to spectral and structural characteristics of the transient species of the shorter diphenylpolyenes are briefly discussed.
Vibrational study on ferroelectric phase transition in NaNH4SO4 · 2H2O
Authors: Kanesaka Isao , Ozaki Kenichi
Published: May 2005

The vibrational spectra of NaNH4SO4 · 2H2O (SASD) and its 5% deuterated system were observed in the region of the O–X and N–X stretches (X = H or D) over the temperature range 300–25 K. A similarity was found in the Raman spectral features associated with water molecules at room temperature and below Tc, which were, however, different from those just above Tc. A λ type of temperature dependence with a large wavenumber jump at Tc was found for the main Raman band at 3423 cm−1. This was explained qualitatively in terms of the strong correlation between the Raman mode and the order parameter. A similar result was observed for the decoupled OD modes. The analysis of their temperature dependence revealed characteristics of the phase transition mechanism in SASD. The λ type of temperature dependence was not found in decoupled modes associated with ammonium ions.
Resonance Raman four‐wave mixing in molecular systems
Authors: Kircheva P. P.
Published: May 2005

Non‐linear vibronic spectra of molecules in solution were considered. Probe profiles (PP) of CARS with three laser frequencies, treated as Raman four‐wave mixing (Raman FWM), were calculated and compared with excitation profiles (EP) of CARS and of spontaneous Raman scattering. It is demonstrated that the PP of Raman FWM is a characteristic that can be used instead of the EP of spontaneous Raman scattering. The dependence of the lineshape for Raman FWM was modelled. The advantages of Raman FWM are mentioned. In contrast to CARS with two lasers, it is easy to penetrate the high‐wavenumber side of the vibronic spectra and to avoid a significant absorption at the exciting wavenumbers.
Raman and infrared spectra of solid chlorofluoromethane
Authors: Schlueter S. A. , Davison T. S. , Fraser J. M. , Anderson A.
Published: May 2005

Raman and infrared spectra of solid CH2CIF (Freon 31) were recorded in both the lattice and internal mode regions for samples at temperatures between 12 and 125 K. No evidence of any solid‐state phase transition was found, but some thin‐film samples deposited at low temperatures appear to exist in a metastable phase. Spectra of the stable phase are compatible with a non‐centrosymmetric unit cell containing four molecules. Lattice peaks are assigned on the basis of geometrical and intensity arguments.
Details of the damage profile in self‐ion‐implanted silicon
Authors: Zhang P. X. , Mitchell I. V. , Schultz P. J. , Lockwood D. J.
Published: May 2005

Raman spectra excited at two laser wavelengths are used to study the damage in self‐implanted silicon. Depending on the implantation conditions, a three‐layer structure can be constructed: a damaged surface crystalline layer (dsc‐Si), an amorphous layer (a‐Si) and a damaged interior crystalline layer (dic‐Si). Raman spectra can provide the structural details of these layers, together with the Rutherford backscattering–chanelling technique. Examination of the scattering intensities shows that the contribution to the Raman signals from different layers can be distinguished and separated. Further analysis of the Raman data reveals a defect‐activated low‐frequency band in the dsc‐Si layer which is sensitive to the damage and may be used for the characterization of dsc‐Si. For totally amorphlzed samples the two Raman spectra excited at 457.9 and 647.1 nm show different scattering intensity ratios for the optical‐ and acoustic‐like phonons. This novel result may indicate a depth‐dependent variation of the disordering in the amorphous layer. Quantitative comparison between the calculated and measured Raman scattering intensities provides the scattering efficiency ratios of dsc‐Si and a‐Si in samples comprising both dsc‐ and a‐Si layers.
Interferometric coherent Raman spectroscopy: Resonant and non‐resonant contributions
Authors: Schaertel S. A. , Albrecht A. C.
Published: May 2005

The theory of the recently discovered interferometric coherent Raman spectroscopy (ICRS) is extended to explicitly include terms resulting from non‐resonant contributions to the overall non‐linear susceptibility. The derived expression is applicable to both interferometric coherent anti‐Stokes Raman spectroscopy (ICARS) and interferometric coherent Stokes Raman spectroscopy (ICSRS) and can be applied to both neat solutions and binary mixtures. It is shown that the total description of ICRS must include a resonant term, a non‐resonant term and a resonant‐non‐resonant cross‐term, each of which exhibits analytically unique behavior in time‐domain ICRS experiments. From the complete expression one can extract relative strengths of the resonant and non‐resonant molecular hyperpolarizabilities. Resonant hyperpolarizabilities thus obtained may be used to determine absolute Raman cross‐sections, without making absolute measurements. Conversely, for a sample for which the absolute Raman cross‐section is independently known, one can determine the value of the non‐resonant hyperpolarizability.
Raman study of dioxane–D2O mixtures by analysis of the O–D band structure
Authors: Nickolov Zh. S. , Earnshaw J. C. , McGarvey J. J. , Georgiev G. M.
Published: May 2005

Changes in the isotropic and anisotropic component profiles of the O—D stretching bands of D2O were studied in the range 0–0.5 mole fraction (m.f.) of 1,4—dioxane. The contribution of the CH Raman band of dioxane was subtracted using Raman spectra of dioxane—water mixtures in the same concentration range. A Fourier deconvolution technique was employed to resolve the overlapped components in the spectra. The information on the positions of the components in the isotropic spectra was used to fit them with symmetric components of mixed Gaussian—Lorentzian type. The wavenumbers of the resolved components in the isotropic and anisotropic spectra and the ratio of the intensities of the symmetric Fermi resonance components in the isotropic spectra were used to determine the concentration dependence of intermolecular, intramolecular and Fermi resonance parameters. The intermolecular and intramolecular interaction constants do not change significantly up to about 0.07–0.10 m.f. of dioxane and then gradually decrease. The Fermi resonance constant W does not change noticeably over the concentration range studied. The wavenumbers of the unperturbed O–D oscillator exhibits two different rates of increase with concentration of dioxane. The observed variations in the analysed parameters are interpreted in terms of hydrophobic hydration, hydrophobic interaction and hydrogen bonding in dioxane–water mixtures.
Raman and 125Te NMR spectroscopic evidence on the solvent extraction of tellurium(IV) species from HCl solutions
Authors: Baker L.‐J. , Taylor Michael J.
Published: May 2005

The Raman spectra of solutions of TeCI4 in HCI up to 12 mol I−1 show a changing pattern of bands consistent with a mixture of complexes, including [TeCI6]2− and [TeCI4(OH)]−. High‐field 125Te NMR spectra at 126.24 MHz of these aqueous solutions consist of a single bind, showing that the TeIV species are in rapid equilibrium, which moves upfield within the range + 1550 to + 1400 ppm as the HCI concentration is increased. Solvent extraction with diethyl ether selects a single species from TeIVHCI solutions. This is identified as the complex acid HTeCI4(OH) by a Raman spectrum marked by νs(TeCI) = 289 cm−1 and ν(TeO) = 667 cm−1, and a characteristic 125Te resonance, δ = 1448 ppm, w1/2 = 80 Hz.
Spectra and structure of organophosphorus compounds. L—Raman and infrared spectra, conformational stability, ab initio calculations and vibrational assignment of fluoromethylphosphonic dichloride
Authors: Durig J. R. , Daeyaert F. F. D. , van der Veken B. J.
Published: May 2005

The Raman (3100–10 cm−1) and infrared (3100–30 cm−1) spectra of fluoromethylphosphonic dichloride FCH2P(O)C12, in the gas and solid phases were recorded. The Raman spectrum of the liquid along with qualitative depolarization ratios were obtained. These data, along with infrared vapor‐phase contours, were interpreted on the basis of an equilibrium between trans (fluorine atom trans to the oxygen atom) and gauche conformers in the gas and liquid phases, with the trans conformer being the more stable form in both of these physical states and the only form present in the crystalline solid. From the study of the Raman spectrum for the liquid as a function of temperature, a value of 277 ± 66 cm−1 (792 ± 189 cal mol−1) was determined for ΔH. Utilizing the trans torsional wavenumber, the gauche dihedral angle and the enthalpy difference between conformers, the potential function governing the interconversion of the rotamers was estimated. A complete vibrational assignment is proposed for both conformers based on infrared band contours, Raman depolarization data, group wavenumbers and normal coordinate calculations. The conformational stabilities, barriers to internal rotation, force constants, infrared and Raman intensities and fundamental vibrational wavenumbers, along with the structural parameters, were obtained from ab initio Hartree–Fock gradient calculations employing both the RHF/3‐21G* and RHF/6‐31G* basis sets. The calculated Raman intensities with the 3‐21G* basis set reproduce the observed Raman spectrum remarkably well. Many of these results were compared with the corresponding quantities for some similar molecules.
Raman and infrared spectra, conformational stability, barriers to internal rotation and ab initio calculations of allyl cyanide
Authors: Durig James R. , Guirgis Gamil A. , Drew A. S.
Published: May 2005

The Raman (3200–10 cm−1) and infrared (3150–50 cm−1) spectra of allyl cyanide, CH2CHCH2CN, were recorded for the gas and solid phases. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were obtained. Both the cis and gauche conformers are present in the gas and liquid phases with the cis conformer being the more stable rotamer and the only conformer present in the annealed solid. The fundamental asymmetric torsion of the cis conformer has been observed in the far‐infrared spectrum of the gas at 141.3 cm−1 with three excited states falling to lower wavenumbers. The corresponding fundamental for the gauche conformer has been observed in the Raman spectrum of the gas at ca. 102 cm−1. From temperature‐dependent studies of the Raman spectrum of the liquid, three pairs of conformer peaks have been used to determine the ΔH value of 245 ± 6 cm−1 (707 ± 17 cal mol−1), with the cis conformer the most stable rotamer. Additionally, a variable‐temperature study of the infrared spectrum of the sample dissolved in liquified xenon gives a ΔH of 336 ± 61 cm−1 (961 ± 175 cal mol−1), which should closely represent the ΔH value for the gas. Utilizing the torsional transitions, the enthalpy difference and the gauche dihedral angle, the potential function governing the conformational interchange was determined. A complete vibrational assignment is proposed for the cis conformer and several fundamentals are identified for the gauche rotamer based on infrared band contours, Raman depolarization data, group wavenumbers, relative intensities and normal coordinate calculations. The experimental conformational stability, barriers to internal rotation, structural parameters and fundamental vibrational wavenumbers are 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.