bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrodes for REMPI spectroscopy in static gases and calculation of REMPI intensities: Application to molecular oxygen
Authors: Rouillé G. , Chaux R. , Berger H. , Pavone F. 
Published: May 2005

AbstractResonance‐enhanced multiphoton ionization (REMPI) of 16O2X3∑g − (ν = 0) through (3sσg)d 1Πg, (ν = 0) by using (2 + 1) one‐colour photons is reported. This REMPI process, already observed and analysed by other authors at low pressure and low rotational temperature with mass spectrometry detection, is used to test our first detector of ionizations. Experimental difficulties have led to the design of an original arrangement of electrodes to collect electrons at room temperature and 1 Torr pressure of static molecular oxygen. A calculated spectrum is compared with the observed REMPI spectrum. The calculation uses the polarizability tensor and takes into account the competition between ionization and predissociation of the Rydberg state.
Light‐scattering spectrum in the region of the upper, lower and double critical points in guaiacol—glycerol solution
Authors: Chaikov L. L. , Fabelinskii I. L. , Krivokhizha S. V. , Lugovaya O. A. , Citrovsky A. , Jany P. 
Published: May 2005

AbstractThe viscosity temperature dependence and the correlation radius of concentration fluctuations have been obtained in guaiacol‐glycerol solutions with various miscibility gaps up to a gap width ΔT = 0.01 °C. The correlation radius critical exponent ν changes from 0.63 when ΔT= 39°C to 0.53 when ΔT = 0.01 °C. Measurements were made using the light correlation spectroscopy method.
Raman and infrared spectra of solid methylene fluoride
Authors: Beardsall A. J. , Smith W. , Anderson A. 
Published: May 2005

AbstractRaman and infrared spectra of solid CH2F2 (Freon 32) were recorded in both the lattice and internal mode regions for samples at temperatures between 12 and 115 K. No evidence of any solid‐state phase transition or of metastable phases was found. The spectra are consistent with a large unit cell, probably non‐centrosymmetric and containing eight molecules, with relatively loose packing compared with the other methylene halides. It is postulated that at temperatures near the melting point, the molecules undergo 180° rotational jumps which are gradually inhibited on cooling.
Polarized single‐crystal Raman spectroscopy of danburite, CaB2Si2O8
Authors: Best Stephen P. , Clark Robin J. H. , Hayward Chris L. , Withnall Robert 
Published: May 2005

AbstractPolarized single‐crystal Raman spectra were collected from the borosilicate feldspar mineral danburite (CaB2Si2O8) over the region 1800–40 cm−1. The symmetry of danburite (orthorhombic) is higher than that of the other feldspars (monoclinic or triclinic) and this simplifies the vibrational analysis. A very high proportion (74/78) of the bands due to Raman‐active fundamentals are observed, making this the first such study in which most of the bands for a feldspar mineral have been observed. Assignment of bands to stretching, bending and lattice modes is problematic because of the framework structure of the feldspar. The physically unrealistic disconnection of the danburite lattice into [Si2O7]6−, [B2O]4+ and Ca2+ ions leads to remarkably good predictions of the numbers of bands for each symmetry species in the wavenumber ranges appropriate for the Si(B)OSi(B) stretching (1300–825 cm−1), bending (825–390 cm−1) and lattice (390–90 cm−1) modes.
Meta‐substituted styrene molecules included in cydodextrins: A Raman spectroscopic study
Authors: Amado Ana M. , Moreira da Silva Aida M. , Ribeiro‐Claro P. J. A. , Teixeira‐Dias J. J. C. 
Published: May 2005

AbstractRaman spectra of styrene (S), 3‐fluorostyrene (3FS), 3‐chlorostyrene (3CS) and 3‐methylstyrene (3MS) and their complexes in α‐, β‐ and γ‐cyclodextrins (α‐, β‐, γCD) were recorded at various temperatures. The substituted styrene molecules were found to provide good group frequencies, namely, vCC and vCH, for probing the guest molecules. Generally, the CC oscillator is shown to be a good probe for studying conformational equilibria of the guest molecule perturbed by complex formation with the various CD molecules. The CH oscillators provide information concerning plausible structures for the complexes. On the whole, all the spectral observations are consistent with different types of structures for the (S, 3MS)–αCD and (3FS, 3CS)–αCD complexes. In particular, the Raman spectroscopic results suggest that, for 3MS–αCD the vinyl group keeps some rotational freedom. For 3FS–αCD and 3CS–αCD, it is suggested that the most electronegative fluorine and chlorine atoms are left outside the the CD cavity, with the vinyl group rotationally hindered. For the γCD complexes, the wider CD cavity sould be able to accommodate all the guest molecules considered keeping the conformer distributions of the pure liquids approximately. However, the inclusion process seems to hinder the internal rotation in such a way that even below 200 K the conformer distribution remains similar to that of the pure liquid at room temperature.
Time‐resolved pump–probe Raman spectroscopy with temporally incoherent light
Authors: Okamoto Hiromi , Nakabayashi Takakazu , Tasumi Mitsuo 
Published: May 2005

AbstractA method for picosecond time‐resolved pump–probe Raman spectroscopy using temporally incoherent light (‘incoherent pump–probe Raman spectroscopy, or simply IPPR spectroscopy’) is proposed. The theoretical formulation of IPPR scattering based on Gaussian random statistics is described. It is predicted that the temporal resolution in IPPR experiment is not determined by the duration of pump and probe pulses, but by the cross‐correlation time between the pump and probe lights. The delay‐time dependence of the IPPR intensity is expected to show the same behaviour as that in conventional time‐resolved Raman spectroscopy which uses coherent ultra‐short light pulses, except for a constant background always existing in IPPR scattering. This method was examined experimentally for Raman scattering from electronically excited trans‐stilbene in n‐hexane solution. In accordance with the prediction, picosecond decay of the Raman band at 1565 cm−1 arising from the trans‐stilbene molecules in the S1, state is observed with the use of nanosecond pump and probe pulses with a cross‐correlation time of ca. 100 ps. No decay is observed for the Raman bands of the solvent. Effects of saturation arising from the frequency‐doubling, pumping and Raman processes on the IPPR signal are also discussed. The ratio of the delaytime dependent part to the background (contrast ratio) is predicted to decrease in the presence of saturation.
Raman spectroscopic study of the molecular conformation of α‐octyl‐ω‐methoxyoligo(oxyethylene)s in the solid state
Authors: Masatoki Sei , Matsuura Hiroatsu , Fukuhara Koichi 
Published: May 2005

AbstractThe Raman spectra of α‐octyl‐ω‐methoxyoligo(oxyethylene)s, CH3(CH2)7(OCH2CH2)mOCH3 (m = 1–4), were measured in the solid state. The molecular conformation of these compounds was determined by a spectral analysis based on the key conformational bands. The conformation of the inner oxyethylene segments changes from an extended structure to a helical structure as the number of oxyethylene units increases. The difference in the conformational behaviour between the present methoxy‐ended compounds and the corresponding hydroxy‐ended compounds is associated with the different layer structures of the crystals.
Rovibrational Raman spectrum of dimethylacetylene
Authors: Meßler P. , Schrötter H. W. , Sarka K. 
Published: May 2005

AbstractThe rovibrational Raman spectrum of dimethylacetylene (but‐2‐yne) was recorded photoelectrically at medium resolution. Depolarization ratios and relative normalized scattering cross‐sections were determined for five fundamentals and a number of strong overtones.
Fourier transform Raman spectroscopy of bacterial cell walls
Authors: Williams A. C. , Edwards H. G. M. 
Published: May 2005

AbstractFourier transform Raman spectra were obtained from viable colonies of bacteria. Despite the highly coloured nature of the samples, the spectra were of sufficient quality to allow comprehensive assignments consistent with the vibrational modes. The spectra showed no clear evidence for the presence of phospholipids, indicating that penetration of the exciting infrared radiation was limited to the outermost components of the bacterial cell walls. The data describing the molecular and conformational state of the bacterial cell wall may aid in probing the modes of action of a wide range of antimicrobial agent.
Band profile analysis of the Raman spectra of sulphate ions in aqueous solutions
Authors: Rull F. , Sobrón F. 
Published: May 2005

AbstractA Raman spectroscopic study of aqueous solutions of sulphates with some mono‐ and divalent cations was performed. The dynamic properties of the sulphate ion were analysed in the wavenumber domain and in the time domain using Fourier transform methods. Special interest is devoted to those systems for which the ν1(SO) band shows an asymmetric profile. This asymmetry has been interpreted in two ways: (a) as arising from different SO oscillators (associated and non‐associated); their relative intensity is calculated using classical fitting methods, although the band parameters are obtained from a self‐deconvolution method performed in the time domain; and (b) as arising from a perturbation of the water molecules in the vicinity of the sulphate ion. This perturbation is modelled in the time domain through a generalized correlation function. This latter represents a perturbed distribution of oscillators which undergo mutual interactions. These interactions are modelled by a feedback mechanism with two main parameters, the mutual coupling energy and the fraction of the distribution having mutual interaction. The correlation function thus modelled leads in the frequency domain to an asymmetric bandshape. The fitting of the experimental correlation function by this model gives essentially the same information as the fitting in the wavenumber domain for all the cases studied. Moreover, in the case of Li and Mg sulphates, both methods give the same value for the spectroscopically measured association enthalpy, 14 kJ mol−1 for Li and 21 kJ mol−1 for Mg.
Low‐wavenumber Raman spectrum of pyrazinic acid
Authors: Kalkar A. K. , Bhosekar N. M. 
Published: May 2005

AbstractThe low‐wavenumber Raman spectrum of pyrazinic acid (PA) crystal (orthorhombic, Pna21/D) was measured in the range 200–10 cm−1. Twelve Raman‐active lattice modes of crystalline PA were observed. Their tentative assignments in terms of hydrogen bond motion are reported. The intra‐ and inter‐chain translational modes were assigned using the isolated single‐chain (Cs) approximation, whereas the rotational modes were separated out mainly on the basis of their polarization behaviour, intensities and the shapes of their band profiles.
Isothermal Raman depolarization ratios of supracritical carbon monoxide at pressures between 20 and 2400 bar
Authors: Rose E. J. , Baglin F. G. 
Published: May 2005

AbstractThe Raman depolarization ratios of carbon monoxide were measured via the zeroth spectral moment, Mo (integrated intensities), and simple peak‐height determinations under isothermal conditions (323 K) over a pressure range of 20–2400 bar in a mixture of CH4 and CO. These conditions correspond to densities ranging from 0.75 to 24 mol I−1. The measurements were carried out so that the depolarization ratios being measured in other experiments from the ν1 totally symmetric stretching mode of supracritical methane could be corrected for instrumental depolarization effects. The values near a pressure of 1 bar have been calculated and measured for CO by several sets of workers. The cell windows were float glass and as a result they are known to contribute much less than quartz to depolarization. Float glass windows cause only a 0.5% error in scrambling uncertainty of the polarized light exiting the high‐pressure cell.
Surface‐enhanced Raman scattering at colloidal silver oxide surfaces
Authors: Li Ying‐Sing 
Published: May 2005

AbstractA colloidal silver oxide hydrosol was prepared for surface‐enhanced Raman scattering (SERS). Its performance as a SERS‐active substrate was tested using benzoic acid and 1,1′‐diethyl‐2,2′cyanine iodide as analytes. SERS and surface enhanced resonance Raman scattering were observed for the adsorbed samples. In the preparation of the sol, the relative amounts of reagents should be an important factor in affecting the surface enhancement of the substrate. The surface enhancement activity of the colloidal hydrosol might indicate that silver oxide films generated in the electrochemical oxidation of a silver electrode could enhance the Raman spectra of adsorbed molecules and/or passivated films.
Resonance Raman enhancement for adenine and guanine residues
Authors: Majoube M. , Millié Ph. , Lagant P. , Vergoten G. 
Published: May 2005

AbstractReliable assignments for normal modes of adenine, 9‐methyladenine, guanine and 9‐methylguanine were obtained from ab initio 3–21G force fields and optimized geometries. In addition, relative itensities were calculated at resonance with the excited states corresponding to the lowest energy π–π * orbital excitations from the change in bond order and the L−1 matrix. Wavenumbers and relative intensities for resonance Raman active modes Were compared with those previously observed for resonance Raman enhanced bands of AMP and GMP in aqueous solutions obtained with excitation near the absorption band at 260 nm and below. There is satisfactory agreement between observed and calculated relative intensities for the guanine residue. In particular, the large increase in intensity observed for the CO stretching band at 1670 cm−1 with excitation below 220 nm is correctly reproduced. On the other hand, there is less agreement for the adenine residue where the distribution of intensity at resonance according to the A term of the resonance Raman theory is probably altered by the presence of vibronic coupling.
Raman and infrared study of neodymium oxide peroxide, Nd2O2(O2)
Authors: Heyns Anton M. , Range Klaus‐Jürgen 
Published: May 2005

AbstractNd2O2(O2) has been formed at very high oxygen pressures in an unsuccessful attempt to prepare neodymium(IV) dioxide, Nd4+ O2, and contains oxide (O2−) and peroxide (O) ions. The structure of Nd2O2(O2) closely resembles that of CaF2 and its full vibrational spectra could be interpreted in terms of this structure. Although Nd2O2(O2) has a monclinic structure, its vibrational spectra are not in agreement with the monoclinic B‐type phase of the lanthanide(III) sesquioxides, and it is shown why this is so. Many of the NdO vibrational modes in Nd2O2(O2) agree, however, with those observed in the trigonal A‐type Nd2O3, and the ν (OO) stretching and NdOO bending modes could be clearly identified.
SERRS of azurin adsorbed on a silver surface
Authors: Silin V. I. , Gaigalas A. K. 
Published: May 2005

AbstractSurface‐enhanced resonance Raman (SERR) spectra of azurin, a copper‐containing protein, were measured on a silver surface with a double grating. Significant differences in intensity and band wavenumber were obtained between SERR and solution resonance Raman spectra in the region 250–300 cm−1 and near 400 cm−1. Preliminary interpretation of these differences suggests a likely orientation of the azurin protein on the silver surface in which the N(His44)N(His115)S(Met119) plane is perpendicular to the metal surface and the imidazole group of His115 is in close proximity to the metal.
Analytical potential of near‐infrared fourier transform Raman spectra in the detection of solid transition metal carbonyl steroid hormones
Authors: Salmain Michèle , Vessières Anne , Top Siden , Jaouen Gérard , Butler Ian S. 
Published: May 2005

AbstractNear‐infrared (NIR) Fourier transform (FT) Raman spectra of four steroid hormones labeled with organometallic fragments, five steroid hormones and five model organometallic complexes were measured at room temperature. The objective was to determine which particular molecular vibrations of the steroid hormones might be best suited for any future quantitative analyses. On the basis of this FT‐Raman study, a classification of the most important vibrations as a function of their relative band intensities is proposed, i.e. v(Co2‐alkyne) ≈︁ v(Co‐Co) < v(C≡C) ≈︁ v(C‐C)Cp(Cp = β5‐C5H5) < v(C≡O) < v(C≡N).
Resonance Raman spectra of phthalocyanine monolayers on different supports. A normal mode analysis of zinc phthalocyanine by means of the MNDO method
Authors: Palys Barbara J. , van den Ham Dirk M. W. , Briels Wim , Feil Dirk 
Published: May 2005

AbstractResonance Raman spectra of monolayers of transition metal phthalocyanines reveal specific interaction with the support. To elucidate its mechanism, Raman spectra of zinc phthalocyanine monolayers were studied. The analysis was based largely on the results of MNDO calculations. Calculated wavenumbers turned out to be in good agreement with the experimental results. It seems plausible that the α‐nitrogen atoms dominate the interaction with the support. Calculation results also show that the usually assumed D4h geometry does not represent the true energy minimum but must be considered as the ‘mean’ of two mesomeric forms.
Application of fourier transform Raman spectroscopy to biomembranes: 1064 NM excited Raman spectra of hog kidney mitochondrial outer membranes
Authors: Omura Yoko , Muraishi Syuichi 
Published: May 2005

AbstractFourier transform Raman spectra with 1064 nm excitation were measured at ambient temperature on hog kidney mitochondrial outer membrane preparations of ultracentrifuged pellet and almost fluorescence‐free Raman spectra with satisfactory signal‐to‐noise ratios were obtained. Fourier transform IR spectra were also measured. The observed Raman and infrared wavenumbers were tentatively assigned to membrane proteins and phospholipids, respectively. CH stretching, phospholipid CC stretching and PO2− stretching vibrations are discussed. To examine the applicability of near‐infrared excited Fourier transform Raman spectroscopy to the study of the inhibitory effects of inorganic ions on membrane‐bound monoamine oxidase activity, measurements were also made on membrane preparations suspended in phosphate buffer (pH 7.0) at ambient temperature in the absence (control) and presence of NaCl, and studies were made of phospholipid CC stretching and PO2− stretching vibrations, which are relatively unaffected by H2O self‐absorption by near‐infrared radiation. It was found that the presence of NaCl decreased the intensity of the 1080 cm− 1 gauche form acyl chain CC stretching Raman band relative to those of the all‐trans CC stretching Raman band at 1126 and 1068 cm− 1. This result was different from that obtained with aqueous dispersions of phosphatidylcholine (PC), for which it has been reported previously that monovalent ions such as Na+ do not affect the Itrans/Igauche ratio.
Transient resonance coherent stokes Raman scattering spectra of photoinduced radical ions of diphenyloctatetraene in polar solvents
Authors: Kamisuki Toshio , Hirose Chiaki 
Published: May 2005

AbstractTransient resonance coherent Stokes Raman scattering (CSRS) spectra of the photoinduced radical ions of all‐trans‐1, 8‐diphenylocta‐1, 3, 5, 7‐tetraene (DPO) were observed in polar solvents such as acetonitrile, N, N‐dimethylformamide and dimethyl sulphoxide. The identification was based on the long lifetimes and the dependence of their formation on the electron‐donating and/or ‐accepting nature of the solvents. The fluorescence spectra of DPO were also observed in the presence of N, N‐dimethylaniline (DMA) and p‐dicyanobenzene (DCNB) in p‐dioxane and in polar solvents without DCNB and DMA. The absence of an indication of exciplex formation, in contrast to the cases of diphenylbutadiene and diphenylhexatriene, can be related to the extremely low efficiency of the radical ion formation by solvent‐assisted photoionization in DPO—DMA and DPO—DCNB in p‐dioxane systems. The strong dependence of the CSRS signal of the DPO radical ions on the content of polar solvent in the high‐concentration region of the binary solvent systems with p‐dioxane suggests a collective behaviour of the polar solvents surrounding an S1 solute for the CT interaction to generate the radical ions. The observed Raman wavenumbers were compared with those of DPO in the S0, S1 and T1 states and qualitative correlation among them is discussed.
Vibrational analysis of poly(L‐lactic acid)
Authors: Kister G. , Cassanas G. , Vert M. , Pauvert B. , Térol A. 
Published: May 2005

AbstractThe Raman and IR spectra of poly(L‐lactic acid) in the amorphous and semicrystalline states were recorded from 3600 to 100 cm−1. Complete vibrational assignments are proposed. In the Raman spectra, the splittings of the vC=O stretching and the δCCO bend are characteristic of the crystalline phase and the presence of the two lines at 923 and 520 cm−1 indicates a 103 helical conformation.
Windowless cell for fourier transform Raman spectra of liquids and aqueous solutions
Authors: Brooker Murray H. , Nielsen Ole Faurskov , Christensen Daniel 
Published: May 2005

AbstractFourier transform (FT) Raman spectra were obtained for water and aqueous solutions in a stainless‐steel, windowless, liquid captive cell of simple design. It was demonstrated that high‐quality Raman spectra in the low‐wavenumber region (down to 100 cm−1) can be obtained from highly colored samples without the presence of interfering bands from the usual sample containers made of glass or plastic. Raman bands at 520 and 232 cm−1 due to the symmetric stretching modes of the Cr‐O vibration of the Cr(H2O) and the Cr‐Cl vibration of the CrCl complexes were observed for very dark samples that are not amenable to conventional Raman techniques. FT‐Raman studies of aqueous Cr(III) solutions can provide valuable information on the slow ligand exchange rates.
X‐ray structure determination and vibrational study of di(diaminophosphoryl)imide
Authors: Hammade Vasilica , Gnado Joseph , Dhamelincourt Paul , Conflant Pierre , Vignacourt Jean Pierre 
Published: May 2005

AbstractDi(diaminophosphoryl)imide (PNH), NH[P(O)(NH2)2]2, has very interesting fireproof properties when linked to cellulosic material. The PNH structure, hitherto unknown, was first established by x‐ray diffraction and was found to be monoclinic (P21/c, a=5.206, b=8.311, c=14.889 Å, β = 92.86°, Z=4). Based on this structure, a normal coordinate analysis was undertaken which has permitted the assignment of most of the observed IR and Raman bands in the spectral range above 1000 cm−1. More particularly, the calculated NH2 stretching wavenumbers are consistent with the different hydrogen bond strengths indicated by x‐ray diffraction measurements. In the spectral range below 1000 cm−1, strong couplings between the NH and the PNH modes prevented a rigorous assignment of the observed bands.
Surface‐enhanced resonance Raman scattering study of the groove binding dye hoechst 33258
Authors: Zimmermann F. , Zimmermann B. , Panitz J.‐C. , Wokaun A. 
Published: May 2005

AbstractThe groove binding dye Hoechst 33258 was investigated both in aqueous solution and in the adsorbed form on silver colloids and island films. Fourier transform Raman, resonance Raman and surface enhanced resonance Raman spectra were used together with the results of a normal coordinate analysis for a comprehensive assignment of the rich vibrational spectrum. Relative band intensities in the SERRS spectra indicate that the molecule is adsorbed with its long axis oriented along the silver surface and with the planes of the benzimidazole rings approximately parallel to the surface. The molecule is bound to the surface as a cation protonated at a piperazine nitrogen atom and is desorbed on complete deprotonation.