bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman spectroscopic studies of the dipalmitoylphosphatidylcholine/glucagon and the dipalmitoylphosphatidylcholine/cardiolipin/insulin systems
Authors: Mendelsohn Richard , Taraschi Theodore , Van Holten Robert W. 
Published: May 2005

AbstractThe phospholipid hydrocarbon chain conformation has been measured in lipid/protein complexes of dipalmitoylphosphatidylcholine (DPPC)/glucagon and dipalmitoylphosphatidylcholine/cardiolipin/insulin using the conformation‐sensitive CH stretching region of the Raman spectrum as a probe. In the DPPC/glucagon complex, which models hydrophobic interactions between (membrane) proteins and phospholipids, the Raman data show that the lateral interactions between phospholipid hydrocarbon chains have been greatly disrupted in the complex. The primary effect of the protein appears to be to induce a disordering of the phospholipid. The gel–liquid crystal phase transition of DPPC is reduced in temperature and is rendered less cooperative. In the DPPC/cardiolipin/insulin complex, which models the electrostatic interaction between peripheral membrane proteins and phospholipids, the primary effect of complexation is to rigidify and order the hydrocarbon chains of the phospholipids. The main interaction of the protein occurs with the cardiolipin and results in the neutralization of the excess charge. The ternary complex undergoes a broad phase separation not present in the binary phospholipid mixture.
High frequency vibrational modes of poly(dA) · poly(dT) and poly(dAT) · poly(dAT)
Authors: Baret J. F. , Carbone G. P. , Sturm J. 
Published: May 2005

AbstractThe Raman and infrared spectra of poly(dA) · poly(dT) and poly(dAT) · poly(dAT) have been recorded. Normal coordinate analyses have been performed for these two polymers to obtain the fundamental modes. We use a valence force field deduced from literature values and from a refinement of a diethyl phosphate potential. Non‐bonded interactions are not included. Extensive descriptions of each mode are given allowing qualitative understanding of some of the spectral difference found between the two polymers.
The Raman and infrared spectra of the dicyanoiodate (I) ion
Authors: Chadwick B. M. , Long D. A. , Qureshi S. U. 
Published: May 2005

AbstractThe interaction of iodine cyanide and cyanide in aqueous solution has been reinvestigated and it has been confirmed that a complex cyanide ion, the dicyanoiodate(I) ion [I(CN)2]− is formed. This ion has been isolated in the solid state for the first time, as its tetraphenylarsonium, tetraphenylphosphonium and caesium salts. Infrared and Raman spectroscopic studies of these salts are reported. These spectra are fully consistent with a linear centrosymmetric (D∞h) structure for the [I(CN)2]−ion. Assignments are made for six of the seven fundamentals of the [I(CN)2]−ion in the caesium salt.
Etude Structurale du Tétrachloroaluminate de Sodium: Comparaison des Spectres de Diffusion Raman de la Famille des MAlCl4 (M = Li, Na, K, Rb, Cs, NO, NH4) à l'Etat Solide
Authors: Wallart F. , Lorriaux‐Rubbens A. , Mairesse G. , Barbier P. , Wignacourt J. P. 
Published: May 2005

AbstractThe crystal structure of NaAlCl4 (a = 10.322(3) Å, b = 9.886(3) Å, c = 6.167(2) Å, Z = 4, space group P212121) was refined to final R and Rω values of 0.025 and 0.039 respectively, for 1240 reflections with I>2σ(I). The thermal motion of the AlCl4− anion is in keeping with the TLS rigid‐body analysis. Crystal and polycrystalline samples of this compound were studied by Raman scattering and an assignment of the observed bands was proposed. The Raman spectrum was compared with those of all members of alkaline (Li, Na, K, Rb, Cs) and pseudo‐alkaline (NH, NO+) tetrachloroaluminates in the solid state.
Raman study of the thermal decomposition of dioxygenyl hexafluoroarsenate, O AsF
Authors: Griffiths J. E. , Distefano Doreen , Sunder W. A. 
Published: May 2005

AbstractThe apparent vapor transport of O2AsF6 by sublimation at modest temperatures is shown to proceed via the reversible reaction, OAsF⇄O2F˙ + AsF5, involving a free radical mechanism. This reaction path is in marked contrast to the vapor transport of O2PtF6, O2RuF6 and O2RhF6 species which proceed via dissociation and recombination with charge transfer, OPtF⇄O2 + PtF6.
Raman scattering of benzene and deuterated benzene chemisorbed on silica‐supported nickel
Authors: Krasser W. , Ervens H. , Fadini A. , Renouprez A. J. 
Published: May 2005

AbstractThe Raman spectrum of chemisorbed benzene and deuterated benzene has been measured in the frequency range of 200–3400 cm−1 in backscattering geometry. In order to suppress the strong second‐order light‐scattering spectrum of glass, a difference Raman scattering cell has been developed. The vibrtational bands are shifted only slightly compared with liquid benzene. Additional bands are found, which are symmetry forbidden in free benzene. These bands result from symmetry lowering produced by the site symmetry of the surface. Compared with the Raman spectrum of liquid benzene, the vibrational bands of chemisorbed benzene are strongly enhanced.
Raman spectroscopic study of glassy aqueous zinc halide solutions
Authors: Kanno H. , Hiraishi J. 
Published: May 2005

AbstractRaman spectra of aqueous zinc halide solutions are obtained in both liquid and glassy states. It is shown that the detection and characterization of weak low frequency Raman bands in aqueous solutions is much easier in the Raman spectrum for the glassy state than for the liquid state. Comparison of the spectra shows that the tetrahedral ZnX ions are the most stable ionic entities in the glassy state.
Vibrational spectra and conformations of vinyloxirane
Authors: Kalasinsky V. F. , Pechsiri S. 
Published: May 2005

AbstractThe infrared spectra of gaseous and solid vinyloxirane have been recorded, while Raman spectra of all three physical states have been obtained. The vibrational data for the liquid and vapor phases are consistent with the presence of three conformations, the s‐trans and two nonequivalent gauche forms. The energy separations between the most stable s‐trans and each of the other confromers have been determined for the liquid state to be 1.1 ± 0.2 and 0.8 ± 0.2 kcal mol−1 by measuring the temperature dependence of sets of Raman lines. A complete vibrational assignment is proposed for the s‐trans conformer, and the identities of the less stable conformers are discussed in terms of previous studies of related molecules.
A Kinetic isotope effect in purinic 8‐CH exchange of guanine nucleotides: Measurement by Raman spectroscopy
Authors: Thomas G. J. , Lane M. J. 
Published: May 2005

AbstractRates of deuterium exchange of the 8‐CH groups of 5′‐rGMP and cGMP in D2O solutions (KH) are compared with rates of protium exchange of the 8‐CD groups of the same compounds in H2O solutions (KD). The ratio of the two rate constants (kH/kD) defines an isotope effect which is a combination of primary kinetic and solvent isotope effects, the former predominating. The net isotope effect was measured by Raman spectrophotometry over the temperature range 30–80°C. The Arrhenius activation energies (Ea) and pre‐exponential frequency factors (A) were also determined. The average values of kH/kD are 1.82 ± 0.15 for 5′‐rGMP and 1.43 ± 0.06 for cGMP. The relatively small kinetic isotope effects are indicative typically of an unsymmetrical transition state. The ratio E/E is unity in both compounds, indicating an early or reactant‐like transition state. The present data are consistent with, and extend the range of, the Bell–Goodall curve relating log (kH/kD) to ΔpK of the two acid–base systems involved in the proton transfer during the rate‐determining step.
Carbon–hydrogen stretching and bending vibrations in the Raman spectra of poly (methylmethacrylate)
Authors: Dirlikov Stoil , Koenig Jack L. 
Published: May 2005

AbstractThe Raman spectra of three deuferated poly(methylmethacrylate) derivatives, —(CH2C(CD3)COOCD3)n, —(CD2C(CH3)COOCD3)n and —(CD2C(CD3)COOCH3)n, are measured and the assignment of the CH stretching and bending vibrations of the methylene, α‐methyl and ester methyl groups of PMMA is made.
Resonance Raman spectroscopy of heme proteins with intensified vidicon detectors: Studies of low frequency modes and excitation profiles in cytochrome c and hemoglobin
Authors: Yu Nai‐Teng , Srivastava R. B. 
Published: May 2005

AbstractWe have designed and assembled a sensitive vidicon Raman spectrometer which is shown to be well suited for the studies of heme proteins in both Soret (near‐ultraviolet) and Q (visible) band regions. This system, employing a dry ice‐cooled silicon intensified target (SIT) detector and an additive dispersion double monochromator (two 600 g mm−1 gratings blazed at 400 nm), has excellent stray light rejection and optimum bandpass and resolution (5–12 cm−1) for biological applications. It is demonstrated that a 600 cm−1 wide section of the low frequency Raman spectrum of ferrocytochrome c excited at 413.1 nm (70 mW) can be obtained in 30 ms, which is ˜ 2×104 times faster than that required by the conventional scanning techniques. Our multichannel Raman system has an enhanced detection capability which enables us to identify at least 41 weak Raman lines below 850 cm−1 in the spectrum of ferrocytochrome c. Using the SIT detection system, the Raman excitation profile of a depolarized line at 750 cm−1 in Fe(II) cytochrome c has been constructed and compared with that reported for Ni etioporphyrin. Instead of strong 0–0 Raman intensity, the cytochrome c profile exhibits weaker 0–0 intensity, indicative of the absence of the Jahn‐Teller effect. It is further demonstrated that the Soret‐excited Raman spectrum of oxyhemoglobin can be readily obtained without photodissociation.
Orientation des Phases par Etirage dans le Polyéthylène: Etude par Effet Raman
Authors: Luu Dang Vinh , Cambon Louis , Lafont Robert 
Published: May 2005

AbstractResearch on the polarization of bending vibrations of CH2 makes it possible to deduce the orientation of the different phases of polyethylene. When the sample is stretched, the orthorhombic monocrystalline phase becomes parallel to the stretching axis but the other two phases take a more or less perpendicular direction.
Raman spectra of molten SbCl3/AlCl3mixtures
Authors: Huglen R. , Mamantov G. , Begun G. M. , Smith G. P. 
Published: May 2005

AbstractRaman spectra were obtained for nine molten mixtures of SbCl3and AlCl3, as well as for the pure components. Also three molten mixtures of AlCl3/NaCl/SbCl3were studied. Molten AlCl3contains molecular Al2Cl6(D2h) while molten SbCl3contains pyramidal (C3v) molecules aligned head to tail. The Raman spectra showed the presence of Al2Cl6molecules in molten SbCl3/AlCl3mixtures containing 40 mol% or more AlCl3but gave no evidence for the formation of SbCl2+and AlCl4−. However, SbCl3is structurally modified by the addition of AlCl3as seen from the shift of the highest SbCl stretching frequency. There is also spectral evidence that points to the formation of polymers that are different from those in pure SbCl3, and it cannot be ruled out that there may be a chloride‐deficient antimony species in the AlCl3‐rich mixtures. The molecular nature of the observed modifications in these mixtures cannot be deduced solely on the basis of the recorded spectra.
Resonance Raman spectra of D and 15N isotopes of methyl orange in aqueous solutions
Authors: Machida Katsunosuke , Lee Hohi , Kuwae Akio 
Published: May 2005

AbstractResonance Raman spectra of methyl orange and its ring‐deuterated and azo‐15N‐substituted derivatives have been recorded in neutral aqueous solution and in solutions in 0.1 M hydrochloric and deuteriochloric acids. Band assignments have been given by referring to the isotope shifts, and on that basis the structures of the base and the acid forms of the dye molecule in the lowest electronic excited state are discussed.
Raman and infrared spectra and structure of some caesium monohalocyanoiodate (I) salts, Cs[XICN] (XCl, Br or I)
Authors: Chadwick B. M. , Fawcett V. , Long D. A. , Qureshi S. U. 
Published: May 2005

AbstractThe [I2CN]− ion, previously only known in aqueous solution, has been isolated as its caesium salt; and the previously unknown [BrICN]− ions [ClICN]− have been isolated as their caesium salts. The Raman and IR vibrational spectra of these three caesium salts have been investigated in detail and indicate that the halide ions coordinate to the I atom of ICN to form linear (C∞ν) [X—I—CN]− ions (X=I, Br or Cl), contained in a centrosymmetric unit cell. This C∞ν structure is supported by a normal coordinate analysis for the [IICN]− ion.
Vibrational spectra and structure of cyclopentylamine
Authors: Kalasinsky V. F. , Little T. S. 
Published: May 2005

AbstractThe Raman spectra of gaseous, liquid and solid cyclopentylamine and the infrared spectra of the gaseous and solid phases have been recorded. Raman depolarization ratios and infrared band contours in the gas phase indicate that cyclopentylamine exists primarily with a gauche orientation of the —NH2 group, and the torsional fundamental for this conformer has been observed at 232 cm−1. In the solid state the temperature characteristics in certain spectral regions are consistent with the existence of two low temperature phases, and the higher temperature phase appears to exist over a range of approximately only 7°C. A complete vibrational assignment is proposed, and the structural features of cyclopentylamine are discussed.
Low frequency vibrations (20–400 cm−1) of some mononucleosides in aqueous solution
Authors: Nielsen O. Faurskov , Lund P.‐A. , Praestgaard E. 
Published: May 2005

AbstractLow frequency Raman scattering (20–400 cm−1) of aqueous solutions of uridine, cytidine, guanosine and adenosine are studied by the recently described construction of a quantity R(ν). Bands with intensity maximum at frequencies below 100 cm−1 are assigned to specific protonized forms. An assignment of these bands to nucoleoside modes is preliminarily discussed.
Laser excited Raman spectroscopy of biomolecules. 13—conformational study of α‐chymotrypsin and trypsin
Authors: Chen Michael C. , Lord R. C. 
Published: May 2005

AbstractThe Raman spectra of bovine pancreatic α‐chymotrypsin and trypsin were determined from 7% aqueous solutions and lyophilized solids containing residual sulfate ion. A large amount of β‐pleated‐sheet structure is present in both molecules, as shown by the contour of the amide III region, but trypsin contains substantially more α‐helical conformation than does chymotrypsin. There is evidence of some change in structure of both molecules in solution as compared with the solids. The tyrosines are all or nearly all weakly hydrogen bonded in both enzymes, and the binding of sulfate ion is also weak in the lyophilized solids.
Solid state vibrational spectroscopy. 8—A thermochemical and vibrational spectroscopic study of the solid state thermal decompositions of alkali metal peroxydisulphates
Authors: Cleaver Kevin D. , Davies J. Eric D. 
Published: May 2005

AbstractThe solid state thermal decompositions of the alkali metal peroxydisulphates M2[S2O8], M = Na, K, Rb, Cs, have been studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), in situ high temperature Raman spectroscopic studies, and by recording the infrared and Raman spectra of the products formed when the salts are heated to various temperatures. In addition to detecting the exotherm associated with the decomposition of peroxydisulphate to pyrosulphate and the endotherm associated with the fusion of pyrosulphate, the DSC study detected previously unreported solid state phase changes of Cs2[S2O8] and K2[S2O7]. These phase changes are also detectable using Raman spectroscopy. The TGA study indicates the formation of an intermediate in the decomposition of pyrosulphate to sulphate, but it is not possible to determine its stoichiometry from the TGA study.
Raman effect: History of the discovery
Authors: Krishnan R. S. , Shankar R. K. 
Published: May 2005

AbstractThe paper gives a historical account of the discovery of the Raman Effect, starting from Raman's voyage to Europe through the Mediterranean Sea in the summer of 1921 to the observation of modified lines in benzene when illuminated by the 435.8 nm radiations of mercury, through a direct vision spectroscope, on 28 February 1928. The important contributions of Raman and his students during the period which form the progressive stages in the road to discovery have been briefly touched upon. The work of the French group, the Russian group and the theoretical work of Smekal are narrated in sequence.
Polarization techniques in coherent Raman spectroscopy
Authors: Levenson Marc D. 
Published: May 2005

AbstractThe advantages of performing coherent Raman spectroscopy with definite input and output polarizations are reviewed. Methods are described for evaluating Raman susceptibility tensor elements, depolarization ratios and nonresonant contributions to the third order nonlinear susceptibility. A systematic development of the signal‐to‐noise ratio reveals the advantages of incomlete suppression of the nonresonant background signal. Results obtained using coherent Stokes and anti‐Stokes Raman spectroscopy, the Raman‐induced Kerr effect and four‐wave mixing are also reviewed with emphasis on liquids and solids.
Interaction of optical phonons with 4f electrons in CecNd1–cF3
Authors: Leiteritz K. , Schaack G. 
Published: May 2005

AbstractUsing Raman spectroscopy we have studied some effects of the 4f electron–phonon (magnetoelastic) coupling in CecNd1–cF3 (0 ≤c≤1). This coupling manifests itself in the splitting of some twofold degenerate phonons in a magnetic field, accompanied by a reduction in linewidth, and in a zero‐field shift of phonon frequencies all depending on c. We have also studied the low lying (electronic) crystal field states of Nd3+(4I9/2) in NdF3 and determined the eigenfunctions which have been used for a theoretical interpretation of the magnetoelastic effects in NdF3.
Vibrational spectra and structure of organophosphorous compounds. 20—infrared and raman spectra, vibrational assignment and normal coordinate calculations of methyldifluorophosphine
Authors: Durig J. R. , Stanley A. E. , Jalilian M. R. 
Published: May 2005

AbstractThe Raman spectra of gaseous, liquid and solid CH3PF2 and the infrared spectra of the gas and solid have been recorded (3200–20 cm−1). The assignment of the 15 fundamentals is given and discussed and is based on the gas phase infrared band contours, depolarization values and group frequencies. A normal coordinate calculation was carried out by utilizing a modified valence force field to calculate the frequencies and the potential energy distributions. Extensive mixing was found between the PF2 stretching and CH3 rocking modes. The methyl torsion was observed at 192 cm−1 in the far‐infrared spectrum of the gas and from this frequency a three‐fold barrier to internal rotation of 1.74 kcal mol−1 was calculated. This value is compared to similar quantities in several other group VA compounds and the observed trends are consistent with those for the corresponding group IVA compounds.
Microprocessors: Applications to Raman and Brillouin spectroscopy
Authors: Rowell N. L. , Lockwood D. J. , Grant P. 
Published: May 2005

AbstractAutomation techniques based upon the latest microprocessor computer technology are described in general terms for applications in light scattering spectroscopy. Two practical systems are described in detail. The first system operates a Raman spectrometer and handles the data collection automatically, storing the spectrum in digital form on disc and providing visual displays simultaneously. The second controls the alignment and scanning of a multi‐pass Fabry‐Perot spectrometer as well as data acquisition. Finally, prospects for future systems are reviewed.
Oblique phonons in uniaxial molecular crystals: Raman spectra of s‐trioxane
Authors: Kubinyi M. , Castellucci E. 
Published: May 2005

AbstractUsing Raman scattering the angular dispersion of extraordinary phonons in s‐trioxane, a uniaxial crystal of trigonal structure, has been measured. It has been found that the transitions are of the type TO → LO or LO → TO so that the anisotropic short‐range forces predominate over the long range electrostatic ones. The LO–TO splittings are of the order of 10 cm−1 or less as expected for molecular crystals. For phonon propagation direction along the optic axis extraordinary and ordinary phonons of E species coincide.
Raman and infrared studies of the hydrogen halide crystals
Authors: Anderson A. , Torrie B. H. , Tse W. S. 
Published: May 2005

AbstractRaman and infrared spectra of polycrystalline samples of HCl, HBr, HI, HF and their deuterated analogues are briefly reviewed and correlated with crystal structures and molecular properties. A simple force constant model is used to describe the vibrations of these crystals in their low temperature ordered phase and to obtain estimates of their hydrogen bond strenghts.
Raman scattering by magnetic excitations in disordered FeF2
Authors: Rezende S. M. , de Araujo Cid B. , Montarroyos E. 
Published: May 2005

AbstractInelastic scattering of light has been used to study the magnetic excitations in antiferromagnetic FeF2 crystals disordered in two ways. In the first the magnetic dilute system Fe1–xZnxF2 is investigated as a function of the concentration x and temperature T, with x varying from zero nearly up to the percolation limit xp = 0.76. The other is the mixed system Fe1–xMnxF2 in the limit of small Mn impurity concentrations. In this case an anomalously large scattering by the impurity associated local modes is observed. The behaviour of the excitations in both magnetic systems is explained satisfactorily by simple theoretical models.
Theory for continuum resonance Raman scattering in diatomics using irreducible spherical tensors
Authors: Baierl P. , Kiefer W. 
Published: May 2005

AbstractA theory is presented which describes resonance Raman scattering via continuum electronic states of diatomic molecules. It is applied to the dissociative continuum of the bounded B(3Πo+u)‐state and the continuum of the repulsive 1Π1u state of the halogen molecules. Using spherical tensors and Wigner 3‐j symbols, closed forms for the resonance Raman intensities for different polarizations are given, which allow first principle calculations for molecules for which the vibrational wavefunctions of ground and electronic excited states as well as the oscillator strengths are known from absorption of fluorescence data.
The second order Raman spectrum of liquid tetrachloroethylene
Authors: Schmid W. J. , Schrötter H. W. 
Published: May 2005

AbstractThe Raman spectrum of liquid tetrachloroethylene in a capillary cell of 20 m length was recorded and about 20 new second order Raman lines were detected in addition to the previously known ones. Using a rectangular cell the depolarization ratios of many of the second order lines were determined and an assignment is given.