bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman and infrared spectra of 2,4,6‐trichlorophenol and 2,4,6‐tribromophenol
Authors: Faniran J. A. , Shurvell H. F. 
Published: May 2005

AbstractRaman spectra of solid 2,4,6‐trichlorophenol and 2,4,6‐tribromophenol (s‐TCP ands‐TBP) have been recorded at 80 and 300 K. Infrared spectra in the region 4000–200 cm−1have also been recorded of the solids and of dilute solutions in CCl4. Vibrational assignments and qualitative descriptions of the normal modes of these compounds are proposed on the basis of substituted benzene molecules withCssymmetry. Some evidence for intermolecular hydrogen bonding has been found in the solid state infrared spectra of both compounds, but they do not appear to self‐associate in CCl4solution.
pH‐induced modification of NAD and NADH solutions detected by Raman spectroscopy
Authors: Barrett T. W. 
Published: May 2005

AbstractAnalysis of the Raman spectra of NAD and NADH indicates that the intensity characteristic of a band at ˜ 1400 cm−1, assigned to the nicotinamide ring vibrations, demonstrates interactive effects correlated with conformational changes of NAD in basic phosphate solutions and NADH in acid phosphate solutions. The Raman lines of these dinucleotides are discussed with respect to the spectra of the individual bases and previous Raman studies of nucleotides. The data reported provide the groundwork for future application of the Raman technique to NAD and NADH reactions.
Second order Raman spectrum of carbon disulphide in the condensed phase
Authors: Umapathy S. , Kesavasamy K. , Krishnamurthy N. 
Published: May 2005

AbstractBelow 162K, carbon disulphide crystallizes in the space group D2h18 with two molecules in the primitive cell. The internal modes v1, v2 and v3 of the isolated CS2 molecule are split due to static and correlation field splittings. Anderson et al. have extensively studied the Raman and infrared spectra of CS2 at 79 K and 18 K and have analysed the internal and external modes with a lattice dynamical calculation of the q = 0 phonons. However, their spectra reveal the presence of extensive second order features accompanying the v1, v2, v3 and 2v1 bands. The present investigation attempts an interpretation of these second order Raman spectra employing Born's theory and the lattice dynamical calculation of phonons at all allowed q points in the Brillouin zone employing the rigid molecule approximation.
The CF3 Rotor: Torsional vibrations for some CF3OX and CF3OOX molecules
Authors: Hammaker R. M. , Fateley W. G. , Manocha Ajit S. , Desmarteau D. D. , Streusand B. J. , Durig J. R. 
Published: May 2005

AbstractThe low frequency Raman spectra of CF3OF (gas, liquid), CF3OCI (liquid), CF3OOH (gas, liquid), CF3OOD (liquid), CF3OOF (gas, liquid) and CF3OOCI (liquid) have been recorded below 300 cm−1. The spectra have been assigned and the CF3 torsional modes were observed for all of these compounds in the liquid state. The assigned frequencies for the liquids and the calculated barriers for the vapor state are: CF3OF, ντ = 144 cm−1, V3 = 4.64 kcal mol−1; CF3OCI, ντ = 122 cm−1, V3 = 4.6 kcal mol−1; CF3OOH, ντ = 155 cm−1, V3 = 6.0 kcal mol−1; CF3OOF, ντ = 78 cm−1, V3 = 2.9 kcal mol−1; and CF3OOCI, ντ = 80 cm−1, V3 = 3.7 kcal mol−1. The assignments are discussed and the barriers are compared to the corresponding quantities in some similar molecules.
Le Spectromètre Raman comme Détecteur Séleitif de la Chromatographie en Phase Liquide
Authors: Chapput André , Roussel Bernard , Montastier Jacques 
Published: May 2005

AbstractThe purpose of this work is to show that it is possible to use microcells in Raman spectroscopy to detect chemical species in various solvents at low concentrations in order to connect a liquid chromatograph with a Raman spectrometer. Several methods are described in static as well as in dynamic processes.
Vibrational dephasing in polar molecular liquids: An application to a fundamental and its overtone in phenyl acetylene
Authors: Baglin Frank Geile 
Published: May 2005

AbstractBased upon the results reported here for phenyl acetylene and the results of other investigators' studies, a working model of phase relaxation in polar molecular liquids is proposed. The model rests upon the established concept of a phase annihilation operator1 and a postulated phase conduction band structure for polar molecular liquids. Three cases are discussed; briefly, they are (I) no effect upon the signal of interest by dilution, (II) narrowing of the signal of interest by dilution, and (III) broadening of the signal of interest by dilution. The latest effect has not been elucidated previously in the literature. Actual examples of each of these cases are discussed. Phenyl acetylene's vcc and 2vcc modes are shown to display Case II behavior. These two modes are found in the Raman spectrum at 2113 cm−1 (vcc) and 4205 cm−1 (2vcc). They have been examined by varying the concentration of this molecule in two dipolar solvents, a quadrupolar solvent and an octopolar solvent. In addition, temperature studies on the neat sample were carried out at 10–30 K intervals for vcc and at 275 K and 90 K for 2vcc. From the results of our investigation, a relaxation mechanism consistent with a quadrupole–quadrupole dephasing type mechanism is postulated for both vcc and 2vcc.
Vibrational spectra and normal coordinate analysis of CF3OF and CF3OCl
Authors: Kuo J. C. , Desmarteau D. D. , Fateley W. G. , Hammaker R. M. , Marsden C. J. , Witt J. D. 
Published: May 2005

AbstractThe IR spectra (1400 cm−1 to 160 cm−1) of the gases at ambient temperature and the Raman spectra (below 1400 cm−1) of the liquids near −196°C are reported for CF3OF and CF3OCl. All fundamentals are assigned under Cs symmetry and the results of a normal coordinate analysis are presented. The assignments of Smardzewski and Fox are adopted with one exception for both CF3OF and CF3OCl: the CF3 rock of A″ symmetry is assigned near 430 cm−1 and the two bands between 200 cm−1 and 300 cm−1 are assigned to an A′ fundamental, involving CF3 rocking and COX bending and a Δν=2 transition in the CF3 torsion. An extra band at 548 cm−1 in the Raman spectrum of liquid CF3 COl near −196°C is assigned to a CF3OCl ⃛Cl2 complex. The values of the force constants d(OX) for CF3OX molecules are suggested to be near those for X2O molecules. More than half the normal modes of A′ symmetry show extensive mixing of symmetry coordinates. In some of these cases the symmetry coordinate for which the normal mode is named is the largest but not the dominant contributor to the potential energy distribution, while in others this symmetry coordinate is not even the largest contributor to the potential energy distribution. No normal modes of A′ symmetry are present in which ν(CO), δs(CF3), δ(COX), or δ(CF3) symmetry coordinates are dominant, and the mode conventionally labeled as v(CO) should be labeled as νs(CF3). For the remaining A′ normal modes and all the A″ normal modes, the symmetry coordinate for which the normal mode is named is dominant in the potential energy distribution.
Vibrational spectra of C2ν deuterium substituted pyridines. 3—pyridine‐3,5‐d2 and pyridine‐3,4,5‐d3
Authors: Dilella Daniel P. 
Published: May 2005

AbstractPyridine‐3,5‐d2 and pyridine‐3,4,5‐d3 have been prepared. Isotopic constitution and label specificity of each of several preparations were verified by mass spectrometry and proton NMR. Liquid phase Raman and both liquid and vapor phase infrared spectra of these molecules are reported. Vibrational assignments consistent with frequency sum and product rule constraints are proposed. The relative rates of base‐catalyzed exchange of hydrogen with deuterium for the ring positions of pyridine‐N‐oxide were estimated during the course of the synthetic work. It is found that the 2 and 6 positions exchange very readily, that the 3 and 5 positions exchange slowly, and that the 4 position exchanges very slowly.
Vibrational spectra of C2ν deuterium substituted pyridines. 4—pyridine‐2,3,5,6‐d4 and pyridine‐d5
Authors: Stidham Howard D. , Dilella Daniel P. 
Published: May 2005

AbstractPyridine‐2,3,5,6,‐d4 has been prepared. The isotopic composition and label specificity of each of three preparations were verified by mass spectroscopy and proton NMR. The liquid phase Raman and the liquid and vapor phase infrared spectra of pyridine‐2,3,5,6‐d4 and pyridine‐d5 at room temperature are reported. The vibrational spectra of these compounds are completely analyzed and a summary of the assignment for all eight C2ν deuterium labeled pyridines is given.
Vibrational spectra of mercury(II) dihydrogen phosphate, mercury(II) phosphate and mercury(I) selenate
Authors: Russell Stephen J. , Tan Kang‐Hai , Taylor Michael J. 
Published: May 2005

AbstractRaman and IR spectra of the crystalline solids Hg2(H2PO4)2, Hg3(PO4)2 and Hg2SeO4 are reported and assigned in terms of vibrational modes of the unit cell. Frequencies v (HgO) and v (HgHg) are located in the ranges 210–280 and 180–190 cm−1, respectively. Inter‐ and intramolecular coupling of HgO modes, and of some ligand vibrations, result in splittings of from 5 to 40 cm−1, which can be related to the crystal and molecular structures.
Vibrational spectra and conformations of (chloromethyl)cyclopropane and epichlorohydrin
Authors: Kalasinsky V. F. , Wurrey C. J. 
Published: May 2005

AbstractThe IR and Raman spectra (4000–50 cm−1) of (chloromethyl)cyclopropane and epichlorohydrin have been recorded in all three physical states. It has been concluded from the spectroscopic data and from variable temperature studies that (chloromethyl)cyclopropane exists as an equilibrium mixture of gauche (95%) and cis (5%) conformers in the liquid state, while only the gauche form persists in the solid phase. The enthalpy difference between these two rotamers was found to be 1.40±0.10 kcal mol−1. Similarly, epichlorohydrin has also been shown to exist as an equilibrium mixture of gauche‐1 (70%), gauche‐2 (21%) and cis (9%) conformers in the liquid state, with only the gauche‐1 form remaining in the solid phase. Enthalpy differences among these conformers were determined to be 1.2±0.2 kcal mol−1 (gauche‐1 vs. cis) and 0.70±0.10 kcal mol−1 (gauche‐1 vs gauche‐2). Apparently steric repulsions between the chlorine atom and β ring‐hydrogens destabilize the cis conformation in each molecule. For each molecule, a vibrational assignment has also been proposed.
Fluorescence‐free resonance Raman spectra of reduced nicotinamide adenine dinucleotide via ultraviolet excitation
Authors: Bowman W. David , Spiro Thomas G. 
Published: May 2005

AbstractExcitation of reduced nicotinamide adenine dinucleotide (NADH) on the high‐energy side (333.6 nm) of its ultraviolet absorption band shifts the Raman scattering away from the fluorescence band and produces a good quality resonance Raman spectrum. It is dominated by the amide I (CO stretch) mode, at 1687 cm−1, but several weaker bands are observed, and are tentatively assigned to amide II and III, and ring modes, consistent with N2H2 and 4‐2H isotope shifts. An identical spectrum is observed for nicotinamide mononucleotide (NMNH), indicating that the adenine and nicotinamide portions of NADH do not interact.
Selective ultraviolet resonance Raman excitation of individual chromophores in nicotinamide adenine dinucleotide
Authors: Rodgers Edward G. , Peticolas Warner L. 
Published: May 2005

AbstractUltraviolet resonance Raman spectra (UVRRS) of reduced nicotinamide adenine dinucleotide (NADH) has been taken with ultraviolet laser excitation wavelengths (λe) of 273 nm, 330 nm and 351.1 nm. These Raman spectra have been compared with the resonance Raman spectra of the model compounds adenosine mononucleotide phosphate (AMP), with λe = 300 nm, and with reduced methyl nicotinamide (MNH), with λe = 351.1 nm, and with the classical Raman spectrum of NADH, with λe = 514.5 nm. The UVRR spectrum of NADH with λe = 273 nm resembles exclusively that of AMP while the UVRR spectra with λe = 330 nm and λe = 351.1 nm show no AMP bands but only those of MNH. The classical Raman spectrum of NADH is shown to be a superposition of bands in the resonance Raman spectra of the two chromophores but includes as well the sugar‐phosphate bands. Thus it is possible selectively to excite a UVRRS of either chromophore independently of the other. This information may prove helpful in developing techniques of UVRRS in studying NADH‐enzyme complexes since only very dilute (˜5×10−4 M) concentrations of NADH are needed for the resonant Raman spectra.
Solid state vibrational spectroscopy. 10—A kinetic study, using Raman spectroscopy, of the solid state thermal decompositions of sodium and potassium dithionate
Authors: Cleaver Kevin D. , Davies J. Eric D. 
Published: May 2005

AbstractThe kinetic behaviour of the solid state thermal decomposition of dithionate to sulphate, M2[S2O6] → M2[SO4], M = Na, K, has been studied by following the temporal decrease in the intensity of the Raman band arising from the vs(SO3) mode of [S2O6]2−. The sodium salt displays first order kinetics, but the kinetic behaviour of the potassium salt could not be accounted for using either the conventional kinetic treatment or the Avrami–Erofeev treatment. The Raman derived data for the sodium salt agree well with previously reported pressure derived data supporting the contention that Raman spectroscopy is a valid technique to use in obtaining solid phase kinetic data.
Raman scattering from alkali graphite intercalation compounds
Authors: Solin S. A. , Caswell N. 
Published: May 2005

AbstractThe stage dependences of the Raman spectra of potassium, rubidium and cesium graphite intercalation compounds are reported. The spectra of each set of compounds are found to be qualitatively and quantitatively consistent with the ‘nearest layer’ model for the carbon intralayer E vibrations of intercalation compounds. To within experimental error the charge exchanged from the intercalant layers to the carbon layers is found to be stage independent and partially localized in type B carbon layers which are contiguous to intercalant layers. The relative Raman cross‐section for scattering from type B and type C (noncontiguous) carbon layers is found to be species independent and is σC/σB = 0.25 ± 0.05.
Resonance Raman spectrum of the transient dimethylsulfide dimer radical cation |(CH3)2S|2+·
Authors: Wilbrandt R. , Jensen N. H. , Pagsberg P. , Sillesen A. H. , Hansen K. B. , Hester R. E. 
Published: May 2005

AbstractThe resonance Raman spectrum of the transient thioether radical cation dimer complex |(CH3)2S|2+·, generated by electron irradiation of an aqueous solution of dimethylsulfide and recorded by optical multichannel detection, is reported. Vibrational bands at 276 cm−1 and 139 cm−1 were detected and are assigned to the stretching mode of the quasi‐three‐electron SS bond and a δ(CSS) deformation mode, respectively.
Low‐frequency vibrations (20–400 cm−1) of some mononucleotides in aqueous solutions
Authors: Nielsen O. Faurskov , Lund P. ‐A. , Praestgaard E. 
Published: May 2005

AbstractLow‐frequency Raman scattering (20–400 cm−1) of aqueous solutions of 5′‐monophosphates of uridine (UMP), cytidine (CMP), guanosine (GMP) and of adenosine (AMP) are studied by construction of a quantity R (ν). The frequencles for intensity maxima below 100 cm−1 depend upon the protonization or the purine and pyrimidine rings, but not upon ionization of the phosphate groups. An assignment to modes very similar to corresponding nucleoside modes is discussed.
Raman active torsion‐libration overtones in crystalline N2H6Cl2 and N2H6Br2
Authors: Ratcliffe C. I. , Sherman W. F. , Wilkinson G. R. 
Published: May 2005

AbstractRaman active torsion‐libration fundamentals and overtones have been observed in crystals of N2H6Cl2 and N2H6Br2. The temperature dependences of these modes have been followed between liquid nitrogen and room temperatures in the case of the chloride. Potential barriers to rotation have been calculated and compared with NMR activation energies to gain insight into the relationship between the two kinds of result. The external barrier for NH3+ reorientation and the internal barrier for N2H62+ have been found to be 3597 and 709 cm−1 respectively for the chloride at 73 K, and 3066 and 676 cm−1 respectively for the bromide at 92 K. The chloride results clearly show that the barriers are slightly temperature dependent. It is concluded that the NMR activation energy for NH3+ reorientation must also have a temperature dependence which is probably of the form Ea = Ea′ ‐ CT. The discrepancies between the two types of results have been tentatively interpreted in terms of small sixfold contributions to the barriers.
Raman spectra of gases: 24—Phenol
Authors: Wilson H. William , Macnamee R. W. , Durig J. R. 
Published: May 2005

AbstractThe medium resolution Raman spectrum of gaseous phenol has been recorded between 4000 and 50 cm−1 using the 5145 Å line of an argon laser. A number of a′ bands have been observed which correspond to previously assigned normal modes, but lines at 1388 and 1285 cm−1, which are not normally observed in the infrared spectrum of the gas, have been assigned as fundamentals. In addition, a strong Raman band at 1007 cm−1 is probably an overtone of an out‐of‐plane vibration at 503 cm−1 in resonance with a nearby a′ fundamental. Two bands at 824 and 810 cm−1 were both found to belong to the symmetric a′ species. Previous assignments have dealt with these two bands as having different symmetries. A reassignment of some of the fundamentals of phenol may be necessary to account for these Raman observations.
Raman spectroscopic study of PCl5‐AlCl3 melts
Authors: Poulsen Finn Willy 
Published: May 2005

AbstractRaman spectra have been recorded from PCl5‐AlCl3 melts containing 30,50,63.7,70,80 and 90 mol% AlCl3, respectively. Raman shifts were identified from the species: PCl5, PCl4,+ AlCl4,− AlCl7− and Al2Cl6. A higher AlxCly−z complex exists in melts with more than 70 mol% AlCl3 and is characterized by Raman shifts of 100, 297 and 395 cm−1. The relative molar scattering intensities of the strongest MCl stretching vibrations of the melt species have been estimated relative to the intensity of the total symmetric stretching vibration of tetrahedral PCl4+.
Spectroscopic and thermodynamic studies of unsaturated nitrile compounds: 2—The infrared and Raman spectra, normal coordinate analysis and values for the ideal gas thermodynamic functions of 3‐methyl‐2‐butenenitrile
Authors: Compton D. A. C. , Murphy W. F. , Mantsch H. H. 
Published: May 2005

AbstractA study of the vibrational spectrum of 3‐methyl‐2‐butenenitrile has been carried out. The infrared spectra above 625 cm−1 of the gaseous, liquid and solid states, and the Raman spectra of the liquid and solid states are reported. An assignment has been made for the observed vibrational frequencies with the aid of a normal coordinate treatment. Estimates were made for the torsional barrier heights and frequencies of the two methyl groups, but only one of the torsional frequencies could be located. Values for the thermodynamic functions of the ideal gas were calculated using the observed spectroscopic data; contributions due to the torsional motions were calculated from the estimated barrier heights.
Configuration‐dependent Raman bands of phospholipid surfaces: 2—Head group and acyl stretching modes in the 800–900 cm−1 region
Authors: Bicknell‐Brown Ellen , Brown Kenneth G. , Person Willis B. 
Published: May 2005

AbstractDeuteration studies, hydration studies, melting studies and model compound studies are utilized to assign and interpret the 800–900 cm−1 region of the Raman spectra of the phospholipids dipalmitoyl phosphatidylcholine and dipalmitoyl phosphatidylethanolamine. Head group Raman bands in this region are shown to be sensitive to hydration and melting. The acyl carbon‐carbon stretches, assigned to Raman bands appearing at 860–890 cm−1, are shown to be sensitive probes of molecular packing order, specifically in the acyl interface region.
Determination of anharmonicity constants from the Raman spectrum of gaseous acetylene
Authors: Finsterhölzl H. , Schrötter H. W. , Strey G. 
Published: May 2005

AbstractFrom an analysis of the photoelectrically recorded Raman band of acetylene at 3950 cm−1, which contains contributions from ν1+ν4 and its hot bands, ν3+ν5 in Fermi resonance with ν2+ν4+2ν5, and the Q‐branch of 2ν2, some anharmonicity constants were determined. In particular x22= −7.4 cm−1 was obtained directly for the first time, other constants are revised due to a more complete consideration of the resonance perturbations. A computer simulation of the ν4 fundamental and the ν1+ν4 combination band shows excellent agreement with the experimental spectra.
Rotational isomers of ethyl dithioacetate and ethyl thionoacetate: A Raman study
Authors: Verma A. L. , Ozaki Y. , Storer A. C. , Carey P. R. 
Published: May 2005

AbstractRaman spectra of ethyl dithioacetate (CH3CS2C2H5) and ethyl thionoacetate (CH3C(S)OC2H5) have been measured as a function of temperature in the liquid phase and in the solid phase at low temperature. For both compounds disappearance of several bands from the liquid spectrum on solidification established the presence of more than one conformer in the liquid phase. Temperature variation studies on band pairs whose components belong to different isomers gave enthalpy differences of 598±48 cal mol−1 and 1072±65 cal mol−1 between the conformers of CH3CS2C2H5 and CH3C(S)OC2H5 respectively. The most probable low‐energy conformer, in both instances, is the s‐cis form with all the heavy atoms contained in a single plane.
Structures of HCI and HBr polymers in nitrogen matrix derived from infrared and Raman data: Comparison with argon matrix
Authors: Perchard J. P. , Maillard D. , Schriver A. , Girardet C. 
Published: May 2005

AbstractThe structures of HCI and HBr polymers trapped in nitrogen matrices are re‐examined at the light of new Raman data. From the comparison with IR vibrational spectra including H/D decoupling experiments, two polymers other than the dimer are identified: an assymetric cyclic trimer in which the three molecules are not equivalent, and a cyclic tetramer in which the molecules are equivalent in pairs. In the case of HCI the trimer is seen to exist with two slightly different forms below 20 K, one of them reversibly disappearing above this temperature. The differences with the results obtained in rare gas matrices are understood as occurring from a strong anisotropic solute‐matrix potential which tends to distort the highly symmetric structure of isolated aggregates. The distorsion is perhaps at the origin of the change in the derivatives of some molecular electrical properties with respect to the intermolecular stretching coordinate from rare gas to nitrogen matrices.
Enhanced Raman spectra of coadsorbed carbon monoxide and hydrogen on small nickel particles
Authors: Krasser W. , Renouprez A. J. 
Published: May 2005

AbstractWe have used vibrational Raman spectroscopy to study the chemisorption of carbon monoxide and of ethylene, and the chemical interactions of coadsorbed carbon monoxide and hydrogen on silica‐supported nickel particles. In each case we observe a strong enhancement of all measured vibrational bands which depends on the excitation wavelength. The maximum enhancement lies always in the excitation wavelength range 5200–4500 Å. The enhancement is of the order 102−104. The complex spectra from coadsorbed CO and H2 indicate the formation of several surface species: adsorbed carbon monoxide, hydrocarbon‐like species, and different oxygen‐containing hydrocarbon compounds. A complete assignment of all vibrational bands is not possible because of the complexity of the Raman spectra.