J. R. Durig

Vibrational spectra of monothiocarbamates-II. IR and Raman spectra, vibrational assignment, conformational analysis and ab initio calculations of S-methyl-N, N-dimethylthiocarbamate

Abstract The IR (3200–30 cm−1) spectra have been recorded for S-methyl-N,N-dimefhylthiocarbamate, (CH3)2NC(O)SCH3, and its isotopomers, S-d3, N-d6 and N-d9, for the gas and liquid. Additionally, the Raman spectra (3200–10 cm−1) for the solid and liquid, with qualitative depolarization ratios, have been obtained for all the isotopes. These data are interpreted on the basis that the s-cis conformer (the S-methyl group oriented eis to the carbonyl group) with Cs symmetry is the only form existing in all three phases for this molecule. A complete vibrational assignment proposed for the -d0 molecule is facilitated by the availability of spectral data for five different isotopomers. A normal coordinate analysis has been carried out utilizing ab initio calculations with the 3–21G* basis set. The potential energy distributions and ab initio calculated frequencies have allowed a clarification of some of the corresponding results obtained from experiment. Structural optimizations and potential surface scan have also been carried out by ab initio calculations with the 3–21G* basis set. These results are compared with some previous studies on this molecule as well as on similar molecules.

Fourier transform raman spectroscopy of synthetic and biological calcium phosphates

AbstractFourier-transform (FT) Raman spectroscopy was used to characterize the organic and mineral components of biological and synthetic calcium phosphate minerals. Raman spectroscopy provides information on biological minerals that is complimentary to more widely used infrared methodologies as some infrared-inactive vibrational modes are Raman-active. The application of FT-Raman technology has, for the first time, enabled the problems of high sample fluorescence and low signal-to-noise that are inherent in calcified tissues to be overcome. Raman spectra of calcium phosphates are dominated by a very strong band near 960 cm−1 that arises from the symmetric stretching mode

Analysis of torsional spectra of molecules with two internal C3v rotors. II. Far infrared and low frequency Raman spectra of dimethylether isotopes

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Low‐Frequency Modes in Molecular Crystals. VI. Methyl Torsions and Barriers to Internal Rotation of C(CH3)4, C(CD3)4, Si(CH3)4, Ge(CH3)4, and Sn(CH3)4

of the phosphate group. Other Raman-active phosphate vibrational bands are seen at approximately 1075

Microwave Spectrum of cis‐Glyoxal

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The determination of the potential function governing the low frequency bending mode of disiloxane

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