Yoshiki Ogawa

Importance of an intramolecular 1,5-CH…O interaction and intermolecular interactions as factors determining conformational equilibria in 1,2-dimethoxyethane: a matrix-isolation infrared spectroscopic study

Abstract The infrared spectra of 1,2-dimethoxyethane in an argon matrix have been measured. Spectral analysis based on ab initio molecular orbital calculations and normal coordinate treatment has shown that the conformers TTT, TGT and TGG′ (T: trans, G: gauche) coexist in the matrix, the TTT being the most stable. The experimental conformational stability agrees with the theoretical prediction from the molecular orbital calculations. The stability of the TGG′ conformer is explained by an intramolecular 1,5-CH…O interaction. The stabilization of the TGT conformer in the liquid and crystalline states is shown to be caused by possible intermolecular interactions.

Tables of Molecular Vibrational Frequencies. Part 10

Fundamental vibrational frequencies of 94 molecular forms of 23 polyatomic chain molecules of halogenoalkanes and halogenoalkyl ethers consisting of the CH3, CH2, O, F, Cl, Br, and I groups are given as an extension of tables of molecular vibrational frequencies published in the NSRDS‐NBS publication series and in this journal. On preparing the tables in this part, an approach, similar to that in Part 9 but different from that in earlier parts, based on the calculations of normal vibration frequencies was adopted. A set of force constants which explains all the frequencies of small molecules for which the assignments had been established was obtained and then the frequencies of larger molecules were calculated and compared with the frequencies observed in the infrared and Raman spectra. The tables provide a convenient source of information for those who require vibrational energy levels and related properties in molecular spectroscopy, thermodynamics, analytical chemistry, and other fields of physics and ...

Far-i.r. reflection spectrum and normal vibrations of red mercuric iodide crystal

Abstract The vibrational frequencies of the transverse and longitudinal modes of red mercuric iodide, HgI 2 , were obtained from the polarized far-i.r. reflection spectrum. The values of effective ionic charges of I and Hg atoms were determined to be −0.37 5 e and 0.75 e , respectively, on the basis of the TO—LO splittings. The normal coordinate analysis near the center of Brillouin zone was performed for the point charge model of the crystal and a good agreement between the observed and calculated frequencies was obtained.