Infrared Absorption Spectra of Tetramethyl Compounds

High-pressure study of tetramethylsilane by Raman spectroscopy

“…[1][2][3] Because of its highly symmetrical character, the normal coordinate analysis of the skeletal vibrations of the molecule of TMS has been reported in a number of papers. [4][5][6][7] After that, an electron diffraction measurement, augmented with ab initio quantum calculations, 8 answered the need for accurate and detailed information on the most fundamental molecules containing silicon, assuredly for TMS. Current interest in hydrogen-rich compounds comes from the attempt to achieve lower pressure superconductivity in these compounds because hydrogen could have already been compressed (chemically precompressed) by other elements in these systems.…”

Isotope Effect Studies on Elimination Reactions: Iii. Nitrogen Isotope Effects in the E2 Reaction of Ethyltrimethyl-Ammonium and 2-Phenylethyltrimethylammonium Ions

“…In contrast t o the very low sulphur isotope effect found by Saunders (20) for the sulphonium salt, an effect of 0.9% is found for the reaction of the corresponding ammonium salt. This value is a little less than one-third the theoretical maximum effect of 3.2% calculated by the method of Bigeleisen and Wolfsberg (reference 19, equation 11.30) using for the C-N+ bond a value of 5.50X105 dynes cm-I for the diagonal force constant (30) and 955 cm-I for the stretching frequency (31). I t is also only about one-half the isotope effect found in the E2 reaction of ethyltrimethylammonium ion (Table 11).…”

Collisional ionization of a highly excited neon atom by vibrational deexcitation of tetramethylsilane and neopentane molecules

“…(3) shows that modes with higher frequencies do not contribute significantly to the cross section. Tetramethylsilane and neopentane have seven infrared-active modes, ~1 3 -~1 9 [12,15,16], but the first four modes, ~13-vI.5, are estimated to have negligible contributions because their wave numbers are all higher than 1200 cm-I. The wave numbers of the vI7-vl9 bands for TMS and NP have been reported by Young et al [12], but the dp/dQ, values available in the literature are only those for the v,, and uI8 bands of TMS [17].…”