Raman spectra and normal coordinate analysis of thirteen selectively deuterated tetramethylsilanes

The Raman spectra of liquid (CH 3 ) 4‐m Si(CD 3 ) m ( m = 0‐4), (CH 2 D) 4‐n Si(CH 3 ) n and (CHD 2 ) 4‐n Si(CD 3 ) n (n = 0‐3) were recorded from 3200 to 50 cm −1 . Normal coordinate analyses were made using both a unique internal valence force field (IVFF 1) for all 13 isotopomers and 13 slightly modified IVFF 2s for each isotopomer, including torsional modes in each case. Vibrational assignments were made using the potential energy distributions and eigenvectors in addition to the depolarization ratios, the IR spectra and the Teller‐Redlich product rule.