Infrared and Raman spectra and normal co-ordinate analysis of dimethyl sulfoxide and dimethyl sulfoxide-d6

The infrared spectra from 250–4000 cm−1 and the Raman spectra of dimethyl sulfoxide and dimethyl sulfoxide-d6 have been determined. From these data a complete assignment-excepting only the torsional modes-has been made and substantiated by a normal co-ordinate analysis carried out using a digital computer. Valence force constants for the C2SO skeleton were calculated and compared with those of the thionyl halides. Potential energy distributions of symmetry co-ordinates among the normal co-ordinates have also been calculated.