Rotational structure of the five lowest frequency fundamental vibrational states of dimethylsulfoxide

We report on the successful extended analysis of the high-frequency (200–700 GHz) part of the gas phase (sub)mm-wave spectra of dimethylsulfoxide (DMSO). The spectrum was recorded at 100 kHz resolution using a solid state subTHz spectrometer. The five lowest energy fundamental vibrational states of DMSO with frequencies below 400 cm−1 were observed as sidebands along with the main 0 ← 0 band. Neglecting the internal rotation of methyls, our rotational Hamiltonian reproduced the spectrum to the subMHz accuracy. We have found that the asymmetric bending state ν 23 is the only low frequency fundamental vibrational state with the “anomalous” rotational structure uncovered in Cuisset et al. [1]. dmsomw 2013-09-04 15:03 © 2013 Elsevier