Millimeterwave and submillimeterwave spectra of sulfur dioxide 32S16O18O and 32S18O2, centrifugal distortion analysis and equilibrium structure

Abstract

The rotational spectra of 32S16O18O and 32S18O2 have been recorded from 150 GHz to 1.52 THz. Accurate rotational parameters have been determined for the ground state and the vibrational states v2 = 1 and v1 = 1, as well as v2 = 2 for 32S18O2. The quality of the fits using the A- or S-type reductions for the Watson Hamiltonian is discussed. An experimental equilibrium structure is determined for the 32S16O18O isotopologue of Cs symmetry. The centrifugal distortion constants are calculated from an anharmonic force field and are found in good agreement with the experimental values.