Theoretical characterization of the HSOH,H2SO and H2OS isomers

The HSOH, H₂SO and H₂OS isomers have been investigated employing the CCSD(T) methodology and the cc-pV(X + d)Z X = 3,4,5,6 basis sets. The anharmonic force fields have been calculated to predict the fundamental vibrational frequencies, rotational constants, vibration–rotation corrections, anharmonic corrections to zero-point energies, and structural parameters. In addition to this, a spectroscopic characterization of the deuterated isomers D₂SO and D₂OS was performed. At the CCSD(T)/CBS limit and including corrections for scalar relativistic, spin orbit and core-valence correlation effects, the estimated enthalpies of formation are ?28.1 ± 1, ?12.3 ± 1, and 10.1 ± 1 kcal/mol for HSOH, H₂SO and H₂OS, respectively. Finally, we discuss the problems faced during the extrapolation to the CBS limit of the properties investigated.