Computational study of the mono- and dianions of SO2, SO3, SO4, S2O3, S2O4, S2O6, and S2O8

DFT theory (B3LYP/6-311+G(2d)//B3LYP/6-31+G(d)) has been used to characterize sulfoxy anions and dianions as large as S2O82-, while post-HF theory ([QCISD(T)/6-31+G(2df)]/MP2/6-31+G(d)) has been used for systems as large as S2O32-. Adiabatic and vertical ionization potentials have been computed to assess the gas-phase stability of the dianions. Three dianions (S2O62-, S2O82-, and SO42-. 4H(2)O) are predicted to have positive vertical ionization energies. S2O62- is predicted to have a negative (exothermic) adiabatic ionization potential; however, a large predicted geometry change between the dianion and monoanion rationalizes the measurable experimental lifetime of the dianion in the gas phase. Isotropic hyperfine coupling constants for S-33 have been calculated for the sulfoxy monoanions and compared with experiment.