ABINITIO STUDY OF THE (SO2)2+ION MOLECULE COMPLEX

The complexes formed between neutral SO2 and the SO2+ cation have been studied by ab initio calculations. The lowest energy structure is characterized by a two-center three-electron interaction and a rather short intermolecular O-O distance of about 2 Å. The binding energy is 27.0 kcal/mol at the highest level ([PMPn/6-31+G*]//6-31G*), which can be compared to a recent gas phase determination of 21.8 ± 0.8 kcal/mol at 475 K. Determination of the binding energy of a structure bound by an ion-dipole interaction is complicated due to symmetry breaking in the SO2+ radical cation. The approximate binding by this interaction is 16 kcal/mol. The properties of SO2 and the first two electronic states of SO2+ are compared. © 1990 American Chemical Society.