A DENSITY-FUNCTIONAL STUDY OF THE HYPERFINE PROPERTIES OF SULFUR-CONTAINING RADICALS AND RADICAL IONS

Geometries, electron affinities and isotropic hyperfine coupling const ants are presented for a set of sulfur oxide radical anions, SOx- (x = 2-4), and the neutral SH and HSO3 radicals. The data reported are com puted at the B3LYP and QCISD levels, using a large set of extended and /or decontracted basis sets. The geometries and electron affinities ar e in close agreement with previously calculated values. There is some variation in the hyperfine structures at various levels of theory. It is concluded that none of the approaches employed is sufficient to ful ly describe the distribution of unpaired spin for all systems investig ated, and that further work is necessary before an approach is availab le that can accurately account for the reactivity and properties of th ese species. The computed sulfur and oxygen hyperfine coupling constan ts are at best within 25% of experimental data.