SCF Calculations of Spin-Density Distributions in Heteroatom Radicals

Unpaired spin densities for a series of prototype heteroatom radicals (p-benzosemiquinone, o-benzosemiquinone, pyrogallolsemiquinone, and 2,5-dihydroxy-p-benzosemiquinone) are calculated using McLachlan's SCF theory with variation of MO parameters. Agreement with ESR hyperfine splittings is considerably improved relative to that obtained by means of Hückel MO theory.