Substituent effects on thermochemical properties of C-, N-, O-, and S-centered radicals. Physical interpretation of substituent effects

Substituent effects on ionization potentials and electron affinities of C-, N-, O-, and S-centered radicals were analyzed in terms of additive operati onal atomic contributions. The physical factors governing the estimated ope rational atomic parameters were analyzed in terms of fundamental atomic pro perties. The operational atomic parameters were found to depend on the elec tronegativity and the covalent radius which for each type of radical is des cribed quantitatively by two separate sets of equations for ionization pote ntials and electron affinities, respectively.