A study of electron spin resonance hyperfine splitting in alkyl radicals by use of a semiempirical molecular orbital method

Abstract

A very simple method of calculation is outlined which can reproduce to a close approximation, e.s.r. α- and β-hyperfine coupling constants. The existence of a mechanism whereby α-hydrogen atoms gain some unpaired-spin density through an inductive effect is suggested. A value for the McConnell constant is obtained by the present method, and the existence of a constant for the inductive transmission of unpaired-spin density is demonstrated. Both are real constants as far as the present method is concerned, and together account with remarkable accuracy for the observed values of α-hyperfine splittings, when α- and β-unpaired-spin densities, calculated by the present method, are used.