Abstract EPR techniques, including spectral double integration, were utilized to measure the equilibrium contants in dimethoxyethane at 195 K for electron transfer between perdeuteriated p-xylene and xylene, α-d 3-p-xylene and α, α′-d 6-p-xylene. The results, coupled with the law of Hess, yield all the relative solution electron affinities (EA). It was found that methyl deuteriation lowers the solution EA by 160 J l mol− 1 per deuterium, ...