Free-ion Yield in the Radiolysis of Dimethylsulfoxide

Dimethylsulfoxide is a dipolar aprotic solvent of high basicity having a large dielectric constant (ε = 48) but very low solvating power for negative ions. The radiation yield of "free ions" in this liquid is in accord with the dielectric constant, G(free ions) = 1.8 ± 0.2, but these "free ions" do not resemble the strongly solvated electrons found in other polar media such as water and aliphatic alcohols. Evidence for this conclusion is based principally on competitive reactions involving a wide range of scavengers in competition with nitrous oxide. The radiation yields of gaseous products from pure liquid dimethylsulfoxide are G(H 2 ) = 0.20 ± 0.01, G(CH 4 ) = 3.3 ± 0.1, and G(C 2 H 6 ) = 0.49 ± 0.03.