Influence of the Dielectric Constant on the Yield of Free Ions Produced during Radiolysis of a Liquid

Abstract

The γ-radiation-induced conductance of liquid diethyl ether is consistent with the previously developed theory. The following values of G(free ion) were determined by the conductance method: n-hexane, 0.10; cyclohexane, 0.10; p-dioxane, 0.05; n-butyl ether, 0.11; ethyl ether, 0.19; n-butyl bromide, 0.27; n-butyl chloride, 0.39. Values of G(free ion) in other systems were obtained from spectroscopic and chemical studies reported in the literature. G(free ion) is roughly proportional to the static dielectric constant of the liquid, over the range studied. A theory is presented which explains the results. It appears that the slowed-down secondary electrons are ``trapped'' in the liquid and solvated before undergoing geminate recombination, even in alkanes. Solvated electrons in alkanes would probably have a charge-transfer type of absorption spectrum, with a broad absorption maximum in the infrared. The major portion of ion pairs that undergo geminate recombination in these liquids does so in a period of 10−10±1 sec. A general mechanism is formulated for the initial stages of the ionic part of a liquid-phase radiolysis reaction.