The radiolysis of dilute solutions of ethane-dϵ, propane-d8, andn-butane-d10in liquid hydrocarbons at 195 °K results in the production of D2and HD in amounts which are determined by the relative ionization potentials of solvent and solute. Solvents of higher ionization potential enhance the production of D2and HD from deuterated solutes of lower ionization potential. When the ionization potentials are in the reverse order the yields are diminished. This solute–solvent interaction, which is ionic in nature, is a general phenomenon in the radiolysis of mixtures of saturated hydrocarbons in the liquid phase and is consistent with charge transfer between solvent and solute.