Chemical Effects of Electron Capture by Solutes in Hydrocarbons during Gamma Irradiation

According to a recent report by Samuel and Magee (1) it is probable that electrons produced by ionizing radiations in liquid water (2)1 will be captured by the parent ions. An electron of 15 ev initial energy will lose energy by exciting vibrational degrees of freedom until at e15 A from the ion its energy is insufficient to overcome the Coulomb attraction. Capture occurs within ~10-14 sec after -10 collisions. This does not allow time for (dipolar) solvation, assumed to be necessary for electron capture by H20. On the other hand, it has been generally considered by experimenters that water undergoes dissociative electron capture (3). It is not evident how this problem can be directly approached by experiments with aqueous systems, but the corresponding problem can be attacked, however, in other media. Thus, in a hydrocarbon solvent containing approximately 10-2 and 10-4 mole fractions of methyl iodide and radioiodine, it is to be expected that, if ionization is followed by recapture of the daughter electron by the parent ion, then methyl iodide as a minor component will seldom become involved in ionic processes. If, however, the electron does not return to its parent ion and is captured by methyl iodide, then methyl radicals should be produced either by (A)