Model for Neutralization and Scavenging of Charges in Irradiated Dielectric Liquids. II Electron Scavenging under γ Radiolysis

Abstract

Yield of a scavenging reaction in competition with charge neutralization is calculated in the diffusion model for the isolated ion‐pair case and also for multiple ion‐pair cases. Following an earlier lead by Hummel, this yield is shown as a Laplace transform of the survival probability against neutralization in absence of scavenger. The Laplace transform itself is evaluated numerically using the earlier work of the present author for the isolated ion‐pair case and the results of the accompanying paper for the multiple ion‐pair cases. Experimental results of Schuler et al. for electron scavenging in γ radiolysis of cyclohexane solutions are compared with the present calculations for the isolated ion pair and also for the entire track. For the latter a probability function for energy deposition derived from our previous work has been used. It is concluded that the square‐root law at low scavenger concentrations is a general result of the classical diffusion theory, independent of the size and shape of the entity being scavenged and indeed independent of the mode of generation of charges. This law is, in fact, not limited to charge scavenging only. A discussion is made of other related experiments, such as of mobility (Schmidt and Allen) and of time dependence of negative‐ion yield (Thomas), and it is concluded that a single set of diffusion and rate constants can consistently explain all the experimental results.