Diffusion kinetics of radical intermediates in radiation chemistry

Abstract

Almost all theoretical papers on the mechanism of radical reactions in the tracks of ionizing particles implicitly assume the independence of the radical distributions. In this paper the effect of correlations arising between the radical distributions in the course of the reaction process on its change in time and the product yields is studied. The problem has been formulated in terms of the joint probabilities of radical pairs according to a one-spur-one-radical model. It is found that the combination and recombination processes in real spurs must be more effective than prescribed by one-radical models assuming the independence of the distributions of the reacting particles. The results of those theories correspond with the results from our model only for local concentrations which are too low to be realistic. On the other hand, for the relative lowering of the molecular yield with increasing scavenger concentration this model gives the same deviations from the experiment for higher scavenger concentrations as other one-radical models.