Investigation of various factors influencing the effect of scavengers on the radiation chemistry following the high-energy electron radiolysis of water

Stochastic independent reaction times (IRT) simulations are used to model the fast reaction in spurs similar to those found following the high-energy electron radiolysis of water and aqueous solutions. The time dependence of the rate coefficient for the reaction of the hydrated electron or the hydroxyl radical with a scavenger is shown to be important in modeling scavenging reactions only when the steady-state rate is large, e.g. for the reactions e_aq^- + O₂ or OH + Br^-. The calculations are used to test the accuracy of the commonly used Laplace relationship between the time dependence of the radicals and the molecular products resulting from the high-energy electron radiolysis of water and the scavenger concentration dependence of the observed yields following the radiolysis of scavenger solutions. Agreement between modeled yields for the scavenger systems and predictions of the Laplace transforms of the decay and the formation kinetics in the absence of scavenger is excellent once the time dependence of the scavenging rate coefficient has been incorporated in the Laplace relationship.