Radiation Chemistry of Oxygenated Aqueous Solutions

Abstract

The activity in radiation chemistry in recent years has been so extensive that it seems impossible to review the whole field. This review will cover only problems in the radiation chemistry of aqueous solutions. Even within this limited field numerous papers have been published as well as several books, symposia, and reviews (1-1 5). Before the techniques of pulse radiolysis were developed about a decade ago, most studies dealt with measurements of yields and relative rate constants. The identity of radicals formed in water was inferred from such studies. The diffusion model was generally accepted to explain the effect of radiations of various LET, the effect of solutes on G values, and various other related phenomena. The subject as it was known in 1 960 was ably summarized by Allen in his book (16). In the last decade more direct kinetic studies of radical-radical reactions and of reactions of radicals with solutes have been carried out. These studies have helped to elucidate reaction mechanisms and specifically identify intermediates and have provided a large compilation of rate constants of reactions of various solutes with eaq, OH, and H atoms (17). For many of these intermediates, physical properties such as absorption spectra, ESR spectra, conductivities pKs, etc were de­ termined. First I would like to make a few general remarks on the diffusion model and then devote the remaining sections of the review to a summary of the problems and properties of the intermediates found in air-free and air­ saturated aqueous solutions as they are currently known.