The role of homogeneous reactions in the radiolysis of water

Chemical effects occur in irradiated systems both in the tracks of particles and in background reactions which take place homogeneously. The latter reactions are considered here in some detail for the case of γ-irradiated water. A model is introduced in which 7 species are involved in 10 reactions to describe irradiated acid water and 11 species are involved in 20 reactions for the case of neutral water. The differential equations of this model are presented. They are ill-conditioned stiff equations and ordinary numerical methods are inadequate to solve them; a method developed by one of us (S.K.D.) has been applied and it is found to yield satisfactory results. This method seems to make possible theoretical studies on irradiated systems involving arbitrary track structure and reaction sequences. Calculations are presented on several cases of γ-irradiated water (acid and neutral). Limited checks with the work of Hochanadel indicate that the model is in satisfactory agreement with experiment if all importa...