Effect of Density in Radiolysis of Ammonia

Abstract

A study of the effect of density on the radiolysis of ammonia at 137-C reveals sharp decreases in G(H2) and G(N2) in the density region ~0.05 to 0.15 gm cc-1. At densities less than ~0.05 gm cc-1, G(H2) = 6.2, and G(N2) = 2.0; at densities exceeding 0.15 gm cc-1, G(H2) and G(N2) are about 1.5 and 0.4, respectively. It is notable that the G values begin to level off at densities well below the critical density of 0.235 gm cc-1. The results are interpreted in terms of the Magee-Funabashi theory of ion clusters. It is assumed that the formation of such clusters reduces the probability of dissociative neutralization of ions by permitting the energy of neutralization to be spread over the molecules of the cluster. Although this interpretation is consistent with the observed density dependence of G(-- NH3), contributions from other effects, in particular deactivation of excited species, may also be involved.