Mechanism of direct and noble-gas sensitized γ-radiolysis of cyclopropane

The direct and Kr and Xe sensitized γ-radiolysis of cyclopropane was investigated through quantitative determination of all significant products as a function of pressure, dose rate, and additives (NO, N2O, SF6). The obtained results were subjected to a kinetic analysis from which numerical values for the probabilities of individual decay processes and other important intermediate reactions could be derived. It was found that the noble gases particularly favor the possible ion reactions in the system. The formation rate of radiolysis products is significantly lower in the case of Kr sensitization compared to direct or Xe sensitized radiolysis. This is attributed to charge transfer from Kr+ ions to cyclopropane molecules, among other things, leading to the formation of the less reactive C3H3+ ions. Xe+ ions primarily generate C3H6-, C3H5+- and -ions, with the latter presupposing the presence of excited xenon ions.