Radiolysis of Methylcyclopentane. I. Nonhomogeneous Kinetics of Charge Scavenging in the Liquid Phase

Methylcyclopentane (MCP) was irradiated in the presence of a number of solutes. The hydrogen yield from pure MCP, $\mathrm{G(}{\mathrm{H}}_2\text{)\hspace{0.17em}=\hspace{0.17em}4.2,}$ was decreased to 2.2 by the addition of N₂O or SF₆, whereas the addition of ND₃ increased the total hydrogen yield above the value in pure MCP. In the ND₃ solutions the yield of HD was twice the decrease in H₂ yield, so not all positive ions formed in the absence of ND₃ lead to H₂ formation. In pure MCP, PH⁺ leads to hydrogen formation and QH⁺ does not. Both types of positive ions react with ammonia by proton transfer: $\mathrm{G(}{\mathrm{PH}}^{+}\text{)\hspace{0.17em}=\hspace{0.17em}2.0}$ and $\mathrm{G(}{\mathrm{QH}}^{+}\text{)\hspace{0.17em}≈\hspace{0.17em}1.2.}$ By using a nonhomogeneous kinetics model of charge scavenging, it was determined that electrons are an order of magnitude more readily scavengable than are positive ions in the radiolysis of methylcyclopentane. Determination of the value of the kinetics parameter $\beta$ in various radiolysis scavenging systems will help to determine the nature of the scavenging reactions that occur in them.