HYDROGEN FORMATION IN γ-IRRADIATED HYDROGEN CHLORIDE

Abstract

Hydrogen yields from pure liquid and solid hydrogen chloride irradiated with Co60 γ-rays were [Formula: see text](liquid) = 6.50 ± 0.10 and [Formula: see text] (solid) = 3.30 ± 0.10 at −79 °C and −196 °C respectively. The yield from solid hydrogen chloride was only slightly reduced by the addition of chlorine; but the yield from liquid samples was reduced sharply by low concentrations of chlorine to a value of about 4.5, and then much more gradually by larger concentrations. A [Formula: see text] value of 2.1 persisted at 10 mole% chlorine. The results were interpreted in terms of the formation of hydrogen in the reactions[Formula: see text]and[Formula: see text]Reduction of the hydrogen yields by chlorine was attributed to the reactions[Formula: see text]and[Formula: see text]Values of k11/k15 and k11*/k15* were estimated to be 1.7 × 10−3 and 0.10 respectively, while those of GH and GH(hot) were 2.4 ± 0.2 and 4.0 ± 0.2. Electron scavenging by chlorine was considered as a less likely mechanism for reduction of the hydrogen yield. Sources of the thermal and hot hydrogen atoms were examined and it was suggested that the decomposition of electronically excited molecules might be an important mode of decomposition.