Formation and decay of transient xenon dihydride resulting from hydrocarbon radiolysis in a xenon matrix

The formation and decay of transient xenon dihydride upon annealing xenon-hydrocarbon systems irradiated with fast electrons at 15 K was monitored by FTIR spectroscopy. It is concluded that XeH2 is a chemically identical species, which can be generated in different ways. The two bands of these species (positioned at 1181 and 1166 cm−1) show essentially different behaviour with annealing temperature. Evidence for a chemical reaction of xenon dihydride with trans-2-butene occurring in a xenon matrix at 60–70 K was obtained. The addition of electron scavengers results in a dramatic decrease in the XeH2 yield. It is suggested that xenon dihydride results from H atoms rather than from charged precursors.