Photoproduction and dynamics of oxygen atoms in xenon matrices

The photodissociation of N2O doped in Xe matrices and the subsequent dynamics of atomic oxygen production have been studied. The O atom concentration is monitored via the laser-induced fluorescence of XeO exciplexes produced by the 193 nm excitation of Xe/O pairs. The O atom photoproduction cross section for 193 nm irradiation of N2O is 6.4±1.0×10−20 cm2 at 27 K, comparable to the gas phase value of 1.1×10−19 cm2. Dissociation of XeO exciplexes generates kinetically hot O atoms which are mobile. This photoinduced mobility can lead to O atom loss by recombination. The extent of O atom production as a function of laser irradiation is governed by a competition between the rates of photoproduction and photoinduced loss. The effects of temperature, concentration, and laser fluence on the production of O atoms are considered. The efficiency of photoinduced O atom loss increases significantly with increasing temperature. An ultraviolet absorption spectrum of XeO has been obtained with an absorption cross section of 1.9±0.4×10−16 cm2 at 248 nm.