PHOTOPRODUCTION AND DYNAMICS OF OXYGEN-ATOMS IN XENON MATRICES

The photodissociation of N2O doped in Xe matrices and the subsequent d ynamics of atomic oxygen production have been studied. The O atom conc entration is monitored via the laser-induced fluorescence of XeO excip lexes produced by the 193 nm excitation of Xe/O pairs. The O atom phot oproduction cross section for 193 nm irradiation of N2O is 6.4 +/- 1.0 X 10(-20) cm2 at 27 K, comparable to the gas phase value of 1.1 X 10( -19) cm2. Dissociation of XeO exciplexes generates kinetically hot O a toms which are mobile. This photoinduced mobility can lead to O atom l oss by recombination. The extent of O atom production as a function of laser irradiation is governed by a competition between the rates of p hotoproduction and photoinduced loss. The effects of temperature, conc entration, and laser fluence on the production of O atoms are consider ed. The efficiency of photoinduced O atom loss increases significantly with increasing temperature. An ultraviolet absorption spectrum of Xe O has been obtained with an absorption cross section of 1.9 +/- 0.4 x 10(-16) cm2 at 248 nm.