Photodepletion and dynamics of oxygen atoms in xenon matrices

The photodepletion and reaction dynamics of O atoms isolated in xenon matrices have been studied. Oxygen atoms are generated by 193 nm photolysis of a N2O dopant and monitored via the laser-induced fluorescence of XeO exciplexes produced by the 248 nm excitation of Xe/O pairs. Dissociative relaxation of XeO exciplexes generates energetic O atoms which may travel significant distances in the matrix. This photoinduced mobility can lead to O atom loss. The O atom loss process is found to be bimolecular from 15 to 42 K at all fluences studied and is ascribed to an O+O recombination process. Higher temperature data (42 K) may exhibit behavior characteristic of a transition from second order to first order kinetics. A kinetic scheme is derived which can be used to model the data and infer a microscopic description of the O atom dynamics.