Kinetics of in oxygen RF discharges

Abstract

Studies of the kinetics in the afterglow of three RF discharges having different configurations are presented. Experiments with a slow flow velocity transverse capacitive RF discharge were performed and detailed measurements of the spatial evolution of , O2(a1Δg), O(3P) and flow temperature were taken. Simulations of three different experimental configurations were in good agreement with the data for the spatial decay of . The simulations also provided reasonable agreement with experimental data for atomic oxygen, O2(a1Δg) and temperature, where the data were available. Updated electron impact cross-sections for oxygen dissociation were included in the simulations; this proved critical for proper modelling of the production of atomic oxygen and the subsequent decay of . At low oxygen atom densities the decay of was principally from heterogeneous quenching. For the slow flow velocity experiment, O atom recombination and deactivation by the walls play an important role; in the far downstream afterglow region a quasi-stationary concentration was found owing to a near-equilibrium between the pooling reaction and losses to the walls for this slow velocity case.