Kinetics of O2(b 1Σg+) in oxygen RF discharges

Studies of the O-2(b(1)Sigma(+)(g)) 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 O-2(b(1)Sigma(+)(g)), O-2(a(1)Delta(g)), O(P-3) and flow temperature were taken. Simulations of three different experimental configurations were in good agreement with the data for the spatial decay of O-2(b(1)Sigma(+)(g)). The simulations also provided reasonable agreement with experimental data for atomic oxygen, O-2(a(1)Delta(g)) 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 O-2(b(1)Sigma(+)(g)). At low oxygen atom densities the decay Of O-2(b(1)Sigma(+)(g)) was principally from heterogeneous quenching. For the slow flow velocity experiment, O atom recombination and O-2(b(1)Sigma(+)(g)) deactivation by the walls play an important role; in the far downstream afterglow region a quasi-stationary O-2(b(1)Sigma(+)(g)) concentration was found owing to a near-equilibrium between the pooling reaction and losses to the walls for this slow velocity case.