DISSOCIATION RATE AND N (4S) ATOM CONCENTRATIONS IN A N2 GLOW-DISCHARGE

The rate of dissociation in N2 and the fractional densities of N(4S) atoms have been self-consistently calculated for typical operating conditions of a low-pressure, moderate current, nitrogen discharge. The present model solves simultaneously the electron Boltzmann equation, a system of rate balance equations for the vibrational levels N2(X,upsilon) and the rate balance equation for the N(4S) atoms. The Boltzmann equation includes both inelastic and superelastic e-V collisions, while the system for the vibrational levels takes into account e-V, V-V and V-T exchanges as well as the processes of dissociation, atom reassociation and vibrational deactivation on the walls of the container. The total dissociation rate includes both dissociation by electron impact and dissociation by the V-V and V-T energy exchange processes. The effects of wall deactivation on the vibrational distribution functions of N2(X,upsilon) molecules and on the rate of dissociation are analysed in detail. The various mechanisms for destruction of N(4S) atoms are discussed and weighted. Predictions and measurements reported in the literature of the rate of dissociation and atom densities are shown to agree reasonably well.