Vibrational kinetics of electronically-excited N2(A 3Σu+, v) molecules in nitrogen discharge plasma

A model on formation of the vibrational distribution function of metastable electronically excited N-2(A (3)Sigma(+)(u), v) states in nitrogen discharge plasma is presented. By means of comparison with the experimental data the rate constants for the reaction N-2(A (3)Sigma(+)(u), v) + N-2(X (1)Sigma(+)(g), v' = 0) -> N-2(A (3)Sigma(+)(u), v - 2) + N-2(X (1)Sigma(+)(g), v' = 1) have been clarified. It is assumed that the probability of population of N-2(A (3)Sigma(+)(u), v) states by collisional deactivation of N-2(B (3)Pi(g), v') molecules is proportional to the Franck-Condon factors of correspondent N-2(B (3)Pi(g), v') -> N-2(A (3)Sigma(+)(u), v) transitions, i.e. that the quenching is essentially vertical. The results of calculations carried out under this assumption are in agreement with measured N-2(A (3)Sigma(+)(u), v) vibrational distribution at the end of pulsed high current discharge in nitrogen. Study of a variation of the population of vibrational level N-2(A (3)Sigma(+)(u), v = 0) in the afterglow of streamer discharge in nitrogen at atmospheric pressure has been performed. It is shown that the dynamics of N-2(A (3)Sigma(+)(u), v = 0) number density depends essentially not only on their loss in the pooling reaction N-2(A (3)Sigma(+)(u), v) + N-2(A (3)Sigma(+)(u), v) -> product, but also on additional population due to the quenching of high vibrational levels. The fraction of dissociation channel in the process of N-2(A (3)Sigma(+)(u), v) deactivation by oxygen molecules have been calculated. It is shown that temporal evolution of the fraction of the dissociation channel is first of all associated with a variation of the relative population of the vibrational level N-2(A (3)Sigma(+)(u), v = 0). In air discharge plasma at high pressure, the population of N-2(A (3)Sigma(+)(u), v = 0) state is relatively low, so the fraction of the dissociation channel in the deactivation of all electronically excited states of nitrogen by oxygen exceeds 90-95%.