Vibrational kinetics of electronically-excited molecules in nitrogen discharge plasma

Abstract

A model on formation of the vibrational distribution function of metastable electronically excited states in nitrogen discharge plasma is presented. By means of comparison with the experimental data the rate constants for the reaction have been clarified. It is assumed that the probability of population of states by collisional deactivation of N2(B 3Πg, v′) molecules is proportional to the Franck–Condon factors of correspondent transitions, i.e. that the quenching is essentially vertical. The results of calculations carried out under this assumption are in agreement with measured vibrational distribution at the end of pulsed high current discharge in nitrogen.Study of a variation of the population of vibrational level in the afterglow of streamer discharge in nitrogen at atmospheric pressure has been performed. It is shown that the dynamics of number density depends essentially not only on their loss in the pooling reaction product, but also on additional population due to the quenching of high vibrational levels. The fraction of dissociation channel in the process of 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 . In air discharge plasma at high pressure, the population of 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%.