Collisional quenching of electronically excited nitrogen atoms, N(22DJ, 22PJ) by time-resolved atomic absorption spectroscopy

Electronically excited nitrogen atoms, N(22DJ) and N(22PJ), generated by the pulsed irradiation of nitrous oxide in the Schumann region, have been studied in absorption by time-resolved attenuation of resonance radiation in the vacuum ultra-violet. The rate constants for the collisional removal of these excited species by the gases H2, N2, O2, NO and N2O are reported. The results are compared with rate data for ground-state atoms obtained from other methods, and hence the rate constants for the reactions of nitrogen atoms in the 4S, 2D and 2P states with a given molecule are discussed in terms of the effects of spin and orbital symmetry. The removal of N(22DJ) in the presence of molecular oxygen is considered in relation to the production of nitric oxide in the upper atmosphere.