Experimental study and modelling of a low-pressure N-2-O-2 time afterglow

The time afterglow of a pulsed discharge is used to investigate the neutral -particle kinetics in N-2-O-2 low-pressure mixtures. The pressure is in the range 0.5-2 Ton at 300 K and the mixture composition in the range 0-20% of oxygen. Time-resolved emission spectroscopy on N-2(B), N-2(C), NO(A) and N O(B) is employed to monitor energy transfers involving the metastable state N-2(A). The influence of N(S-4) and O(P-3) atoms on the kinetics is accura tely treated using absolute concentration measurements by time-resolved abs orption spectroscopy in the VUV range. It is shown that by an appropriate c hoice of the discharge repetition rate, the vibrational excitation of N-2(X ) can be neglected. A chemical model, containing few unknown parameters, is developed in order to fit the experimental fluorescences. The NO(X) kineti cs are investigated and its absolute concentration is deduced. Furthermore, it is shown that the N2(A) density is probably higher for pulsed discharge s than for stationary low-pressure DC discharges.