Nitric oxide vibrational excitation from the N(4S)+O2 reaction

Abstract

Measurements of the vibrational distribution of NO produced in a room temperature flowtube study of N(4S) + O2→NO(0≤v≤7) + O are reported. Ultraviolet laser induced fluorescence detection of NO(v) in levels v=0–7 was employed to study NO production under conditions where O2 vibrational quenching was insignificant. The results indicate that 42% of the NO molecules are produced in infrared-active states, 38% of them in levels ≥2. This is considerably more NO vibrational excitation than had been inferred from infrared chemiluminescence studies. Moreover, production of infrared active states of NO by the N(4S)+O2 reaction may be even more efficient than these numbers indicate owing to possible vibrational relaxation of the nascent NO(v) distribution by nitrogen atoms in the flowtube.