Shock-Tube Study of Nitrogen Dissociation using Vacuum-Ultraviolet Light Absorption

Publisher Website
Google Scholar
Abstract
A shock‐tube investigation of the dissociation of nitrogen diluted in argon is described which utilizes vacuum‐ultraviolet absorption at 1176 Å to monitor the disappearance of molecular nitrogen. Measurements of the dissociation rate coefficients for the process kd(M)N2 + M→2N + M were obtained over the temperature range 8000° to 15 000°K where the collision partner, M, was Ar, N2, and N. The temperature dependence of the individual rate coefficients was found to be the same and was obtained with good precision. The magnitudes of the rate coefficients were generally lower than the currently accepted values obtained in previous shock‐tube investigations, especially the value for kd(N) which, although it was found to be about 10 times greater than kd(Ar) , was six times less than two previous measurements. The results of the investigation may be summarized by the following expressions for the dissociation rate coefficients: kd(Ar) = (2.3 ± 0.2) × 10−3T−1.6exp( − 1.132 × 105 / T) cm3sec−1 , kd(N2) = (6.2 ± 1.6) × 10−3T−1.6exp( − 1.132 × 105 / T) cm3sec−1 , kd(N) = (2.7 ± 1.0) × 10−2T−1.6exp(−1.132 × 105 / T) cm3sec−1 . Encouragingly good agreement between the recombination rate coefficients, kr(Ar) , inferred from the measurements of kd(Ar) , with predictions of kr(Ar) obtained from the theories of Benson and Fueno and Keck and Carrier, were obtained.