Shock Tube Study of the Effect of Vibrational Energy of N2 on the Kinetics of the O+N2→NO+N Reaction

The kinetics of the reaction O+N2+3.3 eV→NO+N were investigated under conditions where the vibrational temperature of the nitrogen was less than the translational temperature. The formation of NO behind incident shock waves in dilute O3–N2 mixtures was studied over the temperature range 3100–6400°K with initial pressures of 2–25 torr. In the shock front O3→O+O2 and the reaction of the O with N2 is then rate-limiting, followed by the fast reaction N+O2→NO+O. The NO was monitored in emission at 5.3 μ and the initial slopes were compared to theoretical calculations which included vibrational relaxation processes. The radiation rose linearly from the shock front with no incubation in accord with the theoretical calculations employing only translational energy to determine the fraction of collisions whose energy was above the endothermicity of reaction.