Monte Carlo simulation of vibrational relaxation in nitrogen

Monte Carlo simulation of nonequilibrium vibrational relaxation of (rotationless) N2 using transition probabilities from an extended SSH theory is presented. A heating case is examined. For the range of temperatures considered, 4000-8000 K, the vibrational levels were found to be reasonably close to an equilibrium distribution at an average vibrational temperature based on the vibrational energy of the gas. As a result, they do not show any statistically significant evidence of the bottleneck observed in earlier studies of N2. Based on this finding, it appears that, for the temperature range considered, dissociation commences after all vibrational levels equilibrate at the translational temperature. These results are a consequence of the fact that the transition probability, p(v, v + 1), which is a function of energy but not temperature, is an increasing function of the vibrational level v. Therefore, a behavior similar to that of a harmonic oscillator should be expected.