The N(4S) + O2(X3Σ −g) ↔ O(3P) + NO(X2Π) reaction: thermal and vibrational relaxation rates for the 2A′, 4A′ and 2A′′ states
The kinetics and vibrational relaxation of the N(4S) + O2(X3Sg)2O(3P) + NO(X2P) reaction is investi-gated over a wide temperature range based on quasiclassical trajectory simulations on 3-dimensionalpotential energy surfaces (PESs) for the lowest three electronic states. Reference energies at the multireference configuration interaction level are represented as a reproducing kernel and the topology ofthe PESs is rationalized by analyzing the CASSCF wavefunction of the relevant states. The
... t states. The forward ratematches one measurement at 1575 K and is somewhat lower than the high-temperature measurementat 2880 K whereas for the reverse rate the computations are in good agreement for temperaturesbetween 3000 and 4100 K. The temperature-dependent equilibrium rates are consistent with resultsfrom JANAF and CEA results. Vibrational relaxation rates for O + NO(n=1)-O+NO(n= 0) are consistentwith a wide range of experiments. This process is dominated by the dynamics on the2A0and4A0surfaceswhich both contribute similarly up to temperaturesTB3000 K, and it is found that vibrationally relaxing andnon-relaxing trajectories probe different parts of the potential energy surface. The total cross sectiondepending on the final vibrational state monotonicallydecreases which is consistent with early experimentsand previous simulations but at variance with other recent experiments which reported an oscillatory crosssection.