This paper presents molecular dynamics calculations of vibrational energy transfer and nonequilibrium dissociation in O2 + O collisions. The O2 + O interactions are modeled using nine potential energy surfaces corresponding to the 11A', 21A', 11A' 0, 13A', 23A', 13A", 15A', 25A', and 15A" states, which govern electronically adiabatic collisions of ground-electronic-state collisions of diatomic oxygen with atomic oxygen. Characteristic vibrational excitation times are calculated over a temperature range of T = 3000 K to T = 15,000 K, and nonequilibrium dissociation rate coefficients are calculated over a temperature range of T = 6000 K to T = 15,000 K. Vibrational relaxation rates, specific to each PES, are found to vary by over an order of magnitude, indicating that all spin couplings and spatial degeneracies must be considered for accurate predictions of O2 + O collisions. It has been observed that the characteristic vibrational excitation time for O2 + O interactions is weakly dependent on temperature and increases slightly with increasing temperature. Predicted nonequilibrium dissociation rates, during quasi-steady state. Agree well with available experimental data, and the coupling between vibrational energy and dissociation is characterized.
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The authors are grateful to Antonio Varandas, Yuliya Paukku, Graham Candler, and Ross Chaudhry for many discussions of the O3 problem over recent years. The research presented here is supported by the Air Force Office of Scientific Research (AFOSR) under Grant No. FA9550-16-1-0161. The views and conclusions contained herein are those of the authors and should not be interpreted as representing the official policies or endorsements, either expressed or implied, of the AFOSR or the U.S. government.
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