Non-equilibrium kinetics of bimolecular reactions. Part 7: The puzzle of the H+O-2 reaction

The steady state master equation is solved to determine the population dist ribution of vibrationally excited O-2 while reacting with H atoms at temper atures ranging from 300 K to 8000 K. State-selected reactive rate constants are used which are consistent with the known theoretical and experimental rates of the H + O-2 reaction at all levels of detail. Known V-T energy tra nsfer rate constants are also used. Calculations are performed for a variet y of H, O-2 and Ar compositions, revealing the conditions where non-equilib rium effects can play a role. The results of the calculation show that the thermal rate coefficient at 2000 K is less than the value expected, by as m uch as 25%. This is due to a much distorted vibrational population distribu tion caused by the reaction itself. Although the predicted behaviour of the rate coefficient qualitatively mimics the experimental one, it does not qu antitatively explain the observed experimental discrepancies, which have pu zzled kineticists and dynamicists for the past 20 years.