Timehyphen;resolved OH(Xthinsp;2Pgr;i,v=1ndash;9) populations have been measured and analyzed to determine parameters relating to formation mechanisms and vibrational relaxation. OH(v) was formed in electronhyphen;irradiated Ar/H2/O3mixtures containing added O2or CO2as relaxer species. OH(vrarr;vminus;1,vminus;2) emission was observed using timehyphen;resolved Fourier spectroscopy. Spectra were then fit to determine timehyphen;dependent populations. Population data were analyzed using a singlehyphen;quantum relaxation model, but the possible effects of multiquantum relaxation were also considered. The model includes provision for OH(v) production via H+O3rarr;OH(v)+O2afterehyphen;beam termination, which has been found to have a significant effect on the results. The following relaxation rate constants are obtained:kv=1ndash;6(O2)=1.3plusmn;0.4, 2.7plusmn;0.8, 5.2plusmn;1.5, 8.8plusmn;3.0, 17plusmn;7, 30plusmn;15 (10minus;13cm3sminus;1) andkv=1ndash;4(CO2)=1.8plusmn;0.5, 4.8plusmn;1.5, 14plusmn;5, 28plusmn;10 (10minus;13cm3sminus;1), respectively. Two different exponential decay rates are necessary to characterize the time dependence of the inferred H atom concentration. The role of O(1D)+H2rarr;OH+H is also discussed.
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