Rate Constant and Possible Pressure Dependence of the Reaction OH+HO2

Article abstract of DOI:10.1021/j100390a025

The technique of laser-induced fluorescence has been used to measure steady-state OH concentrations in the photolysis of water vapor at 184.9 nm and 298 K, with O2 added in trace amounts.He or Ar was present at total pressures in the range 75-730 torr.The results were used to derive the rate-constant ratio k₁/k₅^1/2, where k₁ and k₅ are the rate constants for the reactions OH+HO2->H2O+O2 and HO2+HO2->O2, respectively.When currently available values for k₅ are used, the results give k₁=(1.2+/-0.4)x10^-10 cm³s^-1 at 1-atm pressure, with evidence of a decline of k₁ at lower pressures.No water-vapor effect on k¹ was observed.