Rates of OH radical reactions. II. The combination reaction OH+NO+M

Abstract

The combination of OH+NO+M at 295 °K was studied over the pressure range 25–770 torr of various third bodies M, using the flash photolysis resonance absorption technique. Absolute second order rate constants k_II for the reaction were measured at various pressures of He, N₂, SF₆, CF₄, and H₂O, and at 720 torr of Ar. The data were treated by a simple two step Lindeman scheme. The limiting value of k_II at high pressure, k_II∞, was found to be k_II=1.1×10¹³ cm³ mol⁻¹⋅s⁻¹. The efficiencies of the third bodies for collisional energy transfer, η, relative to the efficiency of H₂O taken as one were calculated to be H₂O=1, CF₄=0.41, SF₆=0.37, N₂=0.12, Ar=0.05, and He=0.02.