Kinetics of the Reactions of IO Radicals with NO and NO2

Article abstract of DOI:10.1021/j100374a034

A laser flash photolysis-long path absorption technique has been employed to study the kinetics of the reactions of IO radicals with NO and NO2 as a function of temperature and pressure.The IO + NO rate coefficient is independent of pressure over the range 40-200 Torr of N2, and its temperature dependence over the range 242-359 K is adequately described by the Arrhenius expression k₁ = (6.9+/-1.7) * 1E-12 exp<(328+/-71)/T> cm³ molecule^-1 s^-1 (errors are 2?, precision only).These Arrhenius parameters are similar to those determined previously for the ClO + NO and BrO + NO reactions.The IO + NO2 association reaction is found to be in the falloff regime over the temperature and pressure ranges investigated (254-354 K and 40-750 Torr of N2).Assuming F_c = 0.4 independent of temperature, a physically resonable set of falloff parameters which adequately describe the data are k₀ = 7.7 * 1E-31(T/300)^-5.0 cm⁶ molecule^-2 s^-1 and k_infinite = 1.55 * 1E-11 cm³ molecule^-1 s^-1 independent of temperature.The IO + NO2 rate coefficients determined in this study are about a factor of 2 faster than those reported in the only previous study of this reaction.