Pressure and temperature dependence kinetics study of the nitric oxide + bromine oxide .fwdarw. nitrogen dioxide + bromine reaction. Implications for stratospheric bromine photochemistry

Abstract

The flash photolysis-ultraviolet absorption technique has been utilized to study the reactivity of nitric oxide
\nwith BrO radicals over a wide range of pressure (100-700 torr) and temperature (224-398 K). Pseudo-first-order
\nconditions were used in order to minimize complications caused by secondary kinetic processes. The reaction
\nand its corresponding Arrhenius expression in units of cm^3 molecule^(-1) s^(-1) can be written 
\nNO + BrO → NO_2 + Br ΔHº_298 = -17.0 kcal mol^(-1)
\nk_1 = (1.28 ± 0.23) x 10^(-11)exp((181 ± 46)/T) (T = 224-398 K)
\nThe results are compared with previous measurements, and atmospheric implications of the reaction are discussed.
\nIt is shown that this reaction is important in controlling the ratios [BrO]/[Br] and [BrO]/[HBr] in the stratosphere
\nbut that it does not affect the catalytic efficiency of BrO, in ozone destruction.