PRESSURE AND TEMPERATURE-DEPENDENCE KINETICS STUDY OF THE NO+BRO-]NO2+BR REACTION - IMPLICATIONS FOR STRATOSPHERIC BROMINE PHOTOCHEMISTRY

The flash photolysis-ultraviolet absorption technique has been utilized to study the reactivity of nitric oxide with BrO radicals over a wide range of pressure (100-700 torr) and temperature (224-398 K). Pseudo-first-order conditions were used in order to minimize complications caused by secondary kinetic processes. The reaction and its corresponding Arrhenius expression in units of cm3 molecule-1 s-1 can be written NO + BrO → NO2 + Br ΔHdeg;298 = -17.0 kcal mol-1 (1) k1 = (1.28 ± 0.23) ± 10-11 exp((181 ± 46)/T) (T = 224-398 K) The results are compared with previous measurements, and atmospheric implications of the reaction are discussed. It is shown that this reaction is important in controlling the ratios [BrO]/[Br] and [BrO]/[HBr] in the stratosphere but that it does not affect the catalytic efficiency of BrOx in ozone destruction. © 1979 American Chemical Society.