Kinetics of the IO Radical. 2. Reaction of IO with BrO

The rate coefficient for the IO + BrO → products (1) reaction was measured using pulsed laser photolysis with a discharge flow tube for radical production and pulsed laser-induced fluorescence and UV absorption for detection of IO and BrO radicals, respectively. Reaction 1 was studied under pseudo-first-order conditions in IO with an excess of BrO between 204 and 388 K at total pressures of 6−15 Torr. The Arrhenius expression obtained for non-iodine atom producing channels is k 1a ( T ) = (2.5 ± 1.0) × 10 -11 exp[(260 ± 100)/ T ] cm 3 molecule -1 s -1 independent of pressure. The rate coefficient for the reaction BrO + BrO → products (2) and the UV absorption cross sections of BrO as a function of temperature were also determined as part of this study. The implications of these results to the loss rate of stratospheric ozone are discussed.