Rates of elementary reactions involving the BrO (X2Π) and IO (X2Π) radicals. Part 2.—Reactions of the BrO and IO radicals

Abstract

The mechanisms and rate constants at 293 K of a number of elementary reactions of the ground state BrO (X²Π, v″= 0) radical are reported. BrO is found to react rapidly only with other free radicals (NO,O), [graphic ommitted] It is unreactive towards singlet ground-state molecules (H₂, CH₄, C₂H₄, C₂H₆), BrO+H₂→products; k₅ < 10^9.5; BrO+CH₄, C₂H₄, C₂H₆→products; k < 10^10.0. Free X atoms (X = Br, Cl)(formed by bimolecular disproportionation of 2 XO radicals) are normally present in low-pressure systems containing XO radicals. The possible effects on reaction rates of the coexistence of XO and X are considered.

The ground state IO(X²Π, v″= 0,1) radical, produced by the reaction,. I(²P)+O₃→IO+O₂, was detected by means of the A²Π—X²Π band absorption system. This reaction leads to preferential population of the vibrational level v″= 1. Detailed quantitative study of the kinetics of reaction of IO was precluded. However, the results suggest that the decay of IO was closely analogous to that of BrO in mechanism and rate, [graphic ommitted], with k₉= 10^12.5±0.3 at 293 K.