Kinetic studies of the reactions of BrO and IO radicals

Abstract

The 193-nm laser photolysis of Br2/N2O mixtures in N2 buffer has been utilized to determine the absorption cross section of BrO and to study the reactions of O(3P) with Br2, O(3P) with BrO, and the self reaction of BrO at room temperature. The measured kinetic data are in good agreement with the literature values. Molecular bromine formation in the self-reaction of BrO can be described by the concerted steps of Br+BrO→BrOBr and Br+BrOBr→Br2+BrO. From a curve fitting of the simultaneously monitored BrO and IO decays in the Br2/I2/N2O system, room temperature rate constants for the BrO+IO→Products and I+BrO-IO→Br reactions of (6.9±2.7)×10-11 cm3/molecule/s and (1.2±0.6)×10-11 cm3/molecule/s, respectively, were derived. Similar experiments using IBr, instead of Br2/I2, revealed a marked sensitivity of the rate constant analysis to the accessible ratio of radical concentrations. Kinetic analysis of this complex reaction system is presented. This paper is not subject to U.S. copyright. Published in 1997 by the American Geophysical Union.