KINETIC-STUDIES OF THE REACTIONS OF BRO AND IO RADICALS

The 193-nm laser photolysis of Br-2/N2O mixtures in N-2 buffer has bee n utilized to determine the absorption cross section of BrO and to stu dy the reactions of O(P-3) with Br-2, O(P-3) with BrO, and the self re action of BrO at room temperature. The measured kinetic data are in go od agreement with the literature values. Molecular bromine formation i n the self-reaction of BrO can be described by the concerted steps of Br+BrO-->BrOBr and Br+BrOBr-->Br-2+BrO. From a curve fitting of the si multaneously monitored BrO and IO decays in the Br-2/I-2/N2O system, r oom temperature rate constants for the BrO+IO-->Products and I+BrO-->I O+Br reactions of (6.9+/-2.7)x10(11) cm(3)/molecule/s and (1.2+/10.6)x 10(-11) cm(3)/molecule/s, respectively, were derived. Similar experime nts using IBr, instead of Br-2/I-2, revealed a marked sensitivity of t he rate constant analysis to the accessible ratio of radical concentra tions. Kinetic analysis of this complex reaction system is presented.