Reaction of atomic oxygen with hydrogen bromide

Abstract

The reaction of atomic oxygen with HBr was studied in a fast discharge flow system by monitoring epr spectra of O(3P2), Br(2P3/2), OH(2pi3/2), and H(2S1/2) at various reaction times. The experimental results were found to be in accord with the mechanism, O + HBr --> OH + Br (1), OH + HBr --> H2O + Br (2), OH + O + H + O2 (3), H + HBr --> H2 + Br (4), and k1 was measured at 298 K as 4.4 +- 1.0 X 10^-14 cm3 molecule-1 sec-1. The radical intermediate, OH(2pi3/2), was detected in both the ground state, and in the first vibrationally excited state. Measurements on the relative population of these states allowed a lower limit of 0.3 to be placed on the ratio k(1b)/k(1a), O + HBr --> OH(v = 0) + Br(2P3/2) (1a) and O + HBr --> OH(v = 1) + Br(2P3/2) (1b).