BrO Disappearance in the Pulse Radiolysis of <tex-math>${\rm O}_{2}+{\rm Br}_{2}$</tex-math> and <tex-math>${\rm N}_{2}{\rm O}+{\rm Br}_{2}$</tex-math> Systems

The BrO transient formed during the pulse radiolysis of <tex-math>${\rm O}_{2}+{\rm Br}_{2}$</tex-math> mixtures decayed according to second-order kinetics, and the rate constant decreased slightly as O₂ pressure was increased from 400 to 1560 Torr. Besides the variation with pressure, the BrO recombination reaction exhibited an initial phase in the time regime 3-50 μsec under certain experimental conditions during which BrO disappearance occurred at a faster rate. In the pulse radiolysis of <tex-math>${\rm N}_{2}{\rm O}+{\rm Br}_{2}$</tex-math> mixtures, the kinetics of BrO disappearance were found to be sensitive to the dose. In the lower dose range used in this work, the second-order rate plots were linear and BrO decay was invariant with pressure. With mixtures irradiated to a higher dose, BrO decay was also rapid but did not follow simple kinetics. The molar extinction coefficient of BrO was measured at three wavelengths in the near-uv region by determining the amount of <tex-math>${\rm Br}_{2}$</tex-math> that temporarily disappears during radiolysis. The molar extinction coefficient (<tex-math>$M^{-1}\times {\rm cm}^{-1}$</tex-math>) was found to be 1,620 at 338 nm, 1,500 at 333 nm, and 1,530 at 321 nm.