Rate constant of the BrO plus BrO reaction over the temperature range 220-950 K

The kinetics of the self-reaction of BrO radicals has been studied over a wide temperature range (T = 220-950 K) at 2 Torr total pressure of He using a low-pressure flow reactor combined with a quadrupole mass spectrometer: BrO + BrO -> 2Br + O-2 (1a) and BrO + BrO -> Br-2 + O-2 (1b). The overall rate constant for this reaction (defined by d[BrO]/dt = -2k(1)[BrO](2)) was found to be k(1) = k(1a) +k(1b) = (1.32 +/- 0.09) x 10(-12) exp(182 +/- 22/T) cm(3) molecule(-1) s(-1) at T = 220-950 K (where the uncertainties represent precision at the 2 sigma level). The channel-specific rate constant for the Br-2 + O-2 forming channel (1b) was determined at T = 220-450 K: k(1b) = (2.83 +/- 0.35) x 10(-13) exp(34 +/- 36/T) cm(3) molecule(-1) s(-1) (with 2 sigma uncertainties). As a result of the comparative analysis of the present data and those from the previous studies, the following Arrhenius expressions are recommended from the present work: k(1) = 1.4 x 10(-12) exp(200/T) at T = 220-950 K (independent of pressure at least for T >= 250 K) and k(1b) = 3.2 x 10(-13) exp(34/T) cm(3) molecule(-1) s(-1) at T = 220-450 K and total pressure of 2 Torr, with a conservative estimate of uncertainty of 25%, independent of temperature.