KINETICS OF THE REACTIONS OF HBR WITH O-3 AND HO2 - THE YIELD OF HBR FROM HO2+BRO

An upper limit on the yield of HBr from reaction (R1) (HO2 + BrO --> products) has been determined by measuring an upper limit for the rate coefficient of the reverse reaction (R1') (HBr + O-3 --> HO2 + BrO). The limits measured at 301 and 441 K were extrapolated to low temperatures to determine that the yield of HBr from reaction (R1) is negligible throughout the stratosphere (< 0.01% of k(1)) An upper limit for the rate coefficient of the reaction of HO2 with HBr was also determined to be very low less than or equal to 3 x 10(-17) cm(3) molecule(-1) s(-1) at 300 K and less than or equal to 3 x 10(-16) cm(3) molecule(-1) s(-1) at 400 K. The implications of these results to stratospheric chemistry are discussed.