| Abstract
| - The reactions of OH + HBr and all isotopic variants have been measured in a pulsed supersonic Laval nozzleflow reactor between 53 and 135 K, using a pulsed DC discharge to create the radical species and laserinduced fluorescence on the A 2Σ ← X 2Π (v‘ = 1 ← v‘ ‘ = 0) transition. All reactions are found to possessan inverse temperature dependence, in accord with previous work, and are fit to the form k = A(T/298)-n,with k1 (OH + HBr) = (10.84 ± 0.31) × 10-12(T/298)(-0.67±0.02) cm3/s, k2 (OD + HBr) = (6.43 ± 2.60) ×10-12(T/298)(-1.19±0.26) cm3/s, k3 (OH + DBr) = (5.89 ± 1.93) × 10-12(T/298)(-0.76±0.22) cm3/s, and k4 (OD +DBr) = (4.71 ± 1.56) × 10-12(T/298)(-1.09±0.21) cm3/s. A global fit of k vs T over the temperature range23−360 K, including the new OH + HBr data, yields k(T) = (1.06 ± 0.02) × 10-11(T/298)(-0.90±0.11) cm3/s,and (0.96 ± 0.02) × 10-11(T/298)(-0.90±0.03) exp((-2.88±1.82 K)/T) cm3/s, in accord with previous fits. In addition,the primary and secondary kinetic isotope effects are found to be independent of temperature withinexperimental error over the range investigated and take on the value of (kH/kD)AVG = 1.64 for the primaryeffect and (kH/kD)AVG = 0.87 for the secondary effect. These results are discussed within the context of currentexperimental and theoretical work.
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