The ratio of rate constants kF+HBr/kF+H2 has been determined by a discharge-flow-mass spectrometric technique and was found to be independent of temperature in the range 203 to 298 K. Based on reported results for kF+H2 it is concluded that kF+HBr exhibits an Arrhenius temperature dependence in this temperature range. The present results indicate that the mechanism for the F+HBr reaction is probably a direct hydrogen atom abstraction, rather than one involving the formation of a FBrH complex, as suggested by Würzberg and Houston, who found a marked non-Arrhenius behavior for this reaction. The present results for F+HBr are consistent with our earlier results for the Cl+HBr reaction.
Bibliographical noteFunding Information:
This research was supported by the Fund for Basic Research Administered by The Israel Academy of Sciences and Humanities.