A preliminary report is given of relative reactive cross sections for four abstraction reactions H + H′Br ← HH′ + Br with attacking atom (A) H or D, and atom under attack (B) H or D. The pattern of reactive cross sections, as obtained in a crossed molecular beam experiment at a collision energy ET = 7 kcal/mol, indicates Sr(D,H) ≤ Sr(D,D) > Sr(H,H) > Sr(H,D). The atoms in parentheses are A and B. We describe a three-dimensional classical trajectory (CT) study on a potential-energy surface proposed in 1969 by Parr and Kuppermann (PK); the CT results are in fair accord with experiment. It is suggested that (D,H) has the largest cross section because it exhibits the most favorable relative timing of A approach to BC rotation. On the basis of CT it appears that the same sequence of cross sections and the same rationale may be applied to the exchange reactions H + BrH′ ← HBr + H′.
|Journal||International Journal of Chemical Kinetics|
|State||Published - 1981|