Direct versus indirect microscopic mechanisms in the Li + HF reaction

Abstract

Quasiclassical trajectory calculations on the chemical reactions Li + XF (v, J = 0) → LiF + X (X = Mu, 1H, 3H, 10H) at selected initial atom-diatom orientations, v = 0, 1 and 2 and 15 kcal mol-1 of collision energy have been carried out. A potential-induced rotation of the target molecule, favoured by the great angular forces of the system, is, as a rule, necessary for the reactive success of the collision if ν = 0 or 1, but not if ν = 2. The ease or difficulty of rotation according to whether the molecule is light (MuF or 1HF) or heavy (3HF or 10HF) explains most of the observed orientational dependence of reactivity.