Perturbed-Stationary-State Calculation of Collisions in a Reactive System

Abstract

Collisions in the reactive system K+HBr are treated quantum mechanically in a perturbed-stationary-state approximation. A potential surface for the system is constructed with Morse potentials for diatomic molecules and switching functions representing three-body effects. The cross section is written in an angular-momentum representation which permits an evaluation of the probability of reaction as a function of the impact parameter in the semiclassical limit. For the perturbed stationary wavefunction we take KBr harmonic-oscillator wavefunctions with the force constant varied so as to conform to the assumed potential surface. Computation of the matrix elements at initial relative kinetic energies of 2, 3.5, and 5 kcal/mole yields total reaction cross sections, probability of reaction vs impact parameter, and rotational- and vibrational-state distributions of products which can be brought to reasonable agreement with experiment upon suitable choice of two adjustable parameters in the switching functions.