Collision dynamics of three interacting atoms: The multiple-collision expansion

Abstract

Inelastic, atom–exchange, and dissociative atom–diatomic collisions are described by means of a multiple‐collision expansion of the Faddeev equations for three atoms. Collision processes are described by a superposition of stripping, single‐, double‐, and so on, atom–atom encounters. The corresponding probability amplitude terms are expressed as integrals in momentum variables which require for their evaluation only two‐body t matrices and the initial and final distributions of diatomic momenta. Analysis of these integrals leads to the spectator‐ and recoil‐stripping models, and to kinematics rules that indicate whether a process may occur by single collisions or not. The kinematic rules are applied to (a) inelastic and reactive collisions of Ar⁺+H₂ and its isotopic variations; (b) inelastic collision of NO⁺+He; and (c) inelastic collision of Li⁺+H₂, in order to illustrate their value in interpreting experimental results.