Formal theory of atom--diatomic molecule reactions

Low energy atom--diatomic molecule scattering is formulated in the adiabatic representation. Explicit care is taken to describe the scattering boundary conditions and the Pauli principle correctly. A set of coupled three-body equations is obtained for the nuclear motion. Coupling represents ''hopping'' from one electronic surface to another. The coupling operator is obtained by a generalization of a method previously used in atom--atom scattering. It has the property of vanishing when the reacting products are well separated and involves the previously introduced electron switching function and a new nuclear switching function