Quantum mechanical theory of a structured atom–diatom collision system: A+BC(1Σ)

The problem of a 2P state atom colliding with a singlet sigma state diatom, which involves multiple potential surfaces, is investigated. Within a diabatic representation for the electronic degrees of freedom (plus spin–orbit interaction), coupled scattering equations are derived in both space-fixed and body–fixed coordinate systems, and coefficients analogous to Percival–Seaton coefficients are exhibited. Approximations to the exact equations, including angular momenta decoupling approximations, are discussed for both the space-fixed and body-fixed formalisms.