Semiclassical Perturbation Theory of Molecular Collisions. I. First and Second Order

Abstract
Explicit formulas are derived for the first- and second-order semiclassical rotationally inelastic transition probability with an electric multipole potential. The symmetry properties of the second-order integrals are discussed, and a method for their evaluation is presented. An expression for the interference terms between first- and second-order perturbation theory is also derived.