Semi-classical theory for non-separable systems:. Construction of “good” action-angle variables for reaction rate constants

A semiclassical expression for bimolecular rate constants for reactions which have a single activation barrier is obtained in terms of the “good” action variables of the (classical) Hamiltonian that are associated with the saddle point region of the potential energy surface. The formulae apply to non-separable, as well as separable saddle points.