Semiclassical theory of direct dissociative recombination

A generalized semiclassical theory of direct dissociative recombination is developed. It covers the possibility that two or more regions of stationary phase can contribute to the Franck-Condon overlap with and without autoionization. The analysis uniformly connects the stationary phase regions of large separation with the caustic region where these regions coalesce. The turning point divergence is also treated. It is shown how various interference effects from stationary phase regions can be exhibited in the cross section for the direct process even if left uncoupled from the indirect mechanism.