Theory of the Dissociative Recombination and Associative Ionization of Hydrogen

Abstract

A brief survey is given of the experimental information which is presently available on dissociative recombination and the dynamically inverse process of associative ionization. The mechanisms by which the reactions can occur are described in terms of adiabatic potential-energy curves of the ion and of the quasi-molecule formed from the union of ion and electron. The paucity of detailed information about the relevant potential-energy curves suggests that one focus attention upon hydrogen, the system about which the most is known. A mathematical theory is then constructed which takes as its basis ingredients a Coulomb—Born description of the scattering of ion and electron and an adiabatic, or perturbed-stationary-state, treatment of atom—atom collisions. A very general approach is abandoned in favor of one based upon an approximate wave-function and which includes coupling of only a few entrance and final-state channels. Equations are derived for the scattering amplitudes in the two sets of channels and formulas are given for the relevant cross sections.