Semiclassical Theory for Molecular AutoIonization
Abstract
In the limit of high vibrational and electronic principal quantum numbers, a semiclassical model for the autoionization of diatomic molecules has been constructed. The molecular vibrations are treated as classical oscillators, whose parameters are chosen from a knowledge (which can be taken either from theory or experiment) of the positions of the quantal vibrational levels and the position and depth of the minimum of the adiabatic potential curve of the residual molecular ion. The theory is designed for the case where vibrational quantum numbers are greater than about 10. Electronic quantum numbers are restricted by the requirement that they be high enough so that (i) the excitedelectroncoreelectron interaction can be represented by the monopole term in the region where the excited electron is always farther from either nucleus than the core electron is, and (ii) the excitedelectronnuclear interactions can be represented by the monopole terms in all regions. An advantage of the theory over the perturbedstationarystate theory is that its validity extends into the region of very high electronic quantum numbers (n=100), where the electron and nuclear velocities are comparable and the BornOppenheimer theory is not valid. Numerical estimates for the autoionization rates are presented for several sample cases for vibrations in the neighborhood of n'=10, excited electrons from n=10 to 20, and zeroenergy ejected electrons. Numerical results are also included for the lower vibrations (n'<=5), n=8, 9, 10 excited electrons, and zeroenergy ejected electrons, and comparison is made with experimental and other theoretical results.
 Publication:

Physical Review A
 Pub Date:
 January 1971
 DOI:
 10.1103/PhysRevA.3.95
 Bibcode:
 1971PhRvA...3...95R