Perturbation Theory for the Bound Polaron

Abstract

The second order energy shifts of 1s, 2s and 2p states of the polaron bound in the Coulomb potential are evaluated by various approximate and “exact” numerical methods, proposed by many authors. The comparison of these results makes clear the validity of the approximate methods. For the 1s-2p transition energy in silver halides, there are large discrepancies between the “exact” numerical results and the approximate results of Bajaj and Clark; the second order perturbation theory does not yield so good agreement with the experiment as previously inferred from an approximate evaluation.