Effects of radiative decay on the bound-continuum transition of highly charged atomic ions

In a system consisting of an electron and a highly charged ion, interaction with the radiation field is strong, and radiation-damping effects must be accurately taken into account. The present work provides a numerical method to study the radiation-damping effect in the processes of photoionization, radiative recombination, and electron scattering. A simple calculation is made for Fe²⁴⁺, Xe⁵²⁺(1s2s)+hν⇆Fe²⁵⁺, Xe⁵³⁺(1s)+e. Special emphasis is placed on the nonapplicability of conventional first-order perturbation theory to photoinduced autoionization of a highly charged ion. The interference effect between the resonant and the nonresonant parts is found to be negligible in the present cases.