Negative-continuum dielectronic recombination into excited states of highly-charged ions

TL;DR

This paper investigates negative-continuum dielectronic recombination into excited states of highly-charged ions, revealing a significant increase in recombination probability when excited states are included, using relativistic perturbation theory.

Contribution

It introduces a detailed study of excited-state contributions to negative-continuum dielectronic recombination in highly-charged ions, with quantitative analysis for uranium ions.

Findings

Approximately 75% increase in total recombination probability when excited states are considered.

Detailed calculations for uranium ions across various collision energies.

Enhanced understanding of recombination processes involving excited ionic states.

Abstract

The recombination of a free electron into a bound state of bare, heavy nucleus under simultaneous production of bound-electron--free-positron pair is studied within the framework of relativistic first--order perturbation theory. This process, denoted as "negative-continuum dielectronic recombination" leads to a formation of not only the ground but also the singly- and doubly-excited states of the residual helium-like ion. The contributions from such an excited--state capture to the total as well as angle-differential cross-sections are studied in detail. Calculations are performed for the recombination of (initially) bare uranium U$^{92+}$ ions and for a wide range of collision energies. From these calculations, we find almost 75 % enhancement of the total recombination probability if the excited ionic states are taken into account.