Major role of multielectronic K-L inter-shell resonant recombination processes in Li- to O-like ions of Ar, Fe, and Kr

TL;DR

This study reveals that multielectronic K-L inter-shell resonant recombination processes significantly influence the total recombination cross sections in highly charged ions of Ar, Fe, and Kr, especially for atomic numbers between 10 and 36, impacting plasma modeling.

Contribution

It provides systematic high-resolution measurements and theoretical analysis showing the dominance of higher-order resonant recombination processes over traditional dielectronic channels in certain ions.

Findings

Higher-order resonant contributions can surpass dielectronic recombination.

Experimental data aligns well with advanced relativistic calculations.

Inter-shell quadruelectronic recombination features observed.

Abstract

Dielectronic and higher-order resonant electron recombination processes including a K-shell excitation were systematically measured at high resolution in electron beam ion traps. Storing highly charged Ar, Fe, and Kr ions, the dependence on atomic number Z of the contribution of these processes to the total recombination cross section was studied and compared with theoretical calculations. Large higher-order resonant recombination contributions are found, especially for systems with 10<Z<36. In some cases, they even surpass the strength of the dielectronic channel, which was hitherto presumed to be always the dominant one. These findings have consequences for the modeling of high-temperatur plasmas. Features attributed to inter-shell quadruelectronic recombination were also observed. The experimental data obtained for the He-like to O-like isoelectronic sequences compare well with the results of advanced relativistic distorted-wave calculations employing multiconfiguration Dirac-Fock bound state wave functions that include threefold and fourfold excitations.