Resonance strengths for KLL dielectronic recombination of highly charged mercury ions and improved empirical $\boldsymbol{Z}$-scaling law

TL;DR

This paper presents experimental and theoretical data on KLL dielectronic recombination resonance strengths in mercury ions, and introduces an improved Z-scaling law that accounts for relativistic effects in heavy ions.

Contribution

It provides new experimental measurements, compares them with advanced calculations, and develops an improved empirical Z-scaling law for DR resonance strengths in highly charged heavy ions.

Findings

Experimental resonance strengths for mercury ions were measured.

The data agree with relativistic atomic calculations.

An improved Z-scaling law including relativistic corrections was derived.

Abstract

Theoretical and experimental resonance strengths for KLL dielectronic recombination (DR) into He-, Li-, Be-, and B-like mercury ions are presented, based on state-resolved DR x-ray spectra recorded at the Heidelberg electron beam ion trap. The DR resonance strengths were experimentally extracted by normalizing them to simultaneously recorded radiative recombination signals. The results are compared to state-of-the-art atomic calculations that include relativistic electron-electron correlation and configuration mixing effects. Combining the present data with other existing ones, we derive an improved semi-empirical $Z$-scaling law for DR resonance strength as a function of the atomic number, taking into account higher-order relativistic corrections, which are especially relevant for heavy highly charged ions.