Comprehensive Laboratory Measurements Resolving the LMM Dielectronic Recombination Satellite Lines in Ne-like Fe XVII Ions

TL;DR

This study combines experimental and theoretical methods to accurately measure and analyze dielectronic recombination satellite lines in Fe XVII, improving understanding of X-ray emissions and revealing discrepancies in existing databases.

Contribution

It provides comprehensive experimental data and advanced theoretical calculations that enhance the accuracy of dielectronic recombination rates for Fe XVII.

Findings

Experimental measurements show negligible contamination effects.

Theoretical calculations using many-body perturbation theory agree well with experiments.

Discrepancies found between measured DR rates and existing databases.

Abstract

We investigated experimentally and theoretically dielectronic recombination (DR) populating doubly excited configurations $3l3l'$ (LMM) in Fe XVII, the strongest channel for soft X-ray line formation in this ubiquitous species. We used two different electron beam ion traps and two complementary measurement schemes for preparing the Fe XVII samples and evaluating their purity, observing negligible contamination effects. This allowed us to diagnose the electron density in both EBITs. We compared our experimental resonant energies and strengths with those of previous independent work at a storage ring as well as those of configuration interaction, multiconfiguration Dirac-Fock calculations, and many-body perturbation theory. This last approach showed outstanding predictive power in the comparison with the combined independent experimental results. From these we also inferred DR rate coefficients, unveiling discrepancies from those compiled in the OPEN-ADAS and AtomDB databases.