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

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.

Automated summary

This study investigated dielectronic recombination in Fe XVII, focusing on the formation of doubly excited configurations. Experimental and theoretical comparisons showed that many-body perturbation theory had outstanding predictive power and was in good agreement with other experimental results. Discrepancies in DR rate coefficients were also revealed from comparison with existing databases.