Coronal lines and the importance of deep core-valence correlation in Ag-like ions

TL;DR

This paper presents highly accurate ab initio calculations of coronal line wavelengths in Ag-like ions, emphasizing the critical role of deep core-valence correlation, with results supporting fusion plasma diagnostics and matching recent experimental data.

Contribution

The study provides the first comprehensive set of recommended wavelengths for Ag-like ions from Z=50 to 94, highlighting the importance of including deep core-valence correlation in theoretical models.

Findings

Excellent agreement with recent experimental measurements.

Core-valence correlation significantly improves wavelength accuracy.

Results achieve near-spectroscopic precision for forbidden lines.

Abstract

We report on large-scale and critically evaluated {\em ab initio} MCDHF calculations of the wavelength of the "coronal", M1 transition $4f\ ^2\mathrm{F}_{5/2}^o-^2\mathrm{F}_{7/2}^o$ in Ag-like ions. The transition between these two fine structure levels, which makes up the ground term for $Z \ge 62$ in the isoelectronic sequence, has recently been observed in Yb$^{23+}$ and W$^{27+}$, where the latter could be of great importance for fusion plasma diagnostics. We present recommended values for all members of the sequence between $Z = 50$ and $94$, which are supported by excellent agreement with values from recent experiments. The importance of including core-valence correlation with the $n=3$ shell in the theoretical model is emphasized. The results show close to spectroscopic accuracy for these forbidden lines.