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

We report on large-scale and critically evaluated ab initio multiconfiguration Dirac-Hartree-Fock calculations of the wavelengthof the "coronal", M1 transition 4f ²F5/2o-²F7/2o in Ag-like ions. The transition between these two fine structure levels, which makes up the ground term for Z≥62 in the isoelectronic sequence, has recently been observed in Yb23+ and W27+, 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. [ABSTRACT FROM AUTHOR]