2019ApJS..245....9S

A comprehensive set of level energies is provided for the valence and K-vacancy states of the ions Fe XVII, Fe XVIII, Fe XIX, Fe XX, Fe XXI, Fe XXII, Fe XXIII, and Fe XXIV. Level energies were calculated with the relativistic Multi-Reference Moller-Plesset Perturbation Theory method (MR-MP). The data set includes level energies coming from the configurations 1s²2(s,p)^q, 1s²2(s,p)^q–1nl, 1s¹2(s,p)^q+1, 1s¹2(s,p)^qnl, 2(s,p)^q+2, and 2(s,p)^q+1nl, where 1 <= q <= 8, n <= 5, and l <= 3. The results have been compared with data from the National Institute of Standards and Technology (NIST) online database and with previous calculations. In general, the deviation from the NIST-recommended values is below 0.6 and 1.0 eV for valence and K-vacancy level energies, respectively. However, we identify numerous outliers among the NIST-recommended values. The extensive data set presented here greatly augments the amount of available reference level energies in the NIST database for L-shell ions of Fe, and we expect our data set to ease line identification and confirm level designations.