Large-scale Multiconfiguration Dirac–Hartree–Fock Calculations for Astrophysics: C-like Ions from O iii to Mg vii

Abstract

Large-scale multiconfiguration Dirac–Hartree–Fock calculations are provided for the n ≤ 5 states in C-like ions from O iii to Mg vii . Electron correlation effects are accounted for by using large configuration state function expansions, built from sets of orbitals with principal quantum numbers n ≤ 10. An accurate and complete data set of excitation energies, wavelengths, radiative transition parameters, and lifetimes is offered for the 156 (196, 215, 272, 318) lowest states of the 2 s 2 2 p 2 , 2 s 2 p 3 , 2 p 4 , 2 s 2 2 p 3 s , 2 s 2 2 p 3 p , 2 s 2 2 p 3 d , 2 s 2 p 2 3 s , 2 s 2 p 2 3 p , 2 s 2 p 2 3 d , 2 p 3 3 s , 2 p 3 3 p , 2 p 3 3 d , 2 s 2 2 p 4 s , 2 s 2 2 p 4 p , 2 s 2 2 p 4 d , 2 s 2 2 p 4 f , 2 s 2 p 2 4 s , 2 s 2 p 2 4 p , 2 s 2 p 2 4 d , 2 s 2 p 2 4 f , 2 s 2 2 p 5 s , 2 s 2 2 p 5 p , 2 s 2 2 p 5 d , 2 s 2 2 p 5 f , and 2 s 2 2 p 5 g configurations in O iii (F iv , Ne v , Na vi , Mg vii ). By comparing available experimental wavelengths with the MCDHF results, the previous line identifications for the n = 5, 4, 3 → n = 2 transitions of Na vi in the X-ray and EUV wavelength range are revised. For several previous identifications discrepancies are found, and tentative new (or revised) identifications are proposed. A consistent atomic data set including both energy and transition data with spectroscopic accuracy is provided for the lowest hundreds of states for C-like ions from O iii to Mg vii .