Energy levels and lifetimes for some core-excited quartet states in Na i and Mg ii

Multiconfiguration Hartree-Fock calculations with Breit-Pauli relativistic corrections are reported for the metastable core-excited quartet states 2p⁵3s3p, 2p⁵3s3d, and 2p⁵3s4s in Na i and Mg ii, and also for 2p⁵3p² in the latter. Both correlation and relativistic effects play an important role, as expected, but in addition it was found that term dependence of the radial functions was important. In Na i the latter tended to reduce the mixing of the different terms. Lifetime determination of the odd quartets included decay to 2p⁵3s3p, 2p⁶3s, and 2p⁶3d levels as well as autoionization. The resulting lifetimes of several levels in Na i are in somewhat better agreement with experiment than those reported from other theories.