Effects of the electron correlation and Breit and hyperfine interactions on the lifetime of the 2p(5)3s states in neutral neon

In the framework of the multiconfiguration Dirac-Hartree-Fock method, we investigate the transition properties of four excited states in the 2p(5)3s configuration of neutral neon. The electron correlation effects are taken into account systematically by using the active space approach. The effect of higher-order correlation on fine structures is shown. We also study the influence of the Breit interaction and find that it reduces the oscillator strength of the P-3(1)o-S-1(0) transition by 17%. It turns out that the inclusion of the Breit interaction is essential even for such a light atomic system. Our ab initio calculated line strengths, oscillator strengths, and transition rates are compared with other theoretical values and experimental measurements. Good agreement is found except for the P-3(2)o-S-1(0) M2 transition for which discrepancies of around 15% between theories and experiments remain. In addition, the impact of hyperfine interactions on the lifetimes of the P-3(0)o and P-3(2)o metastable states is investigated for the Ne-21 isotope (I = 3/2). We find that hyperfine interactions reduce the lifetimes drastically. For the P-3(0)o state the lifetime is decreased by a factor of 630.