FINE-STRUCTURE OF CA-, SR-, BA-, AND RA- FROM THE MANY-BODY THEORY CALCULATION

Atomic many-body theory methods are used to calculate the fine structu re of negative ions formed by binding a p electron into an open shell. Ca-, Sr-, Ba-, and Ra-. This binding is due to a strong correlation p otential acting between the electron and the neutral atom. Comparison with experimental data shows that the second order many-body perturbat ion theory calculation overestimates the correlation potential by 10% to 15% Scaling factors are introduced in the correlation potential to reproduce experimental binding energies of the lower p(1/2) components . This procedure yields fine-structure intervals in excellent agreemen t with experiment for Ca-, Sr-, and Ba-, and allows us to predict that in Ra- the p(1/2) state is bound by 100 meV, and p(3/2) is a resonanc e at 16 meV in the continuum.