Ms. Safronova et al., RELATIVISTIC MANY-BODY CALCULATIONS OF ENERGIES OF N=3 STATES OF BE-LIKE IONS, Journal of physics. B, Atomic molecular and optical physics, 30(10), 1997, pp. 2375-2393
Energies of the 2s3s (S-1(0), S-3(1)), 2S3p (P-1(1), P-3(J)), 2s3d (D-
1(2), D-3(J)), 2p3s (P-1(1), P-3(J)), 2p3p (S-1(0), S-3(1), P-1(1), D-
1(2), P-3(J), D-3(J)) and 2p3d (P-1(1), D-1(2), F-1(3), P-3(J), D-3(J)
, F-3(J)) states for Be-like ions with nuclear charges Z in the range
4-30 and for Z = 54 are determined to second order in relativistic man
y-body perturbation theory starting from a frozen-core Dirac-Fock basi
s. Second-order Coulomb and second-order Breit-Coulomb correlation ene
rgies are evaluated. Corrections for the frequency dependence of the B
reit interaction are taken into account in lowest order. Lamb-shift co
rrections to the energies are also included in lowest order. Compariso
ns are made with other theoretical calculations and with experimental
data. We obtain an excellent agreement with experiment for term splitt
ing, even for low-Z ions. Results for the 2p-3d excitation energies fo
r Xe50+ are also in very good agreement with experiment.