A large discrepancy between Dirac-Fock calculations and experiment for the spin-orbit splitting, ${}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}-{}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$, in the ground states of B- and F-like ions is resolved. The discrepancy arises from spurious terms which are inherent in the relativistic self-consistent-field procedure. Removal of these terms substantially improves the agreement between theory and experiment on spin-orbit splitting.

• Received 9 February 1982

DOI:https://doi.org/10.1103/PhysRevLett.48.1245