In a previous publication [Can. J. Phys. 75, 11 (1997)] we calculated the generalized polarizabilities up to multipole order 3 as well as certain higher-order hyperpolarizabilities for two-electron atoms and ions of $Z=2\mathrm{}–6$ and 10. In this paper we apply some of these results to calculate excited-state energies in three times ionized (lithiumlike) carbon. For states with angular momentum $L>\mathrm{}3\mathrm{}$ accurate results are obtained using an asymptotic polarizability expansion that includes nonadiabatic effects. Comparison is made with recent optical measurements, and a critical discussion of the correct form of the expansion is given. In addition, the possibility of very accurate measurements of the fine-structure splitting encourages us to present a table of such splittings to very high accuracy. An appendix contains similar results for lithiumlike oxygen and neon ions.

• Received 1 June 1999

DOI:https://doi.org/10.1103/PhysRevA.60.2848