The electrostatic fine structure for singly excited lithium is accurately calculated using an effective potential method that has proven to be very useful for helium. Relevant properties of the two-electron ${\mathrm{Li}}^{+}$ ionic core with finite nuclear mass are determined from variational wave functions. From these, non- relativistic level shifts are obtained analytically, and the leading relativistic correction is applied. A comparison with recent experimental results is made.

• Received 22 July 1994

DOI:https://doi.org/10.1103/PhysRevA.51.2926