Theoretical radiative lifetimes of levels in singly ionized lanthanum

Theoretical radiative lifetimes of 29 levels in singly ionized lanthanum are determined using Cowan's 'Hartree-Fock and relativistic corrections' (HFR) method modified by us to include core-valence electron correlations in the core-polarization picture. The configuration mixing coefficients have been determined semiempirically through a least-squares fitting procedure treating Slater and spin-orbit integrals as free parameters. The results obtained compared with available experimental and other theoretical data confirm the importance of valence-core correlation effects.