The Polarized Frozen-Core Approximation: Oscillator Strengths for the Beryllium Isoelectronic Sequence

The primitive frozen core model of the Hartree-Fock approximation has been improved by including an l -dependent core polarization potential in the valence orbital equation. The improved model yields ionization energies in good agreement with observations for a large number of s-p - and d -levels of several members of the Beryllium isoelectronic sequence. These energies and the corresponding orbital wave-functions have been used to calculate oscillator strengths for electric dipole transitions and appear to yield reliable f -values in many cases.