Theoretical oscillator strengths for the resonance transitions in the Zni isoelectronic sequence

Abstract

Nonrelativistic $\mathrm{gf}$ values for the $4s^2{}_{}{}^1{}_{}{}^{}S-4s4p{}_{}{}^1{}_{}{}^{}P$ transition based on multiconfiguration Hartree-Fock wave functions are reported for a number of ions from Zni to Wxlv. In addition to the correlation among the outer electrons, the effects of core polarization associated with the $3d^{10}$ subshell are taken into account to first order. Relativistic effects are estimated by using observed energies and allowing for spin-orbit interactions. When only the correlation among the outer electrons is taken into account, these approximate relativistic $\mathrm{gf}$ values agree well with relativistic calculations published recently, which also include only outershell correlation. The final values are compared with experimental observations. It is found that the discrepancy between theory and experiment is reduced by taking core polarization into account, and that there is good agreement for Zni. However, for the heavier ions a discrepancy remains which increases with increasing ionization to a factor of 2 in Krvii. Possible reasons for this discrepancy are discussed.