Core polarization in Kr viii

The effect of core polarization on fine-structure splitting for the ${\mathit{nf}}^2$${\mathit{F}}_{\mathit{J}}$ levels in ${\mathrm{Kr}}^{7+}$ is investigated in order to explore further the fine-structure inversion of these levels. Core-polarization effects are included via two distinct methods, namely, by performing multiconfigurational Dirac-Fock calculations and single-configuration Dirac-Fock calculations including a core-polarization potential. Both sets of results are compared with presently available experimental values.