Radiative decay from doubly and singly excited states of He-like nickel

Abstract

Fully relativistic calculations on the level energies and radiative lifetimes for all the low-lying levels of He-like Ni have been systematically carried out and attention has been paid to provide a complete tabulation of data for all the conceivable one- and two-electron one-photon transitions from levels of $2{p}^{2}$ configuration decaying sequentially to the ${}^{1}{S}_{0}$ ground state. Large-scale multiconfiguration Dirac-Fock wave functions have been applied to study the level features. The accuracy of our computed data has been highlighted in terms of the uncertainty estimates on the fine structure energy levels and also on the line strengths. The branching ratios of the emitted radiations from various transitions are evaluated. The sensitivity of transition rates to Breit interaction and quantum elctrodynamics effects are analyzed in detail. A comparison of our results with available experimental and previous computations is also made.