Resonance-excitation process for Ni-like tantalum

Abstract

A detailed large-scale calculation on the resonant excitation rate coefficients from the ground state to the 106 fine-structure levels belonging to $3{l}^{17}4{l}^{\ensuremath{'}}$ ($l=0,1,2$; ${l}^{\ensuremath{'}}=0,1,2,3$) configurations of Ni-like tantalum have been performed using the relativistic distorted-wave approximation. The contributions through all possible Cu-like doubly excited states $3{l}^{17}4{l}^{\ensuremath{'}}{n}^{\ensuremath{''}}{l}^{\ensuremath{''}}$ and $3{l}^{17}5{l}^{\ensuremath{'}}{n}^{\ensuremath{''}}{l}^{\ensuremath{''}}$ (${n}^{\ensuremath{''}}\ensuremath{\leqslant}15$, ${l}^{\ensuremath{''}}\ensuremath{\leqslant}8$) are calculated. The validity of ${n}^{\ensuremath{''}\ensuremath{-}3}$ scaling law is investigated. The radiative damping effects on resonant excitation rates are studied. The significant effects arising from decays to autoionizing levels are also investigated. The contributions from resonant excitation are found to be as important as direct excitation processes for most transitions. In some cases, the resonant excitation can enhance the excitation rate coefficients by an order of magnitude. Large discrepancies between the present resonant excitation rate coefficients with previously published values are found, and the present results should be more reliable and accurate.