Electron impact excitation rate coefficients for Ni-like gadolinium

Abstract

A detailed and large-scaled calculation is performed on the total electron impact excitation rate coefficients from the ground state to the 106 fine-structure levels in 3l-14l′ of Ni-like Gd36+ employing the relativistic configuration-interaction distorted-wave approximation. The resonance contributions from 3l174l′n′′l′′ and 3l175l′n′′l′′ doubly-excited states of Cu-like Gd35+ are taken into account using the isolated process and isolated resonances approximation. The effects of the radiative decays from the resonances are investigated carefully and are found to be significant. The present rate coefficients, as well as the collision strength, are compared extensively with the previously published results. We believe our results should be more accurate and reliable.