Relativistic R-matrix calculations of photoionization cross sections of Cu XVIII

Abstract

The total photoionization cross sections for the ground state 2p63s2(1S0) and the lowest three excited states 2p63s3p(3Po0,1,2) of the Mg-like Cu XVIII ion have been calculated by making use of the close-coupling Breit Pauli R-matrix (BPRM) approximation. The lowest 21 target level states of Cu XIX have been included in the photoionization calculations of Cu XVIII. Our calculated target state energies of the core ion Cu XIX show a good agreement with the observed energies tabulated in the NIST database. To further assess the accuracy of our BPRM results, photoionization cross section calculations for the ground state configuration have also been performed by employing the fully relativistic Dirac atomic R-matrix code (DARC). Our two independent calculations show a reasonable agreement between the calculated cross sections in the overall background shape and magnitude. We believe that our cross section data may be beneficial for the modelling and diagnostics of astrophysical and laboratory plasmas.