Influence of hot and dense plasmas on energy levels and oscillator strengths of ions: beryllium-like ions for<i>Z</i>= 26–36

Abstract

An approach based on the self-consistent-field multi-configuration Dirac–Fock model has been developed for the calculation of atomic structures and transition properties of ions in hot and dense plasmas. The correlation effects and the angular momentum coupling among the bound electrons are treated in a way usually employed in a normal multi-configuration Dirac–Fock method. Influence of plasma screening on transition energies and oscillator strengths is investigated by introducing a correction to the one-electron potential to account for the screening of the ionized electrons. This correction is calculated from the ionized electron micro-space distribution, which is obtained based on an average atom model for the temperature- and density-dependent average ionization of atoms in plasmas. As examples, results of beryllium isoelectronic sequence ions for Z = 26–36 demonstrate that the 2s2–[2s1/2, 2p1/2]1 and 2s2–[2s1/2, 2p3/2]1 transition energies increase with plasma density and temperature, leading to a blue-shift of these lines. The overall trend for the relative changes of the oscillator strengths of the same transitions is also presented. Comparisons between the results of the present model and those of the uniform ion sphere model are made to show the significance of the micro-space density variation of the ionized electrons on the calculated results.