Influence of strongly coupled plasma environment on photoionization of H-like O7+ion

Abstract

The effect of strongly coupled plasma environment on the photoionization cross sections of the H-like O7+ ion is studied within the framework of relativistic configuration interaction technique implemented in the flexible atomic code. The analytical b-potential of Li and Rosmej [Phys. Lett. A 384, 126478 (2020)] and uniform electron gas model potential of Saha and Fritzsche [J. Phys. B 40, 259 (2007)] have been employed for incorporating the plasma shielding effects. The level energies for unscreened H-like O7+ ion are in excellent agreement with the National Institute of Standards and Technology values. The bound and continuum state wavefunctions are determined by solving the modified Dirac equations. The photoionization cross sections evaluated in the dipole approximation are obtained from the bound-free transition matrix element. Cross section calculations are performed over an electron density range of 1.0 × 1019–2.0 × 1023 cm−3 and a temperature range of 200–1000 eV. The plasma environment is found to considerably influence the photoionization cross sections. It has been observed that the ionization thresholds move to the low energy region with the increase in free electron densities. The present results will be beneficial for the interpretation of spectra observed in a variety of astrophysical and laboratory plasmas.