Multipole effects in the photoionization processes of Mg isoelectronic series with Z = 12–22
In this paper, we calculate relativistic photoionization parameters for Mg and Mg-like ions for photon energies between 10 eV and 30 keV using Dirac–Fock initial discrete-state wave functions and final central-field continuum wave functions. By taking multipole contributions into account, we achieve results that are in good agreement with both experimental data and theoretical results for neutral Mg atoms, and are within 5% of the experimental data for photon energies above 1 keV. We also find that, in relativistic photoionization calculations, the magnetic quadrupole transition tends to be more important than the magnetic dipole transition. The effect of multipoles is studied in detail by considering the contribution of the electric dipole transition to the full multipole calculation.