Static and dynamic polarizabilities of Mg-like ions

In the present study, we investigate the static and frequency-dependent dipole polarizabilities for the ground state of neutral Mg and four ions of the magnesium sequence: Al(+), Si(2+), P(3+) and S(4+). The wavefunctions are written in terms of configuration interaction (CI) expansions. Radial functions of orbitals up to n = 9 are used in the calculations, some optimized on the polarizability, some on the energies of low-lying states. We present a detailed study of the convergence of the results as the size of the CI expansions is increased. A very satisfactory degree of stability is achieved.