Static and dynamic polarizabilities of Na-like ions

We have calculated static and frequency- dependent polarizabilities for the ground states of neutral Na and four sodium- like ions Mg+, Al2+, Si3+ and P4+. The polarizability is expressed in terms of the second- order energy correction, when the electric field is treated as a perturbation. The zero- and first- order wavefunctions are expressed as configuration interaction expansions. The radial parts of the one- electron functions are optimized, some on the ground or first excited state energies, others on the second- order energy correction ( i. e. the polarizability). The wavefunctions can also be used as target state functions in electron - atom and electron - ion scattering.