CALCULATIONS OF THE SCREENED SELF-ENERGY AND VACUUM POLARIZATION IN LI-LIKE, NA-LIKE, AND CU-LIKE IONS

We present ab initio calculations of the screened self-energy and vacuum polarization for the resonance transitions of Li-like, Na-like, and Cu-like ions, for a degree of ionization of about 10 or greater. The direct part of the Dirac-Fock potential is incorporated to all orders in the radiative corrections, and exchange effects are added in leading order. When combined with previous calculations of correlation and nuclear effects, our results agree with experiment at the level of experimental uncertainty with only a few exceptions, most notably the low-Z part of the Cu isoelectronic sequence. The calculations agree well at low Z with phenomenological estimates of the QED terms based on scalings of the known hydrogenic values but deviate slightly at high Z. We discuss the leading omitted two-photon QED terms.