Excitation-autoionization in highly charged sodiumlike ions

The effects of excitation-autoionization have been studied for nine sodiumlike ions with 26{≤}Z{≤}92. Relativistic-distorted-wave methods were used to calculate cross sections for direct electron-impact ionization of these ions. Relativistic-distorted-wave cross sections were computed for electron-impact excitation of n=2 electrons to n=3 levels of the ions, and detailed relativistic Auger rates and radiative rates were calculated in order to obtain the excitation-autoionization cross sections. We investigated the variation of these cross sections along the Na-like isoelectronic sequence. We found that configuration interaction significantly affects some cross sections in ions where level crossings occur for some of the doubly excited intermediate states.