Orbital electron capture of hydrogen- and helium-like ions

Abstract

Corrections to the ratio of electron capture (EC) rates in hydrogen- and helium-like ions are calculated. We find that the most significant contribution is the electron screening effect. The correction has a simple form $(1\ensuremath{-}5/16Z){}^{3}(1\ensuremath{-}{\ensuremath{\delta}}_{3})$ which ranges from almost $50%$ in helium to $1%$ in heavier nuclei. We discuss also EC in helium-like ions accompanied by an emission of the remaining electron into the continuum, a new decay channel, for which we calculate the decay probability. It is a very exotic type of Auger electron emission.