Dielectronic recombination involving high Rydberg states

Abstract

Dielectronic recombination (DR) rates for ions contain contributions from intermediate states in which at least one electron is raised to or captured in a high Rydberg state ( nl). Although the n-dependence of the Auger and radiative probabilities is usually of the n −3 type, the DR rate, α DR, may have a much weaker n-dependence, if the two active electrons are in high Rydberg states (HRS) or in a light ion. Excitations from the L and M shells of the ions A 7+, Fe 15+ and Mo 31+ are considered and a theoretical formula for the fluorescence yield is given which is applicable for large n. The relative sizes of the contributions to α DR made by select classes of HRS are calculated. Results are strongly influenced by Auger decays accompanied by transitions into excited states.