Experimental study of the deep-lying dielectronic recombination resonances of He-like germanium ions

Dielectronic recombination (DR) for He-like Ge30+ through both one-electron–one-photon and two-electron–one-photon (TEOP) stabilization of Li-like doubly excited states was studied with the Heidelberg electron beam ion trap. The DR resonance strength from He-like Ge30+ 1s2 1S0 to the Li-like Ge29+ specific configuration 1s2s2 2S1/2 was determined to be (2.02 ± 0.2) × 10-20 cm2 eV and the total KLL DR resonance strength was determined to be (63.7 ± 6.5) × 10-20 cm2 eV. The experimental results agree well with a theoretical prediction obtained with the configuration interaction Hartree–Fock method