Dielectronic recombination and spectroscopy of the heaviest Li-like ions

Dielectronic recombination (DR) of very heavy Li-like ions including Pb79+, Bi80+, and U89+ with Deltan = 0 core excitations (1s(2)2s(1/2) --> 1s(2)2p(1/2,3/2)) has been investigated at the electron cooler of the Experimental Storage Ring (ESR) of GSI in Darmstadt, Germany. Absolute rate coefficients and resonance energies of DR via intermediate doubly excited Rydberg states 1s(2)2p(1/2) nl (n greater than or equal to 20) and doubly excited states 1s(2)2P(3/2)nl(j) (n = 6 for Pb79+ and Bi80+, and n = 5 for U89+) of recombined Be-like ions have been determined. For the 1s(2)2p(1/2) nl series Rydberg states up to n approximate to 50 were resolved in the measurement In addition individual fine structure components of the Rydberg resonances can clearly be distinguished. For the first time in such a heavy system the series Emit has directly been observed in DR. For these very heavy ions strong relativistic effects as well as the Breit interaction have to be taken into account in order to explain the experimental findings. The experimental data are compared with fully relativistic multi configuration Dirac Fock (DR/MCDF) calculations.