L-shell alignment observed after resonant transfer and excitation in U90+ → C collisions

Abstract

With heavy, highly-charged ions the electron-electron correlation is probed in the relativistic domain by Resonant Transfer and Excitation, RTE. For the studied case of initially He-like U90+ ions the KLL-RTE splits into three resonance groups according to the j values of the electrons involved in the doubly-excited intermediate states. For a K to L excitation into a j = ½ state with a simultaneous capture also to a j' = ½ state, relativistic effects yield a strong cross section enhancement. The doubly excited states with jj' = 1/2-3/2 show a strong anistropy for the radiative ground state transition of the j' = 3/2 electron manifesting a pronounced non-isotropic population of the magnetic substates.