T. Schussler et al., LASER-STIMULATED RECOMBINATION SPECTROSCOPY FOR THE STUDY OF LONG-RANGE INTERACTIONS IN HIGHLY-CHARGED RYDBERG IONS, Physical review letters, 75(5), 1995, pp. 802-805
The energy shifts of high-angular-momentum Rydberg states in beryllium
like O4+, due to long-range interactions of the Rydberg electron with
the ionic core, are measured by laser spectroscopy, using stimulated t
wo-step recombination of free electrons with O5+ ions. The comparison
of the accurate experimental results with theoretical shifts from the
core polarization model and from ab initio atomic structure calculatio
ns shows considerable disagreement, demonstrating the need for an effi
cient method to include configuration interaction in a long-range inte
raction model.