Electron correlation in three-body Coulomb states of barium.

Abstract

We excited a special class of states of a three-body Coulomb system, populating double Rydberg states of the type Ngng @N55–9, n@N where N (n) is the principal quantum number of the inner ~outer! valence electron# in Ba with both valence electrons in non-core-penetrating orbits with the same orbital angular momentum. Electron correlation effects manifest themselves by the appearance of additional Nhnl resonances, a rapid increase of the observed quantum defects with N , as well as a significant decrease of the autoionization rate for N59. @S1050-2947~96!50807-3#