Abstract

One of the interesting problem of atomic physics is to understand better the dynamic of highly excited two-electron systems (nℓn‘ℓ’). Recently, the exploration of highly excited two-electron states so called "double-Rydberg" states have been performed using multiphoton laser excitation in barium. From a theoretical point of view two classes of "double-Rydberg” states can be considered. At the so-called Wannier ridge (n~n’), the correlation between the electrons becomes pre-dominant. On the other hand, on both sides of the Wannier ridge (n’>>n), the outermost electron is moving in the field of the ionic core, partly screened by the inner electron. Properties of such "double-Rydberg states called "valley states" or planetary atoms could be described in terms of quantum defect theory.

© 1986 Optical Society of America