Long-lived resonant states in Planetary atoms

Abstract

We report on a class of long-lived resonant states of doubly excited twoelectron
atoms which exhibit distinct angular and radial electron correlation.
The states are characterized by a highly polarized inner electron located near the
axis between the nucleus and a dynamically localized outer electron. Classical
mechanics studies prove the stability of the corresponding classical motion and
allow for EBK-quantization to obtain semiclassical energies. The resonance states
are treated further within the framework of a single channel adiabatic approximation.
The adiabatic energies as well as the semiclassical results are in good
agreement with resonance energies obtained by highly accurate solutions of the
full three-body Schrodinger equation. Approximate quantum numbers derived
from the semiclassical and from the adiabatic approach explain the nodal structures
of the full quantum wavefunctions. The decay widths of the resonances turn
out to be extremely small.