In ref. [64] an energy exchange between a Rydberg electron and a molecular
core is investigated in the regime where the Born-Oppenheimer approximation
is violated. The theory developed allows the possibility for a strong energy
exchange even for high orbital momentum of the electron when quantum defects
are small. This regime is completely different from the regime studied by
Labasti, Lombardi and Seligman when electon is colliding with the core
and only small orbital momenta are mixed. Basing on Kramers-Henneberger
transformation it is possible to connect Rydberg molecule problem
with the problem of microwave ionization. Here the frequency of molecular
rotation 
plays the role of microwave frequency while
the effective electric field is given by the dipole moment of the
molecule (
). This connection of two problems
allows to find a classical border of chaotic ionization and
a quantum delocalization border above which strong autoionization
takes place. Similar effects, as discussed in [77],
can take place in atomcule
(helium atom in which one electron is replaced by antiproton)
where antiproton has high quantum numbers and moves quasiclassically.
It is interesting to note that this system gives a physical
example of conservative model in which eigenstates can be localized on
energy surface while a classical trajectory diffusively cover
the whole energy surface. This should lead to Poisson statistics
of levels instead of Wigner-Dyson distribution. A similar situation
happens in rough billiards studied in [89,92] (see discussion in the next
Section). It is interesting to note that the classical
energy exchange between rotating core and electron is very similar
to the energy variation of Halley's comet produced by Jupiter.
Indeed, as had been shown by Chirikov and Vecheslavov the dynamics
of Halley's comet is described by a map very similar to the Kepler map.
In this sense the autoionization of molecular Rydberg
states simulates ionization of a quantum comet.