  The probability that photoionization of the caged atom in an endohedral
system is accompanied by excitation of the fullerene shell is shown to be close
to unity in broad intervals of the photoelectron energies. The result is
obtained by summation of the perturbative series for the interaction between
the photoelectron and the fullerene shell. This result means that the
interaction between the photoelectron ejected from the cage atom and the
fullerene shell cannot be described by a static potential, since inelastic
processes become decisively important.
