  In a quasiclassical framework, we formulate the quadruple ionization by
single photon absorption of the Coulomb five-body problem. We present the
quadruple photoionization total cross section of the ground state of Beryllium
for energies up to 620 eV. Our quasiclassical results for energies close to
threshold are in agreement with the Wannier threshold law for four electron
escape. In addition, the agreement of our results with a shape formula provides
support for the overall shape of our total quadruple cross section. Finally, we
find that the photon energy where the maximum of the total photoionization
cross section occurs for single, double, triple and quadruple photoionization
of H, He, Li and Be, respectively, seems to follow a linear relation with the
threshold energy for complete break-up of the respective element.
