  We present the first microscopic calculation of the spectator fragmentation
observed in heavy ion reactions at relativistic energies which reproduces the
slope of the kinetic energy spectra of the fragments as well as their
multiplicity, both measured by the ALADIN collaboration. In the past both have
been explained in thermal models, however with vastly different assumptions
about the excitation energy and the density of the system. We show that both
observables are dominated by dynamical processes and that the system does not
pass a state of thermal equilibrium. These findings question the recent
conjecture that in these collisions a phase transition of first order, similar
to that between water and vapor, can be observed.
