Fragment excitation energies at freeze-out in Kr-84+Nb-93 collisions at 45MeV/nucleon - art. no. 064610

The emission of light charged particles and intermediate-mass fragments (IM F's) from central collisions of 45 MeV/nucleon Kr-84 with Nb-93 has been st udied. Violent collisions have been selected using the total collected char ge condition. The analysis of the primary IMF excitation energies has been performed for four bins of the detected IMF charge (2< Z(IMF)<20). We find evidence that ia) the mean excitation energy per nucleon for these fragment s is independent of fragment charge and approximately equal to 2.5 MeV, (b) the primary fragments at freeze-out preserve the entrance channel (combine d system) N/Z ratio, and (c) the freeze-out volume itself is far from spher ical.