Dynamics of dissipative binary collisions

In this paper we discuss the reaction mechanisms that occur in the overlap zone for semiperipheral heavy ion collisions at intermediate energies. In p articular we focus on the development of neck instabilities, which could de termine a possible increase of dynamical fluctuations. As observed in recen t experimental data, at beam energies just above 10 MeV/nucleon the most re levant expected consequence is the possibility to obtain large variances in the projectilelike and targetlike observables. With increasing beam energy we pass to ii midrapidity fragment production. In this way we predict a sm ooth transition from a deep-inelastic to a fragmentation reaction mechanism . [S0556-2813(98)06612-6].