Transitional mechanisms for fragment production in peripheral collisions at intermediate energies

The experimental situation of peripheral collisions around the Fermi energy is reviewed. The observation of transitional phenomena is emphasized. The competition between transfer reactions and fragmentation is shown to be a dominant feature of this energy range. The strong effect of the separation energies of the projectile and target into their participant and spectator fragments is shown to account for apparently contradictory behaviours as incomplete fusion and fragmentation. The different mechanisms responsible for the fragmentation process are discussed as well as the consequences for the production of new exotic nuclear species.