MULTIFRAGMENTATION OF HIGHLY EXCITED NUCLEI IN NUCLEUS-NUCLEUS COLLISIONS AT INTERMEDIATE ENERGIES

Nucleus-nucleus collisions leading to the formation of medium-mass fra gments are considered as a two-stage process. The first (nonequilibriu m) stage is calculated by using the intranuclear cascade model and the preequilibrium exciton model. At the second (equilibrium) stage, exci ted the thermalized residual nuclei (TRN), formed at the first stage, undergo a multifragment break-up described within the framework of a s tatistical model of multifragmentation. Comparison of our results with experimental characteristics of medium-mass fragments formed in nucle us-nucleus collisions allows us to extract information on masses and e xcitation energies of TRNs.