STUDY OF THE REACTIONS OCCURRING IN THE FUSION OF C-12 AND O-16 WITH HEAVY-NUCLEI AT INCIDENT ENERGIES BELOW 10 MEV/NUCLEON

The excitation functions for production of many residues in the fusion of C-12 With Ta-181 and Au-197 and of O-16 with Ho-165 and Ta-181 have been measured at incident energies varying from the Coulomb barrier up to about 10 MeV/nucleon. The cross sections for fusion of these ions without fission have been deduced and they show that such a process may only occur for projectile angular momenta smaller than a critical value. The excitation functions for individual reactions provide evidence for the emission of preequilibrium nucleons during the thermalization of the composite nucleus and may be satisfactorily reproduced by a calculation based on the Boltzmann master equation theory.