Fusion of Light Weakly Bound Nuclei

Systematic study of fusion barriers for p and light s-d shell nuclei show an increase of the value of their height as the atomic mass number decreases. Two features are observed to be associated to this effect: one, related to the binding energy of nucleon or cluster, which turns the breakup processes relevant and thus inhibiting the fusion probability; a second, associated to the decrease of the number of nucleons located in the nucleus "core" compared to the "surface". The relative competition of these two features is discussed in the present. A systematic analysis of 14 reactions and up to 50 angular distributions allowed also the extraction of the energy thresholds (E_ef) for the fission channel forming the final products at the ground state ("elastic fission"). A significant suppression of the contribution of statistical processes is observed when the size of the system is reduced. This effect may be related to a relative increase of the fast and peripheral yields.