Symmetrical fusion of heavy ions around the Coulomb barrier energy

Using the liquid-drop model, a systematic study has been performed of symmetrical fusion with a neck degree of freedom and tunnelling effects, the nuclear potential being calculated with the proximity approach. Barrier heights and positions are in very good agreement with experimental data when they are known (light-medium systems); the recent experimental data for the reactions 58Ni + 58Ni and 64Ni + 64Ni are investigated particularly. For heavier systems double-humped fusion barriers and isomeric states are predicted which strongly limit the complete fusion probability. (author)