Dynamics of low-energy heavy-ion fusion

Preliminary data on the fusion of S-36 + Zr-96 are reported; the excitation function near the barrier is intermediate between those of Ca-40 + Zr-90,Zr-96. The peculiar role of the strong 3(-) octupole vibration of 96Zr is pointed out, in addition to the couplings to neutron transfer channels with positive Q-values. Recent data on Ca-40 + Sn-124 are also shown; for that system the fusion barrier distribution is wide without separated peaks, similar to the case of Ca-40 + Zr-96. Simplified coupled-channel calculations have been performed, including surface vibrations and sequential neutron pick-up channels, with form factors that fit the single- and multi-nucleon transfer data for Ca-40 + Sn-124. A good agreement with the data is found.