Nuclear-structure dependence of heavy-ion-fusion partial-wave distributions.

Partial-wave cross sections for fusion of /sup 64/Ni+/sup 92/Zr and /sup 64/Ni+/sup 96/Zr at energies of 5% and 7% above the Bass-model fusion barrier have been measured with the Darmstadt-Heidelberg Crystal Ball. The distribution for fusion with the more neutron-deficient target /sup 92/Zr exhausts the unitarity limit for lower angular momenta. In contrast, fusion with the slightly more neutron-rich target /sup 96/Zr yields a broad angular momentum distribution with cross sections well below unitarity even for small partial waves.