We perform exact coupled-channels calculations, taking into account properly the effects of Coulomb coupling and the finite excitation energy of collective excitations in the colliding nuclei, for three Fm formation reactions, 37Cl + 209Bi, 45Sc + 197Au, and 59Co + 181Ta. For the 37Cl + 209Bi and 45Sc + 197Au reactions, those calculations well reproduce the experimental total fission cross sections, and a part of the extra-push phenomena can be explained in terms of the Coulomb excitations to multi-phonon states. On the other hand, for the heaviest system, the deep-inelastic collisions become much more significant, and the fission cross sections are strongly overestimated. We also discuss the surprisingly large surface diffuseness parameters required to fit recent high-precision fusion data for medium-heavy systems, in connection with the fusion supression observed in massive systems.
Tours Symposium on Nuclear Physics V
- Pub Date:
- April 2004
- Fusion and fusion-fission reactions;
- Coupled-channel and distorted-wave models;
- Nuclear Theory
- 10 pages, 6 ps figures. Uses aipxfm.sty. A talk given at the Tours Symposium on Nuclear Physics V, August 26 - 29, 2003, Tours, France