The influence of the entrance channel dynamics on the evaporation residue formation

The dynamical effects of the entrance channel on the competition between quasifission and fusion processes, and on the evaporation residue formation are investigated. We have analyzed the results and compared our calculations with the experimental data obtained in the ¹⁶ O + ²⁰⁴ Pb and ⁹⁶ Zr + ¹²⁴ Sn reactions having very different mass asymmetries and leading to the ²²⁰ Th ^* compound nucleus. We have found that different partial capture cross-sections for these reactions lead to different fusion-quasifission competitions and, consequently, to different partial fusion cross-sections of the compound nucleus formed in the two reactions. The dynamical conditions also affect the fission-evaporation competition of the excited intermediate nuclei along the CN de-excitation cascade and, consequently, the evaporation residue formation.Received: 8 March 2004, Revised: 5 April 2004, Published online: 25 October 2004PACS: 25.70.Jj Fusion and fusion-fission reactions - 25.70.-z Low and intermediate energy heavy-ion reactions - 27.80. + w - 27.90. + b