Eur. Phys. J. A (2004) 19: 89-104
https://doi.org/10.1140/epja/i2003-10103-6

Formation of heavy and superheavy elements by reactions with massive nuclei

¹ INFN, Sezione di Catania and Dipartimento di Fisica dell’Universitá di Messina, Messina, Italy
² Dipartimento di Scienze della Terra dell’Universitá di Messina, Messina, Italy
³ Dipartimento PAU dell’Universitá di Reggio Calabria, Reggio Calabria, Italy
⁴ Heavy Ion Physics Department, INP, Tashkent, Uzbekistan
⁵ Bogoliubov Laboratory of the Theoretical Physics, JINR, Dubna, Russia
⁶ Theoretical Physics Department, National University of Uzbekistan, Tashkent, Uzbekistan
⁷ Université Libre de Bruxelles, Bruxelles, Belgium
⁸ Institut de Recherches Subatomiques, Strasbourg, France

^* e-mail: giardina@nucleo.unime.it

Abstract

The effects of the entrance channel and shell structure on the experimental evaporation residues have been studied by analyzing the ³²S + ¹⁸²W, ⁴⁸Ti + ¹⁶⁶Er and ⁶⁰Ni + ¹⁵⁴Sm reactions leading to ²¹⁴Th^*; the ⁴⁰Ar + ¹⁸¹Ta reaction leading to ²²¹Pa^*; the ⁴⁸Ca + ²⁴³Am, ²⁴⁸Cm, ²⁴⁹Cf reactions leading to the ²⁹¹115, ²⁹⁶116 and ²⁹⁷118 superheavy compound nuclei, respectively. The fusion mechanism and the formation of evaporation residues of heavy and superheavy nuclei have been studied. In calculations of the excitation functions for capture, fusion and evaporation residues we used such characteristics as mass asymmetry of nuclei in the entrance channel, binding energies and shape of colliding nuclei, potential energy surface, driving potential, partial-fusion cross-sections and survival probability of the compound nucleus, ratio at each step along the de-excitation cascade of the compound nucleus. The calculations have allowed us to make useful conclusions about the mechanism of the fusion-fission process, which is in competition with the quasifission process, and the production of the evaporation residues.