Fission Barriers and Fission Dynamics of Superheavy Nuclei

Fusion, fission, and quasi-fission processes in heavy nuclear system are studied. A careful analysis of the whole body of available experimental data on the fusion and fission of the nuclei of ²⁸⁶112, ²⁹²114 and ²⁹⁶116 produced in the reactions ⁴⁸Ca+²³⁸U, ⁴⁸Ca+²⁴⁴Pu and ⁴⁸Ca+²⁴⁸Cm as well as experimental data on the survival probability in evaporation channels of 3 and 4 neutron emission enables the quite reliable conclusion that the fission barriers of those nuclei are really quite high, which results in their relatively high stability. The lower limits that we have obtained for the fission barrier heights of ^283-286112, ^288-292114 and ^292-296116 nuclei are 5.5, 6.7 and 6.4 MeV. From analysis of derived multi-dimensional fusion-fission driving potential it was found that in fission process a low excited heavy nucleus on its way from the ground state to the scission point passes trough the optimal configurations with minimal potential energies (shape isomer states), which are nothing else but the two-cluster configurations with magic (closed shell) cores.