Low-energy collisions of heavy nuclei: dynamics of sticking, mass transfer and fusion

The dynamics of heavy-ion low-energy collisions is studied within the realistic model based on multi-dimensional Langevin equations. Interplay of strongly coupled deep inelastic scattering, quasi-fission and fusion-fission processes is discussed. Collisions of very heavy nuclei ( 238 U+ 238 U, 232 Th+ 250 Cf and 238 U+ 448 Cm) are investigated as an alternative way for the production of super-heavy elements with increasing neutron number. Large charge and mass transfer were found in these reactions due to the inverse (anti-symmetrizing) quasi-fission process leading to the formation of surviving super-heavy long-lived neutron-rich nuclei. In many events the lifetime of the composite giant system consisting of two touching nuclei turns out to be rather long (≥10 -20 s), sufficient for observing line structure in spontaneous positron emission from super-strong electric fields, a fundamental QED process.