Nuclear fission, especially in heavy and superheavy nuclei, is heavily influenced by strong shell effects. The much more easily obtained quasifission reaction may probe some of the same shell effects, but in order to use quasifission to understand shell effects in fission, we need to understand shell effects in quasifission. To study this, several techniques have been used. Calculation of potential energy surfaces (PES) is important for understanding the driving processes behind fission. The performance of a PES calculation approach was benchmarked with a range of Thorium nuclides and reflects the known competition between symmetric and asymmetric modes. The same techniques were used to calculate a potential energy surface for oganesson-294.
Time-dependent Hartree-Fock (TDHF) software was used to simulate reactions forming oganesson-294 in different entrance channels, at energies chosen to produce mostly quasifission paths. These paths and their resulting fragments were compared with the fission PES. The comparison shows that the quasifission trajectories are strongly influenced towards the same modes as seen in the PES and suggests that quasifission can effectively probe shell effects in the fission of superheavy nuclei. The availability of detailed information about the shape trajectories of the simulated reactions opens avenues for better understanding how and where shell effects play a role.
