Time-dependent Hartree-Fock study of quasifission trajectories in reactions forming $^{294}$Og

Abstract

Background: Fission modes in superheavy nuclei are expected to be impacted by quantum shell effects. Similar shell effects may be present in quasifission reactions, acting to hinder the mass equilibration process in heavy-ion collisions. Purpose: To investigate quasifission mechanisms in five different reactions forming $^{294}$Og as a compound nucleus and compare quasifission trajectories with predicted fission modes. Methods: The potential energy surface (PES) of $^{294}$Og is calculated using the static Hartree-Fock approach with BCS pairing correlations. Quasifission trajectories for central collisions at various energies are studied with the time-dependent Hartree-Fock theory. Results: The exit channel strongly depends on initial mass asymmetry and orientation, but it only exhibits small dependences in the reaction energy. The $^{48}$Ca$+^{246}$Cf reaction is affected by the PES topology, leading to either fusion or asymmetric fission. Spherical shell effects associated with the $Z=50$ magic gap hinder charge and mass equilibrations in $^{126}$Sn$+^{168}$Er, resulting in large total kinetic energies and compact scission configurations. Conclusions: Quasifission trajectories can be interpreted in terms of the underlying PES for low excitation energies. Future investigations of quasifission with temperature and angular momentum dependent PES could be considered.