Time-dependent Hartree-Fock study of quasifission trajectories in reactions forming Og294

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 $^{294}\mathrm{Og}$ as a compound nucleus and compare quasifission trajectories with predicted fission modes.Methods: The potential energy surface (PES) of $^{294}\mathrm{Og}$ 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 dependencies in the reaction energy. The $^{48}\mathrm{Ca}+^{246}\mathrm{Cf}$ reaction is affected by the PES topography, leading to either fusion or asymmetric fission. $^{126}\mathrm{Sn}+^{168}\mathrm{Er}$ reactions exhibit large total kinetic energies and compact scission configurations, which could be interpreted as an effect of the $Z=50$ spherical magic gap.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.