The atomic nucleus is a naturally occurring example of a strongly interacting quantum many-body system. Nuclear reactions at energies near the Coulomb barrier are uniquely sensitive to quantum effects. In particular, collective tunnelling and nuclear shell effects are important to the dynamics of these reactions. Mean-field techniques allow for effective microscopic models of the nucleus but there are still unanswered questions about these models. Can mean-field simulations replicate the shell effects seen in quasifission and fission, and are these the same shell effects in both reaction mechanisms?
Fission was studied through the production of potential energy surfaces via a constrained Hartree-Fock calculation. Quasifission of heavy and superheavy systems was studied via time-dependent Hartree-Fock calculations. I present the methods and results, and discuss the strengths and limitations of mean-field methods for such systems.
The potential energy surfaces revealed features identified with shell effects driving fission in both actinide thorium and superheavy oganesson nuclides. The simulations of quasifission performed correlated with what would be expected experimentally, but were not sufficient on their own to answer the questions posed. Mapping their trajectories onto the calculated potential energy surfaces provided useful information about the details of the process, and how the shell effects in fission relate to quasifission. A model of quasifission which takes into account the topology of the underlying compound nuclear potential energy surface was proposed, and should be tested with experiment.