Microscopic description of induced fission in a configuration-interaction approach

Since the discovery of nuclear fission, many phenomenological models have been proposed and have successfully explained the observed behaviors.

In contrast, a microscopic understanding of fission has still been far from complete.

This is due to the difficulty of a theoretical treatment of the large amplitude collective motion and the associated numerical complexity. In this study, we will employ a configuration-interaction approach to model induced fission reactions at barrier-top energies. The model space is constructed based on particle-hole excitations of reference configurations labeled by deformation parameter $Q$, which can be seen as an extension of the Generator Coordinate Method (GCM) ansatz cite{ring}. Then employing the non-equilibrium Green function method cite{datta}, we will calculate the branching ratio between the fission and the capture process.

At first, we shall apply our approach to a schematic uniform spacing model cite{uniform}. The Hamiltonian includes as the residual interaction the diabatic interaction, the pairing interaction between identical nucleons, and a schematic off-diagonal neutron-proton interaction. We will analyze the role of these interactions in the barrier transmission mechanism by focusing on how they affect the branching ratio. Furthermore, we will discuss the insensitivity of the branching ratio to the final-state scission dynamics, which is assumed in the well-known Bohr-Wheeler theory cite{bw}.