Energy partition between splitting fission fragments

TL;DR

This paper investigates the microscopic energy partition between fission fragments using a dynamical time-dependent Hartree-Fock+BCS approach, revealing sawtooth structures and the influence of pairing strengths on excitation energies.

Contribution

It introduces a microscopic, dynamical model for energy partition in fission, contrasting with traditional statistical models, and highlights the role of pairing interactions.

Findings

Sawtooth structure in excitation energies of fragments

Pairing strengths significantly influence energy partition

Excitation energies increase with neutron number, affecting isotope production

Abstract

From the microscopic view, the energy partition between two fission fragments are associated with the splitting of wave functions of an entangled fissioning system, in contrast to most fission models using an explicit statistical partition of excitation energies by invoking level densities of fragments. The dynamical fission evolution is described within the time-dependent Hartree-Fock+BCS framework. Excitation energies of isotopic fission fragments are obtained with the particle-number projection method after the dynamical splitting of $^{238}$U. The resulting excitation energies of light and heavy fragments illustrate the appearance of sawtooth structures. We find that the paring strengths have significant influences on the partition of excitation energies. Furthermore, excitation energies of isotopic fragments increase with increasing neutron numbers, suppressing the production of neutron-rich beams in rare-isotope beam facilities.