Description of Induced Nuclear Fission with Skyrme Energy Functionals: I. Static Potential Energy Surfaces and Fission Fragment Properties

TL;DR

This paper advances a microscopic, predictive framework for modeling induced nuclear fission, focusing on the 239Pu(n,f) reaction, by analyzing potential energy surfaces and fragment properties using Skyrme density functional theory.

Contribution

It introduces a detailed, quantum many-body based approach to predict fission fragment properties, emphasizing the role of triaxial deformation and parameterization effects.

Findings

Triaxial degree of freedom is crucial near the fission barrier and scission.

Skyrme parameterization significantly affects deformation predictions.

A general template for fission fragment analysis is proposed.

Abstract

Eighty years after its experimental discovery, a microscopic description of induced nuclear fission based solely on the interactions between neutrons and protons and quantum many-body methods still poses formidable challenges. The goal of this paper is to contribute to the development of a predictive microscopic framework for the accurate calculation of static properties of fission fragments for hot fission and thermal or slow neutrons. To this end, we focus on the 239Pu(n,f) reaction and employ nuclear density functional theory with Skyrme energy densities. Potential energy surfaces are computed at the Hartree-Fock-Bogoliubov approximation with up to five collective variables. We find that the triaxial degree of freedom plays an important role, both near the fission barrier and at scission. The impact of the parameterization of the Skyrme energy density on deformation properties from the ground-state up to scission is also quantified. We introduce a general template for the detailed description of fission fragment properties. It is based on the careful analysis of the scission point, using both advanced topological methods and recently proposed quantum many-body techniques. We conclude that an accurate prediction of fission fragment properties at low incident neutron energies, although technologically demanding, should be within the reach of current nuclear density functional theory.