Microscopic description of fission in neutron-rich Radium isotopes with the Gogny energy density functional

TL;DR

This study uses Gogny energy density functional mean field calculations to analyze fission properties of neutron-rich Radium isotopes, revealing insights into barrier heights, fragment characteristics, and stability trends relevant to nuclear physics and astrophysics.

Contribution

It provides detailed potential energy surfaces and fission fragment data for Ra isotopes, highlighting the impact of neutron number on fission stability and fragment properties.

Findings

Fission becomes slower with increasing neutron number beyond N=164.

Existence of a third minimum along fission paths of Ra isotopes.

Fission stability increases for heavier neutron-rich Ra isotopes.

Abstract

Mean field calculations, based on the D1S, D1N and D1M parametrizations of the Gogny energy density functional, have been carried out to obtain the potential energy surfaces relevant to fission in several Ra isotopes with the neutron number 144 $\le$ N $\le$ 176. Inner and outer barrier heights as well as first and second isomer excitation energies are given. The existence of a well developed third minimum along the fission paths of Ra nuclei, is analyzed in terms of the energetics of the "fragments" defining such elongated configuration. The masses and charges of the fission fragments are studied as functions of the neutron number in the parent Ra isotope. The comparison between fission and $\alpha$-decay half-lives, reveals that the former becomes faster for increasing neutron numbers. Though there exists a strong variance of the results with respect to the parameters used in the computation of the spontaneous fission rate, a change in tendency is observed at N=164 with a steady increase that makes heavier neutron-rich Ra isotopes stable against fission, diminishing the importance of fission recycling in the r-process.