Octupole deformation properties of the Barcelona-Catania-Paris energy density functionals

TL;DR

This paper evaluates the octupole deformation properties of the BCP energy density functionals for radium and barium isotopes, comparing results with experimental data and Gogny D1S benchmarks, and explores implications for fission processes.

Contribution

It introduces a detailed analysis of octupole properties using BCP functionals within a mean field framework, including parity restoration and transition probabilities, demonstrating their effectiveness.

Findings

BCP functionals accurately reproduce octupole deformation features.

Computed transition probabilities align well with experimental data.

Studied octupolarity in fission-related configurations of Pu-240.

Abstract

We discuss the octupole deformation properties of the recently proposed Barcelona-Catania-Paris (BCP) energy density functionals for two sets of isotopes, those of radium and barium, where it is believed that octupole deformation plays a role in the description of the ground state. The analysis is carried out in the mean field framework (Hartree- Fock- Bogoliubov approximation) by using the axially symmetric octupole moment as a constraint. The main ingredients entering the octupole collective Hamiltonian are evaluated and the lowest lying octupole eigenstates are obtained. In this way we restore, in an approximate way, the parity symmetry spontaneously broken by the mean field and also incorporate octupole fluctuations around the ground state solution. For each isotope the energy of the lowest lying $1^{-}$state and the $B(E1)$ and $B(E3)$ transition probabilities have been computed and compared to both the experimental data and the results obtained in the same framework with the Gogny D1S interaction, which are used here as a well established benchmark. Finally, the octupolarity of the configurations involved in the way down to fission of $^{240}$Pu, which is strongly connected to the asymmetric fragment mass distribution, is studied. We confirm with this thorough study the suitability of the BCP functionals to describe octupole related phenomena.