Microscopic description of quadrupole-octupole coupling in actinides with the Gogny-D1M energy density functional

TL;DR

This paper investigates quadrupole-octupole interactions in actinides using advanced mean-field and beyond-mean-field methods with the Gogny-D1M functional, comparing results with experimental data.

Contribution

It provides a detailed microscopic analysis of quadrupole-octupole coupling in actinides, incorporating symmetry restoration and generator coordinate methods.

Findings

Weak quadrupole-octupole coupling in studied nuclei

Negative-parity states well described by octupole degree of freedom

Good agreement with experimental excitation energies and transition probabilities

Abstract

The interplay between quadrupole and octupole degrees of freedom is discussed in a series of U, Pu, Cm and Cf isotopes both at the mean-field level and beyond. In addition to the static Hartree-Fock-Bogoliubov approach, dynamical beyond-mean-field correlations are taken into account via both parity restoration and symmetry-conserving Generator Coordinate Method calculations based on the parametrization D1M of the Gogny energy density functional. Physical properties such as correlation energies, negative-parity excitation energies as well as reduced transition probabilities $B(E1)$ and $B(E3)$ are discussed in detail and compared with the available experimental data. It is shown that, for the studied nuclei, the quadrupole-octupole coupling is weak and to a large extent the properties of negative parity states can be reasonably well described in terms of the octupole degree of freedom alone.