Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force

TL;DR

This paper models quadrupole and octupole states in Sm and Gd isotopes using the interacting boson model with parameters derived from Gogny energy density functional calculations, successfully reproducing experimental spectroscopic data.

Contribution

It establishes a link between the interacting boson model and mean field Gogny calculations, providing a consistent framework for describing collective nuclear states.

Findings

Model accurately reproduces low-energy quadrupole and octupole spectra.

Spectroscopic properties align well with experimental data.

Results are consistent with Gogny force GCM calculations.

Abstract

Collective quadrupole and octupole states are described in a series of Sm and Gd isotopes within the framework of the interacting boson model (IBM), whose Hamiltonian parameters are deduced from mean field calculations with the Gogny energy density functional. The link between both frameworks is the ($\beta_2\beta_3$) potential energy surface computed within the Hartree-Fock-Bogoliubov framework in the case of the Gogny force. The diagonalization of the IBM Hamiltonian provides excitation energies and transition strengths of an assorted set of states including both positive and negative parity states. The resultant spectroscopic properties are compared with the available experimental data and also with the results of the configuration mixing calculations with the Gogny force within the generator coordinate method (GCM). The structure of excited $0^{+}$ states and its connection with double octupole phonons is also addressed. The model is shown to describe the empirical trend of the low-energy quadrupole and octupole collective structure fairly well, and turns out to be consistent with GCM results obtained with the Gogny force.