Configuration interaction relativistic Hartree-Fock model

TL;DR

This paper introduces the CI-RHF model, a parameter-free approach for nuclear structure calculations that accurately reproduces properties and spectra of neon isotopes, revealing shell closures and magicity disappearance.

Contribution

The CI-RHF model offers a universal, parameter-free method for studying nuclear properties across different shells, improving upon traditional models by avoiding parameter readjustments.

Findings

Successfully reproduces bulk properties and spectra of neon isotopes.

Reveals shell closure at N=14 for neon isotopes.

Indicates disappearance of N=20 magicity in $^{30}$Ne.

Abstract

The configuration interaction relativistic Hartree-Fock (CI-RHF) model is developed in this work. Compared to the conventional configuration interaction shell model (CISM), the CI-RHF model can be applied to study the structural properties of a wide range of nuclei without readjusting any parameters, as the effective Hamiltonian for different model space can be deduced consistently from a universal density-dependent Lagrangian based on the Hartree-Fock single-particle basis. The convergence of intermediate-state excitations has been examined in evaluating the effective interactions, and the core-polarization effects are illustrated, by using $^{18}$O as an example. Employing the CI-RHF model, both the bulk properties and low-lying spectra of even-even nuclei $^{18\sim 28}$Ne have been well reproduced with the model space restricted to the $sd$ shell. Studies of the isotopic evolution concerning charge radii and low-lying spectra highlight the shell closure at $N=14$ for neon isotopes. Furthermore, the cross-shell calculations extending from the $sd$ to $pf$ shell successfully reproduced the low-lying spectra of $^{30}$Ne and $^{32}$Ne. Notably, remarkably low excitation energies $E(2^{+}_{1})$ of $^{30}$Ne suggest the disappearance of the conventional magicity $N=20$.