Relativistic Continuum Quasiparticle Random Phase Approximation in Spherical Nuclei

TL;DR

This paper develops a relativistic continuum quasiparticle RPA model to accurately predict dipole response strength distributions in spherical nuclei, successfully reproducing experimental giant and pygmy resonances across the periodic table.

Contribution

It introduces a relativistic continuum QRPA framework that explicitly includes the single-particle continuum, improving the accuracy of nuclear dipole response predictions.

Findings

Model reproduces giant dipole resonances accurately.

Model successfully predicts pygmy dipole resonances.

Quantitative agreement with experimental data.

Abstract

We have calculated the strength distributions of the dipole response in spherical nuclei, ranging all over the periodic table. The calculations were performed within two microscopic models: the discretized quasiparticle random phase approximation (QRPA) and the quasiparticle continuum RPA, which takes into account the coupling of the single-particle continuum in an exact way. Pairing correlations are treated with the BCS model. In the calculations, two density functionals were used, namely the functional PC-F1 and the functional DD-PC1. Both are based on relativistic point coupling Lagrangians. It is explicitly shown that this model is capable of reproducing the giant as well as the pygmy dipole resonance for open-shell nuclei in a high level of quantitative agreement with the available experimental observations.