Photoabsorption Cross Sections studied within the axially deformed Relativistic Quasiparticle Finite Amplitude Framework

TL;DR

This study uses the quasiparticle finite amplitude method within a relativistic framework to analyze photoabsorption cross sections across a wide range of nuclei, improving understanding of giant dipole resonances and deformation effects.

Contribution

It applies the axially deformed relativistic quasiparticle finite amplitude method to a broad set of nuclei, extending previous models to odd-A nuclei and systematically examining deformation effects.

Findings

Good agreement with experimental GDR peak energies

Underestimation of resonance widths and overestimation of peak cross sections

Deformation effects significantly influence photoabsorption cross sections

Abstract

Photoabsorption cross sections for 235 stable nuclei, ranging from $^{40}$Ca to $^{209}$Bi, were investigated by the quasiparticle finite amplitude method (QFAM) based on the axially deformed relativistic Hartree-Bogoliubov (RHB) approach using relativistic point-coupling interaction DD-PC1, with extensions to odd-A nuclei. GDR parameters based on the standard Lorentzian (SLO) model were extracted from QFAM results and compared with those from experimental data recommended by IAEA. Good agreement was achieved for giant dipole resonance (GDR) peak energies, while resonance widths were underestimated and hence peak cross sections were overestimated due to the lack of higher-order many-body correlations. These discrepancies were much improved in deformed nuclei. The effects of deformation on photoabsorption cross sections were examined systematically. The comparison of photoabsorption cross sections among QFAM results and discrepant experimental data revealed the potential of QFAM calculations in the evaluation of photonuclear data.