Deformation-induced splitting of isoscalar E0 giant resonance: Skyrme random-phase-approximation analysis

TL;DR

This paper uses a self-consistent QRPA method with Skyrme functionals to analyze how nuclear deformation causes splitting and energy shifts in the isoscalar giant monopole resonance across various nuclei, revealing stronger E0-E2 coupling than previously thought.

Contribution

It provides a systematic analysis of deformation-induced ISGMR splitting using Skyrme QRPA, highlighting a smaller energy difference and stronger E0-E2 coupling compared to earlier studies.

Findings

Deformation causes a double-peak structure in ISGMR.

Stronger E0-E2 coupling leads to more pronounced splitting.

Widths of peaks are largely unaffected by deformation.

Abstract

The deformation-induced splitting of isoscalar giant monopole resonance (ISGMR) is systematically analyzed in a wide range of masses covering medium, rare-earth, actinide, and superheavy axial deformed nuclei. The study is performed within the fully self-consistent quasiparticle random-phase-approximation (QRPA) method based on the Skyrme functional. Two Skyrme forces, one with a large (SV-bas) and one with a small (SkP) nuclear incompressibility, are considered. The calculations confirm earlier results that, due to the deformation-induced E0-E2 coupling, the isoscalar E0 resonance attains a double-peak structure and significant energy upshift. Our results are compared with available analytic estimations. Unlike earlier studies, we get a smaller energy difference between the lower and upper peaks and thus a stronger E0-E2 coupling. This in turn results in more pumping of E0 strength into the lower peak and more pronounced splitting of ISGMR. We also discuss widths of the peaks and their negligible correlation with deformation.