Dipole oscillation modes in light $\alpha$-clustering nuclei

TL;DR

This paper investigates how various alpha-cluster configurations in light nuclei influence dipole oscillation modes and giant dipole resonance spectra, using an extended quantum molecular dynamics model.

Contribution

It provides detailed analysis of alpha cluster structures and their impact on nuclear collective vibrations, highlighting GDR as a probe for cluster configurations.

Findings

Different alpha cluster structures have characteristic GDR spectra.

The geometry and symmetry of clusters determine GDR peak energies.

GDR can diagnose alpha clustering in light nuclei.

Abstract

The $\alpha$ cluster states are discussed in a model frame of extended quantum molecular dynamics. Different alpha cluster structures are studied in details, such as $^8$Be two-$\alpha$ cluster structure, $^{12}$C triangle structure, $^{12}$C chain structure, $^{16}$O chain structure, $^{16}$O kite structure, and $^{16}$O square structure. The properties studied, include as the width of wave packets for different $\alpha$ clusters, momentum distribution, and the binding energy among $\alpha$ clusters. It is also discussed how the $\alpha$ cluster degree of freedom affects nuclear collective vibrations. The cluster configurations in $^{12}$C and $^{16}$O are found to have corresponding characteristic spectra of giant dipole resonance (GDR), and the coherences of different $\alpha$ clusters's dipole oscillation are described in details. The geometrical and dynamical symmetries of $\alpha$-clustering configurations are responsible for the number and centroid energies of peaks of GDR spectra. Therefore, the GDR can be regarded as an effective probe to diagnose different $\alpha$ cluster configurations in light nuclei.