Low-energy cluster vibrations in N = Z nuclei

TL;DR

This study investigates low-energy cluster vibrations in N=Z nuclei using the Finite Amplitude Method within nuclear energy density functional theory, revealing prominent vibrational peaks linked to cluster structures in light, deformed nuclei.

Contribution

It applies the FAM approach to explore isoscalar low-energy responses, identifying vibrational peaks associated with cluster structures in N=Z nuclei, a novel microscopic analysis.

Findings

Identification of vibrational peaks linked to cluster structures.

Cluster excitations are prominent in deformed light nuclei.

Low-energy strength functions depend on nuclear deformation.

Abstract

Significant transition strength in light $\alpha$-conjugate nuclei at low energy, typically below 10 MeV, has been observed in many experiments. In this work the isoscalar low-energy response of N=Z nuclei is explored using the Finite Amplitude Method (FAM) based on the microscopic framework of nuclear energy density functionals. Depending on the multipolarity of the excitation and the equilibrium deformation of a particular isotope, the low-energy strength functions display prominent peaks that can be attributed to vibration of cluster structures: $\alpha$+$^{12}$C+$\alpha$ and $\alpha$+$^{16}$O in $^{20}$Ne, $^{12}$C+$^{12}$C in $^{24}$Mg, 4$\alpha$+$^{12}$C in $^{28}$Si, etc. Such cluster excitations are favored in light nuclei with large deformation.