${}^8$He and ${}^9$Li cluster structures in light nuclei

Abstract

The possibility of the ${}^8$He and ${}^9$Li clusters in atomic nuclei is discussed. Until now most of the clusters in the conventional models have been limited to the closures of the three-dimensional harmonic oscillators, such as ${}^4$He, ${}^{16}$O, and ${}^{40}$Ca. In the neutron-rich nuclei, however, the neutron to proton ratio is not unity, and it is worthwhile to think about more neutron-rich objects with $N>Z$ as the building blocks of cluster structures. Here the nuclei with the neutron number six, which is the subclosure of the $p_{3/2}$ subshell of the $jj$-coupling shell model, are assumed to be clusters, and thus we study the ${}^8$He and ${}^9$Li cluster structures in ${}^{16}$Be (${}^8$He+${}^8$He), ${}^{17}$B (${}^8$He+${}^9$Li), ${}^{18}$C (${}^9$Li+${}^9$Li), and ${}^{24}$C (${}^8$He+${}^8$He+${}^8$He). Recent progress of the antisymmetrized quasi cluster model (AQCM) enables us to utilize $jj$-coupling shell model wave functions as the clusters rather easily. It is shown that the ${}^8$He+${}^9$Li and ${}^9$Li+${}^9$Li cluster configurations cover the lowest shell-model states of ${}^{17}$B and ${}^{18}$C, respectively. To predict the cluster states with large relative distances, we increase the expectation value of the principal quantum numbers by adding the nodes to the lowest states under the condition that the total angular momentum is unchanged (equal to $J^{\pi }=0$). As a result, developed cluster states are obtained around the corresponding threshold energies. The rotational band structure of ${}^{24}$C, which reflect the symmetry of equilateral triangular configuration ($D_{3h}$ symmetry) of three ${}^8$He clusters, also appears around the threshold energy.

References in corpus (10)

• Microscopic Clustering in Light Nuclei
• Evidence for Triangular D_3h Symmetry in 12C
• Important role of the spin-orbit interaction in forming the 1/2^+ orbital structure in Be isotopes
• Simplified modeling of cluster-shell competition in ${}^{20}$Ne and ${}^{24}$Mg
• Triaxial deformation in 10Be
• Novel and simple description for a smooth transition from $\alpha$-cluster wave functions to $jj$-coupling shell model wave functions
• Consistent description of 12C and 16O using finite range three-body interaction
• The possibility of ${}^{14}$C cluster as a building block of medium mass nuclei
• Non-trivial effect for the large radius at the dripline of Oxygen isotopes
• Explicit inclusion of spin-orbit contribution in THSR wave function

Cited by in corpus (7)

• Density profiles near nuclear surface of ${}^{44,52}$Ti: An indication of $\alpha$ clustering
• Imprints of $\alpha$ clustering in the density profiles of ${}^{12}$C and ${}^{16}$O
• Evidence of bicluster structure in the ground state of ${}^{20}$Ne
• Consistent description for cluster dynamics and single-particle correlation
• Role of Tensor Interaction as Salvation of Cluster Structure in ${}^{44}$Ti
• Cluster-shell competition and effect of adding hyperons
• Persistence of cluster structure in the ground state of ${}^{11}$B