2016/04/11 by Chang-Bum Moon, Moon, Chang-Bum
Physics and Astronomy · #FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Nuclear Physics and Applications #Nuclear Theory (nucl-th) #Nuclear physics research studies #Quantum, superfluid, helium dynamics
paper · pdf · doi:10.48550/arxiv.1604.02786
openalex publication_date 2016/04/11 · openalex created_date 2022/09/01 · openalex updated_date 2026/07/28
With the experimental data at the national nuclear data center, NNDC, we investigate systematically the emerging nuclear structure properties in the first 2+ excited energies, E(2+) and their energy ratios to the first 4+ levels, R = E(4+)/E(2+) in the nuclei over 28 < Z < 50 for protons, and 40 < N < 70 for neutrons. By introducing the pseudo-shell configurations built on the combined subshells, we explain the following phenomena; a semi-double shell closure, a shape phase transition, and a reinforced deformation. The reinforced deformation arises suddenly at Z = 40 (or 38), N = 60 and approaches a maximum value, R = 3.3, as being centered at Z = 40, N = 64. We define this reinforced deformation 'a ferro-deformation', as in the previous study [arXiv:1604.01017]. The shape coexistence would be expected to be, as forming a ferro-deformation, with a strong rotational mode, and a near spherical shape, with a vibrational mode, in the transitional region at N = 58, 60, and 62 for the nuclei, with Z = 38 and 40; 96Sr, 98Sr, 100Sr, and 98Zr, 100Zr, and 102Zr. We suggest that the ferro-deformation should be closely associated with a strong spin-orbital interaction between neutrons in the g7/2 orbital and protons in the g9/2 orbital. Such an isospin dependent spin-orbital interaction, with the same angular momentum, l = 4, reinforces nuclear surface toward a sudden and dramatic deformation, giving rise to the ferro-deformation at the critical point, Z = 40, N = 64. We discuss the similarities and differences of the ferro-deformation between the two critical points; Z = 40, N = 64 and Z = 64, N = 104.