Low-energy dipole excitations in neon isotopes and N=16 isotones within the quasiparticle random phase approximation and the Gogny force

Abstract

Low-energy dipole excitations in neon isotopes and N=16 isotones are calculated with a fully consistent axially-symmetric-deformed quasiparticle random phase approximation (QRPA) approach based on Hartree-Fock-Bogolyubov (HFB) states. The same Gogny D1S effective force has been used both in HFB and QRPA calculations. The microscopical structure of these low-lying resonances, as well as the behavior of proton and neutron transition densities, are investigated in order to determine the isoscalar or isovector nature of the excitations. It is found that the N=16 isotones 24O, 26Ne, 28Mg, and 30Si are characterized by a similar behavior. The occupation of the 2s_1/2 neutron orbit turns out to be crucial, leading to nontrivial transition densities and to small but finite collectivity. Some low-lying dipole excitations of 28Ne and 30Ne, characterized by transitions involving the neutron 1d_3/2 state, present a more collective behavior and isoscalar transition densities. A collective proton low-lying excitation is identified in the 18Ne nucleus.

References in corpus (7)

• Exotic modes of excitation in atomic nuclei far from stability
• Constraints on the symmetry energy and on neutron skins from the pygmy resonances in 68Ni and 132Sn
• Role of deformation on giant resonances within the QRPA approach and the Gogny force
• Pygmy dipole strength in 90Zr
• Evolution of the pygmy dipole resonance in nuclei with neutron excess
• Low-lying dipole resonance in neutron-rich Ne isotopes
• The quest for novel modes of excitation in exotic nuclei

Cited by in corpus (5)

• Large-scale deformed quasiparticle random-phase approximation calculations of the $\gamma$-ray strength function using the Gogny force
• Gamow-Teller strength in deformed nuclei within the self-consistent charge-exchange quasi-particle random-phase approximation with the Gogny force
• Nature of low-lying electric dipole resonance excitations in 74Ge
• Pairing in spherical nuclei: quasi-particle random phase approximation calculations with the Gogny interaction
• Tri-axial deformation in nuclei with realistic NN interactions