Neutron shell structure and deformation in neutron-drip-line nuclei

Abstract

Neutron shell-structure and the resulting possible deformation in the neighborhood of neutron-drip-line nuclei are systematically discussed, based on both bound and resonant neutron one-particle energies obtained from spherical and deformed Woods-Saxon potentials. Due to the unique behavior of weakly-bound and resonant neutron one-particle levels with smaller orbital angular-momenta $\ell$, a systematic change of the shell structure and thereby the change of neutron magic-numbers are pointed out, compared with those of stable nuclei expected from the conventional j-j shell-model. For spherical shape with the operator of the spin-orbit potential conventionally used, the ${\ell }_j$ levels belonging to a given oscillator major shell with parallel spin- and orbital-angular-momenta tend to gather together in the energetically lower half of the major shell, while those levels with anti-parallel spin- and orbital-angular-momenta gather in the upper half. The tendency leads to a unique shell structure and possible deformation when neutrons start to occupy the orbits in the lower half of the major shell. Among others, the neutron magic-number N=28 disappears and N=50 may disappear, while the magic number N=82 may presumably survive due to the large $\ell =5$ spin-orbit splitting for the $1h_{11/2}$ orbit. On the other hand, an appreciable amount of energy gap may appear at N=16 and 40 for spherical shape, while neutron-drip-line nuclei in the region of neutron number above N=20, 40 and 82, namely N $\approx$ 21-28, N $\approx$ 41-54, and N $\approx$ 83-90, may be quadrupole-deformed though the possible deformation depends also on the proton number of respective nuclei.

16 pages, 4 figures

References in corpus (3)

• Deformed nuclear halos
• Nilsson diagrams for light neutron-rich nuclei with weakly-bound neutrons
• A further look at prolate dominance in nuclear deformation

Cited by in corpus (31)

• Coupled-cluster computations of atomic nuclei
• Time-dependent density-functional description of nuclear dynamics
• Emergent properties of nuclei from ab initio coupled-cluster calculations
• Rotating deformed halo nuclei and shape decoupling effects
• Neutron drip line in the deformed relativistic Hartree-Bogoliubov theory in continuum: Oxygen to Calcium
• Resonant states of deformed nuclei in complex scaling method
• Probing the resonance in the Dirac equation with quadruple-deformed potentials by complex momentum representation method
• Shell evolution and its indication on the isospin dependence of the spin-orbit splitting
• Multiscale physics of atomic nuclei from first principles
• Triaxial deformation and the loss of the N = 28 shell gap
• Microscopic derivation of the quadrupole collective Hamiltonian for shape coexistence/mixing dynamics
• Microscopic derivation of the Bohr-Mottelson collective Hamiltonian and its application to quadrupole shape dynamics
• Examining possible neutron-halo nuclei heaver than ${}^{37}$Mg
• Coulomb breakup of ${}^{37}$Mg and its ground state structure
• Density matrix renormalization group description of the island of inversion isotopes ${}^{28-33}$F
• Shell-structure of one-particle resonances in deformed potentials
• Elastic Coulomb breakup of ${}^{34}$Na
• Role of quadrupole deformation and continuum effects in the "island of inversion'' nuclei ${}^{28,29,31}$F
• Spectroscopy of ${}^{33}$Mg with knockout reactions
• Role of triaxiality in deformed halo nuclei
• Oblate deformation of light neutron-rich even-even nuclei
• Shape and shell-structure of lighter (N<90) neutron-rich nuclei based on phenomenological Woods-Saxon potential
• Simultaneous analysis of matter radii, transition probabilities, and excitation energies of Mg isotopes by angular-momentum-projected configuration-mixing calculations
• Deformed Halo of ^{29}_{9}F_{20}
• Prediction of two-neutron halos in the $N=28$ isotones ${}^{40}$Mg and ${}^{39}$Na
• Interplay between one-particle and collective degrees of freedom in nuclei
• Nuclear structure and decay properties of even-even nuclei in $Z=70-80$ drip-line region
• Enhanced E1 transition between weakly-bound excited states in the nucleus 27Ne
• Investigation of ground state properties and shape evolution in Hf isotopes using the CDFT approach
• Deformation, halo, and bubble structure: A paradigm shift of exotic phenomena in light to medium mass nuclei
• Estimate of the location of the neutron drip line for calcium isotopes from an exact Hamiltonian with continuum pair correlations