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

Hamamoto-Kuroda, Ikuko LU (2012) In Physical Review C (Nuclear Physics) 85(6).
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. Owing to the unique behavior of weakly bound and resonant neutron one-particle levels with smaller orbital angular momenta l, a systematic change in the shell structure and thereby a change in the neutron magic numbers are pointed out, compared with those of stable nuclei expected from the conventional j-j shell model. For a spherical shape with the operator of the spin-orbit potential conventionally used, the l(j) levels belonging to a given oscillator major shell with parallel... (More)
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. Owing to the unique behavior of weakly bound and resonant neutron one-particle levels with smaller orbital angular momenta l, a systematic change in the shell structure and thereby a change in the neutron magic numbers are pointed out, compared with those of stable nuclei expected from the conventional j-j shell model. For a spherical shape with the operator of the spin-orbit potential conventionally used, the l(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 the levels with antiparallel spin and orbital angular momenta gather in the upper half. This 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 owing to the large l = 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 numbers above N = 20, 40, and 82, namely, N approximate to 21-28, N approximate to 41-54, and N approximate to 83-90, may be quadrupole deformed, although the possible deformation also depends on the proton number of the respective nuclei. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review C (Nuclear Physics)
volume
85
issue
6
publisher
American Physical Society
external identifiers
  • wos:000305740300003
  • scopus:84863436285
ISSN
0556-2813
DOI
10.1103/PhysRevC.85.064329
language
English
LU publication?
yes
id
379ac9b9-90f1-4b7e-8112-87d78e928308 (old id 2866662)
date added to LUP
2012-07-24 15:30:53
date last changed
2017-05-21 04:08:51
@article{379ac9b9-90f1-4b7e-8112-87d78e928308,
  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. Owing to the unique behavior of weakly bound and resonant neutron one-particle levels with smaller orbital angular momenta l, a systematic change in the shell structure and thereby a change in the neutron magic numbers are pointed out, compared with those of stable nuclei expected from the conventional j-j shell model. For a spherical shape with the operator of the spin-orbit potential conventionally used, the l(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 the levels with antiparallel spin and orbital angular momenta gather in the upper half. This 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 owing to the large l = 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 numbers above N = 20, 40, and 82, namely, N approximate to 21-28, N approximate to 41-54, and N approximate to 83-90, may be quadrupole deformed, although the possible deformation also depends on the proton number of the respective nuclei.},
  author       = {Hamamoto-Kuroda, Ikuko},
  issn         = {0556-2813},
  language     = {eng},
  number       = {6},
  publisher    = {American Physical Society},
  series       = {Physical Review C (Nuclear Physics)},
  title        = {Neutron shell structure and deformation in neutron-drip-line nuclei},
  url          = {http://dx.doi.org/10.1103/PhysRevC.85.064329},
  volume       = {85},
  year         = {2012},
}