https://doi.org/10.1140/epjad/i2005-06-041-1
ENAM 2004
Laser and β-NMR spectroscopy on neutron-rich magnesium isotopes
1
Institut für Physik, Universität Mainz, D-55099, Mainz, Germany
2
Instituut voor Kern- en Stralingsfysica, K.U. Leuven, B-3001, Leuven, Belgium
3
Laboratorium voor Vaste-Stoffysica en Magnetisme, K.U. Leuven, B-3001, Leuven, Belgium
* e-mail: kowalska@cern.ch
Received:
15
January
2005
Accepted:
1
March
2005
Published online:
3
May
2005
Ground-state properties of neutron-rich 29, 31Mg have been recently measured at ISOLDE/CERN in the context of shell structure far from stability. By combining the results of β-NMR and hyperfine-structure measurements unambiguous values of the nuclear spin and magnetic moment of 31Mg are obtained. I π = 1/2+ and μ = - 0.88355(15)μN can be explained only by an intruder ground state with at least 2p-2h excitations, revealing the weakening of the N = 20 shell gap in this nucleus. This result plays an important role in the understanding of the mechanism and boundaries of the so called “island of inversion”.
PACS: 21.10.Hw Spin, parity, and isobaric spin – / 21.10.Ky Electromagnetic moments – / 27.30.+t 20 ⩽ A ⩽ 38 – / 32.10.Fn Fine and hyperfine structure –
© Società Italiana di Fisica and Springer-Verlag, 2005
