High-precision quadrupole moment reveals significant intruder component in $^{33}_{13}$Al$_{20}$ ground state
H. Heylen
(1)
,
M. de Rydt
(1)
,
G. Neyens
(1)
,
M.L. Bissell
(1)
,
L. Caceres
(2)
,
Rémy Chevrier
(3)
,
J.M. Daugas
(3)
,
Y. Ichikawa
(4)
,
Y. Ishibashi
(4)
,
O. Kamalou
(2)
,
T.J. Mertzimekis
(5)
,
Pierre Morel
(3)
,
J. Papuga
(1)
,
A. Poves
(6)
,
M.M. Rajabali
(1)
,
C. Stodel
(2)
,
J.C. Thomas
(2)
,
H. Ueno
(4)
,
Y. Utsuno
(7)
,
N. Yoshida
(8)
,
A. Yoshimi
(4)
1
K.U. LEUVEN -
Instituut voor Kern- en Stralingsfysica
2 GANIL - Grand Accélérateur National d'Ions Lourds
3 DAM/DIF - DAM Île-de-France
4 RIKEN RNC - RIKEN Nishina Center for Accelerator-Based Science [Wako]
5 NKUA - National and Kapodistrian University of Athens
6 IFT - Instituto de Física Teórica UAM/CSIC
7 Center for Nuclear Study
8 Department of Physics [Tokyo]
2 GANIL - Grand Accélérateur National d'Ions Lourds
3 DAM/DIF - DAM Île-de-France
4 RIKEN RNC - RIKEN Nishina Center for Accelerator-Based Science [Wako]
5 NKUA - National and Kapodistrian University of Athens
6 IFT - Instituto de Física Teórica UAM/CSIC
7 Center for Nuclear Study
8 Department of Physics [Tokyo]
Y. Ichikawa
- Fonction : Auteur
- PersonId : 755570
- ORCID : 0000-0001-5362-6523
A. Poves
- Fonction : Auteur
- PersonId : 755249
- ORCID : 0000-0001-7539-388X
C. Stodel
- Fonction : Auteur
- PersonId : 177922
- IdHAL : christelle-stodel
- ORCID : 0000-0003-4658-2213
- IdRef : 227006291
J.C. Thomas
- Fonction : Auteur
- PersonId : 738662
- IdHAL : jean-charles-thomas
- ORCID : 0000-0001-6618-9772
Résumé
The electric quadrupole moment of the 33Al20 ground state, located at the border of the island of inversion, was obtained using continuous-beam beta-detected nuclear quadrupole resonance (beta-NQR). From the measured quadrupole coupling constant Q = 2.31(4) MHz in an alpha-Al2O3 crystal, a precise value for the electric quadrupole moment is extracted: Qs= 141(3) mb. A comparison with large-scale shell model calculations shows that 33Al has at least 50% intruder configurations in the ground state wave function, favoring the excitation of two neutrons across the N = 20 shell gap. 33Al therefore clearly marks the gradual transition north of the deformed Na and Mg nuclei towards the normal Z>14 isotopes.