Nuclear moments of the low-lying isomeric 1+ state of 34Al: Investigation on the neutron 1p1h excitation across N = 20 in the island of inversion

• Main Authors: Z.Y. Xu, H. Heylen, K. Asahi, F. Boulay, J.M. Daugas, R.P. de Groote, W. Gins, O. Kamalou, Á. Koszorús, M. Lykiardopoulou, T.J. Mertzimekis, G. Neyens, H. Nishibata, T. Otsuka, R. Orset, A. Poves, T. Sato, C. Stodel, J.C. Thomas, N. Tsunoda, Y. Utsuno, M. Vandebrouck, X.F. Yang
• Format: Article
• Language: English
• Published: Elsevier 2018-07-01
• Series: Physics Letters B
• Online Access: http://www.sciencedirect.com/science/article/pii/S037026931830457X
• ISSN: 0370-2693

The nuclear g factor and quadrupole moment (Qs) have been measured for the low-lying isomeric 1+ state of 34Al, using the β-detected nuclear magnetic resonance (β-NMR) and quadrupole resonance (β-NQR) methods. Spin-polarized 34Al isotopes were produced in a one-neutron pickup reaction induced by a 36S beam on a 9Be target at a kinetic energy of 77.5 MeV/nucleon, and were collected with the LISE fragment separator at GANIL. The measured g factor (|g| in a range of 1.757±0.014) and quadrupole moment (|Qs|=38(5) mb) are in good agreement with shell-model calculations using effective interactions. The similarity between the g factor of 34mAl and that of 32Al confirms a dominant neutron 2p1h configuration π(d5/2)−1⊗ν(d3/2)−1(f7/2)2 of 34mAl. In addition, the enhanced quadrupole moment of 34mAl relative to that of 32Al suggests that the neutron 1p1h excitation across the N=20 shell gap introduces extra nucleon–nucleon correlation and deformation. Keywords: β-NMR/NQR, g factor, Quadrupole moment, 34mAl