The electric quadrupole moment of the Al201333 ground state, located at the border of the island of inversion, was obtained using continuous-beam β-detected nuclear quadrupole resonance (β-NQR). From the measured quadrupole coupling constant νQ=2.31(4) MHz in an α-Al2O3 crystal, a precise value for the electric quadrupole moment is extracted: QsAl33=141(3) mb. A comparison with large-scale shell model calculations shows that Al33 has at least 50% intruder configurations in the ground state wave function, favoring the excitation of two neutrons across the N=20 shell gap. Al33 therefore clearly marks the gradual transition north of the deformed Na and Mg nuclei towards the normal Z≥14 isotopes.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics