Precise nuclear moments of extremely proton-rich nuclus 23Al

Electric quadrupole coupling constant eqQ/h of the extremely proton-rich 23Al (I π = 5/2 + , T 1/2 = 0.47 s) nucleus implanted into an Al2O3 single crystal has been measured for the first time, using the β-ray detecting nuclear quadrupole resonance method (β-NQR) in a high magnetic field. As a preliminary result, the quadrupole coupling constant was determined as |eqQ/h(23Al) | = 2.66±0.77 MHz. Using the quadrupole coupling constant of 27Al in Al2O3 as a reference, the Q moment of the ground state of 23Al was extracted as |Q(23Al)| ~ 160 mb, which is well explained by the shell model calculation in the sd-shell model space with the USD interaction.