Measurement of the electric quadrupole moments of 26–29Na
The nuclear electric quadrupole moments of the isotopes 26Na, 27Na, 28Na and 29Na were measured by β-NMR spectroscopy in single crystals of LiNbO3 and NaNO3. High degrees of nuclear polarization were produced by optical pumping of the sodium atoms in a fast beam with a collinear laser beam. The polarized nuclei were implanted into the crystals and NMR signals were observed in the β-decay asymmetries. Preparatory measurements also yielded improved values for the magnetic moments of 27–31Na and confirmed the spin I = 3/2 for 31Na. The results are discussed in comparison with large-basis shell model calculations.