Measurement of the electric quadrupole moments of ~(26-29)Na

摘要

The nuclear electric quadrupole moments of the isotopes ~(26)Na, ~(27)Na, ~(28)Na and ~(29)Na were measured by β-NMR spectroscopy in single crystals of LiNbO-3 and NaNO_3. 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 ~(27-31)Na and confirmed the spin I = 3/2 for ~(31)Na. The results are discussed in comparison with large-basis shell model calculations.