New measurement and reevaluation of the nuclear magnetic andquadrupole moments ofLi8andLi9

Abstract

The nuclear magnetic moment of ${}^9\mathrm{Li}$ and the quadrupole moments of ${}^8\mathrm{Li}$ and ${}^9\mathrm{Li}$ have been measured by use of the β-asymmetry detection of nuclear magnetic resonance on optically polarized beams at ISOLDE/CERN. The radioactive beams were implanted in Si for g-factor measurements and in Zn, ${\text{LiNbO}}_3$, and ${\text{LiTaO}}_3$ crystals for quadrupole moment measurements. The electric-field gradient $V_{\mathit{zz}}=4.26(4)\times {10}^{15}$ V/${\text{cm}}^2$ is deduced for Li in Zn. Using a recently adopted reference value, $Q($ ${}^7\mathrm{Li}$ $)=-40.0(3)$ mb, we reevaluated all earlier reported nuclear quadrupole moments of ${}^8\mathrm{Li}$ and ${}^9\mathrm{Li}$. Based on all available previous and present data, the adopted quadrupole moments for these isotopes are $Q($ ${}^8\mathrm{Li}$ $)=+31.4(2)$ mb and $Q($ ${}^9\mathrm{Li}$ $)=-30.6(2)$ mb. The magnetic moment of ${}^9\mathrm{Li}$ is deduced as $\mu ($ ${}^9\mathrm{Li}$ $)=3.43678(6){\mu }_N$. The values are compared with predictions from shell-model and cluster-model calculations.