The nuclear magnetic dipole moment $\mu$ and electric quadrupole moment $Q$ of the $\beta$-emitting ${}^{16}\mathrm{N}(I^{\pi }{=2\mathrm{}}^{-}{,T}_{1/2}=7.13\mathrm{s})$ nucleus have been determined for the first time by detecting its $\beta$-NMR in a MgO crystal and $\beta$-NQR (nuclear quadrupole resonance) in a $\mathrm{TiO}{}_2$ crystal to be $|\mu |=(1.9859\pm 0.0011){\mu }_{\mathrm{N}}$ and $|Q|=(17.9\pm 1.7)\mathrm{mb}$, respectively. Although the prediction of $\mu$ given by the Hartree-Fock calculation agrees well with the experiment, an abnormally small effective charge for neutrons is required to account for the experimental $Q$.

• Received 10 October 2000

DOI:https://doi.org/10.1103/PhysRevLett.86.3735