Magnetic moments of76Asand77As

The nuclear magnetic moments of the ground states of ${}^{76}\mathrm{As}$ and ${}^{77}\mathrm{As}$ were measured using nuclear magnetic resonance on oriented nuclei (NMR-ON) by detecting $\ensuremath{\gamma}$ rays and $\ensuremath{\beta}$ rays. The magnetic hyperfine splitting frequencies of ${}^{76}\mathrm{As}\mathrm{Fe}$ and ${}^{77}\mathrm{As}\mathrm{Fe}$ in a zero external magnetic field are 117.99(8) MHz and 225.58(8) MHz, respectively. With the known hyperfine field of ${B}_{\mathrm{hf}}{(}^{75}\mathrm{As}Fe)=34.29(3) \mathrm{T}$ the magnetic moments have been determined as $\ensuremath{\mu}{(}^{76}\mathrm{As}{,2}^{\ensuremath{-}})=(\ensuremath{-})0.9028(10){\ensuremath{\mu}}_{N}$ and $\ensuremath{\mu}{(}^{77}\mathrm{As}{,3/2}^{\ensuremath{-}})=+1.2946(13){\ensuremath{\mu}}_{N}.$ The effective spin-lattice relaxation time for ${}^{76}\mathrm{As}\mathrm{Fe}$ has been measured to be 5.2(8) m and 11.2(16) m at the external magnetic field of 0.2 T and 0.6 T, respectively. The observed magnetic moments are discussed in the framework of the configuration mixing model.