Measurement of the local-moment-induced electric-quadrupole splitting of diluteAu198in iron by NMR on oriented nuclei

The magnetic-dipole and electric-quadrupole hyperfine splitting frequencies ${\nu }_M=\left|\frac{g{\mu }_N{B}_{\mathrm{hf}}}{h}\right|$ and ${\nu }_Q=\frac{e^2\mathrm{qQ}}{h}$ of dilute ${}_{}{}^{198}{}_{}{}^{}\mathrm{Au}$ ($j^{\pi }=2^{-}$; $T_{\frac{1}{2}}=2.7\mathrm{}$ d) in iron were measured with nuclear magnetic resonance on oriented nuclei as 259.48(3) MHz and -2.08(4) MHz, respectively. The quadrupole splitting disagrees in magnitude and sign with the published value measured with single-passage NMR on oriented nuclei. Taking into account the known magnetic and electric hyperfine splittings for ${}_{}{}^{199}{}_{}{}^{}\mathrm{Au}$ in Fe, the ratio of nuclear quadrupole moments is deduced to be $\frac{Q\left({}_{}{}^{198}{}_{}{}^{}\mathrm{Au}\right)}{Q\left({}_{}{}^{199}{}_{}{}^{}\mathrm{Au}\right)}=1.37\mathrm{}\left(3\right)\mathrm{}$. The experimental hyperfine anomalies between ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, ${}_{}{}^{198}{}_{}{}^{}\mathrm{Au}$, and ${}_{}{}^{199}{}_{}{}^{}\mathrm{Au}$ in Fe are discussed in the context of noncontact hyperfine fields.