Spins and Hyperfine Structure Separations of RadioactiveAu198andAu199

Abstract

The focusing atomic beam apparatus has been used to measure the spins and hyperfine structure separations of ${\mathrm{Au}}^{198}$ (2.7 days) and ${\mathrm{Au}}^{199}$ (3.15 days). The observed spins are 2 for ${\mathrm{Au}}^{198}$ and $\frac{3}{2}$ for ${\mathrm{Au}}^{199}$. Observed $\Delta \nu$ for ${\mathrm{Au}}^{198}$ is 21 800±150 Mc/sec, assuming ${\mu }_I$ to be positive, or 22 500±150 Mc/sec, assuming ${\mu }_I$ to be negative. $\Delta \nu$ for ${\mathrm{Au}}^{199}$ is 11 110±130 Mc/sec, assuming ${\mu }_I$ to be positive, or 11 180±130 Mc/sec, assuming ${\mu }_I$ to be negative. The high $\Delta \nu$ for ${\mathrm{Au}}^{198}$ made it necessary to study that element by observation of multiple-quantum transitions.