Nuclear Spin and Moment ofAg110mby Paramagnetic Resonance

Abstract

Paramagnetic resonance was observed in 253-day ${\mathrm{Ag}}^{110m}$, present as ${\mathrm{Ag}}^{2+}$ in the ${\left[{(\mathrm{i}\mathrm{s}\mathrm{o}-{\mathrm{C}}_3{\mathrm{H}}_7)}_2\mathrm{NC}{\mathrm{S}}_2\right]}_2$Ag complex. Eleven hfs lines were observed, the positions of the other two lines being obscured by other absorptions present in the sample, and the nuclear spin of 6 was confirmed. A hfs constant $a_{110m}=(7.108\mathrm{}\pm 0.02)\times {10}^{-3\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$ was determined. A hyperfine anomaly of ${\Delta }_{107,109}=-0.40\%\pm 0.1\%$ was observed for stable ${\mathrm{Ag}}^{2+}$ in this complex, indicating that the hfs arises from contact interaction. A nuclear moment of ${\mu }_{110m}=+3.55\mathrm{}\pm 0.04$ nm was derived after a 3.7% hyperfine-anomaly correction. It is pointed out that hyperfine anomalies can be infinitely large for very small moments, and that the anomaly may cause a finite moment to exhibit vanishing hyperfine structure or conversely. The nuclear moment does not agree with shell-model predictions using empirical $g$ factors, being low by 1 nm. It is suggested that the ${\left(g_{\frac{9}{2}}\right)}^7$ proton configuration might be coupled to spin $\frac{7}{2}$. This yields a moment of +3.54 nm. The hyperfine fields for Ag in Fe and Ni are corrected to -282±20 kG and -87±8 kG, respectively.