Isotope Effect in the Nuclear Magnetic Resonance in Rubidium

Abstract

By performing precise measurements of the nuclear magnetic resonance frequencies at constant field of the stable Rb isotopes in a metallic sample and in RbCl solution, we determined $\Delta =\frac{k^{85}}{k^{87}}-1=(0.38\mathrm{}\pm 0.03)\%$, where $k^{85,87}$ is the Knight shift of ${\mathrm{Rb}}^{85,87}$. $\Delta$ is the hyperfine structure anomaly which will be equal to $\Delta \left(s_{\frac{1}{2}}\right)$, determined from $\mathrm{Rb}\left(5s{S}_{\frac{1}{2}}\right)$ atomic beam experiments only if the hyperfine interaction responsible for the Knight shift arises from $s_{\frac{1}{2}}$ conduction electrons. The experimental results show that to high precision this is the case.