Investigation of NMR-spectra of cesium in aqueous solutions and determination of the magnetic moment of the cesium-133 nucleus

Abstract

The problem of increasing the accuracy of determining the magnetic moment of the cesium-133 nucleus, which is used as a reference standard for determining the magnetic properties of short-lived cesium isotopes, is considered. Experimental results of determining the ratio of the resonance frequencies of water protons and ₁₃₃Cs nuclei for aqueous solutions of CsF, CsCl and CsNO₃ with concentrations from 0.1 to 0.4 Mol/kg H₂O are presented. As a result, of the simultaneous registration of nuclear magnetic resonance signals of water protons and cesium-133 nuclei, random and systematic uncertainty in determining the ratio of the resonance frequencies of water and cesium protons to units of the eighth decimal place are minimized. Extrapolation of the content of cesium salts in water to zero concentrations was carried out. For single cesium ions in water, the resonance frequency ratio 7.6241815(2) was determined. The magnetic moment of the cesium-133 nucleus was calculated taking into account the data for the magnetic moment of the proton, the screening of protons in water, and the known data on the screening of cesium ions in water. As a result, the magnetic moment of the cesium-133 nucleus was determined: 2.58243(12), which was compared with the data of other authors. The study of solutions of cesium salts in water revealed an anomalously large dependence of the resonance frequency of cesium nuclei on the solution temperature, which is 12 times higher than the analogous dependence of the resonance frequency of water protons.