87Strontium NMR studies

With a Fourier transform NMR spectrometer, especially developed for nuclei with weak signals, the ratio of the Larmorfrequencies of⁸⁷Sr in an aqueous solution of SrCl₂ and⁷³Ge in GeCl₄ has been measured with high accuracy. The concentration dependence of the⁸⁷Sr Larmorfrequency in aqueous solutions of SrCl₂, SrBr₂, Sr(ClO₄)₂, and Sr(NO₃)₂, has been determined. Using this dependence, the ratio of the Larmorfrequencies of the⁸⁷Sr²⁺ ion, for infinite dilution, and⁷³Ge in GeCl₄, isν(⁸⁷Sr²⁺)/ν(⁷³Ge)=1.242 344 6 (15). The magnetic moment of the⁸⁷Sr nucleus, in the Sr²⁺ ion merely surrounded by water molecules, isμ(⁸⁷Sr²⁺)=^?1.089 273 (9)μ _N, without correction for the ionic diamagnetism. Comparing this result with that of an optical pumping experiment, an upper limit for the shielding of the⁸⁷Sr²⁺ ions by the water molecules around the ions, is given.