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)μN, 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.