Simultaneous Determination of the Magnetic Moments of ⁶Li and ⁷Li Nuclei Using an NMR Spectrometer

The ratio of NMR frequencies of lithium isotopes f(⁷Li)/f(⁶Li) = 2.6409061846(13) was determined with an error of 4.9·10^–10. The use of a nuclear magnetic resonance spectrometer operating in the mode of simultaneous registration of signals from two nuclei to obtain data allowed the random and systematic errors in the measurement results to be reduced by an order of magnitude. The ratio of the resonant frequencies of water protons and ⁷Li ions was determined: f(H₂O)/f(⁷Li) = 2.557100473(9) with an error of 3.5·10^–9 for solutions with an extremely low concentration of LiOH*H₂O salt in water and at a temperature of 25°C. Based on the obtained data, the magnetic moments of lithium nuclei were calculated: μ(⁶Li) = 0.8220454(25)μ_N, μ(⁷Li) = 3.2564171(98)μ_N. The known data on the magnetic moment of the proton and data on the electronic shielding of these nuclei were used. A comparison of the experimental data for μ(⁶Li) and μ(⁷Li) and the corresponding theoretical calculation data was performed.