THE DEVELOPMENT OF AN NMR SPECTROMETER FOR THE PRECISION DETERMINATION OF THE RATIO OF THE RESONANCE FREQUENCIES OF NUCLEI

A nuclear magnetic resonance (NMR) spectrometer for determining the resonance frequencies of various nuclei at a magnetic field induction of 2.142 T is described. The spectrometer enables the NMR frequency of a nucleus to be recorded simultaneously with the frequency of the signal from a comparison nucleus and enables the magnetic field to be stabilized using the NMR signal from a third nucleus. The ratios of the resonance frequencies of protons and of the lithium-7 nuclei: F(H(2)O) F((7)Li) = 2.573041789(3) are obtained for a solution of lithium chloride in water, and also the ratio for protons and deuterons of an isotopic solution of water: F(H(2)O)/F(D(2)O) = 6.514399603(2). Methods of determining the systematic errors which occur when there are quadratic gradients of the magnetic field in the sample when processing spectral numerical data matrices are discussed.