On Das' Theory of Nuclear Magnetic Resonance in Solids

Das' theory developed the effect of vibratory rotary motion of water molecules in crystalline hydrates on the resonance spectra of the protons. Limitations on applicability of his theory are discussed. The theory is extended to the general case and a further effect on spectra is obtained. This effect is dependent upon the orientation of the proton-proton axis within the crystal, the orientation of the crystal in the magnetic field, the temperature and the height of the twofold potential barrier containing the water molecule. Partial experimental support of the theory is cited. Two methods for measuring proton-proton separations that do not require Das' theory corrections are described. A method for measuring the height of the potential barrier is described.