Dynamic disorder and solid state NMR

The temperature dependences of the second moment (M-2) and spin-lattice relaxation times (T-1 and T-1 rho) in solids with dynamic disorder have been investigated assuming that the potential barrier E for the moving atom (or molecule) is a stochastic function of time. It has been shown that the temperature dependences of M-2, T-1 and T-1 rho exhibit a significant dependence on the kind of standard deviation of the distribution of E and on the form of the activation energy E-b at frequency nu(0) describing the temporal fluctuations of E. The obtained results have been applied to the interpretation of the temperature transformations of the second moment of H-1 NMR spectra of the diffusing water molecules in the mineral natrolite.