Proton Dipolar Spin-Lattice Relaxation in Nano-channels of Natrolite.

The (1)H nuclear magnetic resonance (NMR) spectra and the dipolar spin-lattice relaxation time T 1D for (1)H in the natural natrolite (Na2Al2Si3O10·2H2O) have been measured in the temperature range of 190-390 K. From the temperature transformations of (1)H NMR spectra, it follows that at T > 300 K, the diffusion of water molecules along the nano-channels is observed. From experimental T 1D data, it follows that the 180° flip motion of the water molecules takes place in natrolite. At low temperature (T < 250 K), the dipolar interaction with paramagnetic impurities as a relaxation mechanism of (1)H nuclei becomes significant.