Diffusion and relaxation in interface layers of crystals in nanoporous glass.
Below the freezing point, experimental data provide evidence for the existence of a non-frozen interface layer (NFL) between the crystal in the pore and the pore walls. The molecules in this layer are effectively confined in a quasi-two-dimensional space that forces them to reorient when moving along the curved pore surface. Through this relaxation mechanism, the translational mobility in the unfrozen phase reveals itself in a pronounced frequency dependence of the spin-lattice relaxation time. The experimentally observed drop of the self-diffusion coefficients by more than one order of magnitude below the phase transition can be interpreted in terms of geometric restrictions as well as interactions with the surface.
Zavada
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Sektion Kernresonanzspektroskopie, Universität Ulm, Germany.
Stapf
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Kimmich
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D000473:Alkanes; D003460:Crystallization; D004058:Diffusion; D005898:Glass; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D016062:Porosity; D014867:Water
D000473:Alkanes; C024713:n-tetradecane; D014867:Water