A deuteron NMR study of the tetrahydrofuran clathrate hydrate Part II: Coupling of rotational and translational dynamics of water

Abstract

In polycrystalline clathrate hydrate tetrahydrofuran-h₈·17D₂O both Bjerrum defect dynamics and hydrogen translational diffusion has been identified by deuteron NMR stimulated echo experiments in combination with random walk simulations. By temperature dependent experiments the activation energies of the two processes have been determined as 24.6(3) kJ mol⁻¹ and 12.3(6) kJ mol⁻¹, respectively. The analysis of the “generalized intermediate structure factors” reveals that the elementary step of hydrogen diffusion is the exchange of a covalent bond among neighbouring oxygens.