Guest motion in tetrahydrofuran clathrate hydrate studied by deuteron nuclear magnetic resonance

摘要: The guest dynamics in tetrahydrofuran (THF) clathrate hydrate $(\text{THF}\ensuremath{\cdot}17{\text{H}}_{2}\text{O})$ was studied using several deuteron nuclear magnetic resonance (NMR) techniques. At low temperatures the magnetization recovery proceeds two steps. weight of faster contribution decreases with decreasing temperatures. This behavior is signature a dynamical effect. contributions cannot be ascribed separately to metadeuteron and paradeuteron THF molecule. thermal evolution NMR spectra described semiquantitatively distorted octahedral reorientational jump model. Pseudorotation has no significant impact on spectral width. motional correlation times, measured two-time stimulated-echo spin-relaxation techniques, cover dynamic range nine decades. Four-time measurements reveal statically heterogeneous rotational motion molecules 16-faced polyhedral cages structure II lattice.