Dynamics of molecules in confinement and technical relevance

Abstract
Quasi-elastic neutron scattering allows to characterise molecular diffusion of species adsorbed in porous materials. Diffusion coefficients can be derived, without a model, over space scales where the molecular motion follows Fick's law. Furthermore, using jump diffusion models, one can determine characteristic times and distances for the elementary jumps. These experimental results are of value to understand separation processes and shape-selectivity in catalysis, and also to test molecular simulations performed on these systems. Applications of the QENS technique reviewed here concern mainly molecules adsorbed in zeolites, some results obtained in microporous silica are also presented.