Using Molecular Dynamics simulations for elucidation of molecular traffic in ordered crystalline microporous materials

Robust models to describe mixture diffusion in ordered crystalline microporous materials such as zeolites, metal-organic frameworks (MOFs), and zeolitic imidazolate frameworks (ZIFs) are essential for the development of separation and reaction technologies. The development of appropriate models requires insights into a wide variety of factors that influence the mobilities of guest molecules in the microporous hosts. Such factors include: molecular size, shape, and configuration, degree of confinement, pore topology and connectivity, strength of adsorption on pore walls, molar loadings of guest constituents, and correlations in the molecular jumps between partner molecules. Experimental data, on their own, do not provide sufficient information to set up the requisite models to describe mixture diffusion. The primary objective of this article is to demonstrate the potency of Molecular Dynamics (MD) simulations to offer insights that assist in the interpretation of experimental observations and development of descriptive models. Computational snapshots and video animations are used to provide a visual appreciation of phenomena such as traffic junction, slowing-down, and hindering effects in diffusion.