Toward Rational Design of Metal-Organic Frameworks for Sensing Applications: Efficient Calculation of Adsorption Characteristics in Zero Loading Regime

The Henry's constant of adsorption, differential enthalpy of adsorption, free energy barriers between various compartments of the porous space, and selectivity are important characteristics of a porous material. These characteristics are directly related to the performance of the porous material in a sensing application and can be used as preliminary criteria for computational screening of the candidate porous materials. All these properties are linked to each other through well-established statistical-mechanical relations. In this article we demonstrate that the finely discretized representation of the simulation cell offers a particularly convenient way to exploit these relations, and, for rigid molecules in rigid porous materials, the majority of these characteristics can be calculated from a single simulation run. We apply the methodology to calculate the Henry's constants and other characteristics for several small organic and aromatic molecules in two metal-organic frameworks, IRMOF-1 and MIL-47(V). We further provide predictions for TNT adsorption in these structures and discuss the implications of our findings in the context of sensing applications.