(350a) Applicability of Generic Force Fields for Adsorbent Screening

The availability of accurate, transferable force field parameters is critical in computational screening and discovery of next-generation adsorbent materials, such as metal-organic frameworks (MOFs), for energy and environmental applications. Currently, generic force fields, such as Universal Force Fields (UFF) and Dreiding Force Fields (DFF), are widely used to model the van der Waals interactions between framework atoms in MOFs. Although these force fields have been suggested in the literature to provide similar ranking of materials than more sophisticated DFT-derived force fields, the applicability of “off-the-shelf” force fields to predict experimental ranking of adsorbent materials has not been examined. In this work, we examined the applicability of “off-the-shelf” force fields in scoring the adsorbent materials for on-board methane storage and delivery applications. Although the adsorption properties computed based on UFF and DFF provide similar ranking of adsorbent materials, we find that these “off-the-shelf” force fields do a poor job in predicting the ranking of the adsorbent materials based on experimental isotherms. We briefly discuss our force field development efforts based on the adsorption isotherm from NIST-ISODB.