Avoiding pitfalls in molecular simulation of vapor sorption: Example of propane and isobutane in metal-organic frameworks for adsorption cooling applications

Filip Formalik; Haoyuan Chen; Randall Q Snurr

doi:10.1063/5.0202748

Avoiding pitfalls in molecular simulation of vapor sorption: Example of propane and isobutane in metal-organic frameworks for adsorption cooling applications

J Chem Phys. 2024 May 14;160(18):184118. doi: 10.1063/5.0202748.

Authors

Filip Formalik^{1

2}, Haoyuan Chen³, Randall Q Snurr¹

Affiliations

¹ Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA.
² Department of Micro, Nano and Biomedical Engineering, Faculty of Chemistry, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland.
³ Department of Chemistry, Department of Physics and Astronomy, The University of Texas Rio Grande Valley, Edinburg, Texas 78539, USA.

PMID: 38738606
DOI: 10.1063/5.0202748

Abstract

This study introduces recommendations for conducting molecular simulations of vapor adsorption, with an emphasis on enhancing the accuracy, reproducibility, and comparability of results. The first aspect we address is consistency in the implementation of some details of typical molecular models, including tail corrections and cutoff distances, due to their significant influence on generated data. We highlight the importance of explicitly calculating the saturation pressures at relevant temperatures using methods such as Gibbs ensemble Monte Carlo simulations and illustrate some pitfalls in extrapolating saturation pressures using this method. For grand canonical Monte Carlo (GCMC) simulations, the input fugacity is usually calculated using an equation of state, which often requires the critical parameters of the fluid. We show the importance of using critical parameters derived from the simulation with the same model to ensure internal consistency between the simulated explicit adsorbate phase and the implicit bulk phase in GCMC. We show the advantages of presenting isotherms on a relative pressure scale to facilitate easier comparison among models and with experiment. Extending these guidelines to a practical case study, we evaluate the performance of various isoreticular metal-organic frameworks (MOFs) in adsorption cooling applications. This includes examining the advantages of using propane and isobutane as working fluids and identifying MOFs with a superior performance.