Ab initio Screening of MOFs: A Comparative Study of Exchange-Correlation Functionals and van der Waals Corrections

Metal organic frameworks (MOFs) raise a lot of attention as a result of their diverse technological applications, ranging from gas storage to photocatalysis. Being built up from metal atoms interconnected with organic ligand molecules gives rise to a porous crystal. The interchange of metal nodes and ligands gives the opportunity to tailor the properties of the material towards a specific application, but also broadens the configurational space.

Density functional theory offers an efficient computational tool to screen the configurational space, however, its results crucially depend on the choice of the adopted XC functional. Herein, we consider MOF-5 and its variants [1] as benchmark system to analyze the performance of various XC functionals. The meta-GGA functional R2SCAN demonstrates superior accuracy when compared to its computational costs. The structural parameters align well with the experimental findings, and the charge distribution corresponds favorably with more expensive hybrid functionals such as PBE0 and HSE06. The fundamental gap does improve slightly over PBE, but still lacks the accuracy of hybrid functionals.

[1] J. Edzards, H.-D. Saßnick, J. S. Andreo, and C. Cocchi, J. Chem. Phys. 160, 184706 https://doi.org/10.1063/5.0203605 (2024).