Low-cost periodic calculations of metal-organic frameworks: A GFN1-xTB perspective.

Abstract

Semiempirical extended tight-binding (GFN1-xTB) and semilocal DFT(PBE+D3) calculations were performed to evaluate the structural and electronic properties of five metal-organic frameworks (MOFs): rigid MOF-5(Zn), IRMOF(II)-74(Mg), ZIF-8(Zn); and flexible MIL-53(Al) and MIL-53(Fe). It was found that GFN1-xTB exhibits a similar performance to that of DFT in terms of accuracy of lattice vector preservation. Structural integrity is further supported by the low average RMSD of the atomic positions, which remains below 0.3 A. Consequently, the textural properties are also well preserved by GFN1-xTB, showing good agreement with those obtained from DFT. GFN1-xTB molecular dynamics (MD) simulations exhibit structural stability and correctly predict structural responses to temperature, which is fully consistent with experimental results. In addition, based on MD trajectories, we constructed time-averaged X-ray diffraction patterns that closely aligned with experimental data. More importantly, GFN1-xTB performed exceptionally well at predicting the band gap. Overall, GFN1-xTB offers almost semilocal DFT accuracy with significantly higher computational efficiency, making it a valuable tool for describing the geometric, textural, dynamic, and selected electronic properties of MOFs.