Low-Cost Periodic Calculations of Metal-Organic Frameworks: A GFN1-xTB Perspective

Semiempirical extended tight-binding (GFN1-xTB) and semilocal density functional theory (DFT)(Perdew-Becke-Ernzerhof (PBE)+D3) calculations are 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 is 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 root-mean-square displacement (RMSD) of the atomic positions, which remains below 0.3 Å. 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, this study constructs time-averaged X-ray diffraction patterns that closely aligned with experimental data. More importantly, GFN1-xTB performs exceptionally well at predicting the bandgap. 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.