Ab Initio Derived Force Fields for Zeolitic Imidazolate Frameworks: MOF-FF for ZIFs

Area of Science:

• Materials Science
• Computational Chemistry
• Chemical Physics

Background:

• Zeolitic imidazolate frameworks (ZIFs) are a class of metal-organic frameworks with diverse applications.
• Accurate force fields are crucial for simulating ZIF properties and predicting their behavior.
• Existing force field parametrization methods face challenges with periodic systems and optimization efficiency.

Purpose of the Study:

• To develop and validate a new, consistent force field for various ZIF systems.
• To extend the MOF-FF parametrization methodology by incorporating periodic reference data and a novel optimizer.
• To accurately describe the linker swing effect in ZIF-8 derivatives.

Main Methods:

• Parametrization of a new force field for ZIF-8, ZIF-8(H), ZIF-8(Br), and ZIF-8(Cl) using the MOF-FF methodology.
• Implementation of periodic reference data for cluster generation.
• Employment of the covariance matrix adaptation evolutionary strategy (CMA-ES) for force field optimization.
• Validation of the force field against static and dynamic properties, including ab initio molecular dynamics simulations.

Main Results:

• A new force field for ZIF systems was successfully parametrized.
• The covariance matrix adaptation evolutionary strategy (CMA-ES) proved more efficient and versatile than previous genetic algorithms for force field optimization.
• The developed force field accurately reproduces static and dynamic properties of ZIFs.
• The force field effectively captures the crucial linker swing effect in ZIF-8 derivatives, showing accuracy comparable to ab initio molecular dynamics.

Conclusions:

• The new force field provides a reliable tool for simulating ZIF systems.
• The integration of periodic reference data and CMA-ES represents a significant advancement in force field development for MOFs.
• This work enables more accurate predictions of ZIF properties and facilitates their application in various fields.