Abstract: In this paper, we report force field predictions of hydrogen uptakes for MOFs materials that contain unsaturated coordinate copper metal complexes. The ab initio calculations were performed using RI-UMP2 method with the TZVPP basis set and BSSE correction on square-coordinated copper-acidic complex and hydrogen molecules. A force field was developed based on the ab initio energetic data. The resulting force field was applied to predict hydrogen adsorption isotherms at different temperatures and pressures using GCMC method. The ab initio results indicate that the square-coordinated copper has stronger interaction with hydrogen than tetrahedral-coordinated zinc. However, existing experimental data has not realized the potential yet. In order to predict hydrogen uptakes for similar materials, we adjusted the force field parameters using known experimental isotherm of CuBTC and predicted hydrogen uptakes for other three similar MOFs relative to CuBTC.

Key words: hydrogen storage, MOFs, unsaturated metals, ab initio, molecular simulation