For N2, PBE gives a mean absolute error (MAE) of 8.4 kJ/mol, which drops to 4.9 kJ/mol with the application of the U CCSD(T) correction (Figure ). In the cases of Mn-DOBDC, Ni-DOBDC, and Co2Cl2-BBTA, the heat of adsorption calculated using PBE is already small, within 3 kJ/mol of the experimentally measured value. Here, introducing the U CCSD(T) parameter does not greatly alter the results. For Co-DOBDC and Co2(OH)2-BBTA, PBE overbinds N2, giving errors of 10.7 kJ/mol and 16.4 kJ/mol, respectively. The U CCSD(T) parameter proves to be effective for these systems, decreasing the error to 4.1 kJ/mol for Co-DOBDC and 2.0 kJ/mol for Co2(OH)2-BBTA. In contrast, with Cu-DOBDC and Fe-DOBDC, PBE exhibits underbinding for N2. Given that the U parameter tends to weaken the adsorption strength, 90 it amplifies the error for Cu-DODBC. While the heat of adsorption of Fe-DOBDC atypically gets stronger upon applying the U CCSD(T) parameter, the increase in heat of adsorption for PBE+U is insufficient to achieve good agreement with the experimental heat of adsorption. For CO2, the interaction between the metal atom and the CO2 molecule in these MOFs is primarily driven by the dispersion interaction, with minimal hybridization. Therefore, the U CCSD(T) parameter has little impact on the heat of adsorption, as discussed previously. In summary, while the U CCSD(T) correction is effective in improving the accuracy for N2 in cases of PBE overbinding, it does not enhance the accuracy of CO2 adsorption values, which are primarily due to physisorption processes. O2 adsorption presents additional challenges. There is an uncertainty associated with whether the O2 molecule retains its spin when adsorbing and if that magnetic moment is coupled ferromagnetically (FM) or antiferromagnetically (AFM) to the metal center to which it binds. For all the studied MOFs, PBE exhibits a significant overbinding with AFM coupling, leading to a substantial MAE of 41.3 kJ/mol with respect to experiment. The U CCSD(T) parameter corrects much of this overbinding, reducing the MAE to 12.9 kJ/mol when choosing the coupling case with the lower energy for computing the heat of adsorption (Figure and Supporting Information Table ). When the U CCSD(T) parameter is applied, FM coupling shows stronger adsorption than AFM coupling for Cu-DOBDC, Fe-DOBDC, Co2Cl2-BBTA, and Co2(OH)2-BBTA. However, the U CCSD(T) parameter overcompensates for two outlier systems, resulting in errors of 21.9