ss , c 4 ss , c 0 os , c 1 os , c 2 os , s 8 as well as four osUW12 components c -4 u , c -3 u , c -2 u , c 1 u where coefficients c n u corresponds to the UW12 component Gaussian with exponent γ n . With this combination decided on, energies for all molecules in the training set were recalculated using the self-consistent orbitals obtained using this functional. Energies for all individual components were calculated using these orbitals and the coefficients re-fitted using this new data. This procedure was then repeated multiple times until the coefficients converged. Table shows the values of the coefficients at each cycle of the optimization. The zeroth cycle corresponds to the original fit using coefficients fitted using energies calculated on ωB97X orbitals. The final converged functional is shown in bold in the final column. We name this functional WM21-D3(BJ).