HF-3c differs from HF/STO-3G in several ways: HF-3c uses the MINIX basis set instead of STO-3G and has three empirical corrections accounting for dispersion (E disp ), basis set superposition error (E BSSE ), and bond length errors (E SRB ). These three corrections contribute 1.1 and 4.8 kcal/mol to the errors in the product and reactant half-reactions, respectively. Thus the larger error compared to HF/STO-3G for the product half-reaction is primarily due to the difference in basis set. This observation is also consistent with the fact that the HF/MINIX Dev-2 error for the R19 is -24.8 kcal/mol kcal/mol.