A similar comparison, using the relaxed density matrix to compute the analytic gradient including κ γ, p,q and P γ,[ϕ ] η,π is provided in the Supporting Information (Table ). This result follows the same trend as that observed with the unrelaxed density: the difference between the PTE and PTED approaches is small but slightly larger (0.005 eV ≈ 1 kcal mol -1 ) when using the relaxed density.