We further examined the subtle electron density changes caused by CPCM that may not be reflected in the properties (partial charges, dipole) calculated from integrated density. As defined by Burke and coworkers, 56 the density-driven error in DFAs is given by where 𝐸 u is the approximate functional, and 𝑛 v and 𝑛 are the approximate and exact density. Hence, we can also quantify the difference between the gas phase vs. CPCM densities as the difference between the corresponding gas-phase energies: