We also investigated these zwitterions' dipole moments, which indicate the polarization of charge distribution (Figure ). Consistent with the partial charge results, the dipole moment increases with ε. The optimal ε for recovering the dipole moment values to the CCSD(T) reference for different zwitterions is always between 1.2 and 1.5 for B3LYP calculations, whereas the optimal ε for BLYP is larger, ranging from 1.2 to 6.0 for different molecules (Supplementary Material Figure ). The difference in the optimal ε for recovering different properties (dipole vs. partial charge) indicates that DDE has not been eliminated by applying CPCM, because otherwise the ε value should be consistent. In summary, the SCF tends to converge to a more localized electron density distribution when CPCM is applied, increasing the partial charges and dipole moments. This localization effect could recover some gas-phase density properties affected by DDE when a very small dielectric constant is applied, but the DDE still exists.