Based on the estimation of the intersection point of the two energy distributions, we estimate the LR contribution for Cl -ion as 54.0 kcal/mol. The dramatic increase of the LR contribution (including the sign) for the anion is attributed to the electrostatic potential at the center of the cavity. Assuming that the electrostatic interaction dominates the interactions between the center solute ion and solvent ions outside the cavity of 4 Å , the average energies of both Na + and Cl -ions over the uncoupled configurations gives an estimate of the electrostatic potential at the center of the cavity as -4.55 Volt, relative to the average potential in the bulk region of molten salt liquids.