Cl -, which leads to the extrapolation for the dispersion energy correction as -11.5(1.1) kcal/mol for Na + and -8.8(0.8) kcal/mol for Cl -(in the MP2→DFT direction). The total dispersion energy correction for the solute ion pair is then -20.3(1.4) kcal/mol or +20.3 kcal/mol in the desired DFT→MP2 direction. The Ewald correction in this direction is -1.6 kcal/mol.