The polarization contribution to the free energy of hydration

The magnitude of the polarization contribution to the free energy of hydration is analyzed using several approaches. Monte Carlo quantum mechanical-molecular mechanical (MC-QM/MM), self-consistent reaction field (SCRF), and classical free energy perturbation calculations were used to obtain independent estimates of the polarization contribution to the free energy of hydration. The results derived from these techniques are in reasonable agreement, which supports the reliability of the calculated polarization values. The polarization contribution to the free energy of hydration was partitioned into components to elucidate the nature of the polarization in the solvation process. Strategies to capture the polarization effects in force-field simulations are discussed.