DFT Study of Solvent Effects for Some Organic Molecules Using a Polarizable Continuum Model

Forty ionic molecules are studied by DFT (B3LYP, B3P86), MP4 with different basis sets using the PCM/UAHF model within the self-consistent reaction-field method to assess solvent effects. For these molecules, the solvation free energies (ΔGsol) in water and the dipole moments in vacuoas well as in water are obtained. By comparing the calculated values of ΔGsol with experimental values and molecular simulation results, it is found that the ΔGsol values generated by the DFT method are in better agreement with experimental values. Moreover, especially for the B3LYP/6-31+G∗ level, the results of both ΔGsol and dipole moments are more accurate considering the lower computational cost. It can be noted that the dipole moments of solutes in water show some increase relative to those in vacuo.