Assessment of quantum mechanical continuum models of solvation: the prediction of tautomer equilibria, partition coefficients and amine basicity

Quantum mechanical continuum models of solvation, the self-consistent reaction field (SCRF), and polarizable continuum method, are used at the ab initio SCF level, to study tautomer equilibria, partition coefficients and amine basicity. The predictions are compared both with experimental data and with results from free energy perturbation (FEP) studies. In the SCRF studies, the description of the solute charge distribution beyond the dipole level does not lead to a significant improvement in the accuracy of the predictions. For the range of properties studied, the quality of predictions by these continuum models rivals that obtained by traditional molecular dynamics calculations.