Implicit solvation models for air-water interfaces and aqueous and nonaqueous solution

Three different implicit solvation models are presented. The performance of two of these models for calculating solvation free energies of ions in aqueous and nonaqueous solution is tested using a data set of absolute solvation free energies of single ions that were obtained by applying the previously developed cluster pair approximation to experimental and theoretical gas-phase clustering data. A strategy for improving the performance of these models for ions that involves including a small number of explicit solvent molecules in the calculation is described. A third model for predicting adsorption coefficients at the air-water interface that involves separating the observable free energy of adsorption into a dimensionality change component and a solute-solvent coupling component is presented and applied to a diverse set of pesticides.