I-SOLV: A new surface-based empirical model for computing solvation free energies
We have developed a new empirical model, I-SOLV, for computing solvation free energies of neutral organic molecules. It computes the solvation free energy of a solute molecule by summing up the contributions from its component atoms. The contribution from a certain atom is determined by the solvent-accessible surface area as well as the surface tension of this atom. A total of 49 atom types are implemented in our model for classifying C, N, O, S, P, F, Cl, Br and I in common organic molecules. Their surface tensions are parameterized by using a data set of 532 neutral organic molecules with experimentally measured solvation free energies. A head-to-head comparison of our model with several other solvation models was performed on a test set of 82molecules. Our model outperformed other solvation models, including widely used PB/SA and GB/SA models, with a mean unsigned error as low as 0.39kcal/mol. Our study has demonstrated again that well-developed empirical solvation models are not necessarily less accurate than more sophisticated theoretical models. Empirical models may serve as appealing alternatives due to their simplicity and accuracy.
empirical model solvation free energy solvent-accessible surface atom type i-solv