Our results suggest that IDAC values can potentially play an important role in testing force fields and assisting with force field parameterization. They are frequently measured for applications in engineering while other commonly used quantities, such as hydration free energies (∆G hyd ), are not routinely measured. Furthermore, since IDACs can be calculated in a straightforward manner using solvation free energy calculations, they can be calculated with essentially the same degree of precision as solvation free energies, and with the same procedures. IDACs actually could be even better than solvation free energies, which involve transfer between gas and liquid phases, since they are related to transfer between two condensed phases -pure solute and pure solvent -which makes them an ideal candidate to test how a force field represents condensed-phase environments.