Noteworthy, the assumed similarity between vaporization and van der Waals interaction energies points to a correlation between vaporization and solubility behavior. This assumption is based on the idea that the same intermolecular attractive forces have to be overcome to vaporize a number of molecules as to dissolve it 20 . Thus, one introduces the crucial approximation that the molecules from one substance in the mixture are physically separated from the molecules of the other component.