One such continuum solvation method is known as the Conductor-like Screening Model (COSMO), and allows the solute cavity to be arbitrarily shaped . The method makes calculation of analytical gradients more efficient and geometry optimization can be done faster and more realistically . COSMO-RS is an updating of COSMO for "real solvents", that is, without assumption of dielectric screening theory, which does not hold for very polar solvents . COSMO-RS relies on viewing molecular interactions locally, through pairwise interactions, rather than considering ensembles of molecules interacting electrostatically and through van der Waals forces.