The ddX-library considers solute cavities that can be written as a union of balls, thus including van der Waals (vdW)-and Solvent Accessible Surface (SAS)-cavities . The domain-decomposition approach for Solvent-Excluded Surfaces (SES)-cavities has also been developed , but this does not (yet) fit the ddX-framework. We therefore consider a molecule consisting of N atoms, for each atom we assign a ball Ω j := B rj (x j ), centered at the nucleus position x j ∈ R 3 with radius r j ∈ R. The region occupied by the solute molecule is then given by