There are many pathways to future improvement and applications of DE-FF. For a complete small molecule and biomolecular force field, training and testing of library torsion parameters will be required for proteins and other biomolecules. Again, this will be facilitated through interfaces with OpenFF infrastructure, and the first (LJ-based) OpenFF protein force field is planned for the next major ("Rosemary") release. The accurate transfer free energies and natural soft-core of the DE-FF point to future use in protein-ligand binding free energy calculations for computeraided design. Additional potential applications include the study of molecular phase diagrams, where behaviour of the potential over a wide pressure range is desirable . For completeness, DE-FF parameters will also be required for F, P, S, I and counterions, which are under-represented in the mixture training data at present , but can be trained using the documented procedures developed here.