An additional choice in force field design is whether to include Lennard-Jones parameters on polar hydrogen atoms, or to effectively redistribute them onto the neighbouring heavy atom (see Supporting Information S1.3). Different choices are made for example in the design of the TIP3P and CHARMM modified water model, while there is precedent for improved agreement with liquid data using Lennard-Jones parameters on polar hydrogen atoms. While separate mapping parameters have been previously proposed for polar and non-polar hydrogen atoms, the effect on accuracy has not been directly explored, and so we add this comparison to our list of model protocols to be tested (Table , model 4a).