The only parameters in our model that are fit to experiment are the eight free atom radii (R f ree i ), one for each of the elements studied so far (H, C, N, O, F, S, Cl, Br). This version sees the addition of a bromine parameter that was fit in the same spirit as the rest, that is empirically tuning the free atom radii to recreate liquid properties of a selection of bromine-containing molecules. The dependence of computed liquid properties on the R f ree i parameter of bromine is displayed in Table . A full description of the non-bonded parameter derivation methods can be found in Ref. 48.