Similar trends are observed for the other significant changes in force field parameters: the predicted free energy difference is more accurate for the modified parameters. The largest improvement in this analysis was observed for the changes in the hydroxyl group bound to a sp2 carbon involving the bond (b18) and torsion (t106) parameters. Figure illustrates 2: Comparison of the three force fields OpenFF-1.0, OpenFF-1.2, and OpenFF-2.0 based on the root mean squared error (RMSE) of the ∆∆G values of the converged perturbations. Each row represents a target set (or 'all' for all target sets combined) with a specified number N of perturbations followed by the RMSE between experimental and calculated value for the respective force field. The upper and lower and upper bound of the 95% confidence interval are given as sub-and superscript. All values are in kcal mol -1 . The values are illustrated in Figures and.