In order to calculate the association constants of different La-Cl complexes, well-tempered metadynamics (WMetaD) simulations are performed in the N V T ensemble for ∼6 ns. Hills of height 1 kJ/mol and width 0.02 are deposited every 10 2 timesteps to get a good sampling of the associated and dissociated states within a reasonable simulation time. To allow a direct comparison with the AIMD data from Guan et al. at their studied conditions, boxes #5 and #6 in Table are used for these simulations. WMetaD simulations are also performed with boxes #4 and #7