To converge the forces at the shortest possible cutoff distance, which is at ∼ 24 a.u. for the solute-solvent systems and ∼ 40 a.u. for GB1, requires a fourth-order multipole expansion in the case of Wat(aq), fifth-order for Ace(aq), sixth-order for BuOH(ace), and seventhorder for GB1. The dipole moments (or zinc ion charge in case of GB1) are also converged at around the same cutoff distances (see Fig. ). Using the cutoff distance and order of multipoles where the forces are fully converged, yields an error in the total energy roughly of the order of 10 -5 a.u. for Wat(aq) and BuOH(ace), and 10 -4 a.u. for Ace(aq) and GB1. These errors are negligible compared to the thermal energy of the systems and the dynamics of the two approaches can thus be considered equivalent from a sampling point of view.