Therefore, we explicitly compute the atomic parameters at different conformations, and fit them to a linear model depending on the OH bond lengths and HOH bond angles. For simplicity, we only allow the leading terms of the electrostatic and dispersion components (i.e., charge and 6 C ) to fluctuate, while keeping the higher order terms (dipoles, quadrupoles, 8 C , and 10 C ) fixed. The dimer scan results of the fluctuating charge and 6 C model are in much better agreement with CCSD(T), as shown in Figure (b), validating our methodology. To further examine the performance of the long-range force field in the description of many-body interactions, we test it on flexible trimer scans (see Figure ). The good agreement between our model and CCSD(T) once again proves the capability of our model in the description of long-range three-body interactions. This is expected as we incorporate the induction effects explicitly, while the many-body dispersion is not very important in water systems.