The generation of these reduced potentials along with configuration mapping for reweighting using MBAR has been explained in our previous works. Configuration mapping allows the reweight-ing of simulations of structurally different rigid water models using mathematical constructs which map a rigid water model structure to any other rigid water model structure according to some deterministic map x = T ij (x) from state i to state j. This mathematical approach constructs overlap between these phase spaces of states i and j which otherwise have no overlap, and thus enable the multistate reweighting algorithm to work with changes in rigid geometry of molecules.