(GAFF), Merk Molecular Force Field (MMFF94S), both of them using the open-source software OpenBabel, Effective Fragment Potential (EFP) method using the open-source software LIBEFP, and MB-Pol using the open-source software MBX. All ab initio calculations that are used and presented for this study are obtained from the Gaussian 16 software 60 using the LEO High Performance Computing (HPC) facilities in the University of Innsbruck. The fitting of the exchange and correlation coefficients used to polarize the molecules as described in Equation 19 is performed with the following combination of methods: An initial optimization using the Nelder-Mead simplex algorithm using only 220 randomly picked water dimer configurations of our calibration dataset, followed by another minimization using a low memory Broyden-Fletcher-Goldfarb-Shanno (LBFGS) algorithm, followed by a final minimization using the same LBFGS algorithm against all water dimer configurations in our calibration data set. Exact values for the gradients for the minimization problem to calibrate, and just the calibration, the XC coefficients for the polarization model are obtained using automatic (forward mode) differentiation in Julia using the open-source package ForwardDiff. For the full electron variant of our method only the Nelder-Mead algorithm is employed for the fitting of its parameters, due to numerical noise issues stemming from huge numbers that arise when using this variant of our molecular force field model.