Starting with a water dimer, Figs. , and 8 display the QM/MM energy components while varying the intramolecular distance between the water monomers. Fig. shows the total energy of the system, while Fig. details the part of the permanent QM/MM electrostatic interaction energy, and Figure illustrates the induced QM/MM energy contribution as defined in Eq. 15, that includes T mod . We use various scaling factors f (r cov ) for covalent radii and plot the relative energies w.r.t. f (r cov ) = 1, i.e. the actual covalent radii.