Additionally, the difference between the induced dipole moments ∆µ is also added to the fitting procedure to ensure that differences in density are not overly determined to match the energetic contributions alone. Without this term, the amount of charge movement within a fragment would sometimes become excessively large (on the order of a few electrons), signally that the parameters were overly fit to the energy data alone. Excessive change in electron populations also resulted in very large molecular polarizabilities. Further details about the effect of this fitting procedure will discussed in section 4.