For each set of deprotonated C-H sites in a molecule, we determine the minimum heterolytic dissociation energy (∆G • min ). Hereafter, we assume a linear relationship between the experimental pK a values and ∆G • min , as this assumption allows us to derive the empirical constants a and b and correct any systematic errors; see Equation , where ∆G • is replaced by ∆G • min . After retrieving the empirical constants a and b, we can now determine the QM computed pK a values for all deprotonated C-H sites using Equation .