where A, B,C, D ∈ R are optimized parameters (distinct for the polarization and interaction energy models, hence a total of eight fitting parameters are used regardless of the order of the model) ∀n ∈ N + \ {0}. All zeroth order coefficients are set to zero. Equations 20a through 20d are chosen due to these bearing a strong resemblance the coefficients previously obtained in a numerical experiment, whose values are not presented in this study, in which we perform least squares minimization against our calibration dataset with every coefficient being treated as a free/unconstrained optimization parameter.