By approximating the electronic densities of the separated molecules as linear combinations of s-type Gaussian basis-functions (atom-centered or not) we can easily derive exact closed-form solutions of the integrals of Equations 6a, 6b, 13a and 13b. The exact expressions for these terms are given in the supplementary material up to order 2. of Equation 12 is calibrated using Coupled Cluster Singles and Doubles (CCSD) calculations including triple excitations (CCSD(T)) of dimers of water molecules. We assess the ability of this calibrated model to estimate energies outside of the water dimer set by predicting the interaction in the neutral and anionic O 2 dimer system as well. The reference values were obtained from restricted open (RO) shell CCSD(T) calculations to prevent spin contamination. All CCSD(T) calculations presented in this manuscript use the all-electron basis-set cc-pVTZ .