with those obtained from the two-body expansion of the binding energy: ∑ where the superscript (2) is used to indicate the two-body approximation and is the interaction energy of the isolated fragment pair , computed by removing all other fragments from the coupled cluster calculation. Accordingly, represents the binding energy of the subsystems in the two-body approximation, i.e., that obtained by neglecting cooperativity of different intermolecular interactions. When eqs. ( ) and ( ) are subtracted side by side, the resulting terms represent the effect of higher-body corrections, i.e., the influence of cooperativity into the interfragment interactions: Equation 16 not only allows us to obtain an estimate of the overall cooperativity effect on the binding energy of the subsystems , but it also provides a quantification for the role of cooperativity on the interaction energy of each fragment pair, .