To perform such analysis, we will use the superoperator formalism which has been used in the paper of Rybak et al. and Williams et al. to identify the dispersion energy in the second order to compare them with expressions in Ref. We start with the Møller-Plesset partitioning of the Hamilonians describing the monomers given by the Eq. ( ). The CC equations can be written in convenient superoperator form 22