This thesis is concerned with the development an analysis for decomposing the binding energy of second-order Møller–Plesset perturbation theory into physically meaningful components. This can be defined as an extension to the previous work on an absolutely localized molecular orbitals based EDA for Hartree–Fock. The decomposition of the correlation energy proceeds though physically motivated constrained intermediate wave functions and corrects the HF description of frozen interaction, polarization, and charge transfer, while adding a description of dispersion that is only possible at the correlated level. This method is implemented efficiently and the performance of the implementation is tested. The EDA is then applied to systems of chemical interest to help resolve questions related to intermolecular interactions.