Here ∆E CCSD(T )/CBS and ∆E DF are interaction energies computed by CCSD(T) and approximated density functionals, respectively. Here ∆E DF contains no dispersion correction. After performing single point energy calculation of the systems at all inter-monomer distances by DF methods, we have spliced the larger monomers into smaller fragments. Detailed fragmentation procedure is mentioned in results and discussion section.