Table shows the corresponding interaction energies, calculated at various levels of theory for a 4 × 4 graphene supercell (see Appendix A for computational details). Here, CCSD(T) provides an accurate benchmark. As expected, canonical MP2 significantly overbinds (by 18 meV corresponding to 22.5 %), due to the absence of screening effects. Perhaps surprisingly, the CCSD method in turn underestimates the interaction energy by 25 meV, underscoring the challenging nature of this system.