Fig. 1: CCSD(T) and FN-DMC interaction energies for a medium and a large dimer.
From: Interactions between large molecules pose a puzzle for reference quantum mechanical methods
It can be seen that the interaction energy increases by a factor ~10, near-linearly with the size of the system, whereas the corresponding disagreement between CCSD(T) and FN-DMC increases by a factor of ~76.
