The last parameter affecting the computational cost is the supercell volume that should be as small as possible while accurately decoupling the interactions between periodic images of the system. As we saw, the choice of Ω is mainly dictated by the treatment of low frequency components of the Coulomb operator acting in exchange-like integrals (Section II B 2). Figure shows that significant differences exist between the BAP (Eq.13) and MT (Eq.16) potentials for converging interaction energies. As already observed , BAP greatly accelerates the convergence of the total HF energy compared to the simple neglect of the G = 0 component (Fig. ). However, both schemes perform identically when it comes to HF interaction energies (Fig. ). This is explained by computing the BAP correction