Accordingly, covalent complexes show high EPAULI values, but the charge-transfer and polarization effects overcompensate the Pauli repulsion (ECT+EPOL>EPAULI), leading to stable adsorption. Note that as the fullerene size increases, the intermolecular distance increases to compensate for the repulsion energy. The energy penalty emerges as kinetic energy pressure exerted by electrons when atoms are brought into close interaction . As a result, the EPAULI term decreases as the adsorption energy decreases until the Phos-C44 complex. In other words, we found at this point the fullerene size at which chemisorption is no longer allowed, which is set between C44 and C50 (Fig. ). This limit arises because the intermolecular separations must increase to decrease the repulsion energy; consequently, physisorption is a stable state at longer intermolecular distances for bigger fullerenes (C50, C60, and C70). Therefore, EPAULI is the primary driving force that compensates all the stabilizing effects to establish the energetically optimal intermolecular separation between phosphorene and fullerenes.