, the sum of the water-water two-body terms increases by 0.075 eV, and by 0.505 eV for the complex-water interaction, translating to an overall less bound shell, in the HS state, when only including pairwise additive interactions. This contrasts with the findings from the dimer curves of poses A and B in the previous section, showing the limitations of the capabilities of such models in describing the concerted interactions within a solvation shell. Analysing the higher-order many-body terms first, interestingly, the sum of the three-body terms involving the complex, 17 i<j V 3B (r c , r i , r j ) increases the total interaction energy (anticooperative effect) in all cases. Secondly, despite the metal-center character of both spin states of [Fe(bpy) 3 ] 2+ , we found that the sum of all higher body terms (n>2) contribute differently to the total interaction energy: 10.0% and 18.8% for LS and HS states, respectively. If one solely accounts for the two-body terms of the total interaction energy, one would find that the interaction in the LS state of[Fe(bpy