The Fe-O distances on the curves where we find the minimum of the interaction energies, R e , are also displayed in table . We denote the R e 'equilibrium distances'. The table shows that the reference DLPNO-CCSD(T) potential energy curve R e distances contract from LS to HS state by 0.2 Å and 0.3 Å for poses A and B, and is accompanied by changes in the interaction energy that are below the chemical accuracy limit of 1 kcal/mol or roughly 0.04 eV. The LS and HS PECs are practically the same beyond the Fe-O equilibrium distance.