It is relevant to point out that in these calculations the strongly and partially contracted versions of NEVPT2 lead to slightly different results. In the present work, the pc-NEVPT2 transition has a better linear correlation with the weight than the sc-NEVPT2 results (as shown in Figure ). However, both contractions result in essentially the same relative energies for 20, 40 and 60%, therefore, their analysis give the same conclusion. On the other hand, pc-NEVPT2 results from Graaf et al. (also shown in Figure ) have larger relative energies when compared with their sc-NEVPT2 counterpart. Although it is not clear the reason for this large relative energy change, these pc-NEVPT2 values also have a smaller dependence with the weight. As a consequence, extrapolating these results the crossing point between pc-NEVPT2 and CASSCF is similar to the one using the sc-NEVPT2 values.