For the S 2+ wave function, using small metal weights, in particular m = 0% and 10%, the same qualitative pattern can be seen. That is, a decreasing in d pop with w. With the increase of m, the w dependency shows an inflection point. This indicates that, differently from S + , an additional effect that also increases the d pop is present in the S 2+ ground state. This additional effect is the doccupancy mixing, that is even clear following the points where m = w. To reinforce this tendency, similar calculations were made using the intrinsic basis bonding analysis (IBBA) program, based on the intrinsic atomic orbitals (IBO), that has a smaller basis set dependency. Although the values for both states overshoot the 3d population in around 0.3, the d pop dependency follows the multi-d -occupancy character of each state. Numerically, for the S + ground state the variation with the weights is smaller than 0.1. On the other hand, for the S 2+ the occupancy dependency is around 0.3 as shown in Figure . This was previously explored by us for the cobalt monohydride diatomic system, for which the usual single d -shell CASSCF calculation converges to a pure d 7 -occupancy, while methods with higher accuracy converge into almost pure d 8 -occupancy ground state. A more interesting example is the cobalt monofluoride diatomic system, where the consideration of the multi-d -occupancy character of the states dictates whether the ground state is triplet or quintet.