where we considered only the genuine crossing points and those with the extrapolation, respectively, with residual values of 0.53% and 2.2%, respectively. In these equations the ratio of 1:3 between iv It is possible to modify the active space to avoid such molybdenum internal transition by removing the second molybdenum 4d -orbital. However, due to the copper internal transitions a CAS (11,6) would be necessary. weights is a consequence of the stability among the energy of the crossing points. Moreover, we notice that, like for the copper subsystem, the usual SA-CASSCF crossing point energy matches with region for the crossings using the PFRS approach.