Moreover, for any embedding size, CASSCF significantly overestimates the VEEs as com- In Table we report the VEEs of the E, 1 E, and 1 A 1 states with respect to the ground state ( 3 A 2 ) as well as the 1 E → 1 A 1 VEE, and compare our extrapolated values with the experimental VEEs that correspond to the maximum intensity peaks of the phonon side bands in the experimental absorption spectra. For completeness, the ZPL values have also been included in the table. Notably, the "experimental" ZPLs/VEEs (marked with *) of Reference/Electronic state Moreover, different VEEs have been obtained using the same level of theory and basis set, but different cluster models. The finite size of the clusters may not be large enough to reproduce bulk effects and the spurious surface hydrogens may also alter the electronic distribution in the system, as discussed by Park and co-workers. They calculated a triplet VEE of 2.14 eV, in agreement with the experimental VEE (∼2.18 eV) using a large enough cluster model