For the manganese-oxo intermediate (2), we could not identify the ground spin state at lower aHF values due to convergence issues. At higher aHF values, we see that IS triplet state is preferred (Table ). However, we see that the difference in energetics becomes more and more negative with increasing aHF, i.e., the difference in energies ranges from ca. -7 kcal/mol at aHF = 0.20 to -23 kcal/mol at aHF = 0.30. This may indicate that at lower aHF values (0.00 and 0.10), the preferred ground state could be the low-spin (LS) singlet state (Table ). For both the resting state intermediate and the manganese-oxo intermediate, we find an increasing preference of higher spin states at higher aHF values (Table ).