All calculations were performed in the presence of an implicit solvent with a dielectric constant, ε, of 30.4 which was computed as a weighted average of dielectric constants of one part of dichloromethane (ε = 8.9) and three parts of acetonitrile (ε = 37.5), consistent with prior experimental studies . A conductor-like polarizable continuum implicit solvent model implemented in TeraChem 119 was employed in these calculations. The solute cavity for non-metals was constructed with default parameters of 1.2 x Bondi's van der Waals radii 120 available in TeraChem. Additionally, for Mn, we adopted the procedure employed in prior Optimization calculations of the Mn(TMP) catalyst were carried out in all possible spin states for each intermediate formed during the catalyst cycle. Specifically, the resting state intermediate, Mn(III)(TMP)F with a d 4 electronic configuration for Mn, was studied in three spin states: high-spin (HS) quintet, intermediatespin (IS) triplet, and low-spin (LS) singlet. The oxomanganese intermediate, Mn(V)=O(TMP)F with a d 2 electronic configuration for Mn, was studied in two possible spin states: IS triplet and LS singlet. The metal-hydroxo and difluoro intermediates, Mn(IV)(OH)(TMP)F and Mn(IV)(TMP)F2, both with a d 3 electronic configuration for Mn were studied in the two possible spin states: IS quartet and LS doublet. All calculations of the catalyst intermediates were carried out at the B3LYP-D3/LACVP* level of theory where we varied the amount of Hartree-Fock exchange (aHF) incorporated in the density functional from 0.00 to 0.30 in increments of 0.10, while holding the LDA/GGA exchange ratio fixed, in order to study the sensitivity of the predicted ground state to the density functional used . All the calculations were found to be free of significant spin contamination, evaluated as the difference between the computed expectation of 𝑆 2 operator and the expected value, i.e., S(S+1).