Ab Initio Quantum Calculation of the Diabatic Coupling Matrix Elements for the Self-Exchange Redox Couples M(Cp)20/+ (M = Fe, Co; Cp = C5H5)

The diabatic couplings between the metal centers in M(Cp)20/+ (M = Fe, Co; Cp = C5H5) were evaluated using ab initio methods at the Hartree-Fock level of theory. Excellent agreement with the experimental estimate is found for the Fe(Cp)20/+ couple. For Co(Cp)20/+, the calculated numbers are substantially higher than the experimental estimates, suggesting that the latter may represent a considerable underestimate (a possibility mentioned in the experimental publication).