Ferrocene molecular architectures grafted on Si(111): A theoretical calculation of the standard oxidation potentials and electron transfer rate constant

The standard oxidation potential and the electron transfer (ET) rate constants of two silicon-based hybrid interfaces, Si(111)/organic-spacer/Ferrocene, are theoretically calculated and assessed. The dynamics of the electrochemical driven ET process is modeled in terms of the classical donor/acceptor scheme within the framework of "Marcus theory". The ET rate constants, k_ET, are determined following calculation of the electron transfer matrix element, VRP, together with the knowledge of the energy of the neutral and charge separated systems. The recently introduced Constrained Density Functional Theory (CDFT) method is exploited to optimize the structure and determine the energy of the charge separated species. Calculated ET rate constants are k_ET = 77.8 s^-1 and k_ET = 1.3 × 10^-9 s^-1, in the case of the short and long organic-spacer, respectively.