Constrained Variation Calculations of Electron-Transfer Transition States Using the Lagrange Method

Recently, this lab demonstrated that activation internal energies for those electron-transfer reactions that simultaneously include bond scission and bond formation can be calculated to reasonable accuracy as functions of electrode potential. Using local reaction center models, the electron transfer is assumed to take place when, due to thermal fluctuations, its electron affinity or ionization potential equals the thermodynamic work function of the electrode for the desired potential, for reduction or oxidation reactions, respectively. Transition states for such reactions cannot be located by conventional means. Here is demonstrated how they may be found using constrained variation theory.