Theoretical aspects of electron transfer reactions of complex molecules

Features of electron transfer involving complex molecules are discussed. Th is notion presently refers to molecular reactants where charge transfer is accompanied by large molecular reorganization, and commonly used displaced harmonic oscillator models do not apply. It is shown that comprehensive the ory of charge transfer in polar media offers convenient tools for the treat ment of experimental data for such systems, with due account of large-ampli tude strongly anharmonic intramolecular reorganization. Equations for the a ctivation barrier and free energy relationships are provided, incorporating vibrational frequency changes, local mode anharmonicity, and rotational re organization, in both diabatic and adiabatic limits. Systems for which this formalism is appropriate are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.