Reorganization energy of electron transfer in polar liquids. Dependence on reactant size, temperature and pressure

The solvent reorganization energy of outer sphere electron transfer in polar liquids is derived in a molecular treatment. The reorganization energy is shown to be the sum of two contributions: the reorganization energy of reorientation of liquid permanent dipoles and the energy of reorganization of the liquid density. Reorientation of the dipoles gives the main contribution to the solvent reorganization energy, whereas reorganization of the density contributes mainly to the activation entropy which is positive in the normal and negative in the inverted regions of electron transfer. The reorganization energy of the liquid density contains an explicit temperature dependence which causes the non-Arrhenius temperature dependence of the rate constant. Entropy, enthalpy and volume of activation are found for several solvents.