Self-organized electron transfer

Abstract

As other energy fluxes can be largely enhanced under non-linear conditions which permit local entropy export, such as heat flow under the ordered Benard convection, this should also be possible on a microscopic scale for electron transfer. As a precondition an autocatalytic molecular loop must exist, which transfers a small fraction of the energy, which drives the reaction, through the surrounding medium to assist the electron transfer in a non-linear way. Such an autocatalytic side loop, which may be facilitated by transfer of phonon energy, leads to microscopic self-organization, ie to a temporary dissipative structure. It may significantly improve electron transfer through a non-equilibrium electron distribution and a decrease of the activation barrier. The problem is theoretically treated as a Kramers approach, a Brownian motion in a non-uniform force field, in which the friction term may become active ( eg through phonon assisted autocatalytic energy input leading to a dissipative activated complex). A formula for “self-organized” electron transfer is obtained which yields—for finite activation barriers—significantly higher rates than the Marcus formula. The derived new type of electron transfer mechanism is analyzed. It may help to explain how biological catalysts have evolved the ability of generating favourable energy barriers for multi-electron transfer near the thermodynamic overall potential