Intermolecular electron transfer by quantum mechanical tunneling.

The transfer of electrons from one molecule to another by quantum mechanical tunneling has recently been implicated in biological electron transport. This report describes observations of electron transfer between aromatic molecules in a rigid matrix, in which electrons apparently tunnel through tens of angstroms of inert solvent. The kinetics tend to confirm the tunneling process, which is likely to be an important means of electron transfer when diffusion is blocked by steric factors or immobilization of the reactants.