Long-Range Electron Tunneling

摘要: Electrons have so little mass that in less than a second they can tunnel through potential energy barriers are several electron-volts high and nanometers wide. Electron tunneling is critical functional element broad spectrum of applications, ranging from semiconductor diodes to the photosynthetic respiratory charge transport chains. Prior 1970s, chemists generally believed reactants had collide order effect transformation. Experimental demonstrations electrons transfer between separated by led revision chemical reaction paradigm. investigations electron exchange redox partners molecular bridges elucidated many fundamental properties these reactions, particularly variation rate constants with distance. Theoretical work has provided insights into superexchange mechanism electronic coupling distant centers. Kinetics measurements shown about 2.5 nm proteins on biologically relevant time scales. Longer-distance biological flow requires multiple steps chains cofactors. The range phenomena depends long-range continues expand, providing new challenges for both theory experiment.