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    Electron transfer in DNA (Michel-Beyerle, 1998)
     
     

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    A Nanotube between two gold stripes (Dekker, 1998)
     
     

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    A schematic view of a channel protein in a lipid membrane (Hille)


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    Two views of the Gramicidin-A ionic channel



     
     
     

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    Electron Transmission Through Molecules and
    Molecular Layers

    Electron transmission through molecules and molecular layers is a fundamental physical process that dominates electron transfer and electron transfer reactions in condensed phases. We are interested in such processes at interfaces, in particular the interface between a molecular layer adsorbed on metal or semiconductor surfaces. Such phenomena occur in electrochemistry (electrode processes) and in corrosion, and are important in the operation of molecular electronic devices.

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    • Resonance transmission through water layers

  • It is experimentally known that barrier to tunneling through water is lower than in vacuum and it has been suggested that intermediate barrier resonances may contribute to this effect.

     

     

    We examine the existence and nature of such resonances for the water layers system (see figure). In reality, the transmitted electronic current is an average over a huge number of “configurations”. Therefore a numerical study of a particular resonance event does not directly correspond to any measurement. Instead, one has to find the correlation between the presence of a resonance peak in the electron transition probability and the water configuration used for the calculation. We investigate:

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    •   The existence and origin of the resonances in the water layers system.

      Their dependence on the water configuration.

      The probability of formation of “resonant configurations”.

    The importance of the resonant tunneling as compared to the non-resonant process.


    Resonance electron tunneling through water
     
     
     
     
     
     
     
     

  • Electron trans-mission probability vs. incident energy for several water configurations.
     
     
     
     
     
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    Probability Densities, |yE(x,y,z)|2, obtained from the tunneling wavefunction, for different energies as indicated on top of each plot.
     
     



     
     
     
     
     
     

    A view of the structure that give rise to the resonance). (a) A contour plot of the potential. (b) A contour plot of the oxygen atoms configuration. (c) Tunneling probability vs. electron energy (d) A contour plot of |yE(x,y,z)|2. (All in the same plane).