ABSTRACT Various aspects of electrochemical electron transfer (ECET) reactions in condensed media are critically discussed. The inverted regions of the continuum theory are not experimentally observed for the ECET reactions. It was shown that the use of realistic Morse potentials instead of harmonic potentials does not generate the inverted region. The force constants to compute the free energy of activation using intermediate neglect of differential overlap, INDO/2 method were given. The computed values of force constants were found to agree well with those obtained from the vibrational spectroscopic data. Use of molecular dynamics to compute the free energy of activation from the crossing point of free energy profiles for the ECET reactions agreed well with experimental results. Semimolecular and molecular models for bond breaking ECET reactions are discussed. The influence of solvent dynamics on the ECET reactions were found very important. The rate of ET reactions at biomembrane-covered electrodes was found to depend on the transport and tunneling of electrons across the biomembrane layer.
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