Symmetry or asymmetry of kET and iSTMvs. potential curves

Abstract

The symmetry or asymmetry of STM current vs. bias potential and of electron transfer (ET) rate vs. overpotential curves is discussed for ET and for STM patterns across ordered monolayers. The superexchange expression for the electronic coupling matrix element, the Fermi–Dirac distribution and, for the ET reaction, the reorganization, are included. A mean potential approximation is assumed for the effect of bias or overpotential on the electronic orbitals or the ordered monolayer. Consequences for the symmetry vs. asymmetry of the ln(k_ET)vs. overpotential and for the ln(i_STM) and pattern vs. bias are described. Examples of some relevant experiments are considered.