Quantum Rate Electrodynamics and Resonant Junction Electronics of Heterocyclic Molecules

Abstract

Quantum rate theory encompasses the electron-transfer rate constant concept of electrochemical reactions as a particular setting, besides demonstrating that the electrodynamics of these reactions obey relativistic quantum mechanical rules. The theory predicts a frequency $\nu = E/h$ for electron-transfer reactions, in which $E = e^2/C_q$ is the energy associated with the density-of-states $C_q/e^2$ and $C_q$ is the quantum capacitance of the electrochemical junctions. This work demonstrates that the $\nu = E/h$ frequency of the intermolecular charge transfer of push-pull heterocyclic compounds, assembled over conducting electrodes, follows the above-stated quantum rate electrodynamic principles. Astonishingly, the differences between the molecular junction electronics formed by push-pull molecules and the electrodynamics of electrochemical reactions observed in redox-active modified electrodes are solely owing to an adiabatic setting (strictly following Landauer's ballistic presumption) of the quantum conductance in the push-pull molecular junctions. An appropriate electrolyte field-effect screening environment accounts for the resonant quantum conductance dynamics of the molecule-bridge-electrode structure, in which the intermolecular charge transfer dynamics within the frontier molecular orbital of push-pull heterocyclic molecules follow relativistic quantum mechanics in agreement with the quantum rate theory.