Quantum rate electrodynamics and resonant junction electronics of heterocyclic molecules

Abstract

The quantum rate theory provides a framework to understand electron-transfer reactions by correlating the electron-transfer rate constant (ν) with the quantum capacitance (Cq) and the molecular conductance (G). This theory, which is rooted in relativistic quantum electrodynamics, predicts a fundamental frequency ν=E/h for electron-transfer reactions, where E is the energy associated with the density of states Cq/e2. This work demonstrates the applicability of the quantum rate theory to the intermolecular charge transfer of push-pull heterocyclic compounds assembled over conducting electrodes. Remarkably, the observed differences between molecular junction electronics formed by push-pull molecules and the electrodynamics of electrochemical reactions on redox-active modified electrodes can be attributed solely to the adiabatic setting of the quantum conductance in push-pull molecular junctions. The electrolyte field-effect screening environment plays a crucial role in modulating the resonant quantum conductance dynamics of the molecule-bridge-electrode structure. In this context, the intermolecular electrodynamics within the frontier molecular orbital of push-pull heterocyclic molecules adhere to relativistic quantum mechanics, consistent with the predictions of the quantum rate theory.