New Perspective on Electron Transfer through Molecules

Abstract

Motivated by experiments which display unusual length and temperature effects for electron transfer in the nanometer length regime, we propose a new approach for describing long-range electron transfer (ET) processes through molecules. We posit that the electron reorganization in the molecules (e.g., the electronic polarization of a macromolecule or organic film by an applied electric potential, or the injected charge generating a dipole moment) should be included in the description. We numerically solve a one-dimensional model for the electron transport, which includes electron–electron interactions explicitly, and we show that it generates a power law distance dependence for electron transport similar to that observed in experiments. The model does not include vibrations explicitly and should be consistent with the weak temperature dependences observed experimentally. This approach emphasizes the need to treat the electronic changes in the molecule(s) more explicitly to understand the behavior.

Detection of a Chirality-Induced Spin Selective Quantum Capacitance in α-Helical Peptides

“…These experimental findings support that CISS is persistent 13 and does not require global charge transport. Following theoretical descriptions, 30,31,60 the measurements show that a persistent charge reorganization 31 without external charge flow is responsible for the measured capacitance and potential changes. A model based on a triangular quantum well connects all experimental measurements using physically viable parameters and shows the sensitive interplay between the asymmetric confinement potential, the thermodynamic equilibrium of an open system, and the electron−electron interaction to enhance slight spinsensitive energy differences.…”

“…Similar reasoning based on wave overlap applies to electron transfer with conductive AFM, , molecular junction, photoemission, , and electrochemical transport experiments . The effect of electron reorganization on electron transfer has been discussed in detail . The reorganization creates a potential profile with transfer characteristics resembling the diode clamper mechanism.…”

“…30 Other models only consider electron reorganization and show similar effects. 31 With the previous experimental approaches, 11,18 the timeodd response of the first hypothesis averages out when measuring only the potential difference, impeding the experimental distinction between these two alternative hypotheses. Also, the method of (magnetic) conductive contact AFM 6 cannot discern and has a few crucial disadvantages compared to noncontact KPFM.…”

“…4 The effect of electron reorganization on electron transfer has been discussed in detail. 31 The reorganization creates a potential profile with transfer characteristics resembling the diode clamper mechanism. dynamics, and measuring the related change in quantum capacitance simultaneously.…”

Chirality‐Induced Spin Selectivity: An Enabling Technology for Quantum Applications

“…[159,160] Though attributed to the hopping mechanism, the weak temperature dependence of the transmission efficiency suggests that other mechanisms might contribute. [161] Indeed, CISS is expected to stabilize the RP state. As we have already mentioned, the forward ET is favored for a certain spin polarization of the electron, while the back ET will be likely suppressed for this spin state.…”