Back of the Envelope Selection Rule for Molecular Transmission: A Curly Arrow Approach

Abstract

A new selection rule for transmission under small voltage for molecular electronic devices consisting of alternant hydrocarbons is established, based on curly arrow drawings of the displacement of electrons through the conjugated system of the molecule. If the displacement of electrons from one contact atom to the other can be drawn, transmission is possible. If not, then no transmission will take place. This simple, back of the envelope ansatz allows determination of quantum interferences for a wide range of experimentally studied molecules (linear polyenes, benzenoids, cross-conjugated molecules, ...) avoiding any calculation. This new selection rule bridges the conceptual gap between traditional reactivity theory and molecular electronics.

Exploring Electrical Currents through Nanographenes: Visualization and Tuning of the through‐Bond Transmission Paths

“…“ For an alternant hydrocarbon for which fully paired resonance structures are the main contributors to the resonance hybrid ”) we refer the reader to ref. . We simply note here that every polycyclic aromatic hydrocarbon in the present study fulfills this condition.…”

“…For each of the considered compounds, several combinations of contact positions have been chosen. For each of these combinations of contacts, the transmission spectrum will be presented and the results interpreted based on some of the rules developed in‐house to gain qualitative insight into the magnitude of the transmission probability around the Fermi level . These spectra and their interpretations will then be complemented with local transmission plots, enabling further insight into the transport properties of these molecules.…”

“…For each of these combinationso fc ontacts, the transmission spectrum will be presented and the resultsi nterpreted based on some of the rules developed in-house to gain qualitative insight into the magnitude of the transmission probability aroundt he Fermi level. [16][17][18][19] These spectra and their interpretations will then be complemented with local transmission plots, enabling further insight into the transport properties of these molecules. For the systems not demonstrating quantum interference, these plots will be produced exactly at the Fermi level of the junction, for those that do demonstrate quantum interference they will be produced at the central dip in the transmission probability situatedi nside the HOMO-LUMO gap (ast his enables visualization of the influence of the s-current, see below).…”

Quantum Interference in Real-Time Electron-Dynamics: Gaining Insights from Time-Dependent Configuration Interaction Simulations

“…1a). Stuvyer et al have presented a selection rule for QI based on curly arrow diagrams that are traditionally used to diagnose resonance stabilization patterns in πelectron conjugated systems [25]. Fermi-level destructive QI is noted in a conjugated molecule when curly arrows cannot displace an electron pair from the donor end to at least one of the other sites; Fig.…”

Characterizing destructive quantum interference in electron transport

“…With this observation, many guidelines have been developed for predicting molecules and moleculeelectrode configurations that exhibit DQI [19][20][21][22][23][24][25][26][27], including some graphical approaches [28][29][30]. However, these guidelines tend to focus only on the existence of DQI, and are most applicable to alternant hydrocarbons…”