Charge-transfer selectivity and quantum interference in real-time electron dynamics: Gaining insights from...

Area of Science:

• Quantum chemistry
• Materials science
• Molecular electronics

Background:

• Electron transfer through molecular junctions is crucial for molecular electronics.
• Understanding structure-property relationships is key to designing efficient molecular devices.

Purpose of the Study:

• To model many-electron wavepacket dynamics using time-dependent configuration interaction (TDCI).
• To investigate the influence of para- vs. meta-linkages on electron transfer dynamics in molecular junctions.
• To elucidate the role of quantum interference in dictating electron transfer pathways.

Main Methods:

• Time-dependent configuration interaction (TDCI) simulations for many-electron wavepacket dynamics.
• Analysis of electron conjugation, quantum tunneling, and orbital interference effects.
• Comparison of computational results with experimental conductivity measurements.

Main Results:

• Para-linked cyanobenzene thiolates exhibit enhanced electron migration due to π-network conjugation.
• Meta-linked isomers show superior electron injection via quantum tunneling when conjugation is absent.
• Quantum interference of wavefunctions drives para- vs. meta-selectivity, with constructive interference in para and destructive in meta isomers.
• Computational trends for azulene bridges align with experimental conductivity data.

Conclusions:

• Molecular orbital phase and quantum coherence are critical factors for controlling electron transfer.
• A priori prediction of orbital phase-flip and coherence can guide the design of molecular electronic devices.
• TDCI provides a rigorous framework for quantitatively modeling electron transfer in complex molecular systems.