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Visualizing and comparing quantum interference in the π-system and σ-system of organic molecules
Ning Cao1, William Bro-Jørgensen2, Xiaohong Zheng1
1Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China.
The Journal of Chemical Physics
|April 1, 2023
Summary
Quantum interference effects differ between conjugated and saturated molecules. Unlike conjugated systems, saturated molecules exhibit destructive interference through the cancellation of multiple non-paired orbitals, not paired ones.
Area of Science:
- Quantum Chemistry
- Molecular Electronics
- Organic Chemistry
Background:
- Quantum interference effects are well-studied in conjugated molecules like benzene, primarily focusing on pi-orbitals.
- Recent studies show destructive quantum interference in saturated molecules, but orbital contributions remain unclear due to different sigma-orbital character.
Purpose of the Study:
- To investigate and compare quantum interference effects in conjugated versus saturated molecules.
- To elucidate the distinct orbital contributions to destructive quantum interference in these two molecular classes.
Main Methods:
- Utilized a quantum interference map to analyze electronic transmission.
- Examined orbital contributions (pi-orbitals in conjugated, sigma-orbitals in saturated systems).
Main Results:
- Demonstrated significant differences in quantum interference effects between conjugated and saturated molecules.
- In conjugated systems (benzene), destructive interference at the Fermi energy involves paired occupied and virtual orbitals.
- In saturated systems, destructive interference arises from the cancellation of numerous non-paired orbitals, leading to varied effects.
Conclusions:
- Quantum interference mechanisms differ fundamentally between conjugated and saturated molecules.
- The nature of orbital contributions dictates the manifestation of destructive interference, being more complex in saturated systems.
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