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Electron transfer in multiply bridged donor-acceptor molecules: Dephasing and quantum coherence
Randall H Goldsmith1, Michael R Wasielewski, Mark A Ratner
1Center for Nanofabrication and Molecular Self-Assembly, Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA.
The Journal of Physical Chemistry. B
|October 13, 2006
Summary
Pure local dephasing can eliminate destructive interference in electron transfer through molecular bridges. This finding explains benzene
Area of Science:
- Quantum chemistry
- Molecular electronics
- Theoretical chemistry
Background:
- Nonadiabatic electron transfer is crucial in molecular systems.
- Multiply bridged donor-bridge-acceptor molecules exhibit complex transport phenomena.
- Destructive interference in electron transport can arise from bridge site couplings.
Purpose of the Study:
- To theoretically investigate nonadiabatic electron transfer in multiply bridged systems.
- To explore the role of local dephasing in electron transport.
- To explain interference effects and reactivity patterns in molecular bridges.
Main Methods:
- Density matrix formalism for theoretical treatment.
- Modeling of a four-site Joachim-type molecular interferometer.
- Analysis of elastic dephasing processes.
Main Results:
- Pure local dephasing eliminates destructive interference and restores electron transport.
- Destructive interference explains ortho-meta-para reactivity in benzene bridges.
- Dephasing leads to a coalescence of effective coupling strengths.
Conclusions:
- Local dephasing is a viable mechanism to control electron transport in molecular systems.
- The theoretical framework provides insights into structure-reactivity relationships.
- Experimental verification of dephasing effects on coupling strengths is suggested.
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