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Updated: May 21, 2025
08:04
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
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Electronic Excitation Transfer Dynamics in a 3-Site System Using an Incoherent Born-Markov Rate Model
Amit Kumar Upadhyay1, Karthik Sasihithlu1
1Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, India.
Summary
Coherence significantly influences electronic excitation transfer (EET) in multi-site systems. This study develops a new incoherent model to analyze coherence effects, comparing it with existing quantum dynamical and Fermi's Golden Rule models.
Area of Science:
- Quantum dynamics
- Open quantum systems
- Spectroscopy
Background:
- Electronic excitation transfer (EET) is crucial in various chemical and biological processes.
- Investigating coherence effects in EET typically involves comparing exact quantum dynamics with incoherent models like Fermi's Golden Rule (FGR).
- Recent work shows intersite coupling strongly affects EET dynamics in three-site systems.
Purpose of the Study:
- To develop and validate an incoherent model for analyzing coherence's role in EET dynamics.
- To systematically exclude population-coherence coupling terms from secular Redfield theory.
- To compare the new model's predictions with coherent Lindbladian and incoherent FGR models.
Main Methods:
- Adaptation of secular Redfield theory to create an incoherent model.
- Systematic exclusion of site-basis coupling terms between populations and coherences.
- Comparative analysis of dynamics predicted by the new incoherent model, coherent Lindbladian master equation, and FGR.
Main Results:
- The developed incoherent model provides a framework to evaluate coherence's influence on EET.
- Demonstrated differences in dynamics predicted by coherent and incoherent approaches.
- Established a method for assessing coherence effects in weak system-bath coupling regimes.
Conclusions:
- Coherence plays a critical, configuration-dependent role in multi-site EET dynamics.
- The new incoherent model offers a valuable tool for understanding quantum effects in open systems.
- This approach is generalizable for studying coherence in diverse open quantum systems.
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