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Charge Hopping Dynamics along a Disordered Chain in Quantum Environments: Comparative Study of Different Rate Kernels
Seogjoo Jang1, Andrés Montoya-Castillo2
1†Department of Chemistry and Biochemistry, Queens College and the Graduate Center, City University of New York, 65-30 Kissena Boulevard, Queens, New York 11367-1597, United States.
The Journal of Physical Chemistry. B
|March 25, 2015
Summary
Quantum environments significantly impact charge hopping dynamics, making them more sensitive to disorder than classical models predict. Approximate methods like the semiclassical approximation can be unreliable for accurate simulations.
Area of Science:
- Computational Physics
- Quantum Dynamics
- Materials Science
Background:
- Charge hopping is crucial for organic electronics and energy materials.
- Understanding charge transport in disordered systems is a key challenge.
- The role of quantum environments in charge dynamics requires detailed investigation.
Purpose of the Study:
- To computationally investigate charge hopping dynamics in a disordered 1D chain coupled to a quantum bath.
- To compare the accuracy of various rate kernels, including Fermi's golden rule (FGR), stationary phase interpolation (SPI), semiclassical (SC), Marcus, and Miller-Abrahams expressions.
- To assess the influence of quantum environments on charge transport sensitivity to disorder.
Main Methods:
- Numerical solutions of Pauli master equations were employed.
- Time-dependent square displacements were calculated directly.
- Five distinct rate kernels were evaluated for their predictive capabilities.
Main Results:
- All evaluated methods predicted diffusive charge transport in the steady-state limit.
- The FGR rate expression revealed charge transport is more sensitive to disorder in a quantum bath than classical Marcus theory suggests.
- The SPI approximation showed reasonable agreement, while the SC approximation proved unreliable, even underperforming classical Marcus rates in some cases.
Conclusions:
- Quantum environments can enhance charge transport but effects are fragile.
- Results provide guidance for selecting appropriate rate kernels in large-scale simulations.
- Accurate modeling of quantum effects is essential for understanding charge dynamics in disordered materials.
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