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Diffusion-Limited Kinetics in Reactive Systems.
Matthew S Johnson1, Joy N Mueller1, Craig Daniels1
1Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States.
The Journal of Physical Chemistry. A
|April 26, 2024
Summary
This study introduces a new model extending Smoluchowski theory to chemical reactions, revealing a "reactive transport effect" where faster reactions significantly increase rates beyond predictions. This impacts modeling chemical processes in liquids and on surfaces.
Area of Science:
- Chemical kinetics
- Physical chemistry
- Reaction dynamics
Background:
- Accurate chemical kinetics modeling is crucial for chemical processes.
- Diffusion limitations in liquid and surface phases affect reaction rates.
- Current models like Smoluchowski theory and Kinetic Monte Carlo (KMC) have limitations.
Purpose of the Study:
- Extend Smoluchowski theory to include chemical reactions.
- Derive analytical formulas for diffusion-limited rate coefficients.
- Investigate the
- reactive transport effect
- and its impact on reaction rates.
Main Methods:
- Analytical derivation of rate coefficients based on Smoluchowski theory.
- Extension to 3D, 2D, and 2D/3D interface cases.
- Validation against Particle Monte Carlo (PMC) and KMC simulations.
Main Results:
- Derived analytical formulas for diffusion-limited rate coefficients.
- Demonstrated the
- reactive transport effect
- leading to orders of magnitude faster reactions.
- Validated equations against simulations and proposed corrections for interface cases.
Conclusions:
- The new model accurately predicts reaction rates under diffusion limitations.
- The
- reactive transport effect
- significantly enhances reaction speeds.
- Provides tools for more accurate mean-field simulations of chemical systems.
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