January 16, 2008The Journal of Physical Chemistry A
ReaxFF Reactive Force Field for Molecular Dynamics Simulations of Hydrocarbon Oxidation
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Implication
Molecular dynamics modeling reveals initial chemical pathways during hydrocarbon oxidation, indicating its utility for enhancing combustion models.
Key Points
- Expand and optimize the ReaxFF reactive force field against quantum mechanics data to accurately simulate initial chemical reactions in high-temperature hydrocarbon oxidation.
- Expanded the ReaxFF training set with transition states and reaction pathways relevant to high-temperature gas-phase oxidation, optimizing parameters using quantum mechanics benchmarks.
- Performed NVT molecular dynamics simulations across diverse hydrocarbon and oxygen mixtures, including methane, propene, o-xylene, and benzene under fuel-lean and fuel-rich conditions.
- ReaxFF accurately reproduced the empirical reactivity order (propene > o-xylene > methane > benzene), aligning directly with hydrocarbon carbon-hydrogen bond strengths.
- Under fuel-lean conditions, the primary initiation step was hydrogen abstraction from methyl groups by molecular oxygen to yield hydroperoxyl and hydrocarbon radicals.
- Under fuel-rich mixed conditions, initiation shifted toward direct hydrocarbon thermal decomposition and radical attack, matching quantum mechanics benchmarks and tracking full oxidation to carbon monoxide, carbon dioxide, and water.
Cite This Study
Chenoweth et al. (2008) studied this question.