Post-reaction internal energy distributions of quantum-kinetics model for simulating chemical reactions of polyatomic molecules.

This article focuses on the application and validation of the quantum-kinetics (Q-K) model for simulating chemical reactions involving the polyatomic molecule carbon dioxide (CO₂) in the Martian atmosphere using the direct simulation Monte Carlo (DSMC) method. It compares the Q-K model with the Larsen–Borgnakke (L–B) distribution method for post-reaction energy redistribution in the reversible exchange reaction CO₂ + O ⇋ CO + O₂, demonstrating that detailed balance—a condition where forward and reverse reaction energy distributions match—is achieved only with the Q-K model when activation energy is adjusted by the collision temperature (incorporating translational and vibrational energies) rather than the translational temperature alone. The study also highlights discrepancies between analytical and simplified rate coefficient calculations for exchange reactions, recommending the use of the original integral expressions when the activation energy adjustment coefficient is nonzero. These findings extend previous Q-K model applications from diatomic to polyatomic molecules and have implications for accurately modeling aerodynamic and thermal phenomena during spacecraft entry into the Martian atmosphere.