Quantum-kinetic chemistry model with an anharmonic oscillator model: Model extension and validation

This work proposes an extended version of the quantum-kinetic chemistry models, aiming to accurately reproduce experimental measurements and high-fidelity calculations in both thermal equilibrium and non-equilibrium. The extension involves the development of new formulations, incorporating a set of tunable parameters obtained from a non-linear least squares fit on the dataset. The newly derived analytical expressions are implemented in a direct simulation Monte Carlo (DSMC) solver. These formulations are applied to the 19 most representative chemical reactions of an air mixture involving dissociation and exchange reactions. The DSMC reaction rates demonstrate excellent agreement with the newly derived analytical expressions, providing verification of the successful implementation in the DSMC solver. The study demonstrates excellent reproduction of the baseline dataset for both thermal equilibrium and non-equilibrium. Furthermore, the new formulations are applied to simulate the surface heat flux during the second space transport system (STS-II) mission at an altitude of 92.35 km.