Dissociation cross section for high energy O₂-O₂ collisions.

Area of Science:

• Aerospace Engineering
• Chemical Physics
• Computational Chemistry

Background:

• Accurate modeling of high-energy collisions is crucial for understanding hypersonic flows.
• Existing chemical models may not fully capture the complexities of non-equilibrium reactive flows.
• Ab initio methods offer a pathway to more precise collision dynamics calculations.

Purpose of the Study:

• To generate a comprehensive database of collision-induced dissociation cross sections for O2-O2 collisions.
• To validate the database against experimental data under equilibrium conditions.
• To apply the database in simulating complex hypersonic flow phenomena.

Main Methods:

• Utilized the quasiclassical trajectory method.
• Employed singlet, triplet, and quintet spin ground state O4 potential energy surfaces.
• Performed Direct Simulation Monte Carlo (DSMC) simulations for hypersonic flow.

Main Results:

• Generated a cross section database for O2-O2 collisions up to 30 eV.
• Predicted reaction rate coefficients that align with experimental findings at equilibrium.
• Demonstrated the utility of the ab initio database in simulating high-enthalpy hypersonic oxygen flow over a cylinder.

Conclusions:

• The ab initio-based cross section database provides accurate predictions for O2-O2 collisions.
• This database offers significant advantages for studying complex, non-equilibrium flow conditions compared to phenomenological models.
• The study highlights the potential of advanced computational methods for enhancing fluid dynamics simulations.