Beyond Born Oppenheimer (BBO)-Based Multi-Electronic State Diabatic Hamiltonians: Reactive Scattering Processes

Area of Science:

• Chemical Physics
• Theoretical Chemistry
• Quantum Dynamics

Background:

• Electron-nuclear coupling significantly impacts chemical reaction dynamics.
• Non-adiabatic effects are crucial for accurately describing reactive species.

Purpose of the Study:

• To demonstrate the necessity of including electron-nuclear coupling in tri-atomic reaction calculations.
• To compare theoretical predictions with experimental data for validation.

Main Methods:

• Construction of multi-state diabatic Hamiltonians using Beyond Born-Oppenheimer theory.
• Inclusion of non-adiabatic and spin-orbit couplings.
• Performing scattering calculations and comparing with experimental data.

Main Results:

• Multi-state diabatic calculations show good agreement with experimental cross-sections and rate coefficients.
• Single-surface adiabatic calculations often deviate, especially near conical intersections.
• Jahn-Teller and Renner-Teller interactions significantly influence reaction pathways.

Conclusions:

• Electron-nuclear coupling is essential for accurate theoretical descriptions of chemical reactions.
• Diabatic approaches provide a more reliable mechanism for understanding reaction dynamics.
• Theoretical models incorporating these couplings are vital for complementing experimental findings.