Hydrogen-iodine scattering. II. Rovibronic analysis and collisional dynamics

Area of Science:

• Chemical Physics
• Quantum Mechanics
• Molecular Dynamics

Background:

• Accurate potential energy models are crucial for understanding chemical reaction dynamics.
• Spin-orbit coupling significantly influences the behavior of heavy-atom systems like H + I.

Purpose of the Study:

• To analyze bound and quasi-bound states in H + I collisions using a novel spin-orbit coupled diabatic potential energy model.
• To investigate elastic and inelastic scattering processes and the role of resonances in H + I collisions.
• To compare calculations using a full diabatic model with approximations based on single adiabatic states.

Main Methods:

• Utilized a recently developed spin-orbit coupled diabatic potential energy model for HI.
• Performed thorough analysis of ro-vibronic bound and quasi-bound states.
• Computed elastic and inelastic scattering cross sections and thermal rates up to 12,500 cm⁻¹.
• Analyzed resonances by their energy, width, lifetime, and decay probabilities.

Main Results:

• The spin-orbit coupled diabatic model accurately describes complex dynamics in H + I collisions.
• Calculations revealed detailed properties of bound and quasi-bound states.
• Resonances were identified and characterized, influencing thermal rates.
• Decay probabilities of high-energy resonances were studied for photodissociation branching ratios.

Conclusions:

• The developed potential energy model is effective for studying H + I scattering dynamics.
• Resonances play a significant role in the thermal rates and photodissociation branching ratios.
• Approximations using single adiabatic states were evaluated against the full diabatic model.