Rotational alignment effects in NO(X) + Ar inelastic collisions: a theoretical study.

Area of Science:

• Chemical Physics
• Molecular Dynamics
• Quantum Mechanics

Background:

• Investigating rotational angular momentum alignment in molecular collisions is crucial for understanding chemical reaction dynamics.
• Nitric oxide (NO(X)) scattering with Argon (Ar) provides a benchmark system for studying these effects.

Purpose of the Study:

• To elucidate the primary factors governing rotational angular momentum alignment in NO(X)-Ar inelastic scattering.
• To differentiate the roles of interaction potential and scattering dynamics in observed alignment phenomena.

Main Methods:

• Employed close-coupled quantum mechanical calculations.
• Utilized quasi-classical trajectory simulations.
• Performed Monte Carlo hard shell scattering calculations.

Main Results:

• The hard shell nature of the interaction potential at 66 meV collision energy is the main driver of NO(X) rotational alignment.
• Quantum mechanical parity-resolved alignment parameters show alternating trends with rotational state changes (Δj).
• The kinematic apse model shows excellent agreement with quantum mechanical theory under specific energy conditions.

Conclusions:

• The hard shell potential dominates rotational alignment, while scattering dynamics influence parity-dependent cross sections.
• Rotational alignment and differential cross sections probe distinct aspects of scattering dynamics.
• The kinematic apse model is a valid approximation for NO(X)-Ar scattering when collision energy exceeds potential well depth.