Phase-space reaction network on a multisaddle energy landscape: HCN isomerization

Area of Science:

• Chemical Dynamics
• Physical Chemistry
• Computational Chemistry

Background:

• Chemical reactions often occur on complex, multisaddle energy landscapes.
• Understanding molecular motion is crucial for predicting reaction outcomes and rates.
• Traditional methods may struggle to capture the full dynamics on these complex landscapes.

Purpose of the Study:

• To visualize and understand molecular motion during chemical reactions on multisaddle energy landscapes.
• To provide chemical intuition for how species navigate these landscapes in phase space.
• To explore the relationship between phase-space structure and non-Markovian dynamics.

Main Methods:

• Utilizing the HCN/CNH isomerization reaction as a model system.
• Employing explicit visualizations of molecular trajectories in phase space.
• Analyzing Poincare surfaces of section to identify nonergodic features.
• Elucidating the global phase-space structure.

Main Results:

• Demonstrated a straight-through reaction tube in phase space, eliminating recrossing trajectories.
• Provided a visual comparison of phase-space motion versus configuration-space intrinsic reaction paths.
• Identified distinct nonergodic features in HCN and CNH potential wells.
• Revealed the global phase-space structure responsible for non-Markovian dynamics.

Conclusions:

• Phase-space visualization offers a powerful tool for understanding chemical reaction dynamics on complex energy landscapes.
• The identified phase-space structure governs non-Markovian dynamics in sequential multisaddle reactions.
• Understanding phase-space dynamics is key to controlling product states in chemical reactions.