First-Principles Reaction Dynamics beyond Six-Atom Systems.

Area of Science:

• Computational Chemistry
• Chemical Dynamics
• Theoretical Chemistry

Background:

• First-principles reaction dynamics traditionally focused on small systems (≤6 atoms).
• Investigating complex, multichannel reactions requires advanced computational methodologies.
• Accurate potential energy surfaces (PES) are crucial for reliable dynamics calculations.

Purpose of the Study:

• To explore the new age and future of first-principles reaction dynamics for complex chemical reactions.
• To present a robust methodology for studying post-six-atom systems.
• To demonstrate the accuracy and applicability of the developed computational approach.

Main Methods:

• Benchmark ab initio characterization of stationary points.
• Development of full-dimensional potential energy surfaces (PES) using the Robosurfer program.
• Reaction dynamics computations for selected post-six-atom systems.

Main Results:

• A composite ab initio approach yields benchmark stationary-point properties with subchemical accuracy.
• The Robosurfer system automates PES development.
• Excellent agreement between theoretical predictions and experimental data for Cl + C2H6, F + C2H6, and OH- + CH3I reactions.

Conclusions:

• The presented methodology effectively addresses ab initio challenges in complex reaction dynamics.
• This work paves the way for accurate theoretical investigations of larger chemical systems.
• The synergy between advanced computational methods and experimental validation is highlighted.