New Potential Energy Surface for the H + Cl₂ Reaction and Quantum Dynamics Studies

Area of Science:

• Chemical Kinetics
• Quantum Mechanics
• Computational Chemistry

Background:

• The H + Cl2 reaction is vital across multiple scientific domains.
• Previous investigations lacked accurate quantum mechanical analysis.
• Understanding reaction dynamics is key for chemical process optimization.

Purpose of the Study:

• To develop a precise global potential energy surface (PES) for the H + Cl2 reaction.
• To perform accurate quantum dynamics calculations for the reaction.
• To investigate the influence of initial rotational states on reactivity.

Main Methods:

• Constructed a global PES using neural networks and over 20,000 ab initio energies.
• Employed MRCI-F12+Q method with aug-cc-pV5Z basis set, extrapolated to the CBS limit.
• Included spin-orbit coupling of the Cl atom and conducted product state-resolved quantum dynamics calculations.

Main Results:

• Initial rotational excitation of Cl2 showed minimal impact on reaction rates.
• Integral cross sections and rate constants indicated preferential formation of HCl in the v'=2 vibrational state.
• Calculated rate constants align well with experimental data, confirming PES accuracy.

Conclusions:

• The developed global PES provides a highly accurate representation of the H + Cl2 reaction dynamics.
• The study elucidates product state distributions and reaction kinetics.
• This work sets a benchmark for future theoretical studies on similar reactive systems.