Potential energy surfaces for O + O₂ collisions.

Area of Science:

• Theoretical Chemistry
• Quantum Mechanics
• Spectroscopy

Background:

• Ozone (O3) plays a vital role in atmospheric chemistry and is involved in various collision processes.
• Understanding the electronic states of O3 is essential for accurately modeling its interactions with O2 and O.

Purpose of the Study:

• To compute and present global potential energy surfaces (PES) for nine adiabatic electronic states of ozone.
• To develop accurate analytical representations of these PES for use in dynamical simulations.

Main Methods:

• Utilized XMS-CASPT2 electronic structure calculations with dynamically scaled external correlation.
• Employed a many-body expansion with permutationally invariant polynomials for fitting the adiabatic surfaces.
• Incorporated accurate diatomic potentials with damped dispersion terms.

Main Results:

• Generated global PES for nine adiabatic electronic states of O3 (1 1A', 2 1A', 1 1A″, 1 3A', 2 3A', 1 3A″, 1 5A', 2 5A', 1 5A″).
• Developed analytic functions to represent these surfaces, suitable for high-energy collision dynamics.
• Ensured accuracy by fitting to extensive electronic structure data points.

Conclusions:

• The presented potential energy surfaces provide a robust foundation for studying the dynamics of O3 formation and reactions.
• These surfaces are critical for simulating energy transfer and dissociation in high-energy O2-O collisions.
• The methodology enables accurate theoretical investigations of ozone's complex electronic behavior.