Approximate photochemical dynamics of azobenzene with reactive force fields

Area of Science:

• Computational Chemistry
• Photochemistry
• Molecular Dynamics

Background:

• Azobenzene isomerization is crucial for molecular machines.
• Simulating photochemical reactions requires accurate electronic state descriptions.
• Existing methods struggle with large-scale reactive dynamics.

Purpose of the Study:

• To develop a force-field-based method for simulating azobenzene isomerization.
• To enable large-scale dynamics simulations of photochemical processes.
• To model molecular machines and photochemical engines.

Main Methods:

• Fitted ReaxFF reactive force fields to ground and excited states of azobenzene.
• Employed global parameter optimization using genetic algorithms.
• Coupled force fields with an energy-gap transition probability model.

Main Results:

• Achieved qualitatively acceptable quantum yields for azobenzene isomerization.
• Enabled fully force-field-based simulations of cis-trans and trans-cis isomerization.
• Demonstrated feasibility for simulating bond breaking and formation.

Conclusions:

• The developed method allows for efficient, large-scale simulations of photochemical reactions.
• This approach is promising for designing and understanding molecular machines and engines.
• Reactive force fields offer a powerful tool for complex photochemical dynamics.