Restoring electronic coherence/decoherence for a trajectory-based nonadiabatic molecular dynamics

Area of Science:

• Quantum Chemistry
• Molecular Dynamics
• Computational Chemistry

Background:

• Standard nonadiabatic molecular dynamics algorithms struggle to accurately capture quantum coherences and decoherences.
• Trajectory-based methods often simplify the complex quantum behavior of electronic systems.

Purpose of the Study:

• To develop modified coupled time-dependent Schrödinger equations that restore quantum coherences and decoherences.
• To improve the accuracy of nonadiabatic molecular dynamics algorithms.

Main Methods:

• Utilizing the time-independent semiclassical phase integral.
• Modifying existing trajectory-based nonadiabatic molecular dynamics algorithms (Tully's fewest switches and semiclassical Ehrenfest).

Main Results:

• Simulated nonadiabatic transition probabilities closely matched exact quantum electronic oscillations for most model systems.
• The modified theory accurately predicts nonadiabatic transitions using statistical ensembles of trajectories.

Conclusions:

• The developed theory accurately restores quantum coherences and decoherences in nonadiabatic molecular dynamics.
• This approach offers a more accurate way to simulate photochemical and photophysical processes involving electronic excited states.