Toward a Correct Description of Initial Electronic Coherence in Nonadiabatic Dynamics Simulations

Area of Science:

• Quantum dynamics
• Theoretical chemistry
• Ultrafast spectroscopy

Background:

• Advancements in ultrafast coherent light sources necessitate improved theoretical methods for molecular systems.
• Current nonadiabatic molecular dynamics techniques like fewest-switches surface hopping and Ehrenfest mean-field dynamics fail to capture initial electronic coherence.
• Numerically exact quantum dynamics methods and coupled-trajectory algorithms can describe coherence but are computationally expensive.

Purpose of the Study:

• To develop accurate and efficient theoretical approaches for treating electronic coherence in molecular dynamics.
• To enable the description of molecular dynamics initiated with electronic coherence using independent-trajectory methods.

Main Methods:

• Utilizing independent-trajectory methods derived from the semiclassical mapping formalism.
• Introducing initial sampling over the electronic phase space.
• Incorporating phase interference between trajectories within the semiclassical framework.

Main Results:

• Demonstrated that semiclassical mapping methods can correctly describe dynamics with initial electronic coherence.
• Showcased the natural incorporation of phase space sampling and interference within the semiclassical mapping framework.
• Provided a computationally feasible alternative to computationally intensive methods for studying electronic coherence.

Conclusions:

• Semiclassical mapping formalism offers a viable solution for accurately simulating molecular dynamics with initial electronic coherence.
• This approach overcomes the limitations of traditional independent-trajectory methods.
• The developed methods pave the way for more accurate theoretical investigations of light-induced molecular processes.