Phase-space sampling of propagated wavefunctions

Area of Science:

• Quantum dynamics
• Chemical physics
• Computational chemistry

Background:

• Simulating quantum dynamics is computationally demanding.
• Mixed quantum-classical methods offer approximations but require accurate initial conditions.
• Standard surface hopping can lack accuracy in certain scenarios.

Purpose of the Study:

• To introduce propagated Wigner sampling for transitioning between quantum and mixed quantum-classical dynamics.
• To generalize Wigner sampling for multi-state wavefunctions.
• To improve the accuracy of trajectory-based simulations for non-adiabatic dynamics.

Main Methods:

• Propagating initial dynamics quantum mechanically.
• Calculating and sampling the Wigner function at a transition time.
• Using trajectory-based surface hopping for the remaining dynamics.
• Exploiting the Wigner phase-space representation.

Main Results:

• The method accurately represents quantum dynamics.
• Propagated Wigner sampling outperforms standard surface hopping on Tully models.
• Strategies for generating trajectories from the Wigner function are proposed.

Conclusions:

• Propagated Wigner sampling is an effective method for mixed quantum-classical simulations.
• The approach enhances accuracy in non-adiabatic excited-state dynamics.
• This method provides a valuable tool for complex chemical system simulations.