Multiconfigurational Surface Hopping: a Time-Dependent Variational Approach with Momentum-Jump Trajectories

Area of Science:

• Quantum dynamics simulations
• Computational chemistry and physics
• Nonadiabatic processes

Background:

• Ehrenfest mean field dynamics and trajectory surface hopping are standard methods for nonadiabatic dynamics.
• The multiconfigurational Ehrenfest (MCE) method extends traditional Ehrenfest dynamics using the time-dependent variational principle (TDVP).
• Applying TDVP to surface hopping is challenging due to momentum jumps during surface hops.

Purpose of the Study:

• To develop a novel multiconfigurational surface hopping (MCSH) method to overcome limitations in simulating nonadiabatic dynamics.
• To enable accurate application of TDVP to surface hopping trajectories by addressing momentum discontinuities.
• To improve the overall performance and accuracy of surface hopping simulations.

Main Methods:

• Proposed a multiconfigurational surface hopping (MCSH) method.
• Implemented continuous momenta via linear interpolation across surface hops.
• Constructed TDVP basis functions in a postprocessing manner using interpolated trajectories.

Main Results:

• MCSH demonstrated high accuracy in simulations of representative spin-boson models.
• The method achieved significant improvements with only several hundred trajectory bases.
• MCSH uniformly enhanced the performance across various surface hopping scenarios.

Conclusions:

• MCSH provides an accurate and efficient approach for nonadiabatic dynamics simulations.
• The method successfully handles momentum jumps, a key challenge in TDVP-based surface hopping.
• MCSH is versatile and can be combined with various mixed quantum-classical methods for general nonadiabatic dynamics.