Non-adiabatic molecular dynamics with complex quantum trajectories. I. The diabatic representation

Area of Science:

• Quantum Chemistry
• Chemical Physics
• Computational Chemistry

Background:

• Non-adiabatic transitions are crucial in chemical dynamics.
• Existing quantum trajectory methods often rely on surface hopping.
• A new quantum trajectory method was recently developed.

Purpose of the Study:

• To extend a quantum trajectory method to handle non-adiabatic transitions.
• To implement and validate the method using benchmark models.
• To explore the diabatic representation for non-adiabatic dynamics.

Main Methods:

• Utilizing a quantum trajectory method with complex positions and momenta.
• Evolving trajectories on single potential energy surfaces governed by Newton's laws.
• Deriving equations of motion that naturally incorporate amplitude transfer between surfaces.

Main Results:

• Successfully applied the method to Tully's benchmark models.
• Obtained accurate probability branching ratios between surfaces.
• Reconstructed time-dependent wavepackets with quantitative agreement to converged quantum calculations.

Conclusions:

• The extended quantum trajectory method effectively treats non-adiabatic transitions without surface hopping.
• The diabatic representation is viable for trajectory-based non-adiabatic dynamics.
• The method provides a robust and accurate approach for simulating quantum dynamics.