Quasi-Diabatic Representation for Nonadiabatic Dynamics Propagation

Area of Science:

• Quantum chemistry
• Computational physics
• Chemical dynamics

Background:

• Simulating nonadiabatic dynamics is crucial for understanding chemical reactions.
• Existing methods often require computationally expensive diabatic electronic structure calculations.
• Interfacing with widely available adiabatic electronic structure methods remains a challenge.

Purpose of the Study:

• To develop a novel quantum dynamics propagation scheme.
• To enable the combination of diabatic quantum dynamics with adiabatic electronic structure calculations.
• To improve the efficiency and accessibility of nonadiabatic dynamics simulations.

Main Methods:

• A quasi-diabatic (QD) scheme is introduced, utilizing adiabatic states as QD states.
• QD states are updated at each step of the short-time quantum dynamics propagation.
• The partial linearized density matrix (PLDM) path-integral method is employed as a specific diabatic dynamics approach.

Main Results:

• The QD scheme demonstrates high accuracy across various model nonadiabatic systems.
• Successful on-the-fly propagation was achieved using density functional tight-binding (DFTB) calculations.
• The method effectively bridges the gap between diabatic dynamics and adiabatic electronic structure methods.

Conclusions:

• The developed QD scheme provides a robust interface between diabatic quantum dynamics and adiabatic electronic structure calculations.
• This work significantly enhances the feasibility of accurate nonadiabatic dynamics simulations.
• It opens new avenues for studying complex chemical processes computationally.