Consistent and Generalizable Effective Model Hamiltonian Framework for Studying Nonadiabatic Dynamics in the...

Area of Science:

• Computational Chemistry
• Condensed-Phase Physics
• Quantum Dynamics

Background:

• Simulating nonadiabatic dynamics in condensed-phase systems is computationally challenging.
• Traditional models often neglect crucial environmental correlations due to the isolated bath assumption.
• Existing models like the spin-boson and Frenkel exciton models have limitations.

Purpose of the Study:

• To introduce and detail the multistate harmonic (MSH) model for simulating condensed-phase nonadiabatic dynamics.
• To overcome the limitations of previous models by incorporating environmental correlations.
• To provide a general framework for mapping all-atom simulation data onto effective Hamiltonians.

Main Methods:

• Development of the multistate harmonic (MSH) model.
• Extension of nuclear coordinate space to represent a correlated bath.
• Construction of the MSH Hamiltonian and its multistate reaction coordinate (MRC) representation.
• Application with quantum master equations and semiclassical dynamics.

Main Results:

• The MSH model systematically satisfies multistate reorganization energy constraints.
• It provides a physically grounded representation of a globally shared, correlated bath.
• The MSH/MRC models enable accurate simulations of charge and energy transfer.

Conclusions:

• The MSH/MRC models offer a robust platform for predictive simulations in the condensed phase.
• These models serve as a valuable tool for benchmarking approximate quantum dynamics methods.
• The framework enhances the simulation of complex electronic and nuclear interactions.