Relaxation dynamics through a conical intersection: Quantum and quantum-classical studies

Area of Science:

• Theoretical Chemistry
• Photochemistry
• Molecular Dynamics

Background:

• Rhodopsin's visual cycle involves the photo-isomerization of the retinal chromophore.
• Understanding this process requires modeling nonadiabatic dynamics through conical intersections.
• A minimal two-electronic-state, two-dimensional Hamiltonian models key features of retinal isomerization.

Purpose of the Study:

• To analyze the relaxation dynamics of a photo-excited retinal chromophore model.
• To evaluate the performance of trajectory-based schemes for nonadiabatic dynamics.
• To investigate the impact of initial condition sampling on dynamics simulations.

Main Methods:

• Utilized a two-electronic-state, two-dimensional Hamiltonian based on Hahn and Stock.
• Compared quantum-classical trajectory simulations with numerically exact quantum vibronic wavepacket dynamics.
• Analyzed electronic and nuclear observables to assess dynamics.

Main Results:

• Quantum-classical methods were compared against exact quantum dynamics for accuracy.
• The influence of initial condition sampling on simulation outcomes was investigated.
• Performance of various nonadiabatic dynamics schemes was evaluated.

Conclusions:

• Initial condition sampling is a critical factor affecting the accuracy of nonadiabatic dynamics simulations.
• The study provides insights into the dynamics of photo-excited retinal chromophores.
• Findings aid in refining computational models for photochemical processes.