State-pairwise decoherence times for nonadiabatic dynamics on more than two electronic states

Area of Science:

• Computational Chemistry
• Quantum Dynamics
• Theoretical Chemistry

Background:

• Independent trajectory (IT) nonadiabatic molecular dynamics simulations model electronic state transitions.
• Decoherence corrections enhance the accuracy of IT methods like Ehrenfest dynamics and trajectory surface hopping.
• Existing decoherence corrections face challenges with multistate systems.

Purpose of the Study:

• Identify limitations in current decoherence corrections for multistate systems.
• Develop improved decoherence-corrected Ehrenfest schemes.
• Introduce novel one-dimensional models for testing decoherence corrections.

Main Methods:

• Developed decoherence-corrected Ehrenfest schemes using state-pairwise decoherence times.
• Introduced new one-dimensional model problems for multistate systems.
• Compared state-pairwise methods against state-wise methods for coherence loss.

Main Results:

• Identified unphysical coherence decay in state-wise decoherence correction methods for >2 electronic states.
• Demonstrated that state-pairwise decoherence corrections accurately model coherence loss in multistate systems.
• Showcased the "collapse to a block" state-pairwise method as effective in preserving correct coherence dynamics.

Conclusions:

• State-pairwise decoherence times are crucial for accurate modeling of coherence loss in multistate systems.
• The proposed decoherence-corrected Ehrenfest schemes offer improved accuracy over state-wise approaches.
• The new one-dimensional models serve as valuable benchmarks for future decoherence correction development.