Coherence penalty functional: a simple method for adding decoherence in Ehrenfest dynamics.

Area of Science:

• Quantum chemistry
• Chemical physics
• Computational molecular dynamics

Background:

• Decoherence significantly impacts electronically non-adiabatic molecular dynamics.
• Accurate modeling of decoherence is crucial for understanding complex chemical processes.
• Existing semiclassical methods often struggle with artificial interference and accuracy.

Purpose of the Study:

• To introduce a novel semiclassical method for describing decoherence in molecular dynamics.
• To improve the accuracy and efficiency of simulating non-adiabatic processes.
• To provide a practical tool for studying electron transfer in realistic systems.

Main Methods:

• Formulation based on Ehrenfest dynamics and Meyer-Miller-Thoss-Stock mapping.
• Introduction of a Coherence Penalty Functional (CPF) to penalize wavefunction coherences.
• Randomization of wavefunction phase in regions of strong non-adiabatic coupling.

Main Results:

• The CPF method eliminates artificial interference observed in other semiclassical approaches.
• Improved agreement with fully quantum calculations for model systems.
• Enhanced accuracy in predicting timescales for electron transfer dynamics in nanoscale systems.

Conclusions:

• The CPF method offers a computationally efficient and accurate way to model decoherence.
• Its simplicity makes it suitable for application to complex, realistic molecular systems.
• This approach advances the simulation of quantum effects in molecular dynamics.