Vibrational coherence and energy transfer in two-dimensional spectra with the optimized mean-trajectory approximation

Area of Science:

• Chemical Physics
• Computational Chemistry
• Spectroscopy

Background:

• The optimized mean-trajectory (OMT) approximation is a semiclassical technique for calculating vibrational response functions.
• It utilizes action-quantized classical trajectories linked by transitions representing radiation-matter interactions.

Purpose of the Study:

• To extend the OMT approximation to incorporate vibrational coherence and energy transfer.
• To apply the generalized OMT to a system of coupled anharmonic chromophores and a bath.
• To analyze the resulting 2D spectra for evidence of coherence transfer.

Main Methods:

• Semiclassical approximation
• Optimized Mean-Trajectory (OMT) method
• Calculation of vibrational response functions
• Simulation of anharmonic chromophores coupled to a bath

Main Results:

• The extended OMT successfully includes vibrational coherence and energy transfer processes.
• Application to coupled anharmonic chromophores demonstrates the method's capability.
• The computed 2D spectra explicitly show coherence transfer between normal modes.

Conclusions:

• The generalized OMT approximation provides a powerful tool for studying complex vibrational dynamics.
• This extended method accurately reflects energy transfer and coherence phenomena in molecular systems.
• The findings offer new insights into the interpretation of 2D spectra for coupled chromophores.