Two-Dimensional Vibrational Spectroscopy of a Dissipative System with the Optimized Mean-Trajectory Approximation
Mallory Alemi1, Roger F Loring1
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States.
The Journal of Physical Chemistry. B
|October 3, 2014
Summary
The optimized mean-trajectory (OMT) approximation accurately models vibrational response functions for complex molecular systems. This semiclassical method effectively captures line shapes and dynamics, even with energy transfer broadening.
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 apply the OMT method to an anharmonic chromophore coupled to a harmonic bath.
- To develop a forward-backward trajectory implementation addressing numerical challenges in large, multi-scale systems.
Main Methods:
- Semiclassical computation of vibrational response functions.
- Forward-backward trajectory implementation of the OMT approximation.
- Application to an anharmonic chromophore-harmonic bath system.
Main Results:
- The OMT method successfully reproduces line shapes and waiting time dynamics in the weak coupling (pure dephasing) limit.
- The OMT accurately describes systems where energy transfer is the primary cause of line broadening.
Conclusions:
- The OMT approximation is a robust method for studying vibrational dynamics in complex molecular systems.
- The forward-backward implementation enhances the applicability of OMT to larger and more challenging systems.
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