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Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
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Time-dependent non-equilibrium dielectric response in QM/continuum approaches
Feizhi Ding1, David B Lingerfelt1, Benedetta Mennucci2
1Department of Chemistry, University of Washington, Seattle, Washington 98195, USA.
The Journal of Chemical Physics
|January 24, 2015
Summary
This study introduces a new time-dependent continuum embedding method to accurately model solvent effects on excited molecules. This approach captures non-equilibrium solvation dynamics crucial for understanding photoexcitation processes.
Area of Science:
- Computational Chemistry
- Quantum Mechanics
- Physical Chemistry
Background:
- Polarizable Continuum Models (PCMs) are widely used for solvation effects in quantum calculations.
- Traditional PCMs assume equilibrium or pre-excitation solvent configurations, limiting their use for time-dependent processes.
- Existing methods fail to capture non-equilibrium solvent dynamics following photoexcitation.
Purpose of the Study:
- To develop a time-dependent continuum embedding method for non-equilibrium solvation.
- To extend PCMs to accurately describe time-dependent solvent effects on excited states.
- To model the real-time dynamics of solvated molecules after photoexcitation.
Main Methods:
- Derived a time-dependent continuum embedding formalism within the PCM framework.
- Developed an equation of motion for dielectric polarization using frequency-dependent dielectric constants.
- Numerically integrated the new method alongside time-dependent Hartree-Fock/density functional theory equations.
Main Results:
- Successfully simulated time-dependent solvent effects on electronic excitation.
- Observed dipole quenching and electronic state dephasing/relaxation.
- Demonstrated out-of-phase charge fluctuations between the solvent and solute.
Conclusions:
- The new time-dependent method accurately captures non-equilibrium solvation dynamics.
- This formalism is essential for studying ultrafast processes after photoexcitation.
- The approach provides deeper insights into solvent-solute interactions in excited states.
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