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Updated: May 8, 2026
08:04
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Effective tight-binding models for excitons in branched conjugated molecules.
Hao Li1, Sergey V Malinin, Sergei Tretiak
1Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
The Journal of Chemical Physics
|August 17, 2013
Summary
A new tight-binding model effectively describes electronic excitations in branched molecules. This method uses lattice parameters derived from quantum-chemical computations to analyze exciton behavior and scattering.
Area of Science:
- Computational Chemistry
- Materials Science
- Quantum Mechanics
Background:
- Vertical electronic excitations in branched conjugated molecules are complex.
- Understanding exciton behavior is crucial for molecular electronics.
Purpose of the Study:
- To introduce an effective tight-binding model for describing vertical electronic excitations.
- To characterize excited-state electronic structure using quantum particles (excitons) on an irregular lattice.
Main Methods:
- Developed a tight-binding model approach.
- Utilized time-dependent Hartree-Fock computations on phenylacetylene oligomers.
- Identified on-site energies and hopping constants from exciton dispersion and scattering matrices.
Main Results:
- The model successfully describes exciton spectra and energy-dependent exciton scattering matrices.
- Resonant and bound states were reproduced for a symmetric quadruple branching center.
- Lattice parameters were obtained from quantum-chemical computations.
Conclusions:
- The tight-binding model provides an effective tool for analyzing electronic excitations in branched conjugated systems.
- The methodology simplifies the description of complex molecular structures.
- Future work can explore exciton-phonon coupling and energetic disorder.
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