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Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Two-photon absorption of hydrogen-bonded octupolar molecule clusters
Kai Liu1, Yanhua Wang, Yaoquan Tu
1Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
The Journal of Physical Chemistry. B
|March 19, 2008
Summary
Molecular clustering significantly impacts two-photon absorption (TPA) spectra. Aggregation-induced structural distortions in TATB clusters cause red shifts in TPA, with stability increasing in larger clusters.
Area of Science:
- Molecular spectroscopy
- Computational chemistry
- Materials science
Background:
- Charge-transfer octupolar molecules can aggregate in solution via hydrogen bonds.
- Molecular clustering can alter photophysical properties, such as two-photon absorption (TPA).
Purpose of the Study:
- To investigate the influence of intermolecular hydrogen bonding and clustering on the TPA spectra of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB).
Main Methods:
- Utilized density functional quadratic response theory.
- Examined TATB dimers, trimers, and tetramers from molecular dynamics simulations.
- Calculated and compared TPA spectra of monomeric and clustered TATB.
Main Results:
- Significant red shifts in TPA spectra were predicted for all TATB clusters compared to the monomer.
- Aggregation-induced structural distortions were identified as the primary cause of spectral shifts.
- TPA spectra exhibited strong conformation dependence for dimers and trimers, but greater stability for tetramers.
- Enhanced TPA absorption was observed in less distorted clusters linked by hydrogen bonds.
Conclusions:
- Molecular clustering profoundly affects TPA spectra of charge-transfer molecules.
- Hydrogen bonding and structural conformation within clusters play a critical role in modulating TPA properties.
- TATB clustering offers a pathway to tune TPA characteristics for potential applications.
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