Torsional effects on excitation energies of thiophene derivatives induced by β-substituents: Comparison between time-dependent density functional theory and approximated coupled cluster approaches
✍ Scribed by M. Piacenza; F. Della Sala; E. Fabiano; T. Maiolo; G. Gigli
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 244 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0192-8651
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✦ Synopsis
Abstract
The influence of methyl or phenyl substitution in β‐position of dioxygenated terthiophene and diphenylthiophene on the optical properties is investigated by first‐principles calculations. We compare the approximated singles and doubles coupled cluster (CC2) approach with time‐dependent density functional theory methods. CC2 reproduces experimental excitation energies with an accuracy of 0.1 eV. We find that the different substituents modify the inter‐ring torsional angle which in turn strongly influences the excitation energies. The steric contribution to the excitation energies have been separated from the total substituent effects. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008