| Autor: |
Olga V. Przhonska, Mykola P. Shandura, Yu.L. Bricks, M.O. Kudinova, O.D. Kachkovsky, Oleksandr O. Viniychuk, Svitlana M. Levchenko, Yu. P. Kovtun, Ye.M. Poronik, O.I. Tolmachev |
| Rok vydání: |
2014 |
| Předmět: |
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| Zdroj: |
Journal of Molecular Structure. 1060:30-37 |
| ISSN: |
0022-2860 |
| DOI: |
10.1016/j.molstruc.2013.12.038 |
| Popis: |
Several series of polymethine dyes containing terminal groups, which can generate the local levels close to the HOMO/LUMO energy gap, have been investigated by spectroscopic and quantum-chemical methods. The analysis of the obtained data has shown that the participation of the local levels in the electronic transitions leads to the appearance of the specific quasi-local transitions which differ from the transitions between delocalized molecular orbitals by their sensitivity to the length of the π-conjugated chromophore and to the chemical constitution of the terminal groups. These quasi-local transitions can be experimentally detected by measuring of the ordinary absorption spectra or by the excitation anisotropy spectra, in case when their low-intensive bands are covered by the intensive absorption band. In the unsymmetrical dyes, containing different terminal groups, the delocalized and quasi-local transitions can be mixed producing complicated absorption spectra with two comparatively intensive bands, and their shapes can be gradually transformed upon the lengthening of the π-conjugated chromophore. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect