Electronic properties of polymethine systems. 6. Bond order and bond length changes upon excitation
Autor: | A.D. Kachkovski, O.O. Zhukova |
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Rok vydání: | 2004 |
Předmět: | |
Zdroj: | Dyes and Pigments. 63:323-332 |
ISSN: | 0143-7208 |
DOI: | 10.1016/j.dyepig.2004.01.006 |
Popis: | The dependence of bond order and bond length changes upon the excitation on the molecular topology of linear conjugated systems has been investigated using quantum-chemical methods. It has been found that the molecular geometry and π-bond orders in the excited state of polymethine dyes (odd ionic π-systems) and substituted polyenes (even neutral π-systems) containing residues with their localized MOs differ significantly from that in the typical π-systems having a totally delocalized HOMO and LUMO. Also, the extraordinary π-bond order changes upon excitation have been shown to exist in relatively long polymethine dyes when the symmetry breaking occurs. These results are consistent with spectral data. |
Databáze: | OpenAIRE |
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