Excited-state properties and emission spectra of nonplanar heterocyclic helicenes.
J Phys Chem A
; 110(38): 11018-24, 2006 Sep 28.
Article
em En
| MEDLINE
| ID: mdl-16986834
ABSTRACT
We discuss the electron-vibration coupling in mono-aza-[5]helicenes on the basis of a Franck-Condon analysis and density functional theory (DFT) calculations of the fluorescence and phosphorescence spectra measured in ethanol. The geometries of the initial states were obtained from time-dependent DFT (S(1)) and unrestricted DFT (T(1)) excited-state optimizations. In general, the position of the nitrogen atom has only a minor impact on the vibronic fine-structure in both absorption and emission. The shapes of the emission spectra from the lowest singlet and triplet states are found to be determined by contributions from multiple normal modes. The results of the calculations demonstrate how the interplay among these normal modes results in qualitatively and quantitatively different spectra for fluorescence and phosphorescence.
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Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2006
Tipo de documento:
Article