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.

Schmidt, K., Brovelli, S., Coropceanu, V., Bredas, J., Bazzini, C., Caronna, T., et al. (2006). Excited-state properties and emission spectra of nonplanar heterocyclic helicenes. JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY, 110(38), 11018-11024 [10.1021/jp0616258].

Excited-state properties and emission spectra of nonplanar heterocyclic helicenes

BROVELLI, SERGIO;TUBINO, RICCARDO;MEINARDI, FRANCESCO
2006

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.
Articolo in rivista - Articolo scientifico
Helicene
English
28-set-2006
110
38
11018
11024
none
Schmidt, K., Brovelli, S., Coropceanu, V., Bredas, J., Bazzini, C., Caronna, T., et al. (2006). Excited-state properties and emission spectra of nonplanar heterocyclic helicenes. JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY, 110(38), 11018-11024 [10.1021/jp0616258].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/1689
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