Excited-state properties and emission spectra of nonplanar heterocyclic helicenes

Karin Schmidt, Sergio Brovelli, Veaceslav Coropceanu, Jean Luc Brédas*, Cristina Bazzini, Tullio Caronna, Riccardo Tubino, Francesco Meinardi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)11018-11024
Number of pages7
JournalJournal of Physical Chemistry A
Volume110
Issue number38
DOIs
StatePublished - Sep 28 2006
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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