A "Twist" on the Interpretation of the Multifluorescence Patterns of DASPMI

Mireia Segado, Enrico Benassi, Vincenzo Barone

Результат исследований: Материалы для журналаСтатья

6 Цитирования (Scopus)

Выдержка

In this computational study, we describe the decay mechanism of DASPMI, providing robust and documented answers to some crucial questions of still open debates on the photophysical behavior of this cationic dye. After the initial excitation, the system evolves along a torsional motion, characterized by a quite flat potential energy surface, which crosses an intramolecular charge transfer (ICT) excited state with higher energy. A nonemissive twisted-ICT (TICT) minimum is populated, and this enhances the radiationless deactivation to the ground state. Additionally, during the twisting motion path toward the TICT minima, the system can emit in a quite wide range of angles, which should lead to a red shift of the locally excited (LE) emission and asymmetric broadening of fluorescence. This picture is fully supported by experimental evidence of the multifluorescence of DASPMI. Three twisted minima are found with different energies (namely, T1, T2, and T3). The extension of the work to charge properties shows that, in the GS, the positive charge of the molecule is mainly localized on the acceptor moiety (i.e., methyl-pyridinium), and after the excitation, the charge delocalizes over the whole molecule with a slight preference for the acceptor moiety. Because of the subsequent deactivation via twisting motions, the positive charge moves from the acceptor to the donor moiety (dimethylaminophenyl moiety) so that in TICT minima the positive charge is localized in the donor part. These large differences between charge localization in LE and TICT minima are responsible for a larger population of twisted forms in solvents of increasing polarity and the enhancement of radiationless deactivation.

Язык оригиналаАнглийский
Страницы (с-по)4803-4813
Число страниц11
ЖурналJournal of Chemical Theory and Computation
Том11
Номер выпуска10
DOI
СостояниеОпубликовано - 2 сен 2015
Опубликовано для внешнего пользованияДа

Отпечаток

Charge transfer
Potential energy surfaces
Molecules
deactivation
Excited states
Ground state
twisting
Coloring Agents
Dyes
Fluorescence
charge transfer
excitation
red shift
molecules
polarity
dyes
potential energy
2-(4-(dimethylamino)styryl)-1-methylpyridinium
fluorescence
ground state

ASJC Scopus subject areas

  • Computer Science Applications
  • Physical and Theoretical Chemistry

Цитировать

A "Twist" on the Interpretation of the Multifluorescence Patterns of DASPMI. / Segado, Mireia; Benassi, Enrico; Barone, Vincenzo.

В: Journal of Chemical Theory and Computation, Том 11, № 10, 02.09.2015, стр. 4803-4813.

Результат исследований: Материалы для журналаСтатья

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