Following Coupled Electronic-Nuclear Motion through Conical Intersections in the Ultrafast Relaxation of β-Apo-8'-carotenal

Thomas A A Oliver, Graham R Fleming

Research output: Contribution to journalArticle (Academic Journal)

22 Citations (Scopus)

Abstract

Ultrafast transient electronic absorption, one- and two- dimensional electronic-vibrational spectroscopies were used to study the nonradiative relaxation dynamics of β-apo-8'-carotenal (bapo), a model aldehyde containing carotenoid, in cyclohexane and acetonitrile solutions. 2D electronic-vibrational (2DEV) spectroscopy allows for a direct correlation between the intrinsically coupled electronic and vibrational degrees of freedom, which are thought to play an important role in driving relaxation of bapo from the bright S2 and lower-lying dark S1 state. Line shapes of features in the 2DEV spectra allow us to make more definitive assignments of excited state vibrations of bapo in acetonitrile. Anisotropy studies definitively demonstrate that the excited state dynamics of bapo do not involve a trans-cis isomerization, counter to prior hypotheses. For specific vibrational modes, the electronic and vibrational line shapes remain correlated beyond the decay of the S2 excited state, indicating that the transfer of molecules to the S1 state is impulsive and involves a conical intersection in the vertical Franck-Condon region.

Original languageEnglish
Pages (from-to)11428-41
Number of pages14
JournalJournal of Physical Chemistry B
Volume119
Issue number34
DOIs
Publication statusPublished - 27 Aug 2015

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