Experimental Detection of Branching at a Conical Intersection in a Highly Fluorescent Molecule

Johanna Brazard, Laurie A. Bizimana, Tobias Gellen, William P. Carbery, Daniel Turner

Research output: Contribution to journalArticle

Abstract

Conical intersections are molecular configurations at which adiabatic potential-energy surfaces touch. They are predicted to be ubiquitous, yet condensed-phase experiments have focused on the few systems with clear spectroscopic signatures of negligible fluorescence, high photoactivity, or femtosecond electronic kinetics. Although rare, these signatures have become diagnostic for conical intersections. Here we detect a coherent surface-crossing event nearly two picoseconds after optical excitation in a highly fluorescent molecule that has no photoactivity and nanosecond electronic kinetics. Time-frequency analysis of high-sensitivity measurements acquired using sub-8 fs pulses reveals phase shifts of the signal due to branching of the wavepacket through a conical intersection. The time-frequency analysis methodology demonstrated here on a model compound will enable studies of conical intersections in molecules that do not exhibit their diagnostic signatures. Improving the ability to detect conical intersections will enrich the understanding of their mechanistic role in molecular photochemistry.

Original languageEnglish (US)
Pages (from-to)14-19
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume7
Issue number1
DOIs
StatePublished - Jan 7 2016

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intersections
Molecules
signatures
molecules
Potential energy surfaces
Kinetics
touch
Photoexcitation
Photochemical reactions
kinetics
electronics
Phase shift
photochemical reactions
phase shift
Fluorescence
potential energy
methodology
fluorescence
configurations
pulses

Keywords

  • conical intersection
  • femtosecond transient absorption
  • oxazine molecules
  • surface crossing
  • vibrational wavepacket

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Experimental Detection of Branching at a Conical Intersection in a Highly Fluorescent Molecule. / Brazard, Johanna; Bizimana, Laurie A.; Gellen, Tobias; Carbery, William P.; Turner, Daniel.

In: Journal of Physical Chemistry Letters, Vol. 7, No. 1, 07.01.2016, p. 14-19.

Research output: Contribution to journalArticle

Brazard, Johanna ; Bizimana, Laurie A. ; Gellen, Tobias ; Carbery, William P. ; Turner, Daniel. / Experimental Detection of Branching at a Conical Intersection in a Highly Fluorescent Molecule. In: Journal of Physical Chemistry Letters. 2016 ; Vol. 7, No. 1. pp. 14-19.
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