Deactivation mechanism of the green fluorescent chromophore

Rinat Gepshtein, Dan Huppert, Noam Agmon*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We report time-resolved fluorescence data for the anion of p-hydroxybenzylidene dimethylimidazolinone (p-HBDI), a model chromophore of the green fluorescence protein, in viscous glycerol-water mixtures over a range of temperatures, T. The markedly nonexponential decay of the excited electronic state is interpreted with the aid of an inhomogeneous model possessing a Gaussian coordinate-dependent sink term. A nonlinear least-squares fitting routine enables us to achieve quantitative fits by adjusting a single activation parameter, which is found to depend linearly on 1/T. We derive an analytic expression for the absolute quantum yield, which is compared with the integrated steady-state fluorescence spectra. The microscopic origins of the model are discussed in terms of two-dimensional dynamics, coupling the phenyl-ring rotation to a swinging mode that brings this flexible molecule to the proximity of a conical intersection on its multidimensional potential energy surface.

Original languageEnglish
Pages (from-to)4434-4442
Number of pages9
JournalJournal of Physical Chemistry B
Issue number9
StatePublished - 9 Mar 2006


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