Re: Self-quenching

Posted by Jurriaan Zwier on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Self-quenching-tp591076p591079.html

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Hi Marc,

One of the mechanisms involves so called excimer-formation or
excited-state dimer formation. When one excited molecule encounters its
counterpart it can form a more stable excited state. This state can
fluoresce itself (at a longer wavelength then the monomer) or be quenched
through different pathways then the monomer. Because the energy of this
excimer is lower then the monomer excited state quenching pathways are
usually more available for the excimer, hence an overall decrease of
fluorescence intensity. A famous example of excimer fluoresence is the
pyrene excimer (page 9 Lakowicz)

Hope this helps a bit,

Jurriaan

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> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
> Hi all,
>
> I'm having difficulty finding information on the mechanisms behind
> fluorescence self-quenching. Why when packed together, molecules stop
> emitting light ?
> Do they relax via collisional or heat transfer, but why this change ? Any
> info will be greatly appreciated.
> Thanks in advance,
> M
> ------------------------------------------------
> Marc Thibault, Ph.D.
>
> Postdoctoral Fellow
> NSERC/Biosynthech Chair in Hybrid Biomaterials
> for Innovative Regenerative Technologies
> Department of Chemical Engineering
> Ecole Polytechnique
> Montreal, Qc, Canada
> 514 340 4711 (4781)
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