From mahmud1999 from yahoo.com  Wed Oct 24 14:05:18 2007
From: mahmud1999 from yahoo.com (Mahmudur Rahman)
Date: Wed Oct 24 14:41:07 2007
Subject: [Fluorescent-proteins] Re: Dynamic quenching
Message-ID: <635608.10341.qm@web37908.mail.mud.yahoo.com>

Hello everybody I need help. I was surfing the net for
this problem and came across this Bionet. 

I have a question about fluorescence
dynamic/collisional quenching. I know in static
quenching fluorophore makes complex with quencher in
the ground state, the uncomplexed fluorophore
concentration decreases and hence emission intensity
decreases. In collisional quenching, fluorophore is
excited to the excited state and quencher diffuse to
the fluorophore during the lifetime of the fluorophore
and then fluorophore returns to the ground state
without emission, and hence emission intensity
decreases. From stern-volmer equation we know that
lifetime also decreases with quencher concentration.
But my question is Why/How the lifetime of the
fluorophore decreases and why the decrease in lifetime
is quencher dependent; quencher concentration inceases
lifetime of fluorophore decreases.

I really appretiate any comment/explanation.

Thank you very much
rahman

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