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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: tksubbu on August 02, 2006, 02:51:20 PM

Title: Fluorescence
Post by: tksubbu on August 02, 2006, 02:51:20 PM

Hi,
Does anyone know if the fluorescence emission and excitation spectrum of a compound with known ex and em wavelengths, should have same fluorescence intensities?

subbu

Title: Re: Fluorescence
Post by: Dude on August 02, 2006, 03:27:31 PM

If I understand the question correctly, the answer would be no.  The emitted fluorescent light intensity should be lower than the excitation intensity due to the absorbed light undergoing other fates than fluorescence.  A parameter called the quantum yield describes the efficiency of fluorescence.  Keep in mind that the intensity will be an integrated sum across a range of wavelengths (even lasers are not monodisperse).

http://www.jobinyvon.com/usadivisions/fluorescence/applications/quantumyieldstrad.pdf

Title: Re: Fluorescence
Post by: tksubbu on August 03, 2006, 10:33:04 AM

Thanks for the post. It was helpful