Fluorescence study of dyes

Fluorescence Study of the Kinetics of Energy Transfer Between Dyes 1. Introduction Coumarin 1 and Sodium fluorescein are two dyes which absorb and emit light in the visible region. By using a spectrophotometer we are recording an absorption spectrum and then determining the molar decadic absorption coefficients, which will be used later to interpret and analyse the fluorescence spectra. For fluorescence spectra, there are two kinds, the excitation and the emission spectrum. The excitation spectrum is obtained …

…gives us the following graph. Values obtained: JDA = 6.897x1031 nm mol -1 R0 = 0.14 nm (R0)eff = 0.584 nm based on equation (A3-13) So we see that those are very clearly quite different, and that could show that it does not obey to Forster's theory. 3. Conclusion So we have shown that the quenching of Coumarin 1 by Sodium fluorescein is obeyed by Stern-Volmer kinetics, that there is mainly dipole-dipole transfer, but could not agree with Forster's theory.