Agilent Technologies 1100 Series Reference Manual page 240

7 Introduction to the Fluorescence Detector
Figure 71
Photoluminescence is the collective name for two phenomena, fluorescence and
phosphorescence, which differ from each other in one characteristic way--the delay of
emission after excitation. If a molecule emits light 10
illuminated then the process was fluorescence. If a molecule emits light longer than 10
3
Phosphorescence is a longer process because one of the electrons involved in the
excitation changes its spin, during a collision with a molecule of solvent, for example.
The excited molecule is now in a so-called triplet state, T, see
240 1100 Series FD Reference Manual
Relationship of Excitation and Emission Wavelengths
seconds after illumination then the process was phosphorescence.
-9 -5
to 10 seconds after it was
Figure 72.
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