Correction of Emission and Excitation Spectra

Similarly, the instrumental excitation spectrum depends on the wavelength characteristics of the excitation monochromator and of the light source. Mercury arcs which emit line spectra are not suitable and xenon arcs are normally used. Correction is made against a reference such as a solution of Rhodamine which has a wavelength-independent fluorescence quantum yield. 

The absolute excitation spectrum is then identical to the absorption spectrum. The correction factor can again be stored in a computer memory and used to multiply other instrumental excitation spectra (so long as the lamp is not changed). 

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