Rayleigh scattering and Raman bands

This last expression reveals that the intensity of fluorescence depends upon the concentration (C), the experimental conditions (/,/g) and of the compound (e, Of). If all the parameters due to the instrument and most due the compound are factored into a global constant AT, then the following equation can be used for weak concentrations (A 0.01)  

Measurements by fluorimetry make use of several classic methods employing one or more standards (single point calibration or calibration curve, or methods of addition), but to obtain the best results, the solutions must be very dilute. 

Raman scattering, which is 100 to 1000 times weaker than that of Rayleigh scattering, is produced by the transfer of a part of the excitation radiation energy to 

The Raman scattering of water serves as a sensitivity test for fluorometers. This consists of measuring the signal/noise ratio of the Raman peak with a cell filled with water, for example at 397 nm if the excitation wavelength is fixed at 350 nm, as a result of the specific shift of 3380 cm for this solvent, and to compare with the background signal. 

The excitation source is often a xenon arc lamp with a power of 150 to 800 watts. The measurement of the light intensity is carried out using a photomultiplier tube or a photodiode. The solvent, the temperature, the pH and the concentration are the principal parameters which affect the intensity of fluorescence. For solution samples, rectangular 1 cm glass or fused silica cuvettes are used. 

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