Spectroscopy based on photon detection

When atoms or molecules absorb light, the incoming photon excites the particle from its ground state to a 

The emission intensity of an emitting species is linearly proportional to the analyte s concentration, at least for low concentrations in this way, quantification of the emitting species can be realized, provided a number of other parameters are known (see Chapter 7). 

When a beam of electromagnetic radiation passes through matter, most of the radiation continues in its original direction however, a small fraction is scattered in other directions. 

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