General Discussion and Elementary Theory of

7 General Discussion and Elementary Theory of Flame Spectrometry (Atomic Absorption Spectrometry and Flame Photometry) 

Clearly the transition finm Ej Eq correspond to the emission of radiation of frequency v. Since an atom of a given element gives rise to a definite, characteristic line spectrum, it follows that there are different excitation states associated with different element. The consequent emission spectra involve not only transitions finm excited state to the grormd, state e.g. Eg Eq (as indicated by bold 

Thus it follows that emission spectrum of a given element is quite complex. Theoretically it is always possible for absorption of radiation by already excited states to occur e.g. Ej  

Eg etc. But in practice the ratio of excited to grormd state atoms is extremely small, and thus the absorption spectrum of a given element is usually only associated with transitions from the grormd state to higher energy states and is th os much simpler in characteristics than the emission spectrum The relationship between grormd state and excited state population is given by the Boltzmann equation. 

KLN where Nq = concentration of the atoms in the flame (number of atoms per cm ), L = path length, through the flame (cm), K = constant related to the absorption coefficient. 

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