Nonresonance spectrum function

Let both the emission and absorption line be centered at Eq and have the same natural line width F = Ff, = F. The distribution of the ground-state Mbssbauer atoms in question (e.g., Fe) is taken to be uniform in both the source and the absorber. The distribution of the parent atoms (e.g., Co) producing the excited Mossbauer atoms ( Fig. 25.7) (and thus the y photons) is described by the density function p x) along the x-axis (see Fig. 25.6 for the notation). In the derivation of the peak shape of the Mossbauer spectrum, nonresonant and resonant absorption processes are to be considered in both the source and the absorber as illustrated schematically in Fig. 25.6. 

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