Lorenzian line shape

In general, it may be expected that the sites for Fe2+ and Fe3+ in these noncrystalline ion exchange resins will have a large distribution of chemical environments. This expectation should be reflected as a significant broadening of the Mbssbauer resonance, as experimentally observed by Johansson 188). In addition, this broadening should result in a non-Lorenzian spectral line shape. Indeed, a computer analysis of the spectra showed that Gaussian peaks provided a better fit of the data than did Lorenzian peaks. In this case then, the linewidth and peak shape provide information about the distribution of support interactions for the various resonant atoms in the sample. 

In the liquid state, ESR lines are generally Lorenzian in shape, as theoretically predicted by Bloch s theory i.e.,... 

The Pearson VII model contains four adjustable parameters and is particularly well suited for the curve fitting of large spectral windows containing numerous spectral features. The adjustable parameters a, p, q and v° correspond to the amplitude, line width, shape factor and band center respectively. As q —the band reduces to a Lorenzian distribution and as q approaches ca. 50, a more-or-less Gaussian distribution is obtained. If there are b bands in a data set and... 

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