Lorentzian distribution, absorption band

Eq. (4.28) implies that the absorption band-shape for m -> n is Lorentzian with half-width ynm. In thermal equilibrium, the Boltzmann distributions can be used for and In this case Eq. (4.28) becomes... 

The band distortion has been interpreted in terms of a non-uniform distribution of the external load in the regions of different state of order resulting in a non-symmetrical displacement of the individual atomic absorption frequencies about the maximum of the band Thus, Vettegren postulated that overstressed segments are predominantly located in the amorphous regions of the polymer. In a recent publication Wool has derived that for Lorentzian absorption bands... 

In physical terms the site inhomogeneous component may be conceived of either as slightly different protein binding sites for chromophores or as a distribution of protein conformational substates [127] at any one site. In operational terms the spectral forms are represented by the sub-bands of a gaussian or lorentzian decomposition analysis of absorption or fluorescence spectra. 

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