**This algorith can only be run on windows due to f2py support and the underlying fortran code**
The model that is being fitted is that of a \delta-function (elastic component) of amplitude A(0) and Lorentzians of amplitude A(j) and HWHM W(j) where j=1,2,3. The whole function is then convolved with the resolution function. The -function and Lorentzians are intrinsically normalised to unity so that the amplitudes represent their integrated areas.
For a Lorentzian, the Fourier transform does the conversion: 1/(x^{2}+\delta^{2}) \Leftrightarrow exp[-2\pi(\delta k)]. If x is identified with energy E and 2\pi k with t/\hbar where t is time then: 1/[E^{2}+(\hbar / \tau)^{2}] \Leftrightarrow exp[-t