A method is described in which approximate correction for spectral slit broadening is performed at the same time that reflectance or transmittance data are being fitted with analytic dispersion curves. The method is valid for spectra whose structure is not too sharp on a scale comparable with the spectrometer resolution. It is not to be used for sharp line spectra. The key problem that is solved is to find the fastest way to compute the slit broadening effect on the spectra obtained from the trial dispersion curves. The method is applied, as an example, to analyze some reststrahlen data taken with a grating spectrometer in the far ir from a sample of PrCl3. The same approximate method could also be used with data from other types of spectrometers having different slit broadening functions, such as from two-crystal x-ray spectrometers, in regions where very sharp spikes do not appear in the spectra.
D. W. Berreman, "Unfolding Spectrometer Slit Broadening Effects from Broad Spectra," Appl. Opt. 7, 1447-1453 (1968)