Distortionsin the IR spectra may be due to several processes: reflection losses, interference and scattering, dependingon the conditions of registration. Such deviations should be taken into account quantitativespectralanalysisof surface species.The effect of scattering can be particularly strong in thespectra of dispersedsystems with high surface area. To see the purespectrum of adsorbed species,the background spectrum ofthe sample before adsorption has to be subtracted. For veryintense bands of gases adsorbed on highly scattering media the scattering coefficient changes near theabsorption bands, following the variations of refractionindex, and the bandshape of adsorbate becomesdistorted. To minimize thedistortion, one can run thespectrum of the beam going straightforwardandthe lightdeviateddue to scattering andcombiningthe two spectra, it is possible to reconstruct thespectrum of pure absorption or pure scattering.