Through the analysis of some spectroscopic spectra (e.g. XRD, PL, FTIR and Raman) various baseline mode can be applied for obtaining a well defined Gaussian or lorentzian peaks, hence baseline mode has an effect on some parameter like peaks positions, area and FWHM.
Based on the above illustration, I hope to have more demonstration about this point.
A spectral distribution is a term which describes an intensity as function of the energy. XRD displays the angular distribution of a monochromatic radiation, i.e. the energy is (practically) constant. Therefore, a diffraction pattern should not be called spectrum but diffractogram. For XRF it is different of course...
I assume that baseline mode is your term for background radiation. This is a quite difficult topic since there is a lot of unused information hidden which is often ignored, unfortunately. Mainly, because it is not clear which parameters are all affecting and (more problematic) in which way. Therefore, simple approaches like polynoms are used. However, they do not have any physical meaning, so that it often happens that the applied background processing was wrong or very bad. This may delete important parts in diffractograms but also e.g. in EDS spectra. This part of analysis is per default automatically done, but how an automatic can detect a physically unknown impact of different influences? Therefore, good background processing is still nowadays a mainly manual procedure in order to prevent at least a very "stupid" processing of a black-box code.
The same is true in FTIR. In case of layered samples usually interference fringes occur in spectra. Not only that from these fringes the index of refraction in the visible and the layer thickness can be calculated. Naive removement as it is usually performed on the absorbance spectra prevents to remove the electric field standing wave effects in the spectra of these layers. Accordingly, it is not possible to calculate the true absorbance and one is left the apparent absorbance which can have considerable errors of 100 % and more.
See e.g.
Article The electric field standing wave effect in infrared transfle...
Article The Electric Field Standing Wave Effect in Infrared Transmis...
Article Employing Theories Far beyond Their Limits-The Case of the (...
https://www.researchgate.net/project/Fast-and-reliable-Determination-of-the-true-Absorbance- Badges
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- Methodology
- Crystallography
- X-ray Diffraction