For polymer film samples, if reflectivity and transmissivity in the mid-infrared region (here, 4 to 16 micrometers) are desired, and using a FTIR & ATR spectrometer (Bomem MB Serie Hartmann & Braun) :
1-Is it possible to use the output spectrum to evaluate the reflectivity and transmissivity?
2-Should not the baseline be corrected by OMNIC Software? Using normalize scale is not allowed?
3-If there are more than 100% reflection in some cases, what corrections should be made? Thanks*
Example: fig 2-f in this article:Article A dual-mode textile for human body radiative heating and cooling
1-Yes, this is possible. You have to perform dispersion analysis on your spectrum. By that, you get the optical constants from which you can calculate external specular reflectance and transmittance
2-I would not try to correct the baseline with a software that does not "understand" the optical reasons for the existence of this baseline. In ATR there are a couple of "obvious" mistakes, like using a diamond crystal under 45° incidence which means that if your sample has an index of refraction above 1.7 you do not perform an ATR experiment at all. Since absorption is accompanied with dispersion, this also means that your band shapes become distorted because you locally violate the ATR conditions. Dispersion analysis corrects your baseline taking all this properly into account.
3-No corrections at all if possible - try to repeat the experiment and more often record your background spectrum.
Thank you very much Dr. Thomas Mayerhöfer
Is there any reference for reading more and citation in this case?
Even better, there are programs available with which you can analyze your spectra. E.g RefFIT by Alexey Kuzmenko (https://reffit.ch/) or CODE by Wolfgang Theiss (https://www.wtheiss.com/). Both have good manuals. Also SpIRIT by Konstantin Shportko (http://www.shportko.com/spirit.html) should be up to the task.