"Normally, we perform the background measurement with KBr, and subsequently, the material to be analyzed is diluted in KBr. However, I am conducting kinetic measurements of in-situ oxide samples that are measured in their pure form without dilution in KBr. I conducted some tests and observed a strange distortion in some bands (abrupt signal drops), which I believe might be due to distortions caused by the initial background. What would be the best strategy to perform a more appropriate background measurement?"
how are you measuring the background? Are you using diffuse reflectance from pure KBr powder? pure KBr (or NaCl if you don't need below 600 cm-1) will give the instrumental response function that you need (source, detector etc) to correct the sample spectrum. other issues that can cause the behavior you are describing are from apodization or phase correction.
Hello, thank you very much for your answer! I am measuring the background by diffuse reflectance of pure KBr powder, previously calcined before the measurements. I understand, could you recommend any specific literature that discusses apodization or phase correction?
This is a good resource - i have an earlier edition but this goes through the whole process.
Apodization weights the data points in the interferogram. Typical ones are rectangular (boxcar), trapezoid, triangle.
the phase is also part of the FT process - poorly phased peaks look like derivative peaks - up on one side, down on the other.
Chapter Fourier Transform Infrared Spectrometry
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