Hi all,

I often notice that the built-in Bruker OPUS atmospheric compensation does not always completely remove water vapor and CO2 bands from my micro-ATR spectra (I use a Ge IRE on a Hyperion 2000 microscope, coupled to a Bruker Vertex v80). This is especially apparent in the ~1750–1500 1/cm region.

Does anyone know when exactly in the 'mathematical pipeline' this correction is implemented? Is this done before Fourier-transformation and/or conversion to an ATR spectrum, or after? If this is done after the latter, does the algorithm take into account the shifts in relative band intensities and positions of (mostly strongly absorbing) bands that occur with the wavelength-dependent ATR correction/conversion?

Maybe the atmospheric artifacts could be a consequence of a poor fit of the software's internal 'atmosphere reference' to an ATR spectrum, while it might be optimized to be fit better on transmission and/or transreflection spectra?

Thank you in advance for any suggestions.

Kind regards,

Pjotr