What is the angle of incidence for a G8180-68001 (Diamond ATR) sample interface?
We have an Agilent 4300 with a Diamond ATR sample interface. While we use the 4300 with its diffuse interfaces regularly the ATR interface has mostly been collecting dust due to our lack of understanding of it. All of the spectral libraries that we have collected over the past two decades are transmission and reflectance based. We would like to begin using our ATR for collections but understand that ATR spectra are not directly comparable to transmission spectra. We know there is a ton of software out there that will directly convert ATR spectra to transmission spectra but we'd like to understand the conversion algorithms that are used in order to better understand both the limitations of the ATR and the assumptions and potential sources of error/uncertainty in the different conversion algorithm options.
Both the peak intensity adjustment formulas and the peak wavenumber shift formulas appear to be heavily reliant on the angle of incidence of the IR beam. Our other interfaces (grazing angle, reflectance, and diffuse) all spell their angles out right on their datasheets but we can't seem to find that information for the ATR interface.