Dear Researchers,
Would anyone help me understand the set up information about FTIR with Smart accessory ATR with diamond crystal?
Typically, I am looking this information for Thermo Scientific FT-IR spectrometer and the model for ATR accessory is SMART iTX with diamond crystal. My question is what is the shape of this diamond crystal? and what is the incident angle it uses?
Would someone uses this tool with similar model and crystal, I would be very grateful if you can share with me this information.
Many thanks.
Patrick
For any interface, there is a critical angle where reflection becomes total: no light passes through the interface, all is reflected. This phenomenon is used in optical fibers (total internal reflection) and in ATR. If the angle is steeper than critical, there will be some reflection and some light will go through the interface with refraction. The precise value of the critical angle depends on the properties of the two materials making the interface. For ATR, we want the angle to be so shallow that it is in the total reflection regime for any possible medium - air, water, various organic or inorganic liquids or solids. Critical angle for diamond/air is about 25 degrees - it will be greater for samples we want to measure.
Many thanks for good explanations, Professor James.
I still have a question about the ATR in FTIR. I think for every ATR coupled to FTIR has a fix angle of incident, is that right?
otherwise, one needs to change that incident angle depending on the sample to reach the TIR condition inorder to have ATR.
another question, is about the geometry/shape of the crystal. is it a prism?
someone who uses ATR with SMART iTX and diamond crystal, can assit about the shape of this diamond crytal.
Many thanks.
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