This diagram is a close-up of the crystal (in our case, diamond) used as the ATR surface, and the sample itself (blue). The path of the infrared light is shown. Light undergoes multiple internal reflections in the crystal of high refractive index, shown in yellow. The sample is in contact with the crystal.
Resources which explain sample preparation and use of the ATR:
- This page (by Thermo-Fisher, the company that sells our Nicolet FTIR) describes attenuated total reflectance:https://www.thermofisher.com/us/en/home/industrial/spectroscopy-elemental-isotope-analysis/spectroscopy-elemental-isotope-analysis-learning-center/molecular-spectroscopy-information/ftir-information/ftir-sample-handling-techniques/ftir-sample-handling-techniques-attenuated-total-reflection-atr.html
- ATR Basics (please note- don’t get hung up on the details. I don’t expect you to understand or write about the technical details, but there is an explanation of what is going on in the diamond and sample):
- ATR sample preparation:
- Running a sample on the ATR (This is great – he uses the same type of instrument that we now have at JMU):