ATR-FTIR works by directing an infrared beam onto an ATR crystal, which has a high refractive index. The beam undergoes multiple internal reflections within the crystal before it reaches the detector. When a sample is placed in contact with the crystal, the evanescent wave penetrates a few micrometers into the sample, allowing for the collection of its infrared spectrum. This method is particularly suitable for studying thin films and surface layers of nanomaterials.
