In ATR-IR spectroscopy infrared light is reflected trough a crystal, where it re
ID: 528930 • Letter: I
Question
In ATR-IR spectroscopy infrared light is reflected trough a crystal, where it reflects "totally" as it bounces off the crystal surface. If the set-up behaved classically, we know that the IR radiation would not penetrate to the other side of the crystal because the energy of the light is below the potential barrier. To the contrary, photons act as quantum particles. Discuss how the IR radiation penetrates into the sample. In addition, tell how you would expect the depth of penetration into the sample to depend on the angle of reflection, theta.Explanation / Answer
ATR- Attenuated total reflectance - It is the sampling technique which is combined with Infrared spectroscopy .
Using this sampling method Samples are used directly in the form of solid and liquid .
The principle behind this is based on the reflection which is as follows:
when the IR wave intract to the surface of the crystal wth the sample it gives atleast one reflection which fades .the reflections and gives the information .
depth of the penetration in to the sample is in the range of 0.5 to 2 micrometer. and the exact value is determined by the wavelength of the light , incident angle is being calculated and the number of reflections depends upon the inciedent angle. lastly the beam is collected by dectector.
Crystal is used mostlly germanium , Zinc selenide