Attenuated Total Refraction

Attenuated Total Reflection (ATR) Reflectance measurements can be. divided into two basic categories ie Internal /external reflectance AIR is employed for Internal reflectance measurements as the beam of infrared radiation passes through an ATR element (rystal) in contact with the sample For external reflectance measurements, the infrared beam of radiation is reflected directly from the sample Surface. This type of external reflectance measurement can also be divided into two types - Diffuse - / specular. ATR (Internal) Sample Crystal K Angle of incider Sample Here the parallelogram shaped ATR crystal is wvered on two surfaces with a black sample material The beam of Infrared light tran traversing through the ATR orystal at a Particular angle of incidence is being

internally reflected at the top and bottom surface and this instance. there are 6 point y contact with the sample material (3at the top and 3 below). Reflectance external Diffuse reflectance Types Specular reflectance Incident bean. Diffusely reflected light Diffice reflection Sample (usually Powder / irregular surface material) Incident beam Specularly reflected beam I Specular reflectance Sample (usually smooth minor like surface medenal)