Specifications include, but are not limited to: A Thermo Scientific Nicolet Smart iXT attenuated total reflectance (ATR) Accessory made for an Si50 FTIR Spectrometer. This is a single bounce attenuated total reflectance device that enables the full capabilities of the FTIR with diamond, ZnSe, or Ge plates. This allows the FTIR to analyze solid or liquid materials rather than only in-line gas effluents. This unit has an automatic set up and recognition chip for the software. The FTIR currently in use is capable of in-line gas sampling and analysis. In order to use this FTIR for solid materials and liquid sample types, the ATR accessory must be used. Many of our materials are aerosol particles in line with an airflow system; however, the need for analyzing solid and liquid particles produced by certain processes after retention is part of our scope of work for the soot and combustion studies, the salt deliquesence studies, and the degradation profile studies. The Nicolet Smart iXT ATR accessory is the only unit made for use with the Nicolet Si50 FTIR Spectrometer that features a recognition chip for immediate setup and proper software and hardware use. This oven is the only option for instrument compatibility and communication with software. Additionally, the instrument has increased throughput that is necessary for our sampling requirements. The monolithic and AR-coated diamond’s higher energy throughput (variable based on sample type) is the ratio of the energy transmitted of the accessory compared to the open beam path, and for all sample types, exceeds other accessories for other FTIR units.