The Laboratory of Electrochemistry possesses a spectrophotometer FT 8400 from Shimadzu, which additionally has a liquid nitrogen cooled MCT type detector and a set of accessories which allow to study sold and liquid state samples as well as monolayers and thin films deposited on top of light reflecting surfaces. Surface spectra of monolayers and thin films are recorded with the help of Specular Reflectance (Infrared Reflection Absorption Spectroscopy – IRRAS) method: the intensity of light reflected from a samples surface is measured. The set up for Specular Reflectance studies is shown below:
It possible to study samples of various thickness due to the incident beam angle tuning option. For monolayer studies large angles are used, e.g. 80° from normal to surface. A detailed description of dependence between incident beam angle and specular reflectance intensity is given by R.G. Greenler in J. Phys. Chem. 44 (1966) 310-314. IR reflectance spectra provide information about the way a particle is attached to a surface, its orientation and conformation. It also allows to estimate possible interactions between individual particles, which form a monolayer.
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