Spectroelectrochemistry reflection mode

Spectroelectrochemistry, reflection mode — The interaction of electromagnetic radiation with matter (-> spectroscopy) may occur by absorption or scattering when radiation impinges on matter or passes through matter. In the latter case (transmission mode) the radiation before and after passage is evaluated in order to obtain the desired spectrum. In studies of opaque materials or of surfaces interacting with matter inside the (bulk)... 

Fig. 5.39. Thin layer cell for NIR spectroelectrochemistry in the external reflection mode according to [145]...

In conclusion, UVAds/NIR spectroelectrochemistry in both transmission and reflection mode are extremely useful techniques that yield a wealth of complementary data additional to those obtained in pure electrochemical voltammetric experiments. Especially when based on computer simulation models, this data may be used to unravel the kinetics and thermodynamics of complex electrode processes. 

In the reflection mode, typically specular reflectance is measured on the electrode surface. It is anticipated that the variation of the surface structure (e.g., surface adsorption, phase transitions, etc.) will result in appreciable changes in the reflectivity properties. One can thus correlate the structural characterislics gleaned from spectroscopic measurements with electrochanical results. Figure 2.15 shows a cell assembly for internal reflection spectroelectrochemistry. Several spectroscopic techniques have been used, such as infrared, surface plasmon resonance, and X-ray based techniques (reflectivity, standing wave, etc.). Figure 2.16 depicts a cell setup for (A) infrared spectroelectrochemistry (IR-SEC) and (B) surface X-ray diffraction. 

Sometimes the desired electrode cannot be rendered transparent. Then, the spectroelectrochemistry of solution species may be performed using a reflective electrode (Figure 2). The results are, of course, identical to those in the transmission mode, except that the path length and hence the absorbance of dissolved species is increased by the factor (2/cosfi) where 0 is the angle of incidence (angle between the... 

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