Field measurements with infrared surface

In this chapter, we have chosen from the scientific literature accounts of symposia published at intervals during the period 1920 1990. They are personal choices illustrating what we believe reflect significant developments in experimental techniques and concepts during this time. Initially there was a dependence on gas-phase pressure measurements and the construction of adsorption isotherms, followed by the development of mass spectrometry for gas analysis, surface spectroscopies with infrared spectroscopy dominant, but soon to be followed by Auger and photoelectron spectroscopy, field emission, field ionisation and diffraction methods. 

Incidentally, the way to measure surface temperatures in the field is with an infrared handheld thermometer. The response time of these thermometers is infinitely faster than in old-style, contact thermometers. You can buy one from any good instrument catalog1 for a few hundred dollars. 

Many other applications and developments of the ATR method and accessories have been undertaken, including devising special apparatus for specific purposes. Monitoring chemical reactions in solution is an important application of the ATR method, and a variety of studies have been reported. An important example in this field of research is a combination of the ATR method with the surface-enhanced infrared absorption (SEIRA) [5] technique SEIRA is a phenomenon by which the intensities of the infrared absorption bands of a chemical species adsorbed onto the surface of a thin metal layer consisting of very small metal particles are enhanced. When the ATR method is used for measuring SEIRA,... 

Frequently, electrochemical information can be interpreted better in the presence of additional nonelectrochemical information. Typically, however, there is one significant restriction electrochemical and spectroscopic techniques often do not detect exactly the same mechanisms. With spectroscopic measurements (e.g., infrared spectroscopy), products that are formed by electrochemical processes may be detected. In other cases (luminescence techniques) mechanisms may be found by which charge carriers are trapped and recombine. Other techniques (electroreflection studies) allow the nature of electronic transitions to be determined and provide information on the presence or absence of an electric field in the surface of an electrode. With no traditional technique, however, is it... 

In the normal-incident transmission measurements of LB films deposited on transparent substrates, the electric vector of the infrared beam is parallel to the film surface (Figure 5A). Therefore, only absorption bands which have the transition moments parallel to the film surface can be detected by this method. On the other hand, in the above-mentioned RA measurements, in which the p-polarized infrared beam is incident upon the LB film prepared on Ag-evaporated substrates at a large angle of incidence, we have a strong electric field perpendicular to the film surface as shown in Figure 5B. Therefore, in this case, only absorption bands which have the transition moments perpendicular to the film surface can be detected with a large intensity enhancement. Thus, if the molecules are highly oriented in the LB films, the peak intensities of particular bands should be different between the transmission and RA spectra. 

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