Plasma extinction coefficient

More recently Tibbitt, Bell and Shen (56,57) carried out quantitative determinations of the structure of plasma polymerized hydrocarbons by infrared spectroscopy. Typical spectra of films deposited on sodium chloride substrates are shown in Figure 15. Absorptions peaks were identified to be associated with various group frequencies, corroborated with the findings from NMR spectra of dilute solutins of the oily products. From the knowledge of the extinction coefficients, concentrations of the functional groups in the plasma polymerized materials were determined. 

A photometric procedure which is based on the reaction of unsaturated fatty acids with concentrated sulfuric acid and a mixture of phosphoric acid and vanil-line with development of a pink color was introduced by Zollner and Kirsch (1962). Since in this reaction the various lipids show different extinction coefficients calibration is necessary according to gravimetric values. This method is also applicable directly to plasma samples without previous extraction. 

Adsorption of biologically important materials, such as fibrinogen from plasma proteins and barbiturates, " and organic molecules including corrosion inhibitors have been studied, often as functions of potential of the substrate, by ellipsometry in situ. Jovancicevic, Yang, and Bockris used time-resolved ellipsometry to measure the thickness, refractive index, and extinction coefficient of the adsorption layer of l-octyne-3-ol on iron as functions of time. They showed that the layer thickness increased stepwise, due to change of the adsorption configuration from flat... 

Optical and electrical properties of plasma deposited films, sometimes unique indeed, as well as the easy of their deposition, at low temperature and low cost, on inexpensive substrates of almost any size and shape, render these materials very attractive for optoelectronic applications. The possibility to tailor optical parameters, such as refractive index and extinction coefficient, and what is particularly important - the ability to adjust parameters of the electronic structure, such as transport p, optical gap, density of localized states, etc., recommend these plasma films as active photoelectric elements, e.g. for solar cells and water splitting cells. 

As an important consequence of resonance stabilization there will be low-lying charge transfer bands in the absorption spectrum. Hemocyanin has a molar extinction coefficient Cmax = 750. Laccase of mammalian plasma has an absorption band at 6050 A with. e,nax = 1200. We may wonder if those bands are really charge transfer bands. On the other hand we must note that the theory of ESR spectra is still in its infancy and that we should be cautious in our interpretation. 

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