Bockris ellipsometry

The influence of the metal on electrosorption was also considered in the adsorption of aromatic compounds. Extensive studies of adsorption of different aliphatic and aromatic compounds on a polycrystalline Pt electrode in O.OIMHCI solution were done by Bockris etal. Using different techniques (radiotracer, FTIR, and ellipsometry), they were found that aromatic molecules are adsorbed parallely to the electrode surface and that the potential dependence of adsorption is symmetrical around the pzc. It was concluded that the dependence of adsorption on the potential is mostly determined by the interaction of water with the Pt surface. 

Fig. 7.59. Optics of a film-covered surface. (W. Paik, Ellipsometry in Electrochemistry, in Modem Aspects of Electrochemistry, Vol. 25, J. O M. Bockris, B. E. Conway, and R. E. White, eds., Plenum, 1993, p. 200.)...

In Section 12.2.4, the remarkable efficacy of octynol in reducing the rate of corrosion of stainless steel by 99%, even in concentrated boiling HC1, was noted. Such a remarkable inhibitory solution has been examined in detail (Bockris and Bo Yang, 1991) using XPS, ellipsometry, and a technique (MacFarlane, 1990) that uses a study of the bombardment of a surface by particles emitted by the new element, Californian, to obtain information on groups adsorbed there. 

Much of the earlier studies of the anodic layer with ellipsometry were carried out by Bockris and his group. Reddy, Genshaw, and... 

Bockris followed the formation of the anodic film on Pt using ellipsometry. Whereas oxygen adsorption begins at Eu = 0.8 V, these workers found no evidence of such in their ellipsometric measurements below 0.95 V. At more anodic potentials, distinctive changes of A were found and attributed to the formation of the oxide film. These workers assumed that real component... 

This modified ellipsometry is the combined reflectance-ellipso-metry technique, also known as the three-parameter ellipsometry (TPE) in contrast to the conventional two-parameter ellipsometry. Since it was first introduced in 1971 by Paik and Bockris to study passivation film formed anodically on cobalt, TPE has proven to be a powerful technique for determining all three unknowns from purely optical measurements alone. The measurements for A, and R are made with the same experimental setup as for the conventional ellipsometer, with minor modifications of the measurement routine if necessary. Here, R is the reflectance at the same angle of incidence as for the A and if/ measurements. Therefore, no alignment change is necessary for additional measurement of R. With some automatic ellipsometers (see Section III.5), all three measurements can be recorded simultaneously. It should be emphasized once more that A, ij/, and R are mutually independent functions, despite the fact that both il/ and R are defined by combinations of and r. ... 

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... 

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