Chemisorption of atoms

Chemisorption of atomic oxygen to form a partial or complete monolayer. 

Further chemisorption of atomic oxygen into a second layer and/or further physical adsorption of Oj. 

Recently a novel experimental approach using Schottky diodes with ultra-thin metal films (see Fig. 11) makes direct measurement of reaction-induced hot electrons and holes possible. See for example Refs. 64 and 65. The chemical reaction creates hot charge carriers which travel ballistically from the metal film towards the Schottky interface and are detected as a chemicurrent in the diode. By now, such currents have been observed during adsorption of atomic hydrogen and deuterium on Ag, Cu and Fe surfaces as well as chemisorption of atomic and molecular oxygen, of NO and N02 molecules and of certain hydrocarbons on Ag. Similar results have been found with metal-insulator-metal (MIM) devices, which also show chemi-currents for many exothermic surface reactions.64-68... 

Upton,T.H. and Goddard,W.A. (1979), Chemisorption of atomic hydrogen on large scale nickel cluster surfaces , Phys.Rev.Lett, 42, 472... 

The mutual depolarization of the surface dipoles may be responsible for a third contribution. This effect is of importance in the chemisorption of atoms of alkali metals on metal surfaces. It causes, also in the chemisorption of other gases a minimum or a maximum in the surface potential as a function of 0. 

Atoms or molecules are physisorbed into a porous structure -such as a zeolite or a sample of coal- or onto a surface, and the amount of gas adsorbed is a measure of the surface area available for adsorption. Chemisorption of atoms or molecules on surfaces yields surface concentration of selected elements or adsorption sites. 

It may be concluded from their calculations that strong chemisorption of atoms and radicals prevents not only molecule formation but ejection or desorption from the grain surface as well. However, on top of the chemisorbed layer physical adsorption is possible and the adsorbed particles can move over... 

Volpe, M. and Cleri, F. (2003). Chemisorption of atomic hydrogen in graphite and carbon nanotubes. Surf. Sd., 544, 24-34. 

A detailed discussion of the two parallel reactions is beyond the scope of this paper on ionomers, but it is appropriate to note that the fast and slow reactions are tentatively assigned to chemisorptions of atomic oxygen and molecular oxygen (O2-), respectively, on the surface of silver particles in PFSA. 

The interaction of iodine with palladium and platinum electrodes was studied in different electrolyte solutions and on single crystals with electrochemical techniques and UHV spectroscopic ex situ measurements [111]. The chemisorption of atomic iodine on palladium researched extensively because of its ability to protect the surface from air and water interactions. Moreover, it is able to induce a surface reconstruction from a stepped surface to a (1 x 1) unreconstructed one. 

Fig. 40. The potential curve of the chemisorption of atom A on the surface of the catalyst K (the explanation is in the text).

One prediction of these theoretical models is that the heat of chemisorption of atoms should increase from right to left in the periodic table. This trend is well-documented in Chapter 6, and there is good agreement between experiments and theory. Thus, one of the important functions of transition metals in catalytic reactions is to atomize... 

Gasification stimulated by non-thermal plasma excitation and subsequent dissociation of H2 was also observed in experiments with production of hydrides of sulfur, arsenic, germanium, tin, tellurium, and selenium (Bonhoeffer, 1924 Pearson, Robinson, Stoddart, 1933 Radford, 1964). The mechanism of hydride production includes in this case volume and surface dissociation of excited hydrogen molecules, chemisorption of atomic... 

Jacob T, Muller RP, Goddard WA III (2003) Chemisorption of atomic oxygen on Pt(lll) from DFT studies of Pt-clusters. J Phys Chem B 107 9465-9476... 

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