Abstract
In this study, the interactions between H atoms and the (100), (110), and (111) surfaces of platinum have been investigated by using the London-Eyring-Polanyi-Sato (LEPS) potential function. The adsorption zones (sites) and LEPS energy values of these sites have been determined theoretically. In addition, the potential-energy surfaces for each Pt surface have been obtained in detail. Further, the adsorption sites on the surface, scattering from the surface, diffusion paths on the surface, and transition regions to the subsurface, have been determined and the differences have been examined in detail among the surfaces. From these results, it is found that an H atom has the lowest binding energy at the hollow sites on the Pt (100) and Pt (111) surfaces and that it has the lowest binding energy at the long-bridge sites on the Pt (110) surface. It has also been determined that the hollow sites on the three surfaces are the regions through which H atoms can penetrate into the subsurface. In addition, it has also been found that, for each of the three Pt surfaces, the diffusion of an H atom across the surface may follow a bridge-hollow-bridge pathway. These results are in agreement with previous experimental and theoretical results. Besides, the adsorption and diffusion manners of hydrogen atoms on each of the Pt surfaces have been analyzed deeply.
Highlights
Large quantities of nitrogen adsorb after the gas is atomized :by a high-frequency discharge on both surfaces
We recently investigated the interactions of isocyanic acid ;with Pt(llO) and Cu(lll) surfaces by means of LEED, Auger and !thermal desorption mas3 spectrometry [1,2)
The nature of the surface interaction was established by LEED, Auger, UPS and a PS methods [3] Exposure of the clean surface to ac tivated nitrogen at 300 K led to the appearance of a nitrogen signal at 380 eV
Summary
Large quantities of nitrogen adsorb after the gas is atomized :by a high-frequency discharge on both surfaces. Nitrogen desorbed from Cu(lll) surfaces in two stages, with one peak maximum which shifted from 620 to 700 K with, increasing coverage (/?q state), and Auger signal at approximately 330 eV, due to adsorbed nitrogen, was observed, when the nitrogen was activated.
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