The adsorption of krypton on the (1,1,1) face of copper single crystals
| Autor: | Robert A. Pierotti, J.L Carden |
|---|---|
| Rok vydání: | 1974 |
| Předmět: |
Auger electron spectroscopy
Krypton Analytical chemistry chemistry.chemical_element Flory–Huggins solution theory Copper Virial theorem Surfaces Coatings and Films Electronic Optical and Magnetic Materials Biomaterials Crystallography Colloid and Surface Chemistry Adsorption Reflection (mathematics) chemistry Monolayer |
| Zdroj: | Journal of Colloid and Interface Science. 47:379-394 |
| ISSN: | 0021-9797 |
| DOI: | 10.1016/0021-9797(74)90270-7 |
| Popis: | Single crystals of copper were grown which displayed predominantly the (1, 1, 1) plane. The crystals were electropolished and characterized by acid etch patterns, X-ray back reflection orientation and topology techniques and by Auger electron spectroscopy. The crystals having a geometric surface area of 78 cm2 were specially mounted in a bakeable ultrahigh vacuum volumetric adsorption apparatus. Krypton adsorption isotherms were determined on these copper crystals at 78.9°, 91.2°, 98.6°, and 108.0°K. Pressures were measured using an MKS all-welded bakeable capacitance manometer. The isotherm data encompassed the very low coverage region, the monolayer region and for the two lower temperature isotherms a portion of the multilayer region. The low coverage isotherm data were analyzed in terms of the virial approach to physical adsorption. The gas-solid interaction parameter, ϵ 1s ∗ /k , was found to be 1678°K. The virial approach was found to yield reasonably good values of the surface area of the crystals. This is the first application of the virial approach to very small surface area samples. The intermediate coverage region was analyzed in terms of the significant structure theory of adsorption. The analysis yields a value of ϵ 1s ∗ /k of 1654 ± 50°K and a value for the lateral interaction parameter ϵ 1s ∗ /k of 48 ± 7°K. The high value of ϵ 12 ∗ /k and the unusually low value of ϵ 1s ∗ /k are in accord with quantum mechanical theories of many-body interactions involving metal substrates and with the results of the virial analysis of the low coverage data. Isosteric heats of adsorption were determined as a function of coverage. The zero coverage heat, qs10/R, was found to be 1770°K and the slope of the heat versus coverage curve in the monolayer region is about 270°K which is in agreement with the small value of ϵ 12 ∗ /k reported above. |
| Databáze: | OpenAIRE |
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