Layer growth of methane on MgO: An adsorption isotherm study
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)
The layering properties of methane on MgO (100) were measured between 70 K and 96 K using high-resolution adsorption isotherms. The results demonstrate that at least five layers can form. Phase transitions for the different layers were identified by monitoring the changes in the isothermal compressibility of a particular layer as a function of chemical potential. A phase transition (melting) for the monolayer is observed at about 80 K, whereas layers 2 through 4 show a similar transition at about 85 K. The isosteric heat of adsorption was calculated as a function of coverage to gain insight into the growth process of the CH{sub 4}/MgO system. The thermodynamic quantities determined here are compared with published experimental values. Our data provide key information for defining current methane-MgO interaction potentials. (c) 2000 The American Physical Society.
- OSTI ID:
- 20217705
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 62, Issue 12; Other Information: PBD: 15 Sep 2000; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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