Layer growth of methane on MgO: An adsorption isotherm study

Journal Article · Fri Sep 15 04:00:00 EDT 2000 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.62.8360· OSTI ID:20217705

Freitag, Andrea ^[1]; Larese, J Z ^[1]

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1. 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, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 12 Vol. 62; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ADSORPTION HEAT
ADSORPTION ISOTHERMS
EXPERIMENTAL DATA
LAYERS
MAGNESIUM OXIDES
MELTING
METHANE
PHASE TRANSFORMATIONS