Wetting and adsorption of ammonia on magnesium oxide

Journal Article · Mon Mar 01 04:00:00 EST 1999 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.59.8247· OSTI ID:341177

Johnson, D E; Larese, J Z ^[1]

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1. Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)

High-resolution volumetric adsorption isotherms of ammonia-on-MgO(100) surfaces have been recorded over the temperature range 160{endash}200 K (using powder prepared by a recently introduced process). Evidence is presented that indicates that multilayer formation is possible at T{ge}173&hthinsp;K (at least three layers). We have observed a series of layering transitions including a crossover from incomplete to complete wetting near the triple point of ammonia. The isothermal compressibility and isosteric heat of adsorption are determined. These data are compared with earlier results obtained for ammonia on graphite and used to describe the status of the film with regard to temperature and coverage. The importance of high-quality MgO substrates is discussed and areas for further study using structural methods are mentioned. {copyright} {ital 1999} {ital The American Physical Society}

• OSTI ID: 341177
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 12 Vol. 59; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
ADSORPTION
ADSORPTION HEAT
ADSORPTION ISOTHERMS
AMMONIA
COMPRESSIBILITY
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
POWDERS
SUBSTRATES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0065-0273 K
TRIPLE POINT
VOLUMETRIC ANALYSIS