Water adsorption and desorption kinetics on single crystal and thin film MgO(100) surfaces

Conference · Tue Oct 01 04:00:00 EDT 1996

OSTI ID:370135

Stirniman, M J; Smith, R S; Joyce, S A ^[1]

---

1. Pacific Northwest National Lab., Richland, WA (United States)

Molecular beam scattering and temperature programmed desorption are used to study the adsorption and desorption kinetics of H{sub 2}O (D{sub 2}O) on single crystal, sputtered single crystal, and thin film MgO(100) surfaces. We find that water adsorbs on all three substrates via precursor mediated adsorption kinetics with near unit sticking probability, independent of coverage or temperature below 200K, with a high temperature peak at about 235K that saturates at approximately 1 water molecule per surface metal ion, and a non-saturable low temperature peak at about 160K, corresponding to the formation of multilayer ice. The high temperature desorption feature is strongly substrate dependent, with features of first order (associative) kinetics on the well ordered substrate, and features of second order (dissociative) kinetics on the highly defective thin film and sputtered substrates.

• OSTI ID: 370135
• Report Number(s): CONF-960376--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ADSORPTION
DESORPTION
ELECTRON DIFFRACTION
MAGNESIUM OXIDES
MICROSCOPY
MONOCRYSTALS
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THIN FILMS
WATER