Interaction of O[sub 2] with Li-Au and Cs-Au films. A photoemission and thermal desorption study

Journal Article · Thu May 06 00:00:00 EDT 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100120a029· OSTI ID:6297819

Rodriguez, J A; Hrbek, J ^[1]; Kuhn, M; Sham, T K ^[2]

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1. Brookhaven National Lab., Upton, NY (United States)
2. Univ. of Western Ontario, London (Canada)

The reaction of O[sub 2] with thick Li-Au or Cs-Au films supported on Ru(001) has been investigated using thermal desorption mass spectroscopy and core- and valence-level photoemission. The interaction of O[sub 2] with CsAu at 100 K produces O[sub 2][sup [minus]] (the only oxygen species at low O[sub 2] exposures) and O[sub 2][sup [minus]]. Annealing of the O[sub 2]/CsAu film to 300 K leads to the disappearance of O[sub 2] and the appearance of O[sup 2[minus]]. The adsorption of O[sub 2] on Li-Au alloys at 300 K produces the O[sub 2][sup [minus]] ion together with another oxygen species. The presence of oxygen shifts the Au(4f) and Cs(3d) levels of CsAu approximately 1 eV toward lower binding energy, with the final peak positions being very close to those observed for metallic Au and oxidized Cs. A similar result was observed for O[sub 2]/Li-Au. No evidence for bonding between the oxygen ions and Au was found. At T [le] 300 K, oxygen breaks the Au-alkali bonds to form Li-O or Cs-O and very small Au clusters that are dispersed on the film. Annealing to 500 K produces sintering of these Au clusters into large three-dimensional particles. The existence of Li-O or Cs-O bonds increases the thermal stability of the alkali in the film. The Li-O and Cs-O compounds decompose at much higher temperatures than the LiAu and CsAu alloys. 28 refs., 10 figs., 2 tabs.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6297819
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 97:18; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CESIUM ALLOYS
CHEMICAL REACTIONS
SORPTIVE PROPERTIES
GOLD ALLOYS
LITHIUM ALLOYS
OXYGEN
ADSORPTION
DESORPTION
ANNEALING
EXPERIMENTAL DATA
FILMS
MASS SPECTROSCOPY
PHOTOEMISSION
RUTHENIUM
ULTRAHIGH VACUUM
ALLOYS
DATA
ELEMENTS
EMISSION
HEAT TREATMENTS
INFORMATION
METALS
NONMETALS
NUMERICAL DATA
PLATINUM METALS
SECONDARY EMISSION
SORPTION
SPECTROSCOPY
SURFACE PROPERTIES
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties
400102 - Chemical & Spectral Procedures