Phase diagram of chemisorbed oxygen layer on the tungsten (112) surface
The adsorption of oxygen on the W(112) surface results in an ordered p(2 x 1) structure which exists over a wide range of temperature and submonolayer coverage. By analyzing the low-energy electron diffraction angular profile and peak intensity of the half-order beams as a function of coverage (CTHETA) and temperature (T), the growth and disordering of the overlayer were studied. The order-disorder transition temperature (T/sub c/) depends on the coverage with the highest T/sub c/ obtained at a coverage of 0.5 monolayer (ML). From the coverage-dependent transition temperatures the phase diagram (T-CTHETA) was obtained. Oxygen atoms are only partially mobile at the dissolution temperature of the first-order phase boundary. Adatom-adatom interactions were estimated from the phase diagram. The measured angular width at room temperature also depends on coverage. With the use of an island-size-broadening model, the smallest islands are estimated to be less than 20 A in length, and the largest islands occur at 0.5-ML coverage.
- Research Organization:
- Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
- OSTI ID:
- 5320111
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Vol. 28:12
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
OXYGEN
CHEMISORPTION
ELECTRON DIFFRACTION
ORDER-DISORDER TRANSFORMATIONS
TUNGSTEN
SORPTIVE PROPERTIES
EXPERIMENTAL DATA
HIGH TEMPERATURE
LAYERS
LOW TEMPERATURE
MEDIUM TEMPERATURE
PHASE DIAGRAMS
SURFACES
ULTRAHIGH VACUUM
VERY HIGH TEMPERATURE
CHEMICAL REACTIONS
COHERENT SCATTERING
DATA
DIAGRAMS
DIFFRACTION
ELEMENTS
INFORMATION
METALS
NONMETALS
NUMERICAL DATA
PHASE TRANSFORMATIONS
SCATTERING
SEPARATION PROCESSES
SORPTION
SURFACE PROPERTIES
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties