Laser-induced desorption determinations of surface diffusion on Rh(111)
Surface diffusion of hydrogen, deuterium and CO on Rh(111) has been investigated by laser-induced thermal desorption (LITD) and compared with previous results for these species on Pt(111) and on other metals. For deuterium in the coverage range 0.02 < theta < 0.33, the pre-exponential factor D/sub 0/ - 8 x 10/sup -2/ cm/sup 2//s, with a diffusion activation energy 3.7 < E/sub diff/ < 4.3 kcal/mol. For CO, E/sub diff/ = 7 kcal/mol, but D/sub 0/ rises from 10/sup -3/ to 10/sup -2/ cm/sup 2//s between theta = 0.01 and 0.40. Values of E/sub diff/ on different surfaces appear to correlate with differences in heats of adsorption in different binding states which form saddle point configurations in surface diffusion. In addition, oxidation reactions on Rh and on several other transition metal surfaces may be limited to CO or H surface diffusion. 30 refs., 3 figs., 1 tab.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA); Minnesota Univ., Minneapolis (USA). Dept. of Chemical Engineering and Materials Science
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5743074
- Report Number(s):
- SAND-87-1603C; CONF-8708209-1; ON: DE88005159
- Resource Relation:
- Conference: LASST-ACSIS conference on interfacial diffusion, New Brunswick, Canada, 18 Aug 1987; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON MONOXIDE
DESORPTION
DIFFUSION
DEUTERIUM
HYDROGEN
RHODIUM
SURFACE PROPERTIES
ACTIVATION ENERGY
CHEMISORPTION
LASER RADIATION
MONOCRYSTALS
TEMPERATURE DEPENDENCE
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTALS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
METALS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
RADIATIONS
SEPARATION PROCESSES
SORPTION
STABLE ISOTOPES
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties