Interaction of hydrogen with the Ag(111) surface
- Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (United States)
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States) Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6057 (United States)
The interaction of atomic hydrogen with the Ag(111) surface was studied with low-energy electron diffraction (LEED), high-resolution electron-energy-loss spectroscopy (HREELS), thermal desorption spectroscopy, and work function measurement. The adsorption of atomic hydrogen at 100 K induces a reconstruction of the Ag(111) surface, as indicated by an intense (2[times]2) (at 0.25--0.5 ML) and a mixture of (2[times]2) and (3[times]3) (at 0.5--0.6 ML) superstructures in LEED. The H-induced work function change ([Delta][Phi][sub max]=+0.32 eV) is uncharacteristically large for the close-packed surface and indicative of the surface structural change. HREELS data show that H occupies a single site of high symmetry for all coverage. The observation of two vibrational modes (one dipole active at 106 meV and the other not dipole active at 87 meV at [similar to]0.5 ML) allows an assignment of bonding at a threefold hollow site. Both modes show measurable shifts in energy with increasing coverage, indicating an appreciable H-H lateral interaction. Atomic hydrogen adsorbed on Ag(111) recombines and desorbs at a temperature [similar to]180 K, appreciably lower than those for Cu and transition metals. The properties of H adsorption on Ag will be compared to Cu and to transition metals.
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6459276
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 51:11; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360104* -- Metals & Alloys-- Physical Properties
ADSORPTION
COHERENT SCATTERING
DESORPTION
DIFFRACTION
ELECTRON DIFFRACTION
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FUNCTIONS
HYDROGEN
METALS
NONMETALS
SCATTERING
SILVER
SORPTION
SURFACE PROPERTIES
TRANSITION ELEMENTS
VIBRATIONAL STATES
WORK FUNCTIONS