Theory of H bonding and vibration on close-packed metal surfaces
Self-consistent linearized augmented plane-wave calculations for H monolayers adsorbed on Pt(111), Ru(0001), Cu(111), and Cu(1 x 1)/Ru(0001) thin slabs predict the following: the H-atom equilibrium position on these substrates is generally in the face-centered cubic threefold hollow at a height above the surface where the clean-metal electron density is about 0.015 a.u. The symmetric stretch (SS) frequency lies in the range 130--165 meV, and is about 30% greater than the asymmetric stretch (AS) frequency on the same substrate. These results contradict the mode assignments of Baro et al. (A. M. Baro, H. Ibach, and H. D. Bruchman, Surf. Sci. 88, 384 (1979)) for H/Pt(111) which were based on the observation of weak dipole scattering by the low-lying mode, and of Barteau et al. (M. A. Barteau, J. Q. Broughton, and D. Menzel, Surf. Sci. 133, 443 (1983)) for H/Ru(0001). The pairwise spring model of H--metal vibration invoked by these groups in support of their mode assignments neglects a major component of the H--metal interaction, that between the adsorbed H and the delocalized electrons of a metal surface. It is this interaction which is responsible for the fact that the frequency of the SS vibration is greater than that of the AS.
- Research Organization:
- Sandia National Laboratories, Albuquerque, New Mexico 87185
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6559412
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Vol. 5:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
COPPER
SORPTIVE PROPERTIES
HYDROGEN
ADSORPTION
CHEMICAL BONDS
PLATINUM
RUTHENIUM
SURFACE PROPERTIES
THIN FILMS
ELEMENTS
FILMS
METALS
NONMETALS
PLATINUM METALS
SORPTION
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties
360104 - Metals & Alloys- Physical Properties