Effect of surface charge fluctuations on the spectral density of chemisorbed atoms
- 15 March 1980
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 21 (6), 2309-2327
- https://doi.org/10.1103/physrevb.21.2309
Abstract
Basing our analysis on the Anderson-Newns model for H chemisorption, we develop a systematic method of calculating the adatom self-energy arising from the effect of substrate charge fluctuations. Using the method of functional derivatives, we generate a Dyson equation for the adatom Green's function and evaluate the self-energies due to the hopping and Coulomb interactions between metal and atom to second order. The latter involves the substrate density response function, and this allows us to include the effect of surface plasmons, bulk plasmons, and the particle-hole continum of the metal surface on an equal footing. The latter become increasingly important close to the surface, where simple image-potential arguments are no longer adequate. We formulate our theory treating the adatom Coulomb repulsion perturbatively (Newns, Hertz and Handler) as well as in the atomic limit (Brenig and Schönhammer, Bell and Madhukar). Keeping only surface plasmons, we discuss the relaxation shifts and surface-plasmon satellites of the H-atom spectral density within the context of the Brenig-Schönhammer approximation. In particular, we show how the effective Coulomb repulsion is reduced to . We also prove that the substrate-induced self-energy term which gives rise to the above changes on the spectral density has no effect on the net chemisorption energy. The small image-potential energy shift of the main resonance is canceled by the large shift associated with the weak surface-plasmon satellite. Much of our theoretical analysis is applicable to the core-level spectrum, and not just the valence electrons involved in chemisorption.
Keywords
This publication has 38 references indexed in Scilit:
- A soluble relaxation model for core level spectroscopy on adsorbed atomsSurface Science, 1978
- Plasmon effects on core level spectra of adsorbatesSolid State Communications, 1978
- Surface relaxation energies in core level spectroscopies of adsorbed atoms and moleculesSurface Science, 1977
- Shape of core level spectra in adsorbatesSolid State Communications, 1977
- Core holes in chemisorbed atomsPhysical Review B, 1977
- Ultraviolet photoemission studies of hydrogen chemisorption bonding to Ni, Pd and Pt surfacesSurface Science, 1977
- Screening energies in photoelectron spectroscopy of localized electron levelsPhysical Review B, 1976
- On the theory of chemisorptionThe European Physical Journal A, 1974
- Self-Consistent Model of Hydrogen ChemisorptionPhysical Review B, 1969
- Electron interaction in the band theory of chemisorptionPhysics Letters A, 1967