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Potassium adsorptio...
Potassium adsorption on graphite(0001)
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- Österlund, Lars, 1967- (författare)
- Uppsala universitet,Fasta tillståndets fysik
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- Chakarov, D V (författare)
- Chalmers University of Technology
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- Kasemo, B (författare)
- Chalmers University of Technology
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(creator_code:org_t)
- 1999
- 1999
- Engelska.
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 420:2-3, s. 174-189
- Relaterad länk:
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https://urn.kb.se/re...
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visa fler...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Potassium adsorption on graphite has been studied with emphasis on the two-dimensional K adlayer below one monolayer. Data are presented for the work function versus coverage, high-resolution electron energy loss spectroscopy (HREELS) vibrational spectra of K-adlayers, low energy electron diffraction and ultraviolet photoemission spectroscopy (UPS) spectra at different coverages. The data provide information regarding the vibrational properties of the K-adlayer, the metallization of the adlayer at submonolayer coverages, and the charge transfer from the It adatoms to the graphite substrate. Analysis of the work function, HREELS, and UPS data provides a qualitatively consistent picture of the charge state of the K adatoms, where at low coverages, below a critical coverage theta(c) (theta(c) = 0.2-0.3), the K adatoms are dispersed and (partially) ionized, whereas at theta > theta(c) islands of a metallic 2 x 2 K phase develop that coexist with the dispersed K adatoms up to theta = 1. We show that it is possible to understand the variation of the work function data based on a two-phase model without invoking a depolarization mechanism of adjacent dipoles, as is normally done for alkali-metal adsorption on metal surfaces. Similarly, the intensity variation as a function of coverage of the energy loss peak at 17 meV observed in HREELS, and the photoemission peak at E-b = 0.5 eV seen in UPS can be understood from a two-phase model. A tentative explanation is presented that connects apparent discrepancies in the literature concerning the electronic structure of the K adlayer. In particular, a new assignment of the K-induced states near the Fermi level is proposed. (C) 1999 Elsevier Science B.V. All rights reserved.
Nyckelord
- alkali metals
- chemisorption
- graphite
- surface electronic phenomena
- Engineering Science with specialization in Solid State Physics
- Teknisk fysik med inriktning mot fasta tillståndets fysik
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- ref (ämneskategori)
- art (ämneskategori)
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