Chemisorption on a Model Transition Metal

Abstract The effect of chemisorption on the (100) surface of a model transition metal is investigated using Green's functions coupled with the phase shift technique. A change in the electronic density of states (DOS) is obtained for two different binding sites, the on-site and the bridge-site; strong steric-effects are present. The importance of the substrate DOS for chemisorption is pointed out.

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Chemisorption of Ordered Overlayer on a Tight-Binding Metal Surface Two-Level Adsorbate

Zeitschrift für Naturforschung A ◽

10.1515/zna-1982-1007 ◽

1982 ◽

Vol 37 (10) ◽

pp. 1147-1164

Author(s):

K. Masuda

Keyword(s):

Phase Shift ◽

Transition Metal ◽

Density Of States ◽

Tight Binding ◽

Electronic States ◽

Bridge Site ◽

Bonding Interaction ◽

Model Transition ◽

Adsorbate Structure ◽

Shift Technique

The chemisorption of a two-level (at E1 and E2) adsorbate on the (001) surface of a tightbinding metal is investigated using the Green's function formalism and the phase shift technique. The adorbital density of states (DOS)ϱa(E) as well as the change in the electronic DOS Δϱ(E; E1, E2) due to chemisorption are calculated for the ordered overlayers with c(2 x 2), p(2 x 1), p(2 X 2), p(4 X 1) and c(4 X 2) structures. It is assumed that the chemisorbed species sit over the twofold bridge site of the (001) surface of the model transition metal and have a π-bonding interaction with the two substrate atoms. It is shown that the electronic states of the overlayers are very sensitive to the adsorbate coverage (0), adsorbate structure and adsorbate species (one level or two level adsorbates). Furthermore, it is shown that there are marked differences in the Δϱ(E) curves between the chemisorption of two level adsorbates Δϱ(E; E1, E2) and that of single level adsorbates Δϱ(E; E1) + Δϱ(E; E2) (simulating the changes in the electronic DOS during the dissociation of diatomic molecules).

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Changes in Density of States Caused by Chemisorption: Monolayer of Adatoms on a Model Transition Metal

Zeitschrift für Naturforschung A ◽

10.1515/zna-1978-0113 ◽

1978 ◽

Vol 33 (1) ◽

pp. 66-73

Author(s):

Kin-ichi Masuda

Keyword(s):

Electronic Structure ◽

Phase Shift ◽

Transition Metal ◽

Density Of States ◽

Anderson Model ◽

Surface Density ◽

Direct Interaction ◽

Coverage Dependence ◽

Model Transition ◽

Shift Technique

The effect of chemisorption of a monolayer of atoms on the (001) surface of a model transition metal is investigated using the Green's function formalism and the phase shift technique. The electronic structure of the surface is obtained by the application of the Kalkstein and Soven method. For comparison, both a single and two peaked model of the surface density of states (DOS) are used. The change in the DOS upon chemisorption as well as the adatom DOS are calculated within the Newns-Anderson model for chemisorption. It is shown that the two peaked substrate DOS model can qualitatively account for the strong coverage dependence of the photoemission spectra observed in the H/W(100) system. In addition, it is shown that the direct interaction between the adatoms plays an important role in the monolayer chemisorption.

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