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Journal ArticleDOI: 10.1016/0039-6028(86)90781-8

Calculation of coverage dependence of electronic density of states and binding energy for chemisorbed oxygen on Ni(001)

01 Mar 1986-Surface Science (North-Holland)-Vol. 167, Iss: 1
Abstract: We present a tight-binding calculation of the electronic local density of states (LDOS) and binding energy for chemisorbed oxygen on a Ni(001) surface at various coverages. The electronic structure is determined by treating explicitly the 4s and 3d electrons and their hybridization for the substrate Ni atoms and the oxygen 2p electrons. The continued-fraction technique is used to determine the LDOS. The obtained LDOS for the p(2x2) and c(2x2) structures is in good agreement with photoemission measurements. Our calculation shows that with increasing oxygen coverage, the binding energy of oxygen decreases, whereas the charge transfer on oxygen increases. These results are discussed in connection with oxidation of the surface nickel occurring at high coverages. more

Topics: Binding energy (56%), Local density of states (54%), Electronic structure (54%) more

Journal ArticleDOI: 10.1016/0039-6028(93)90695-G
Ingomar Jäger1Institutions (1)
10 Jan 1993-Surface Science
Abstract: Based on Persson's [Surf. Sci. 258 (1991) 451] idea the concept of linear relaxation with respect to the strongest interaction between adsorbates is established. This simple but powerful concept not only destroys the characteristic but unrealistic particle-hole symmetry of all pairwise-potential models, as already shown by Persson, but introduces at least one new phase into the Ising antiferromagnetic model on the simple quadratic lattice and distinguishes between the p(2 × 2) and the c(4 × 2) phases without the need of third-neighbor interactions. The ground state phase diagram for the antiferromagnetic Ising model including nnn interactions and relaxation as well as methods of estimating the magnitude of the relaxation effect to be expected are given. more

Topics: Ising model (57%)

2 Citations

Journal ArticleDOI: 10.1088/0031-8949/35/5/015
01 May 1987-Physica Scripta
Abstract: A positive ion (ionized adsorbate) on atop position surrounded by a cluster of neutral adsorbates is placed on the (100) surface of a simple cubic crystal. An attractive Coulomb interaction between the ion and the metal atom directly below is explicitly included to prevent the ion from being quickly neutralized by electron transfer from the metal. No lateral interactions are placed at the outset, so that only indirect interactions through the metal (Rudeman-Kittel-type) enter. The degree of coverage (θ) is simulated by considering different clusters of neutral adsorbates and the ion line width, which controls the stimulated desorption ion yield, is calculated by a tight-binding Green function approach. It is found that the neutralization rate reaches a minimum (maximum ion yield) somewhere between θ = 1/4 and θ = 1/2 in agreement with experiment. more

Topics: Ion (55%), Atom (50%)

2 Citations

Journal ArticleDOI: 10.1088/0031-8949/38/4/016
01 Oct 1988-Physica Scripta
Abstract: We study the position and chemisorption energy of O on Ni(100) as a function of coverage and including atomic relaxations. A Hubbard like tight-binding Hamiltonian and the Hartree-Fock approximation is used. The repulsive interaction between atoms is described by a Born-Mayer type potential. Results are given for atomic relaxations and for the binding energy of O at various chemisorption sites. Our results do not indicate the pseudo-bridge position as a stable one. more

Topics: Chemisorption (59%), Binding energy (56%), Hubbard model (54%) more

1 Citations


Journal ArticleDOI: 10.1103/PHYSREV.94.1498
John C. Slater1, G. F. Koster1Institutions (1)
15 Jun 1954-Physical Review
Abstract: The LCAO, or Bloch, or tight binding, approximation for solids is discussed as an interpolation method, to be used in connection with more accurate calculations made by the cellular or orthogonalized plane-wave methods. It is proposed that the various integrals be obtained as disposable constants, so that the tight binding method will agree with accurate calculations at symmetry points in the Brillouin zone for which these calculations have been made, and that the LCAO method then be used for making calculations throughout the Brillouin zone. A general discussion of the method is given, including tables of matrix components of energy for simple cubic, face-centered and body-centered cubic, and diamond structures. Applications are given to the results of Fletcher and Wohlfarth on Ni, and Howarth on Cu, as illustrations of the fcc case. In discussing the bcc case, the splitting of the energy bands in chromium by an antiferromagnetic alternating potential is worked out, as well as a distribution of energy states for the case of no antiferromagnetism. For diamond, comparisons are made with the calculations of Herman, using the orthogonalized plane-wave method. The case of such crystals as InSb is discussed, and it is shown that their properties fit in with the energy band picture. more

Topics: Tight binding (61%), Brillouin zone (54%), Linear combination of atomic orbitals (51%) more

3,413 Citations

Journal ArticleDOI: 10.1080/03602457908065102
I. Toyoshima1, Gabor A. Somorjai1Institutions (1)
Abstract: One of the important physical-chemical properties that characterizes the interaction of solid surfaces with gases is the bond energy of the adsorbed species. The determination of the bond energy is usually performed indirectly by measuring the heat of adsorption (or heat of desorption) of the gas [1, 2], In order to define the heat of adsorption, let us consider the chemisorption of a diatomic molecule, X2, onto a site on a uniform solid surface, M. The molecule may adsorb without dissociation to form MX2. M represents the adsorption site where bonding occurs to a cluster of atoms or to a single atom. In this circumstance, the heat of adsorption, ΔHads, is defined as the energy needed to break the MX2 bond: more

Topics: Bond energy (62%), Adsorption (58%), Chemisorption (58%) more

292 Citations

Journal ArticleDOI: 10.1103/PHYSREVLETT.52.1830
Abstract: We argue that the widely held view that MnO, FeO, CoO, and NiO are Mott insulators is incorrect. Intra-atomic potential energies do not dominate interatomic kinetic energies, to the extent commonly believed; both are 1-2 eV in magnitude. A measure of the importance of interatomic effects is our finding that both the crystal structure and the magnetic structure of these materials are crucial to their insulating behavior. more

207 Citations

Journal ArticleDOI: 10.1016/0039-6028(75)90150-8
P. M. Marcus1, J. E. Demuth1, D. W. Jepsen1Institutions (1)
01 Dec 1975-Surface Science
Abstract: Recent work on the structure of ordered overlayers of chalcogens on nickel is reviewed, and discussed as a convincing example of the use of LEED intensity spectra for surface structure determination. Guidelines are suggested for successful application of LEED to surface structure, and the special suitability of the muffin-tin potential for the LEED calculation is brought out. The model of the complex crystal potential used for the calculation, and the systematic determination of the four parameters of the model from the data for clean Ni are described. The application to chalcogen overlayers is illustrated by the case of c(2 × 2)S and c(2 × 2)O on Ni(001) surfaces, and the correspondence between experiment and theory is exhibited for the intensity versus energy spectra of 1 2 1 2 beams. The correspondence is close and detailed; the complex shapes of broad features are reproduced and the average of the magnitude of the deviation between peaks in measured and calculated spectra is less than 2 eV, whereas the accidental correspondence of two spectra is shown to fluctuate around 4 eV. The observed values of the bond lengths of O, S, Se, Te on Ni are shown to be plausible on the basis of the covalent radii and the expected deviations from them. Results for other surfaces and other structures are tabulated. In all cases but one [O/Ni(110)] the chalcogen occupies sites that the next layer of Ni atoms would use. more

Topics: Bond length (51%), Covalent radius (50%)

203 Citations

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