Adsorption on Clusters
01 Jan 1998-pp 193-201
TL;DR: In this article, the authors present results of their studies of adsorption of Li, Na, Mg, Al, Si, P, S and CI atoms on AI7 and AI13 clusters using the ab initio molecular dynamics method.
Abstract: We present results of our studies of adsorption of Li, Na, Mg, Al, Si, P, S and CI atoms on AI7 and AI13 clusters using the ab initio molecular dynamics method. We find a large variation in the binding energy of Li, Na, Mg and CI with the cluster size. In the case of CI on Al7, even the site to site variation in the binding energy is ≈ 1 eV which is much higher than normally found on semi-infinite surfaces. Silicon reconstructs both the clusters and induces covalency in Al-Al bonds. We compare our results with those on Al surfaces and discuss the adsorption behaviour in terms of the superatom-atom interactions where Al7 behaves like an alkali type superatom while, Al13, a halogen.
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01 Feb 1995
TL;DR: In this article, the Car-Parrinello method was used to solve electronic structure problems with the recursion method, R.P. Das and R.K. Kumar selfconsistent Green's function method for random alloys and their surfaces, J.B. Mookerjee magnetism and compositional order in transitional metal alloys.
Abstract: Density functional theory - many body effects without tears, M.P. Das density functional theory beyond LDA, U. von Barth tight binding LMTO, O.K. Andersen metal-semiconductor interfaces, G.P. Das solving electronic structure problems with the recursion method, R. Haydock real space electronic structure calculation using the recursion method, P. Vargus pseudopotentials, G.B. Bachelet ab-initio molecular-dynamics - the Car-Parrinello method, G. Pastore Car-Parrinello molecular dynamics and the Vanderbilt's ultrasoft pseudopotentials, K. Laasonen atomic and electronic structure of clusters from Car-Parrinello method, V. Kumar self-consistent Green's function method for random alloys and their surfaces, J. Kudrnovsky et al the augmented space and electronic structure of random binary alloys, A. Mookerjee magnetism and compositional order in transitional metal alloys, J.B. Staunton et al KKR approach to random alloys, R. Prasad.
7 citations
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TL;DR: In this article, a unified scheme combining molecular dynamics and density-functional theory is presented, which makes possible the simulation of both covalently bonded and metallic systems and permits the application of density functional theory to much larger systems than previously feasible.
Abstract: We present a unified scheme that, by combining molecular dynamics and density-functional theory, profoundly extends the range of both concepts. Our approach extends molecular dynamics beyond the usual pair-potential approximation, thereby making possible the simulation of both covalently bonded and metallic systems. In addition it permits the application of density-functional theory to much larger systems than previously feasible. The new technique is demonstrated by the calculation of some static and dynamic properties of crystalline silicon within a self-consistent pseudopotential framework.
8,852 citations
TL;DR: In this paper, a simple way has been discovered to put model pseudopotentials, $V(\stackrel{\ensuremath{\rightarrow}}{\mathrm{r}}), into a form which reduces the number of integrals required for an energy-band calculation from ϵ(n+1) to ϵ (n+2) for each $l$ in the sum.
Abstract: A simple way has been discovered to put model pseudopotentials, $V(\stackrel{\ensuremath{\rightarrow}}{\mathrm{r}})={\ensuremath{\Sigma}}_{\mathrm{lm}}|{Y}_{\mathrm{lm}}〉{V}_{l}(r)\ifmmode\times\else\texttimes\fi{}〈{Y}_{\mathrm{lm}}|$, into a form which reduces the number of integrals of $V(\stackrel{\ensuremath{\rightarrow}}{\mathrm{r}})$ required for an energyband calculation from $\frac{\mathrm{mn}(n+1)}{2}$ to $\mathrm{mn}$ for each $l$ in the sum (where $n$ is the number of plane waves used in the expansion and $m$ the number of points in the Brillouin zone at which the calculation is performed). The new form may be chosen to improve the accuracy of the pseudopotential when used in other chemical environments.
4,301 citations
TL;DR: In this paper, a simple surface reaction, the dissociation of H2 on the surface of gold and of three other metals (copper, nickel and platinum) that lie close to it in the periodic table, was studied.
Abstract: THE unique role that gold plays in society is to a large extent related to the fact that it is the most noble of all metals: it is the least reactive metal towards atoms or molecules at the interface with a gas or a liquid. The inertness of gold does not reflect a general inability to form chemical bonds, however—gold forms very stable alloys with many other metals. To understand the nobleness of gold, we have studied a simple surface reaction, the dissociation of H2 on the surface of gold and of three other metals (copper, nickel and platinum) that lie close to it in the periodic table. We present self-consistent density-functional calculations of the activation barriers and chemisorption energies which clearly illustrate that nobleness is related to two factors: the degree of filling of the antibonding states on adsorption, and the degree of orbital overlap with the adsorbate. These two factors, which determine both the strength of the adsorbate-metal interaction and the energy barrier for dissociation, operate together to the maxima] detriment of adsorbate binding and subsequent reactivity on gold.
2,721 citations
Book•
01 Jan 1994TL;DR: The Structure of Surfaces: An Introduction as mentioned in this paper The structure of surfaces and its properties are discussed in detail in Section 5.1.2.3 The Dynamics at Surfaces. 4 Electrical properties of surfaces. 5 Surface Chemical Bond.
Abstract: Preface. Introduction. 1 Surfaces: An Introduction. 2 The Structure of Surfaces. 3 Thermodynamics of Surfaces. 4 Dynamics at Surfaces. 5 Electrical Properties of Surfaces. 6 Surface Chemical Bond. 7 Mechanical Properties of Surfaces. 8 Polymer Surfaces and Biointerfaces. 9 Catalysis by Surfaces. Index.
2,346 citations
TL;DR: In this article, a consistent set of pseudopotentials has been developed for the entire Periodic Table, and a scheme used to generate the numerical potentials, the fitting procedure, and the testing of the fit are discussed.
Abstract: Recent developments have enabled pseudopotential methods to reproduce accurately the results of all-electron calculations for the self-consistent electronic structure of atoms, molecules, and solids. The properties of these potentials are discussed in the context of earlier approaches, and their numerous recent successful applications are summarized. While the generation of these pseudopotentials from all-electron atom calculations is straightforward in principle, detailed consideration of the differences in physics of various groups of atoms is necessary to achieve pseudopotentials with the most desirable attributes. One important attribute developed here is optimum transferability to various systems. Another is the ability to be fitted with a small set of analytic functions useful with a variety of wave-function representations. On the basis of these considerations, a consistent set of pseudopotentials has been developed for the entire Periodic Table. Relativistic effects are included in a way that enables the potentials to be used in nonrelativistic formulations. The scheme used to generate the numerical potentials, the fitting procedure, and the testing of the fit are discussed. Representative examples of potentials are shown that display attributes spanning the set. A complete tabulation of the fitted potentials is given along with a guide to its use.
2,238 citations