Showing papers by "Jens K. Nørskov published in 1991"
TL;DR: In this paper, a review of the present understanding of catalytic chemical reactions on metal surfaces is given, and an attempt is made to single out some of the important properties of the reactants, intermediates, products and the surface that determine the reactivity.
128 citations
TL;DR: In this article, the diffusion paths and activation energies of a Cu adatom on Cu(100, Cu(111), and Cu(110) were studied using the effective medium theory to calculate the energetics.
Abstract: The diffusion paths and activation energies of a Cu adatom on Cu(100), Cu(111), and Cu(110) are studied using the effective-medium theory to calculate the energetics. For the (100) and (110) faces, diffusion via an exchange mechanism is found to be important. The transition state for these paths is stabilized by a direct covalent interaction as proposed by Feibelman. On the (111) face and for diffusion along the close-packed rows on the (110) surface, a simple hopping mechanism is found to be most favorable.
110 citations
TL;DR: The ``magic'' clusters retain their large stability even at elevated temperatures, and the equilibrium geometrical structures are determined and found to be determined by a Jahn-Teller distortion, which is found to affect the geometry also at high temperatures.
Abstract: Equilibrium structures of small (3--29)-atom Cu clusters are determined by simulated annealing, and finite-temperature ensembles are simulated by Monte Carlo techniques using the effective-medium theory for the energy calculation. Clusters with 8, 18, and 20 atoms are found to be particularly stable. The equilibrium geometrical structures are determined and found to be determined by a Jahn-Teller distortion, which is found to affect the geometry also at high temperatures. The ``magic'' clusters retain their large stability even at elevated temperatures.
66 citations
51 citations
TL;DR: In this article, the vibrational properties of the (111) surface of aluminum and nickel and all the low-index surfaces of copper are examined and the surface phonon spectrum is calculated using the effective medium theory to get the total energy and forces of the metallic system.
25 citations
TL;DR: In this paper, the authors extract atomic-like electron densities which, when overlapped in the crystal, reproduce the self-consistent density except for those components for which the structure factor is zero.
Abstract: From ab initio pseudopotential calculations of the solid the authors extract atomic-like electron densities which, when overlapped in the crystal, reproduce the self-consistent density except for those components for which the structure factor is zero. They demonstrate the universality of the optimized densities for different crystal structures at varying volumes. These densities are the optimized choice for the Harris functional, and they compare their result with the Finnis contraction of the free atom density and with the effective medium theory ansatz of embedding an atom in a homogeneous electron gas.
18 citations
TL;DR: In this paper, the relationship between the microscopic description of the dynamics of chemical reactions at metal surfaces and the understanding of the activity of heterogeneous catalysts is discussed, and it is shown that in some cases we start understanding some of the factors determining the catalytic activity of a given surface.
Abstract: The relations between the microscopic description of the dynamics of chemical reactions at metal surfaces and our understanding of the activity of heterogeneous catalysts is discussed. It is shown that in some cases we start understanding some of the factors determining the catalytic activity of a given surface. Examples will be given, ranging from detailed reaction dynamics studies of simple adsorption reactions to a prediction of the trends in the ammonia synthesis rate along the transition metal series.
8 citations