Journal ArticleDOI
Surface segregation effect for transition-metal alloys in the coherent-potential approximation: general considerations and calculations for Cu-Ni alloys
M Brejnak,P. Modrak +1 more
TLDR
In this paper, the authors used the realistic tight-binding Hamiltonian to calculate the surface segregation for Cu-Ni alloys, and the model for all reasonable values of parameters predicts the segregation of copper for all alloy compositions.Abstract:
The surface segregation is calculated in the coherent-potential approximation. The influence of the surface potential, d-band fillings and d-level splitting of alloys components on the segregation is examined for a model density of states. The realistic tight-binding Hamiltonian is used to calculate the segregation for Cu-Ni alloys. The model for all reasonable values of parameters predicts the segregation of copper for all alloy compositions.read more
Citations
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Surface segregation and catalytic properties of Pd-Ru alloys
TL;DR: In this article, a model for the electronic structure of surface layers of transition metal alloys is suggested and the model has been applied for the calculation of the electron density of states and surface segregations in Pd-Ru alloys.
Journal ArticleDOI
Electronic theory of surface segregation in the coherent potential approximation: The surface segregation in CoNi, IrPt and RhPt
M. Brejnak,P. Modrak +1 more
TL;DR: In this article, the surface segregation in CoNi, IrPt and RhPt is calculated within the coherent potential approximation, assuming that the metals form substitutional alloys and only diagonal disorder is taken into account.
Journal ArticleDOI
Electronic theory of surface segregation in transition metal alloys
TL;DR: In this paper, the surface segregation effect in transition metal alloys is described with the use of the tight-binding linear-muffin-tin orbital method in the coherent potential approximation to calculate the band contribution to the alloy free energy.
Journal ArticleDOI
Surface segregation of hydrogen isotopes in transition-metal hydrides
M. Brejnak,A. Holas,P. Modrak +2 more
TL;DR: In this paper, the surface segregation of hydrogen isotopes in ordered transition-metal hydrides is studied under the following assumptions: (i) each hydrogen isotope atom vibrates independently, (ii) the vibrations are harmonic (therefore, in particular, the frequencies of the various isotopes at equivalent positions are scaled by the square root of their mass ratio).
Journal ArticleDOI
Theory of surface segregation in transition metal alloys and hydrides
TL;DR: In this article, the surface segregation of one component in binary transition metal alloys and the surface separation of one hydrogen isotope in transition metal hydrides containing a mixture of hydrogen isotopes are discussed in the scope of the same thermodynamic model.
References
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Journal ArticleDOI
Embedded-atom-method functions for the fcc metals Cu, Ag, Au, Ni, Pd, Pt, and their alloys.
TL;DR: A consistent set of embedding functions and pair interactions for use with the embedded-atom method was determined empirically by fitting to the sublimation energy, equilibrium lattice constant, elastic constants, and vacancy-formation energies of the pure metals and the heats of solution of the binary alloys as discussed by the authors.
Journal ArticleDOI
Coherent-Potential Model of Substitutional Disordered Alloys
TL;DR: In this paper, a substitutional alloy based on the concept of an effective or coherent potential was introduced, which, when placed on every site of the alloy lattice, will simulate the electronic properties of the actual alloy.
Journal ArticleDOI
Single-Site Approximations in the Electronic Theory of Simple Binary Alloys
TL;DR: In this paper, a single-band model Hamiltonian is used to describe the electronic structure of a three-dimensional disordered binary alloy, and several common theories based on the single-site approximation in a multiple-scattering description are compared with exact results for this Hamiltonian.
Journal ArticleDOI
On the Numerical Calculation of the Density of States and Related Properties
G. Lehmann,M. Taut +1 more
TL;DR: In this article, a method for numerical calculation of energy surface integrals within the Brillouin zone like density of states, conductivity, susceptibility, dielectric function etc is given.
Journal ArticleDOI
Catalytic hydrogenolysis and dehydrogenation over copper-nickel alloys
TL;DR: In this article, the effect of adding copper to nickel was investigated for the hydrogenolysis of ethane to methane and the dehydrogenation of cyclohexane to benzene over a series of copper-nickel alloys.