Density of configurational states from first-principles calculations: the phase diagram of Al-Na surface alloys.

Borg, Mikael; Stampfl, Catherine; Mikkelsen, Anders; Gustafson, Johan; Lundgren, Edvin; Scheffler, Matthias; Andersen, Jesper N

Borg, Mikael; Stampfl, Catherine; Mikkelsen, Anders; Gustafson, Johan; Lundgren, Edvin; Scheffler, Matthias; Andersen, Jesper N.

Afiliación

Borg M; Department of Synchrotron Radiation Research, Institute of Physics, Lund University, Sweden.

Chemphyschem ; 6(9): 1923-8, 2005 Sep 05.

Article en En | MEDLINE | ID: mdl-16086344

RESUMEN

The structural phases of Al(x)Na(1-x) surface alloys have been investigated theoretically and experimentally. We describe the system using a lattice-gas Hamiltonian, determined from density functional theory, together with Monte Carlo (MC) calculations. The obtained phase diagram reproduces the experiment on a quantitative level. From calculation of the (configurational) density of states by the recently introduced Wang-Landau MC algorithm, we derive thermodynamic quantities, such as the free energy and entropy, which are not directly accessible from conventional MC simulations. We accurately reproduce the stoichiometry, as well as the temperature at which an order-disorder phase transition occurs, and demonstrate the crucial role, and magnitude, of the configurational entropy.

Asunto(s)

Aleaciones/química; Aluminio/química; Modelos Químicos; Sodio/química; Simulación por Computador; Propiedades de Superficie; Temperatura; Factores de Tiempo

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Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Sodio / Aleaciones / Aluminio / Modelos Químicos Tipo de estudio: Prognostic_studies Idioma: En Revista: Chemphyschem Asunto de la revista: BIOFISICA / QUIMICA Año: 2005 Tipo del documento: Article País de afiliación: Suecia Pais de publicación: Alemania

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