First-principles study of the lattice dynamics of c(2 x 2)-CO on Cu(001)

    Authors

    M. A. Ortigoza; T. S. Rahman; R. Hield;K. P. Bohnen

    Comments

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    Abbreviated Journal Title

    J. Phys.-Condes. Matter

    Keywords

    GENERALIZED GRADIENT APPROXIMATION; DENSITY-FUNCTIONAL THEORY; POTENTIAL-ENERGY SURFACE; HELIUM ATOM SCATTERING; X-RAY-ABSORPTION; SITE; PREFERENCE; CO ADSORPTION; CU(100); MOLECULES; CU(111); Physics, Condensed Matter

    Abstract

    The density-functional perturbation theory formalism is applied to investigate the dynamics of c(2 x 2)-CO/Cu(100), using both the local (LDA) and the generalized-gradient (GGA) density approximations through the Hedin-Lundqvist and the Perdew-Burke-Ernzerhof functionals, respectively. In the framework of the mixed basis pseudopotential approach, GGA reproduces notably well helium atom scattering (HAS) data for the frustrated translation (FT) mode and hence points to a harmonic nature of the Cu-C bond. LDA, on the other hand, is found to lead to instabilities of the FT mode inside the surface Brillouin zone (SBZ). The C-O internal stretch mode disperses in the two-dimensional SBZ by similar to 10 meV along the Delta direction. The Cu-CO stretch mode involves a significant contribution from first-layer Cu atoms. The frustrated rotation and FT modes disperse slightly and have their degeneracy removed by similar to 1 meV and similar to 3 meV, respectively, along the Sigma direction. The latter is in quantitative agreement with HAS data.

    Journal Title

    Journal of Physics-Condensed Matter

    Volume

    20

    Issue/Number

    22

    Publication Date

    1-1-2008

    Document Type

    Article; Proceedings Paper

    Language

    English

    First Page

    7

    WOS Identifier

    WOS:000256145700012

    ISSN

    0953-8984

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