کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
68175 48506 2008 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Electronic structure and atomic positions of metallic surface alloys
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Electronic structure and atomic positions of metallic surface alloys
چکیده انگلیسی

Photoemission spectra collected over a large solid angle give information about the form and energies of spectral features, which are related to the underlying electronic structure of the sample. Spectra measured as a function of exit angle reflect the phenomenon of photoelectron diffraction, which is related to the underlying crystallographic structure of the sample. We report applications of these techniques by our group to the study of a number of systems involving ultra-thin metallic layers on surfaces, which can be true surface alloys, whose properties are often very different from those in the bulk. The surface systems we chose manifest surfactant behavior, catalytic activity and intercomponent effects. Our electronic structure results were derived from photoemission and X-ray excited Auger spectroscopies: interpretation of these data requires inclusion of the phenomena of relaxation and screening. Our crystallographic results were derived from photoelectron diffraction in combination with LEED: derivation of the results requires comparison with multiple scattering theoretical simulations and involves considerable computational effort. We have studied In, Sn and Sb on Pd(1 1 1) and Ni(1 1 1), Cu on Pd(1 1 1) and Pd on Cu(1 1 1), Sb on Ag(1 1 1) and Pd and Mg oxides on Ag(1 1 1)—we present representative results of these studies.

We present electronic and crystallographic structure determinations of metallic surface alloys. Core level photoemission and Auger energy shifts, which are appropriate for bulk alloys can no longer be used for surface alloys. In this case, it is possible to use the spectral form of the XPS spectra to understand the surface electron structure and XPD to determine atomic positions.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Catalysis A: Chemical - Volume 281, Issues 1–2, 18 February 2008, Pages 9–13
نویسندگان
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