کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1883853 1043313 2006 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Ab initio and XPS studies of pyrite (1 0 0) surface states
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم تشعشع
پیش نمایش صفحه اول مقاله
Ab initio and XPS studies of pyrite (1 0 0) surface states
چکیده انگلیسی

Ab initio quantum chemical modelling (GGA, CASTEP and B3LYP, CRYSTAL03) is used to predict differences in electronic structure between the (1 0 0) surface and bulk of pyrite. Experimental X-ray photoelectron spectroscopic (XPS) data for the S 2p core lines show the presence of two types of S surface states: surface S2− monomers at a S 2p3/2 binding energy (BE) of 161.2 eV, and (S–S)2− surface dimer states at a S 2p3/2 BE of 162.0 eV, compared to the S 2p3/2 BE of bulk pyrite at 162.7 eV. The Fe 2p surface XPS displays several multiplets (implying high spin configuration) at higher BE than the bulk Fe 2p signal, which can be ascribed to surface state contributions. The quantum chemical simulation predicts an S 2p core level shift of 0.69 eV between the S bulk and S surface dimers, in good agreement with the 0.6 eV found in XPS measurements. A Mulliken population analysis confirms the conjectured charge distribution on the surface, which leads to the two different S surface states, as well as the surface high spin configuration responsible for the high BE Fe multiplets. Evidence for surface Fe2+ and Fe3+ surface states can be seen in the Fe projected valence band density of states, confirming the interpretation of the photoemission spectra.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Radiation Physics and Chemistry - Volume 75, Issue 11, November 2006, Pages 1855–1860
نویسندگان
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