کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5426623 | 1395893 | 2007 | 5 صفحه PDF | دانلود رایگان |
We report on the precise location of Cl atoms chemisorbed on a Cu(0Â 0Â 1) surface and the interlayer relaxations of the metal surface. Previous studies have shown that chlorine dissociates on Cu(0Â 0Â 1) to form a c(2Â ÃÂ 2) chemisorbed layer with Cl atoms occupying four-fold hollow sites. A Cu-Cl interlayer spacing of 1.60Â Ã and a slightly expanded Cu-Cu first interlayer spacing of 1.85Â Ã (1.807Â Ã for bulk Cu) was determined by LEED. The resulting Cu-Cl bond length, 2.41Â Ã , is very similar to the SEXAFS value of 2.37Â Ã . Contradictory results were obtained by angle-resolved photoemission extended fine structure: while confirming the Cu-Cl interlayer spacing of 1.60Â Ã , no first Cu-Cu interlayer relaxation has been observed. On the other hand, a small corrugation of the second Cu layer was pointed out. We carried out a detailed structural determination of the Cu(0Â 0Â 1)-c(2Â ÃÂ 2)-Cl system using surface X-ray diffraction technique with synchrotron radiation. We find a Cu-Cl interlayer spacing of 1.584(5)Â Ã and confirm the expansion of the first Cu-Cu interlayer, with an average spacing of 1.840(5)Â Ã . In addition, we observe a small corrugation of the second Cu layer, with Cu atoms just below Cl atoms more tightly bound to the surface layer, and even a second Cu-Cu interlayer expansion.
Journal: Surface Science - Volume 601, Issue 14, 15 July 2007, Pages 2962-2966