کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5423172 | 1507952 | 2010 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Vibrational spectroscopy of oxygen on the (100) and (111) surfaces of lanthanum hexaboride
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Reflection absorption infrared spectroscopy (RAIRS) and high resolution electron energy loss spectroscopy (HREELS) have been used to study the adsorption of oxygen on the (100) and (111) surfaces of lanthanum hexaboride. Exposure of the surface at temperatures of 95 K and above to O2 produces atomic oxygen on the surface and yields vibrational peaks in good agreement with those observed in previous HREELS studies. On the La-terminated (100) surface, RAIRS peaks correspond to vibrations of the boron lattice that gain intensity due to a decrease in screening of surface dipoles that accompanies oxygen adsorption. A sharp peak at â¼Â 734 cmâ1 in the HREEL spectrum shows isotopic splitting with RAIRS into two components at 717 and 740 cmâ1 with full widths at half maxima of only 12 cmâ1. The sharpness of this mode is consistent with its interpretation as a surface phonon that is well separated from both the bulk phonons and other surface phonons of LaB6. On the boron-terminated LaB6(111) surface, broad and weak features are assigned to both vibrations of the boron lattice and of boron oxide. On the (100) surface, oxygen blocks the adsorption sites for CO, and adsorbed CO prevents the dissociative adsorption of O2.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 604, Issues 13â14, 15 July 2010, Pages 1202-1207
Journal: Surface Science - Volume 604, Issues 13â14, 15 July 2010, Pages 1202-1207
نویسندگان
Thomas Yorisaki, Aashani Tillekaratne, Yukihiro Moriya, Chuhei Oshima, Shigeki Otani, Michael Trenary,