کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5424121 | 1507957 | 2010 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Common fingerprint of hydroxylated non-polar steps on MgO smoke and MgO films
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
The infrared spectra of MgO smoke exposed to water are compared to high-resolution electron energy loss spectra (HREELS) of hydroxylated ultrathin MgO(1Â 0Â 0)/Ag(1Â 0Â 0) films. Very similar bands are observed at 3458-3480Â cmâ1 and 3710-3714Â cmâ1. On the basis of first principle calculations, these bands are interpreted as the stretching modes of the two distinct OH groups that are formed at monatomic steps parallel to ã1Â 0Â 0ã crystallographic directions. The lower frequency band is due to H adsorbed on O at the step edge, while the higher frequency one originates from OH groups that are twofold coordinated with Mg. Consistently, scanning tunnelling microscopy images of MgO films, prepared in similar conditions as during the HREELS experiments, show that the MgO/Ag(1Â 0Â 0) island edges are mainly non-polar, i.e. oriented along the ã1Â 0Â 0ã direction. In spite of that, a minor contribution to the OH-stretch intensity from hydroxylated polar ã1Â 1Â 0ã steps cannot be excluded; for such geometry density functional theory predicts indeed a single OH species with a vibrational frequency very close to the high-frequency band of OH adsorbed at ã1Â 0Â 0ã steps.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 604, Issues 3â4, 15 February 2010, Pages 252-257
Journal: Surface Science - Volume 604, Issues 3â4, 15 February 2010, Pages 252-257
نویسندگان
L. Savio, M. Smerieri, A. Orzelli, L. Vattuone, M. Rocca, F. Finocchi, J. Jupille,