کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5423623 | 1395796 | 2009 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Probing the properties of the (1Â 1Â 1) and (1Â 0Â 0) surfaces of LaB6 through infrared spectroscopy of adsorbed CO
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کلمات کلیدی
Solid–gas interfaceChemisorption - جذب سطحی شیمیاییLow index single crystal surfaces - سطوح منفرد کریستال پایینInfrared absorption spectroscopy - طیف سنجی جذب مادون قرمزX-ray photoelectron spectroscopy - طیف سنجی فوتوالکتر اشعه ایکسVibrations of adsorbed molecules - لرزش مولکول های جذب شدهDensity functional calculations - محاسبات عملکردی تراکم
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Probing the properties of the (1Â 1Â 1) and (1Â 0Â 0) surfaces of LaB6 through infrared spectroscopy of adsorbed CO Probing the properties of the (1Â 1Â 1) and (1Â 0Â 0) surfaces of LaB6 through infrared spectroscopy of adsorbed CO](/preview/png/5423623.png)
چکیده انگلیسی
The adsorption of carbon monoxide on the LaB6(1Â 0Â 0) and LaB6(1Â 1Â 1) surfaces was studied experimentally with the techniques of reflection absorption infrared spectroscopy and X-ray photoelectron spectroscopy. The interaction of CO with the two surfaces was also studied with density functional theory. Both surfaces adsorb CO molecularly at low temperatures but in markedly different forms. On the LaB6(1Â 1Â 1) surface CO initially adsorbs at 90Â K in a form that yields a CO stretching mode at 1502-1512Â cmâ1. With gentle annealing to 120Â K, the CO switches to a bonding environment characterized by multiple CO stretch values from 1980 to 2080Â cmâ1, assigned to one, two, or three CO molecules terminally bonded to the B atoms of a triangular B3 unit at the (1Â 1Â 1) surface. In contrast, on the LaB6(1Â 0Â 0) surface only a single CO stretch is observed at 2094Â cmâ1, which is assigned to an atop CO molecule bonded to a La atom. The maximum intensity of the CO stretch vibration on the (1Â 0Â 0) surface is higher than on the (1Â 1Â 1) surface by a factor of 5. This difference is related to the different orientations of the CO molecules on the two surfaces and to reduced screening of the CO dynamic dipole moment on the (1Â 0Â 0) surface, where the bonding occurs further from the surface plane. On LaB6(1Â 0Â 0), XPS measurements indicate that CO dissociates on the surface at temperatures above 400Â K.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 603, Issue 19, 1 October 2009, Pages 3011-3020
Journal: Surface Science - Volume 603, Issue 19, 1 October 2009, Pages 3011-3020
نویسندگان
Thomas Yorisaki, Aashani Tillekaratne, Qingfeng Ge, Chuhei Oshima, Shigeki Otani, Michael Trenary,