Enhanced infrared absorption of CO on smooth iron ultrathin films in correlation to their crystalline quality

被引:8
作者
Priebe, A
Fahsold, G
Geyer, W
Pucci, A
机构
[1] Univ Heidelberg, Kirchhoff Inst Phys, D-69120 Heidelberg, Germany
[2] Univ Heidelberg, Lehrstuhl Angew Phys Chem, D-69120 Heidelberg, Germany
关键词
infrared absorption spectroscopy; vibrations of adsorbed molecules; surface electronic phenomena (work functions; surface potential; surface states; etc.); iron; carbon monoxide; metallic films;
D O I
10.1016/S0039-6028(01)01983-5
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We studied the infrared absorption lines for the stretching mode of CO on ultrathin Fe(100) prepared as smooth as possible on MgO(001) by various methods. For films that Dive different atomic force microscopic pictures but similar LEED patterns the signal strength and the CO-line shapes were investigated in normal transmission and also in reflection at grazing, incidence of p-polarized light. The comparison of both types of spectra for various degrees of film smoothness made obvious that asymmetric absorption lines may occur Only in the susceptibility component parallel to the surface. The oscillator strength of these asymmetric lines is correlated to the number of holes in the film. The usual reflectance change that arises due to CO Vibrations perpendicular to the film may be considerably modified by the adsorbate induced changes in the parallel susceptibility. (C) 2002 Elsevier Science B.V. All rights reserved.
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页码:388 / 393
页数:6
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