Carbon monoxide adsorption on an ordered Fe sub 3 Si(100) single crystal surface

• Published in: Surface science Vol. 331-333; pp. 685 - 690
• Main Authors: Busse, H, Eltester, B, Kandler, J, Castro, G R, Wandelt, K
• Format: Journal Article
• Language: English
• Published: 19.09.1994
• ISSN: 0039-6028

Photoemission results for CO absorbed at 300K on mixed terminated regions of an ordered Fe sub 3 Si(100) surface are presented and discussed in comparison to room-temperature CO and Fe(100). While the current literature suggests a lying-down CO adsorption on Fe(100), the UPS derived 4 sigma -binding energy, the relative 5 sigma /1 pi -4 sigma energy separation, the relative 5 sigma /1 pi and 4 sigma intensities as well as the greater thermal stability of CO and Fe sub 3 Si(100) suggest an upright orientation of the CO molecule on the Fe sub 3 Si(100) surface. CO is assumed to adsorb in the fourfold hollow sites which are geometrically very similar to those on Fe(100). One main reason for the altered adsorbate orientation may then be the alloy-induced modification of the electronic structure of the second layer Fe atoms in the hollow centers.