Regensburg 2002 – wissenschaftliches Programm

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O: Oberflächenphysik

O 32: Adsorption an Oberfl
ächen (IV)

O 32.10: Vortrag

Donnerstag, 14. März 2002, 17:45–18:00, H43

Quantitative determination of the adsorption structure of carbonate on Ag(110) — •D.I. Sayago1, M. Kittel1, J.T. Hoeft1, M. Polcik1, M. Pascal2, C.L.A. Lamont2, R.L. Toomes3, and D.P. Woodruff3,11Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, DE — 2University of Huddersfield, Huddersfield HD1 3DH, UK — 3University of Warwick, Coventry CV4 7AL, UK

The formation of carbonate (CO3) on Ag(110) by the reaction of CO2 with preadsorbed oxygen has been investigated by various techniques, but there has not been a full quantitative structural determination of the system until now. We have used C 1s photoelectron diffraction in scanned-energy mode to determine the adsorption geometry of the (1x2) phase of CO3 on Ag(110). The experiments have been performed at the storage ring Bessy II on the UE-56/2 beamline. Our results confirm the added-row model proposed by Guo and Madix [1]. The carbonate adsorbs parallel to the surface and bonds through at least one of the oxygen atoms to silver adatoms in agreement with quantum-chemical calculations [2]. The distance between this oxygen and its next neighbour Ag atom in the added row is 1.9(±0.2) Å. The average C-O distance is 1.3(±0.07) Å. The very large separation of the carbon from its nearest neighbour Ag atom (2.64(±0.09) Å) contradicts [3] in which the carbonate is supposed to bond via its carbon atom .

[1] X.-C. Guo and R. J. Madix, Surface Science, 489:37, 2001

[2] J. A. Rodriguez and C. T. Campbell, Surface Science, 206:426, 1988

[3] B. Krenzer, L. Constant and H. Conrad, Surface Science, 443:116, 1999

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