Local adsorption geometry of acetylene on Si(100)(2x1): Multiple sites and the role of substrate temperature
UNSPECIFIED. (2002) Local adsorption geometry of acetylene on Si(100)(2x1): Multiple sites and the role of substrate temperature. PHYSICAL REVIEW B, 66 (8). -. ISSN 1098-0121Full text not available from this repository.
Official URL: http://dx.doi.org/10.1103/PhysRevB.66.085333
Using C 1s scanned-energy mode photoelectron diffraction the local adsorption geometry of acetylene on the Si(100)(2x1) surface has been investigated at both low and room temperatures. Clear differences in the data at the two sample temperatures are attributed to the co-occupation of at least two distinct local sites. Quantitative modeling based on a two-site model indicates that the majority state at low temperature is bridge site adsorption with the C-C axis of the acetylene directly above, and parallel to, Si-Si surface dimers. At room temperature a second state accounts for more than 50% of the adsorbed acetylene molecules, and the favored model places these acetylene molecules midway between pairs of Si dimers, although the azimuthal orientation of the C-C axes is ambiguous. One possible geometry for this second species is the "pedestal site" tetra-sigma species previously proposed by Xu [Phys. Rev. Lett. 84, 939 (2000)], although the specific geometry proposed by this group can be excluded. An alternative "rotated pedestal" site is comparably probable. There is no direct evidence for any occupation of a rotated bridge site across the ends of two adjacent Si dimers, but partial occupation of this site cannot be excluded.
|Item Type:||Journal Article|
|Subjects:||Q Science > QC Physics|
|Journal or Publication Title:||PHYSICAL REVIEW B|
|Publisher:||AMERICAN PHYSICAL SOC|
|Official Date:||15 August 2002|
|Number of Pages:||15|
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