Refinement of the Pt(111)+c(4x2)-2CO structure using automatedtensor LEED

Journal Article · Mon Nov 01 04:00:00 EST 1999 · Surface Review and Letters

OSTI ID:894397

Zasada, I; Van Hove, M A

The structure of Pt(111)+c(4x2)-2CO has been refined usingthe powerful capabilities of automated tensor LEED, in particular todetermine hitherto unexplored adsorbate-induced relaxations in thesubstrate. The refinement considerably improves the fit to experimentobtained in a previous structural analysis performed with low-energyelectron diffraction (LEED). This study confirms that CO occupies bothtop and bridge sites. It finds a buckling of the outermost Pt layer, suchthat the Pt atoms bonded to CO molecules are raised out of the surface by0.06(plus/minus)0.04 Angstrom relative to the Pt atoms which do not bondto CO. The raised atoms have a spacing of 2.28(plus/minus)0.04 Angstromto the next Pt layer, expanded from the bulk spacing of 2.2655 Angstrom,while the depressed Pt atoms have a reduced spacing of2.22(plus/minus)0.04 Angstrom to the next Pt layer. The second Pt layeritself shows minor buckling of 0.03(plus/minus)0.04 Angstrom. No lateralrelaxations in the substrate are detected within 0.1 Angstrom. The COmolecules are perpendicular to the surface, with bond lengths of1.12(plus/minus)0.04 Angstrom and 1.19(plus/minus)0.04 Angstrom in topand bridge sites, respectively. The C-Pd spacings, measured betweenbonding atoms, are 1.92(plus/minus)0.04 Angstrom and 1.4(plus/minus)0.04Angstrom in top and bridge sites, respectively.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director, Office of Science. Office of Basic EnergySciences. Division of Materials Sciences
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 894397
• Report Number(s): LBNL--44369
• Journal Information: Surface Review and Letters, Journal Name: Surface Review and Letters Journal Issue: 1-2 Vol. 7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
low-energy electron diffraction catalysis chemisorption surfacerelaxation platinum carbon monoxide