Geometric And Electronic Structure of Methane Adsorbed on a Pt Surface

Journal Article · Wed Nov 21 04:00:00 EST 2007 · J.Chem.Phys.127:144702,2007

DOI:https://doi.org/10.1063/1.2781470· OSTI ID:920008

Ostrom, H; Ogasawara, H; Naslund, L A; Andersson, K; Pettersson, L G.M.; Nilsson, A

The electronic structure of methane adsorbed on Pt(977) is investigated using angle-resolved x-ray absorption spectroscopy (XAS) in combination with density functional theory spectrum calculations. XAS, which probes the unoccupied states atom specifically, shows the appearance of the symmetry-forbidden gas-phase lowest unoccupied molecular orbital due to s-p rehybridization. In addition new adsorption-induced states appear just above the Fermi level. A systematic investigation, where computed XA spectra are compared with the experiment, indicates elongation of the C-H bond pointing toward the surface to 1.18+/-0.05 Angstroms. The bond elongation arises due to mixing between bonding and antibonding C-H orbitals. Computed charge density difference plots show that no covalent chemical bond is formed between the adsorbate and substrate upon adsorption. The changes in electronic structure arise in order to minimize the Pauli repulsion by polarizing charge away from the surface toward the carbon atom of the methane molecule.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 920008
• Report Number(s): SLAC-REPRINT-2007-236
• Journal Information: J.Chem.Phys.127:144702,2007, Journal Name: J.Chem.Phys.127:144702,2007 Vol. 127; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
ABSORPTION SPECTROSCOPY
ADSORPTION
ATOMS
BONDING
CARBON
CHARGE DENSITY
CHEMICAL BONDS
ELECTRONIC STRUCTURE
ELONGATION
METHANE
Other
OTHER
PLATINUM
PROBES
SPECTRA
SUBSTRATES