Electronic Structure of the Thiophene/Au(111) Interface Probed by Two-Photon Photoemission
| Autor: | Ping Liu, Yixiong Yang, N. Camillone, Michael G. White, J. Zhou |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Inverse photoemission spectroscopy
Fermi level Electronic structure Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry.chemical_compound symbols.namesake General Energy chemistry Thiophene symbols Molecular orbital Density functional theory Physics::Chemical Physics Physical and Theoretical Chemistry Atomic physics Spectroscopy HOMO/LUMO |
| Zdroj: | The Journal of Physical Chemistry C. 114:13670-13677 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp1025009 |
| Popis: | The electronic structure of thiophene adsorbed on Au(111) has been investigated by two-photon photoemission (2PPE) spectroscopy and density functional theory (DFT) calculations. The dominant interfacial feature observed in the 2PPE spectra is a nondispersive unoccupied state whose width and energy (referenced to the Fermi level) decrease with increasing coverage. We assign this feature to a thiophene LUMO-derived state of mixed sulfur and carbon p−π character. DFT calculations indicate that the experimentally observed decrease in width of this state with increasing coverage is a result of weakening of the thiophene−Au(111) interaction. Increasing the molecular density forces the thiophene plane to tilt away from the surface, rotating the molecular orbitals away from an orientation more favorable for S−Au and π−Au hybridization. We attribute the ∼0.2 eV shift of the LUMO toward the Fermi level to stabilization of the transient anion due to the increasing effect of charge-induced polarization of the neighbo... |
| Databáze: | OpenAIRE |
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