Evolution of the core and unoccupied orbitals of biphenyl and bithiophene on Cs doping
| Autor: | Falko P. Netzer, Michael G. Ramsey, D. Steinmüller‐Nethl, D.R. Lloyd, D. Steinmüller |
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| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | The Journal of Chemical Physics. 97:4489-4495 |
| ISSN: | 1089-7690 0021-9606 |
| Popis: | X‐ray photoelectron spectroscopy (XPS) and near‐edge x‐ray absorption fine structure (NEXAFS) have been used to study the core and unoccupied orbitals of condensed multilayers of biphenyl and bithiophene on Cs dosing. The CK XPS shifts, observed on dosing are understandable in terms of repositioning of the Fermi level due to creation of states in the band gap, and at higher Cs concentrations to the high polarizability of the charge transfer complexes formed. The behavior of the CK XPS satellites on increasing Cs exposure are related to changes observed in the electron energy loss spectra (EELS). The CK NEXAFS of biphenyl and the SL23 NEXAFS of bithiophene indicate that an unoccupied molecular orbital is filled by charge transfer from Cs. In the case of bithiophene, both the SL23 XPS and NEXAFS features shift by 2 eV to lower binding and adsorption energy, respectively. This strong chemical shift suggests significant localization of the transferred charge on the S sites. Comparison of the SL23 NEXAFS of do... |
| Databáze: | OpenAIRE |
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