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| 2. |
- Schnadt, J., Schiessling, J., O'Shea, J.N., Gray, S.M., Patthey, L., Johansson, M.K.J., Shi, M., Krepansky, J., Åhlund, J., Karlsson, P.G., Persson, P., Mårtensson, N., and Brühwiler, P.A.
(författare)
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Structural study of adsorption of isonicotinic acid and related molecules on rutile TiO2(110). I: XAS and STM
- 2003
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Ingår i: Surface Science. ; 540, s. 39-
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Puglia, C, et al.
(författare)
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XPS and XAS study of oxygen coadsorbed with a dispersed phase of K on graphite
- 2001
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Ingår i: SURFACE SCIENCE. - : ELSEVIER SCIENCE BV. ; 488:1-2
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The adsorption of O-2 onto a dispersed (low coverage) phase of K on graphite has been characterized by X-ray photoemission and X-ray absorption spectroscopy. We identify two oxygen adsorption phases before physisorbed oxygen appears. The first species dom
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| 4. |
- Schnadt, J, et al.
(författare)
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Adsorption and charge-transfer study of bi-isonicotinic acid on in situ-grown anatase TiO2 nanoparticles
- 2004
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Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 108:10, s. 3114-3122
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Tidskriftsartikel (refereegranskat)abstract
- Bi-isonicotinic acid (2,2'-bipyridine-4,4'-dicarboxylic acid) is an important ligand in the chemistry of organometallic devices. Here, the adsorption of a monolayer of the molecule on in situ-grown anatase TiO2 nanoparticles has been investigated by means of X-ray photoemission spectroscopy and X-ray absorption spectroscopy. The bonding geometry is determined to be 2M-bidentate. Furthermore, resonant core spectroscopies have been used to study the excited-state-dependent electron transfer from the core-excited molecule to the substrate. For an excitation to the lowest unoccupied orbital, the excited electron is localized on the molecule because of a core-excitonic effect. Excitation to the two following unoccupied orbitals leads to a charge transfer on a low-femtosecond time scale. This study shows that there is no essential difference in charge-transfer characteristics, compared to the case of adsorption on the rutile (110) surface, for states degenerate with the conduction band.
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| 7. |
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| 8. |
- J. Schnadt, J. N. O`Shea, L. Patthey, J. Schiessling, M. Shi, J. Krempasky, J. Åhlund, N. Mårtensson, and P. A, Brühwiler
(författare)
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Structural study of adsorption of isonicotinic acid and related molecules on rutile TiO2(110) II.: XPS
- 2003
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Ingår i: Surf. Sci.. ; :544, s. 74-
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Tidskriftsartikel (refereegranskat)
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| 9. |
- O'Shea, J. N., et al.
(författare)
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Hydrogen-bond induced surface core-level shift in isonicotinic acid
- 2001
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1089-5647 .- 1520-6106 .- 1520-5207. ; 105:10, s. 1917-1920
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Tidskriftsartikel (refereegranskat)abstract
- Intermolecular hydrogen-bonding in thick films of isonicotinic acid evaporated onto rutile TiO2(110) has been investigated with X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The rate of deposition is found to be a key factor in overcoming the kinetic barriers to extensive hydrogen-bond formation, which, when present, gives rise to large energy shifts between bulk and surface in both the N1s XPS and XAS. The origin of the surface core-level shift is attributed to the presence of non-hydrogen-bonded nitrogen atoms in the surface layer.
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| 10. |
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| 11. |
- O'Shea, J. N., et al.
(författare)
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Hydrogen-bond induced surface core-level shift in pyridine carboxylic acids
- 2001
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Ingår i: Surface Science. - 0039-6028 .- 1879-2758. ; 486:3, s. 157-166
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Tidskriftsartikel (refereegranskat)abstract
- Intermolecular hydrogen bonding in thick films of pyridine carboxylic acids (isonicotinic; picolinic and bi-isonicotinic acid) evaporated onto rutile TiO2(1 1 0) has been investigated with X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. These molecules are shown to be strongly H-bonded in the condensed phase, and a surface core-level shift is observed due to the presence of non-H-bonded nitrogen atoms in the surface layer. Density functional theory calculations are used to relate the experimental data to the proposed bonding configurations based on the surface termination of the known equilibrium solid-state structure. A kinetic barrier, attributed to the high degree of molecular orientation required for the formation of extended H-bonding networks, has also been investigated.
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| 12. |
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| 13. |
- Persson, Petter, et al.
(författare)
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N1s x-ray Absorption Study of the Bonding Interaction of Bi-Isonicotinic Acid on Rutile TiO2 (110)
- 2000
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 112:9, s. 3945-3948
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Tidskriftsartikel (refereegranskat)abstract
- N1s x-ray absorption spectra of bi-isonicotinic acid (2,28-bipyridine–4,48-dicarboxylic acid! on rutile TiO2(110) have been studied experimentally and quantum chemically. Differences between multilayer and monolayer spectra are explained by the adsorbate bonding to the substrate. A connection to the electronic coupling in dye-sensitized electrochemical devices is made.
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| 14. |
- Schiessling, Joachim, 1971-
(författare)
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Angle-Dependent Electron Spectroscopy Studies of C60 Compounds and Carbon Nanotubes
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fullerenes have been shown to constitute a prototypical building block for truly nanometer-sized devices and exotic nanounit-based materials, e.g., high-temperature superconductors. This makes the detailed understanding of fullerene electronic states in compounds and at interfaces of primary importance, since the high symmetry of the molecule greatly simplifies the starting point of the analysis. Carbon nanotubes, which combine one macroscopic with two nanoscopic dimensions, are perhaps of even greater practical interest.Angle-dependent electron spectroscopies have been employed in the present work to study these materials, characterizing their structure, bonding, and electronic states. For solid C60, the photoelectron angular distribution has been found to be essentially that of the free molecule, modified by solid state scattering; a similar distribution is found for K3C60.The surface and bulk electronic structure of K3C60 has been identified by angle-dependent core and valence photoelectron spectroscopy (PES) and x-ray emission spectroscopy. An insulating surface layer has been identified for this high-temperature superconductor.Angle-dependent valence PES is used to investigate the electronic states of C60/Al(110). Electron correlations are found to be the origin of the splitting observed in the molecular orbitals, which is quite sensitive to the molecular orientation. The components of the highest occupied molecular orbital are differentiated according to their overlap with the substrate.A rigid shift of valence- and core-levels has been observed even for ionic and covalent C60 compounds, reflecting the efficient static polarizability screening of the molecule. The alignment of multi-walled carbon nanotubes has been investigated by x-ray absorption spectroscopy, using the spectral intensity ratio of π*- and *-resonances. Core level combined with valence PES shows that the degree of defect structure varies from position to position on the sample. Valence photoelectron spectra of defect-free sample spots closely resembles the total DOS of graphite.
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