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Puschnig P, Boese AD, Willenbockel M, Meyer M, Lüftner D, Reinisch EM, Ules T, Koller G, Soubatch S, Ramsey MG, Tautz FS. Energy Ordering of Molecular Orbitals. J Phys Chem Lett 2017; 8:208-213. [PMID: 27935313 PMCID: PMC5220489 DOI: 10.1021/acs.jpclett.6b02517] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 12/09/2016] [Indexed: 05/17/2023]
Abstract
Orbitals are invaluable in providing a model of bonding in molecules or between molecules and surfaces. Most present-day methods in computational chemistry begin by calculating the molecular orbitals of the system. To what extent have these mathematical objects analogues in the real world? To shed light on this intriguing question, we employ a photoemission tomography study on monolayers of 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) grown on three Ag surfaces. The characteristic photoelectron angular distribution enables us to assign individual molecular orbitals to the emission features. When comparing the resulting energy positions to density functional calculations, we observe deviations in the energy ordering. By performing complete active space calculations (CASSCF), we can explain the experimentally observed orbital ordering, suggesting the importance of static electron correlation beyond a (semi)local approximation. On the other hand, our results also show reality and robustness of the orbital concept, thereby making molecular orbitals accessible to experimental observations.
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Affiliation(s)
- P. Puschnig
- Institute
of Physics, University of Graz, NAWI-Graz, Universitätsplatz
5, 8010 Graz, Austria
- E-mail:
| | - A. D. Boese
- Institute
of Chemistry, University of Graz, NAWI Graz, Heinrichstraße 28/IV, 8010 Graz, Austria
| | - M. Willenbockel
- Peter
Grünberg Institut (PGI-3), Forschungszentrum
Jülich, 52425 Jülich, Germany
- Jülich
Aachen
Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - M. Meyer
- Peter
Grünberg Institut (PGI-3), Forschungszentrum
Jülich, 52425 Jülich, Germany
- Jülich
Aachen
Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - D. Lüftner
- Institute
of Physics, University of Graz, NAWI-Graz, Universitätsplatz
5, 8010 Graz, Austria
| | - E. M. Reinisch
- Institute
of Physics, University of Graz, NAWI-Graz, Universitätsplatz
5, 8010 Graz, Austria
| | - T. Ules
- Institute
of Physics, University of Graz, NAWI-Graz, Universitätsplatz
5, 8010 Graz, Austria
| | - G. Koller
- Institute
of Physics, University of Graz, NAWI-Graz, Universitätsplatz
5, 8010 Graz, Austria
| | - S. Soubatch
- Peter
Grünberg Institut (PGI-3), Forschungszentrum
Jülich, 52425 Jülich, Germany
- Jülich
Aachen
Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
| | - M. G. Ramsey
- Institute
of Physics, University of Graz, NAWI-Graz, Universitätsplatz
5, 8010 Graz, Austria
| | - F. S. Tautz
- Peter
Grünberg Institut (PGI-3), Forschungszentrum
Jülich, 52425 Jülich, Germany
- Jülich
Aachen
Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich, Germany
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Willenbockel M, Lüftner D, Stadtmüller B, Koller G, Kumpf C, Soubatch S, Puschnig P, Ramsey MG, Tautz FS. The interplay between interface structure, energy level alignment and chemical bonding strength at organic-metal interfaces. Phys Chem Chem Phys 2014; 17:1530-48. [PMID: 25475998 DOI: 10.1039/c4cp04595e] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
What do energy level alignments at metal-organic interfaces reveal about the metal-molecule bonding strength? Is it permissible to take vertical adsorption heights as indicators of bonding strengths? In this paper we analyse 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) on the three canonical low index Ag surfaces to provide exemplary answers to these questions. Specifically, we employ angular resolved photoemission spectroscopy for a systematic study of the energy level alignments of the two uppermost frontier states in ordered monolayer phases of PTCDA. Data are analysed using the orbital tomography approach. This allows the unambiguous identification of the orbital character of these states, and also the discrimination between inequivalent species. Combining this experimental information with DFT calculations and the generic Newns-Anderson chemisorption model, we analyse the alignments of highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) with respect to the vacuum levels of bare and molecule-covered surfaces. This reveals clear differences between the two frontier states. In particular, on all surfaces the LUMO is subject to considerable bond stabilization through the interaction between the molecular π-electron system and the metal, as a consequence of which it also becomes occupied. Moreover, we observe a larger bond stabilization for the more open surfaces. Most importantly, our analysis shows that both the orbital binding energies of the LUMO and the overall adsorption heights of the molecule are linked to the strength of the chemical interaction between the molecular π-electron system and the metal, in the sense that stronger bonding leads to shorter adsorption heights and larger orbital binding energies.
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Affiliation(s)
- M Willenbockel
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
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Fleming AJ, Netzer FP, Ramsey MG. Nucleation and 3D growth of para-sexiphenyl nanostructures from an oriented 2D liquid layer investigated by photoemission electron microscopy. J Phys Condens Matter 2009; 21:445003. [PMID: 21832462 DOI: 10.1088/0953-8984/21/44/445003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The deposition in an ultrahigh vacuum of prototypical linear para-sexiphenyl (6P) molecules onto the anisotropic reconstructed surface of Cu(110)2 × 1-O presents an ideal system with reduced symmetry for investigation. A dynamic photoemission electron microscopy (PEEM) study of the nucleation and growth of 6P, combined with data obtained from static techniques, is shown to facilitate our understanding of the requirements for 6P nuclei formation and self-assembly into long anisotropic needles. High-rate image acquisitions in PEEM are shown to reveal dynamic phenomena, such as meta-stable layer de-wetting and nanostructure growth in real time, that are the result of nucleation and self-assembly processes. Furthermore, time dependent studies of the relaxation of the meta-stable layer give insights into the molecular diffusion kinetics, whereas temperature dependent studies allow nucleation energies and molecular binding energies to be quantitatively measured. The deposition of the first monolayer of material is found to assemble without the formation of islands until full coverage (1 ML) is achieved. The second layer fills homogeneously and remains in a liquid smectic phase until a total deposition of 1.95 ± 0.07 ML is reached, whereupon critical nuclei of 6P crystallize out of the 2D liquid layer. The maximum of the diffusion coefficient is estimated to be 2 × 10(-9) cm(2) s(-1). The resulting de-wetting of the meta-stable second layer rapidly increases the size of the nuclei while maintaining the anisotropic needle nanostructure shape. Probing the de-wetting layer reveals that 6P diffusion is 1D up to 100 °C. The nucleation energy and intermolecular binding energy are measured to be 675 meV and 2.1 eV, respectively.
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Affiliation(s)
- A J Fleming
- Surface and Interface Physics, Institute of Physics, Karl-Franzens Universität Graz, Universitätsplatz 5, 8010 Graz, Austria
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4
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Koller G, Berkebile S, Oehzelt M, Puschnig P, Ambrosch-Draxl C, Netzer FP, Ramsey MG. Intra- and Intermolecular Band Dispersion in an Organic Crystal. Science 2007; 317:351-5. [PMID: 17641196 DOI: 10.1126/science.1143239] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The high crystallinity of many inorganic materials allows their band structures to be determined through angle-resolved photoemission spectroscopy (ARPES). Similar studies of conjugated organic molecules of interest in optoelectronics are often hampered by difficulties in growing well-ordered and well-oriented crystals or films. We have grown crystalline films of uniaxially oriented sexiphenyl molecules and obtained ARPES data. Supported by density-functional calculations, we show that, in the direction parallel to the principal molecular axis, a quasi-one-dimensional band structure of a system of well-defined finite size develops out of individual molecular orbitals. In contrast, perpendicular to the molecules, the band structure reflects the periodicity of the molecular crystal, and continuous bands with a large dispersion were observed.
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Affiliation(s)
- G Koller
- Institute of Physics, Surface and Interface Physics, Karl-Franzens University Graz, 8010 Graz, Austria.
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5
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Affiliation(s)
- M. G. Ramsey
- a Institut für Experimentalphysik, Karl-Franzens-Universität , Graz , Austria
| | - M. Schatzmayr
- a Institut für Experimentalphysik, Karl-Franzens-Universität , Graz , Austria
| | - G. Leising
- b Institut für Festkorperphysik , TU-Graz , Austria
| | - F. P. Netzer
- a Institut für Experimentalphysik, Karl-Franzens-Universität , Graz , Austria
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6
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Schoiswohl J, Mittendorfer F, Surnev S, Ramsey MG, Andersen JN, Netzer FP. Chemical reactivity of Ni-Rh nanowires. Phys Rev Lett 2006; 97:126102. [PMID: 17025981 DOI: 10.1103/physrevlett.97.126102] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Indexed: 05/12/2023]
Abstract
The properties of bimetallic Ni-Rh nanowires, fabricated by decorating the steps of vicinal Rh(111) surfaces by stripes of self-assembled Ni adatoms, have been probed by STM, photoemission, and ab initio density functional theory calculations. These Ni-Rh nanowires have specific electronic properties that lead to a significantly enhanced chemical reactivity towards oxygen. As a result, the Ni-Rh nanowires can be oxidized exclusively, generating novel quasi-one-dimensional oxide structures.
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Affiliation(s)
- J Schoiswohl
- Institute of Physics, Surface and Interface Physics, Karl-Franzens University Graz, A-8010 Graz, Austria
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7
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Abstract
Ultrathin glycine-ice films (nanolayers) have been prepared in ultrahigh vacuum by condensation of H(2)O and glycine at 110 K and 150 K on single crystalline Al(2)O(3) surfaces and have been investigated by temperature programed thermal desorption, x-ray photoelectron spectroscopy, and work function measurements. Various layer architectures have been considered, including glycine-on-ice, ice-on-glycine, and mixed glycine-ice nanolayers. Low coverages of adsorbed glycine molecules on amorphous ice surfaces suppress the amorphous-to-crystalline phase transition in the temperature range 140-160 K in near-surface regions and consequently lead to a lower desorption temperature of H(2)O molecules than from pure ice layers. Thicker glycine overlayers on ice provide a kinetic restriction to H(2)O desorption from the underlying ice layers until the glycine molecules become mobile and develop pathways for water desorption at higher temperature (>170 K). Ice overlayers do not wet glycine film surfaces, but the glycine molecules on ice are sufficiently immobile at 110 K, so that continuous glycine overlayers form. In mixed glycine-ice nanolayers the glycine phase displays hydrophobic behavior and a phase separation takes place, with the accumulation of glycine near the surfaces of the films.
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Affiliation(s)
- G Tzvetkov
- Institut für Physik, Oberflächen- und Grenzflächenphysik, Karl-Franzens Universität Graz, Austria
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8
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Schoiswohl J, Tzvetkov G, Pfuner F, Ramsey MG, Surnev S, Netzer FP. Reactivity of V2O3(0001) surfaces: molecular vs dissociative adsorption of water. Phys Chem Chem Phys 2006; 8:1614-23. [PMID: 16633646 DOI: 10.1039/b515179a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The adsorption of water on V2O3(0001) surfaces has been investigated by thermal desorption spectroscopy, high-resolution electron energy loss spectroscopy, and X-ray photoelectron spectroscopy with use of synchrotron radiation. The V2O3(0001) surfaces have been generated in epitaxial thin film form on a Rh(111) substrate with three different surface terminations according to the particular preparation conditions. The stable surface in thermodynamic equilibrium with the bulk is formed by a vanadyl (VO) (1x1) surface layer, but an oxygen-rich (radical3xradical3)R30 degrees reconstruction can be prepared under a higher chemical potential of oxygen (microO), whereas a V-terminated surface consisting of a vanadium surface layer requires a low microO, which can be achieved experimentally by the deposition of V atoms onto the (1x1) VO surface. The latter two surfaces have been used to model, in a controlled way, oxygen and vanadium containing defect centres on V2O3. On the (1x1) V=O and (radical3xradical3)R30 degrees surfaces, which expose only oxygen surface sites, the experimental results indicate consistently that the molecular adsorption of water provides the predominant adsorption channel. In contrast, on the V-terminated (1/radical3x1/radical3)R30 degrees surface the dissociation of water and the formation of surface hydroxyl species at 100 K is readily observed. Besides the dissociative adsorption a molecular adsorption channel exists also on the V-terminated V2O3(0001) surface, so that the water monolayer consists of both OH and molecular H2O species. The V surface layer on V2O3 is very reactive and is reoxidised by adsorbed water at 250 K, yielding surface vanadyl species. The results of this study indicate that V surface centres are necessary for the dissociation of water on V2O3 surfaces.
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Affiliation(s)
- J Schoiswohl
- Institute of Physics, Surface and Interface Physics Division, Karl-Franzens University Graz, A-8010, GRAZ, Austria
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9
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Tzvetkov G, Koller G, Zubavichus Y, Fuchs O, Casu MB, Heske C, Umbach E, Grunze M, Ramsey MG, Netzer FP. Bonding and structure of glycine on ordered Al2O3 film surfaces. Langmuir 2004; 20:10551-10559. [PMID: 15544384 DOI: 10.1021/la048726m] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The interaction between glycine (NH2CH2COOH) layers and an ultrathin Al2O3 film grown epitaxially onto NiAl(110) was studied by temperature-programmed desorption, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, work function measurements, and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. At monolayer coverages at 110 K, there are two coexisting molecular forms: the anionic (NH2CH2COO-) and the zwitterionic form (NH3+CH2COO-) of glycine. As deduced from the photoemission data, the buildup of multilayers at 110 K leads to a condensed phase predominantly in the zwitterionic state. In contrast to the monolayer at 110 K, the monolayer formed at 300 K consists primarily of glycine molecules in the anionic state. The latter species is adsorbed with the oxygen atoms of the carboxylic group pointing toward the substrate. The polarization-dependent C K- and O K-edge NEXAFS spectra indicate that the glycinate species in the monolayer at 300 K is oriented nearly perpendicular to the surface, with the amino group pointing away from the surface.
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Affiliation(s)
- G Tzvetkov
- Institut für Experimentalphysik, Karl-Franzens-Universität Graz, Universitätsplatz 5, A-8010 Graz, Austria.
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10
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Schoiswohl J, Kresse G, Surnev S, Sock M, Ramsey MG, Netzer FP. Planar vanadium oxide clusters: two-dimensional evaporation and diffusion on Rh(111). Phys Rev Lett 2004; 92:206103. [PMID: 15169371 DOI: 10.1103/physrevlett.92.206103] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Indexed: 05/24/2023]
Abstract
The formation of novel vanadium oxide cluster molecules by oxidative two-dimensional evaporation from vanadium oxide nanostructures is reported on a Rh(111) metal surface. The structure and stability of the planar V6O12 clusters and the physical origin of their 2D evaporation process have been elucidated by high-resolution scanning tunneling microscopy (STM) and ab initio density functional theory calculations. The surface diffusion of the clusters has been followed in elevated-temperature STM experiments, and the diffusion parameters have been extracted, indicating diffusion by hopping of the entire surface stabilized cluster units.
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Affiliation(s)
- J Schoiswohl
- Institut für Experimentalphysik, Karl-Franzens-Universität Graz, A-8010 Graz, Austria
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11
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Pauer G, Eichler A, Sock M, Ramsey MG, Netzer F, Winkler A. Identification of new adsorption sites of H and D on rhodium(100). J Chem Phys 2003. [DOI: 10.1063/1.1597196] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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12
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Surnev S, Sock M, Kresse G, Andersen JN, Ramsey MG, Netzer FP. Unusual CO Adsorption Sites on Vanadium Oxide−Pd(111) “Inverse Model Catalyst” Surfaces. J Phys Chem B 2003. [DOI: 10.1021/jp0223408] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. Surnev
- Institut für Experimentalphysik, Karl-Franzens Universität Graz, A-8010 Graz, Austria, Institut für Materialphysik, Universität Wien, A-1090 Vienna, Austria, and Department of Synchrotron Radiation Research, Institute of Physics, Lund University, S-223 62 Lund, Sweden
| | - M. Sock
- Institut für Experimentalphysik, Karl-Franzens Universität Graz, A-8010 Graz, Austria, Institut für Materialphysik, Universität Wien, A-1090 Vienna, Austria, and Department of Synchrotron Radiation Research, Institute of Physics, Lund University, S-223 62 Lund, Sweden
| | - G. Kresse
- Institut für Experimentalphysik, Karl-Franzens Universität Graz, A-8010 Graz, Austria, Institut für Materialphysik, Universität Wien, A-1090 Vienna, Austria, and Department of Synchrotron Radiation Research, Institute of Physics, Lund University, S-223 62 Lund, Sweden
| | - J. N. Andersen
- Institut für Experimentalphysik, Karl-Franzens Universität Graz, A-8010 Graz, Austria, Institut für Materialphysik, Universität Wien, A-1090 Vienna, Austria, and Department of Synchrotron Radiation Research, Institute of Physics, Lund University, S-223 62 Lund, Sweden
| | - M. G. Ramsey
- Institut für Experimentalphysik, Karl-Franzens Universität Graz, A-8010 Graz, Austria, Institut für Materialphysik, Universität Wien, A-1090 Vienna, Austria, and Department of Synchrotron Radiation Research, Institute of Physics, Lund University, S-223 62 Lund, Sweden
| | - F. P. Netzer
- Institut für Experimentalphysik, Karl-Franzens Universität Graz, A-8010 Graz, Austria, Institut für Materialphysik, Universität Wien, A-1090 Vienna, Austria, and Department of Synchrotron Radiation Research, Institute of Physics, Lund University, S-223 62 Lund, Sweden
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13
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Surnev S, Schoiswohl J, Kresse G, Ramsey MG, Netzer FP. Reversible dynamic behavior in catalyst systems: oscillations of structure and morphology. Phys Rev Lett 2002; 89:246101. [PMID: 12484958 DOI: 10.1103/physrevlett.89.246101] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2002] [Indexed: 05/24/2023]
Abstract
Exposing vanadium oxide nanoparticles on a Pd(111) surface to reducing conditions is shown to cause a spreading of the oxide over the metal until a reduced oxide phase covers the entire surface. Reoxidation reverses this process and oxide island structures and bare metal patches are reestablished. The physical origin of this wetting-dewetting process is revealed at the atomic level by in situ variable-temperature scanning tunneling microscopy and in terms of a surface oxide phase stability diagram, as calculated by density functional theory as a function of the chemical potential of oxygen and the vanadium concentration.
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Affiliation(s)
- S Surnev
- Institut für Experimentalphysik, Karl-Franzens-Universität Graz, Austria.
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14
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Surnev S, Kresse G, Ramsey MG, Netzer FP. Novel interface-mediated metastable oxide phases: vanadium oxides on Pd(111). Phys Rev Lett 2001; 87:086102. [PMID: 11497963 DOI: 10.1103/physrevlett.87.086102] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2001] [Indexed: 05/23/2023]
Abstract
In the growth process of ultrathin films of vanadium oxides on Pd(111), a sequence of novel oxide phases with layer-dependent structures and oscillating oxidation states has been detected experimentally and understood theoretically. These phases are interface mediated and metastable with respect to further oxide growth. Transformation into the stable oxide configuration occurs beyond a critical thickness, where energetics combined with kinetic limitations determine the oxide multilayer structure.
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Affiliation(s)
- S Surnev
- Institut für Experimentalphysik, Karl-Franzens-Universität Graz, A-8010 Graz, Austria
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15
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Blyth RIR, Mittendorfer F, Hafner J, Sardar SA, Duschek R, Netzer FP, Ramsey MG. An experimental and theoretical investigation of the thiophene/aluminum interface. J Chem Phys 2001. [DOI: 10.1063/1.1332080] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Ramsey MG, Smith PV. A pseudopotential approach to the electronic structure of dilute transitional and noble metal impurity systems. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4608/12/8/015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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Schatzmayr M, Koller G, Kardinal I, Ramsey MG, Stafström S, Netzer FP. Electronic and vibrational structure of thin films of bithiophene: Undoped and alkali-doped states. J Chem Phys 1999. [DOI: 10.1063/1.478707] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Steinmüller D, Ramsey MG, Netzer FP. Polaron and bipolaronlike states in n-doped bithiophene. Phys Rev B Condens Matter 1993; 47:13323-13329. [PMID: 10005639 DOI: 10.1103/physrevb.47.13323] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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19
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Hofmann R, Henle WA, Öfner H, Ramsey MG, Netzer FP, Braun W, Horn K. Physical and chemical effects at rare-earth-metal-SiO2-Si structures. Phys Rev B Condens Matter 1993; 47:10407-10414. [PMID: 10005151 DOI: 10.1103/physrevb.47.10407] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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20
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Lögdlund M, Dannetun P, Stafström S, Salaneck WR, Ramsey MG, Spangler CW, Fredriksson C, Brédas JL. Soliton pair charge storage in doped polyene molecules: Evidence from photoelectron spectroscopy studies. Phys Rev Lett 1993; 70:970-973. [PMID: 10054251 DOI: 10.1103/physrevlett.70.970] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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21
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Ramsey MG, Netzer FP, Steinmüller D, Steinmüller‐Nethl D, Lloyd DR. Evolution of the core and unoccupied orbitals of biphenyl and bithiophene on Cs doping. J Chem Phys 1992. [DOI: 10.1063/1.463892] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Matthew JA, Henle WA, Ramsey MG, Netzer FP. 4f7-4f7 transitions in Gd, oxidized Gd, and epitaxial Gd silicide. Phys Rev B Condens Matter 1991; 43:4897-4901. [PMID: 9997862 DOI: 10.1103/physrevb.43.4897] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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23
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Rösch N, Fox T, Netzer FP, Ramsey MG, Steinmüller D. Modeling of lateral interactions in densely packed adsorbate overlayers: How far do chemisorbed C2N2 molecules tilt on a Ni(110) surface? J Chem Phys 1991. [DOI: 10.1063/1.459799] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Henle WA, Ramsey MG, Netzer FP, Cimino R, Braun W, Witzel S. Reactions at the Gd-Si(111)7 x 7 interface: Promotion of Si oxidation. Phys Rev B Condens Matter 1990; 42:11073-11078. [PMID: 9995387 DOI: 10.1103/physrevb.42.11073] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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25
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Ramsey MG, Steinmüller D, Netzer FP. Explicit evidence for bipolaron formation: Cs-doped biphenyl. Phys Rev B Condens Matter 1990; 42:5902-5905. [PMID: 9996183 DOI: 10.1103/physrevb.42.5902] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ramsey MG, Steinmüller D, Netzer FP. Valence band photoemission spectra and molecular geometry of biphenyl in condensed and chemisorbed phases. J Chem Phys 1990. [DOI: 10.1063/1.458344] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Clark CW, Matthew JA, Ramsey MG, Netzer FP. Electron-excited 4d-->4f Ba resonances in YBa2Cu3O7- delta : Selection rules at intermediate electron energy. Phys Rev A Gen Phys 1989; 40:4902-4906. [PMID: 9902746 DOI: 10.1103/physreva.40.4902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Ramsey MG, Netzer FP, Matthew JA. Electron-energy-loss spectra of the high-Tc superconductors Y-Ba-Cu-O and La-Sr-Cu-O. Phys Rev B Condens Matter 1989; 39:732-735. [PMID: 9947214 DOI: 10.1103/physrevb.39.732] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ramsey MG, Russell GJ. Autoionization and Auger features of clean and oxygen-exposed surfaces of Fe, Co and Ni. Phys Rev B Condens Matter 1985; 32:3654-3661. [PMID: 9937514 DOI: 10.1103/physrevb.32.3654] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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