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  • 1
    Electronic Resource
    Electronic Resource
    Site-dependent binding of methoxy on Cu(111): Cluster model studies (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 10173-10180 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Model calculations on CunOCH3 clusters with n ranging from 1 to 25 are carried out using ab initio Hartree–Fock and configuration interaction (CI) methods. The Cun clusters are chosen to simulate the substrate near the (111) surface and various adsorbate geometries modeling different lateral adsorption sites (top, bridge, fcc hollow, hcp hollow) at the Cu(111) surface are considered. A comparison of the different adsorption sites identifies the face-centered-cubic (fcc) hollow site as energetically preferred for OCH3 binding (D=2.8 eV at the CI level) in agreement with recent experimental results. Correlation contributions account for about 0.9 eV of the binding energies and do not depend on the binding site nor on cluster size. The OCH3–Cu interaction is characterized by metal to methoxy charge transfer filling partially occupied 2e (O 2p lone pair) radical orbitals. This leads to a negatively charged adsorbate such that ionic binding contributions become important. The binding scheme is qualitatively similar to that of other lone pair radical adsorbates like OH and influences the results of adsorbate core and valence ionization in the clusters. The present model results are consistent with experimental data concerning adsorbate geometries and binding as well as photoemission. © 1994 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.468006
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  • 2
    Electronic Resource
    Electronic Resource
    Binding of radical species to surfaces: Cluster models for OH on Cu(111) (1993)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 99 (1993), S. 610-619 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The chemisorptive interaction of the hydroxy radical (OH) with the Cu(111) surface and its consequences for the surface electronic structure are studied by CunOH (n ranging from 1 to 25) cluster models using ab initio Hartree–Fock and correlated wave functions. A comparison of the adsorbate binding at the Cu(111) on top, bridge, and the two threefold hollow [face-centered-cubic and hexagonal-close-packed (fcc and hcp)] sites based on extended geometry optimizations yields the fcc site energetically favored with a binding energy EB=3.1 eV at the configuration interaction (CI) level. Correlation contributions account for about 0.9 eV of the binding and are almost independent of the binding site and cluster size. The OH–metal interaction is characterized by considerable Cu to OH charge transfer filling the partially occupied O 2p lone pair orbitals (OH 1π), while OH to Cu charge transfer involving the OH 3σ orbital is small. As a result, the adsorbate is negatively charged in the presence of the surface and ionic binding contributions become important. This makes the OH–metal binding very similar to that of other radicals such as, e.g., OCH3. The adsorbate binding character is also reflected in the results of cluster core and valence hole states corresponding to OH adsorbate ionization. These results may be compared with experimental photoionization data as they become available.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.465733
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  • 3
    Electronic Resource
    Electronic Resource
    The electronic structure of the surface methoxy species on Cu{111}
    Amsterdam : Elsevier
    Chemical Physics 177 (1993), S. 363-371 
    Details
    ISSN: 0301-0104
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0301-0104(93)80018-5
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  • 4
    Electronic Resource
    Electronic Resource
    CH"3CNalkali coadsorption at metal surfaces: model studies for alkali induced adsorbate geometry changes
    Amsterdam : Elsevier
    Surface Science 307-309 (1994), S. 53-59 
    Details
    ISSN: 0039-6028
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0039-6028(94)90369-7
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  • 5
    Electronic Resource
    Electronic Resource
    Hydrogen assisted oxygen desorption from the V2O5(010) surface (2000)
    Springer
    Topics in catalysis 11-12 (2000), S. 67-75 
    Details
    ISSN: 1572-9028
    Keywords: vanadium pentoxide ; oxidation reaction ; hydrogen adsorption ; surface oxygen vacancies ; oxygen desorption ; surface binding ; density functional theory ; cluster studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Vanadium oxide surfaces are well known to play an active role as catalysts in hydrocarbon oxidation reactions where oxygen from different surface sites participates in the reaction. Due to the ubiquity of hydrogen in these systems, reaction steps involving (temporary) hydrogenation are possible and may influence the overall reaction scheme. This work examines structural and energetic consequences of hydrogen interacting with different oxygen sites at the V2O5(010) surface where the local surface environment is modeled by embedded clusters. The electronic structure and equilibrium geometries of the clusters are obtained by density functional theory (DFT) using gradient corrected functionals (RPBE) for exchange and correlation. Hydrogen is found to stabilize preferentially near oxygen sites forming surface OH and H2O species with binding energies of 0.5–2.3 eV per H atom depending on the site and species. Hydrogen adsorption weakens the binding of the surface oxygen with its vanadium neighbors considerably where the weakening is larger for H2O than for OH formation as evidenced by bond order analyses and results of the binding energetics. Thus, the studies suggest strongly that the presence of hydrogen at the oxide surface facilitates oxygen removal and, therefore, contributes to the enhanced yield of oxygenated products near vanadia based surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1027206705195
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  • 6
    Electronic Resource
    Electronic Resource
    New concepts in bonded functions theory. III. Orthogonalization problem (1989)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 35 (1989), S. 425-432 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: One of possible approaches to the CI method is based on Boys bonded functions which can be generated in a systematic way forming an independent set of high internal symmetry. The main disadvantage of bonded functions is their nonorthogonality. In this paper a scheme is proposed for passing to orthogonalized set of bonded functions together with the appropriate algorithm for the transformation of the energy matrix H. The orthogonalization matrices are shown to reflect high symmetry of the canonical set of bonded functions, and in what follows they can be defined by short vectors. Moreover, the orthogonalization transformation can be handled in a blockwise manner.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560350307
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  • 7
    Electronic Resource
    Electronic Resource
    New concepts in bonded functions theory II. Canonical set of high internal symmetryThe Editor deeply regrets announcing the death of Professor gołȩbiewski on march 27, 1987. (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 33 (1988), S. 247-262 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new definition of a canonical set of bonded functions has been introduced. For a given configuration with r singly occupied orbitals and given multiplicity, the set exhibits symmetry properties of a group of order r. It simplifies the evaluation of the energy matrix H as well as the orthogonalization procedure.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560330307
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