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  • 1
    Electronic Resource
    Electronic Resource
    The electronic structure of metal-molten salt solutions: A tight-binding approach (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 7241-7248 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present a computer simulation study of simple models of alkali metal–alkali halide melts Mx[MX]1−x. The geometries are modeled using the primitive model of hard spheres, the electronic structure is described by a tight-binding Hamiltonian including the crucial component of Madelung potential fluctuations. Electronic defects like F centers are treated by a novel variational ansatz. We focus on the computation of experimentally measured quantities like the optical absorption or the electronic conductivity and the paramagnetic susceptibility as a function of x. Despite the simplicity of the underlying model, simulation and experiment are in good agreement in the entire region from nonmetallic to metallic states. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.473736
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  • 2
    Electronic Resource
    Electronic Resource
    Localized and extended electronic eigenstates in proteins: A tight-binding approach (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 12233-12239 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present a numerical study of the electronic structure of the cytochrome subunit of the photoreaction center of the bacterium Rhodopseudomonas viridis. The electronic structure is described by a tight-binding Hamiltonian, the resulting large secular matrix is diagonalized applying sparse matrix methods. In the highly structured density of states, localized chromophore eigenstates can be observed around the HOMO-LUMO gap. In the low energy range, optical excitations originate from transitions between these states. Eigenfunctions that are extended on a length scale of up to ∼190 Å can be found in the bulk of the valence band density of states. Stretched along α-helices, conduction band eigenstates are characterized by a cylindrical shape. We discuss the role of these states within electron transport and possible extensions of the model presented here. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.479161
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  • 3
    Electronic Resource
    Electronic Resource
    Electronic Structure of Liquid Charge-Transfer Alloys: A Numerical Study (1994)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 98 (1994), S. 9146-9152 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100088a010
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  • 4
    Electronic Resource
    Electronic Resource
    Refractory metals in molten salts: Theory and simulation of geometry, electronic structure, and electron transport (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 10703-10711 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In this work, we present a theoretical and numerical study of the microscopic and electronic structure of solutions of refractory metal halides in alkali halide melts, [NbCl5]x[KCl]1−x and [TaCl5]x[KCl]1−x with 0≤x≤0.5. The geometry of the melts is described by ensembles of charged hard spheres, the electronic structure is modeled by a tight-binding Hamiltonian, which is extended by a reaction field to describe the diabatic energy profile of the electronic self-exchange in many-orbital mixed-valence systems. Despite its simplicity, the model leads to the formation of distorted octahedral [NbCl6]− and [TaCl6]− clusters, as evident both from the inspection of the simulation geometries and from the analysis of the partial pair distribution functions. Even in the presence of the strong potential energy fluctuations characteristic of ionic liquids, the octahedral structure is manifest in the density of states in a t2g–eg splitting of the conduction band. The Hamiltonian that describes mixed-valence systems is solved self-consistently. Using an attractive Hubbard parameter of 1.5 eV, we show that the numerical results can be interpreted by Marcus' theory of outer-sphere electron transfer reactions with a reorganization energy of 2.2 eV, an electronic coupling parameter of 0.12 eV, and an activation energy of 0.42 eV. Both anion-d metal cation and intervalence charge transfer excitations contribute to the optical absorption spectrum, the latter leads to a pronounced polaron absorption peak. These findings are compared to recent experimental results. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1324709
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  • 5
    Electronic Resource
    Electronic Resource
    Ester von (Hydroxymethyl)diorganylsilanen: Synthese und thermisch induzierte Umlagerung (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 591-605 
    Details
    ISSN: 0009-2940
    Keywords: (Hydroxymethyl)diorganylsilanes, esters of ; Rearrangement, thermally induced ; Kinetics ; DSC ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Esters of (Hydroxymethyl)diorganylsilanes: Synthesis and Thermally Induced RearrangementTwenty silanes of the type R1R2Si(H)CH2OR3 (A) were synthesized [R1, R2 = Me, Ph, 1-naphthyl, PhCH2,Me3SiCH2; OR3 = OC(O)Me, OC(O)Ph, OC(O)CF3, OS(O)2CF3, OP(O)Ph2, OC(O)Cl] and studied for their thermal behaviour. The silanes A undergo a thermally induced rearrangement to give the corresponding silanes R1R2Si(OR3)Me (B). For compounds with OR3 = OC(O)Cl, an additional decarboxylation takes place to yield the chlorosilanes R1R2Si(Cl)Me. Except for the derivatives with OR3 = OC(O)Cl, the energetic (reaction enthalpy) and kinetic data (reaction order, frequency factor, enthalpy and entropy of activation) of these reactions were studied by means of differential scanning calorimetry (DSC). In addition, the kinetics of all reactions were investigated by 1H-NMR spectroscopy. The transition state of the rearrangement was investigated by an ab initio study based on the model compound H3SiCH2OC(O)H [→ MeH2SiOC(O)H]. The theoretical data and the experimentally obtained energetic and kinetic data are discussed in terms of mechanistic aspects of the rearrangement reaction A → B.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250310
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