ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • American Institute of Physics (AIP)  (8)
  • Oxford University Press  (1)
Collection
Publisher
Years
  • 1
    Electronic Resource
    Electronic Resource
    Molecular photo cross sections with the LCGTO–Xα method using Stieltjes imaging (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 5563-5572 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A method for calculating and symmetry analyzing total molecular photoionization cross sections is presented. The technique is based on the LCGTO–Xα method and employs Stieltjes imaging. It allows applications to molecular systems comparable in size to those treated so far with the continuum multiple-scattering Xα method, but avoids the pitfalls of the muffin-tin approximation to the electronic potential. Photo cross sections for valence ionization of CO are found in good agreement with experiment and with previous calculations. From a final state symmetry analysis for the 1π level, the absence of kσ* shape resonance which appears in the 4σ and the 5σ ionization channels is attributed to small transition moments. This is in contrast to a previous treatment where this difference has been rationalized as caused by a channel dependent final state potential. The photoionization cross sections for the four highest valence orbitals of benzene were calculated in better agreement with experiment than found in a previous Xα–SW treatment. The improvement is especially significant for the 1e1g(π) highest occupied molecular orbital where at least part of the experimentally observed structures are attributed to shape resonances. Some of the observed resonance features in the valence orbital photo cross sections of benzene were identified with resonances found in carbon K-shell ionization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459626
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Modeling of lateral interactions in densely packed adsorbate overlayers: How far do chemisorbed C2N2 molecules tilt on a Ni(110) surface? (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 3276-3279 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: It is proposed to investigate geometric arrangements in chemisorption systems by standardized force fields. This "molecular modeling'' technique is particularly simple to apply to densely packed adsorption layers with dominating nonbonding interactions where the substrate essentially acts as a template for interadsorbate distances. The approach is exemplified for Ni(110/c(2×2)C2N2. Tilting of the molecular axis by about 20–30 degrees with respect to the surface (the molecules oriented perpendicularly to the troughs) is deduced, supporting a corresponding interpretation of angular resolved photoemission data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459799
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Chemisorption of sulfur on nickel: A study of cluster convergence in the linear combination of Gaussian-type orbitals local density functional approach (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 6578-6590 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Chemisorption of sulfur at the (100), (110), and (111) surface of nickel has been studied, using the linear combination of Gaussian-type orbitals local density functional (LCGTO-LDF) method. Employing various cluster models consisting of 11 to 29 substrate atoms, adsorption at the experimentally known sites has been considered. Besides the equilibrium distance and the force constant of the vertical adsorbate motion, the dynamical dipole moment was evaluated and it turned out to provide a sensitive probe of cluster convergence. The influence of atoms from the third substrate layer on the various observables is found to be considerable in some cases. With increasing cluster size, bond lengths are stabilized to 0.02 A(ring), frequencies to 20 cm−1, and dipole moments to 0.1 D. The converged results agree very well with experiment. Adsorption induced population changes are restricted to only four to six neighboring substrate atoms of the modifier atom. However, energy resolved charge density differences reveal a possible mechanism for the transmission of the long-range electronic effects caused by the adatom.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.467067
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Charge separation and covalent bonding in metal oxide surfaces: A local density functional study on the MgO(001) surface (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 6826-6836 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A first principles local density functional investigation on extended, two-dimensional periodic slab models of the MgO(001) surface is performed, using the linear combination of Gaussian-type orbitals (LCGTO) technique as implemented in the FILMS program package. Stimulated by recent theoretical evidence for a reduced charge separation in MgO(001), a detailed analysis of the charge distribution and its influence on the electrical field above the surface is carried out. Two different methods to quantify the charge separation in the ionic substrate are employed, a local one based on the topological atom approach and a global one derived from the Madelung field of the surface near potential adsorbates. Both procedures lead to a charge separation significantly (10%–20%) below the nominal ionic value of ±2 a.u. A variational atomic orbital analysis is utilized to discuss the origin of the Mg 3s and 3p structures discernible in the crystal orbitals of the MgO slab systems. They are identified as covalent magnesium valence orbital admixtures to the oxygen dominated valence bands in consistence with the reduced charge separation. Their influence on the cohesive energy of crystalline MgO, however, is found to be only 5% (∼0.5 eV).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.467042
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Interpretation of x-ray emission spectra: NO adsorbed on Ru(001) (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 4704-4713 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A density functional investigation of the x-ray emission spectrum of NO adsorbed on Ru(001) has been carried out using model cluster calculations. The dipole matrix elements governing the emission probability were evaluated in the frozen ground-state approximation. The resulting simulated spectra exhibit all characteristic features of the experimental data. A detailed analysis of the electronic structure of the model clusters permits a complete rationalization of all observed trends. Furthermore, a picture of the surface chemical bond results in which the classical Blyholder frontier orbital model is extended to a three-orbital description for both the π and σ interactions. Comparison of different adsorption sites reveals that threefold coordinated NO features a stronger orbital interaction with the substrate than NO adsorbed in an on-top position. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.479232
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A linear combination of Gaussian-type orbitals (LCGTO) Xα study of ferrocene: The metal-to-ring distance and ionization potentials (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 84 (1986), S. 5967-5968 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The metal-to-ring distance of ferrocene, Fe(C5H5)2, has been optimized using the LCGTO-Xα method. The resulting distance is 0.047 A(ring) shorter than the experimental value of 1.65 A(ring). The corresponding symmetric stretching frequency of 331 cm−1 shows good agreement with experiment (303 cm−1). The two lowest (Fe 3d derived) ionization potentials are calculated almost degenerate but in reverse order compared to experiment (2A'1 below 2E2). The errors of all these results are discussed in the light of known inadequacies of the local density approximation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450854
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Density functional investigation of the geometric and electronic structure of ethylene adsorbed on Si(001) (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 108 (1998), S. 9868-9876 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A detailed first-principles density functional analysis of the geometric and electronic properties of ethylene adsorbed on the dimer reconstructed Si(001)-(2×1) surface is presented. This theoretical study was carried out in close reference to a recent angle-resolved photoemission spectroscopy investigation of the same adsorption system. Adsorbate weighted Kohn-Sham one-particle spectra are calculated and compared to the band structure derived from the angle-resolved photoemission spectra. In addition, the symmetry character of the concomitant Bloch waves is determined to yield information which can directly be related to the results of a dipole selection rule analysis of the corresponding photoemission signals. Total energy minimization of a model slab reveals a distortion of the adsorption complex at saturation coverage to local C2 symmetry involving an 11° rotation of the ethylene molecule around the surface normal and a 27° twist of the methylene groups around the CC axis. This finding is confirmed by a comparison of the calculated band dispersions with those found in the angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) experiments. The driving forces for the distortion of the adsorption complex can be traced to direct Pauli repulsion between the hydrogen atoms of neighboring ethylene molecules and to a bonding overlap contribution from the ethylene 1b2g-derived orbitals of the adlayer. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.476425
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The adsorption of acetylene on Ni(110): An experimental and theoretical study (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 9709-9724 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The adsorption of acetylene on Ni(110) was investigated by temperature programmed desorption (TPD), low energy electron diffraction (LEED), angle resolved ultraviolet-photoelectron spectroscopy (ARUPS), and near edge x-ray absorption fine structure (NEXAFS) measurements, as well as by detailed model cluster calculations and slab model band structure calculations. By combining the experimental results and those of the cluster studies an orientation of the molecules is deduced with the C–C axis parallel to the surface and preferentially aligned along the substrate troughs ([11¯0] azimuth) as well as with a highly coordinated adsorption site in the substrate troughs. A detailed analysis of the photoemission spectrum is given. The proposed adsorption geometry is corroborated by band structure calculations for various alternative sites and orientations that are shown to be very sensitive to the azimuthal orientation of the adsorbed molecules. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.468790
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    facet.materialart.
    Unknown
    Search for non-Newtonian gravitation-a gravimetric experiment in a hydroelectric lake (1990)
    Oxford University Press
    Details
    Publication Date: 1990-05-01
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Royal Astronomical Society.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...