Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 1990-1994  (22)
  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 52 (1994), S. 595-610 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Electronic structure investigations on a broad range of gold compounds, including naked and ligated gold clusters, are reviewed. The calculations have been carried out with a recently introduced relativistic variant of the linear combination of Gaussian-type orbitals density-functional (LCGTO-DF) method which affords all-electron investigations for very large systems. The accuracy of the method will be evaluated for the gold dimer. Then the electronic structure of the naked cluster Au55 is studied, both in Ih and Oh symmetry. Nonrelativistic and relativistic results obtained by the present method are compared to those of the much simpler jellium model. Since triphenylphosphine is among the most common ligands in gold chemistry a series of mononuclear gold phosphine compounds MeAuPR3 with increasingly complex ligands PR3 (R = H, CH3, C5H6) is discussed. The calculations reveal the success and the limitations of simpler phosphines often employed as model ligands in theoretical studies. Some aspects of the phosphine gold interaction in these simpler compounds carry over to the main group element centered gold clusters. Thereby one arrives at a rationalization of the particularly high stability of the carbon-centered octahedral cluster cation [(R3PAu)6C]2+ as compared to the neighboring isoelectronic boron and nitrogen-centered clusters. © 1994 John Wiley & Sons, Inc.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 6322-6323 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 7004-7007 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: The electronic structure of high nuclearity carbonylated Ni clusters [Ni32C6(CO)32]n− and [Ni44(CO)48]n− (n=0–6) has been investigated by means of all-electron calculations within the local density functional approach. The transition from the molecular to the metallic state was studied by determining the magnetic properties of bare and carbonylated clusters. The appearance of the metallic magnetic behavior is connected with the presence of metal atoms with bulklike coordination. The effect of interstitial impurity atoms in quenching the magnetic moment is also discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 1153-1162 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: A two-component scalar relativistic method which is based on the no-pair projection operator formalism of quantum electrodynamics has been studied within the framework of local density functional theory. This projection operator formalism, first proposed by Sucher for wave function based methods, provides a stable approach to the relativistic electronic structure problem without the well-known deficiencies of some variational procedures for the Dirac equation. Several approximations of increasing accuracy have been investigated. Besides the method based on free-particle projectors and on external field projectors for the singular nuclear potential, projectors on the full electronic potential are presented here for the first time. Atomic all-electron calculations within this framework give excellent results compared to a fully numerical solution of a scalar relativistic approximation to the corresponding one-particle Dirac problem. Calculations for cerium and for lead are analyzed in detail. About 96% of the relativistic shift of the one-electron energies and about 98% of the relativistic effect on the total energy are covered within this method. The method allows for a rather straightforward generalization to molecular systems with multinuclear potentials.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 96 (1992), S. 9095-9097 
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Inorganic chemistry 32 (1993), S. 2963-2964 
    ISSN: 1520-510X
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    ISSN: 1520-510X
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 1353-1365 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: An intermediate neglect of differential overlap method for examining the electronic structure of actinide complexes is developed. It is characterized by a basis set obtained from relativistic Dirac–Fock atomic calculations, the inclusion of all one-center two-electron integrals, and a parameter set based on molecular geometry and ionization spectra. The model is successful in reproducing the geometries of many small test molecules, especially the hexahalides and tetrahalides of the early actinides. We also investigate the bonding in actinocenes and the photoelectron spectra of pentavalent uranium amide/imide complexes as two diverse examples in which this model can be used to help in understanding and prediction.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 2808-2820 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: A method for the calculation of electronic continuum wave functions is presented which is based on the logarithmic derivative version of the Kohn (LDK) variational principle. The variational principle is cast into algebraic form by introducing a finite basis set that consists of spherical harmonic Gaussian-type functions (GTOs) and of Lobatto shape functions with the latter representing the translational part of the basis. A local effective potential which is obtained from density functional theory results in fairly accurate photoionization cross sections. Also studied are asymptotic corrections to the effective potential for the photoelectron which, in many cases, lead to improved results. The Lobatto procedure is applied to the diatomics N2 and CO and to benzene which may be regarded as a prototype for larger non spherical symmetric systems for which the method is targeted. For the two diatomics, results in excellent agreement with experiment have been found. For benzene the results are compared to those obtained by the Stieltjes–Tchebychev (ST) imaging technique and by the continuum multiple scattering (CMS) method which both have been applied to similar effective local potentials. Comparison with the ST imaging technique shows that the LDK Lobatto (LDKL) method provides qualitatively similar results, but the LDKL cross sections are of higher resolution and allow a more detailed analysis because of the explicit determination of the continuum wave function. For most of the valence orbitals of benzene the CMS method does not lead to satisfactory agreement with experiment due to the well-known deficiencies of this technique. The LDKL method implemented with a combined basis set does not suffer from the limitations of the ST and the CMS methods, but remains applicable to larger-size molecules.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: High-resolution electron energy loss spectra (HREELS) of NO adsorbed at low temperature on the Ru(001) surface are reported with particular emphasis on the low coverage regime. The improved resolution compared to earlier studies allowed one to clearly separate the various vibrational bands and to establish correlations among them. The experimental data are analyzed with the help of linear combination of Gaussian-type orbitals local density functional model cluster calculations. We conclude that the loss peak of the low coverage samples at 1130 cm−1 can be attributed to the stretching vibrations of upright oriented μ3-bridge nitrosyl species which are bound in an unusual configuration, i.e., via the oxygen atom. The dominating feature at small coverages around 1400 cm−1, corresponding to the intramolecular vibration of NO moieties at the same site but bound via nitrogen, is calculated in agreement with experiment. Bent structures of the adsorbate are energetically less favored both for the μ3-ON and μ3-NO adsorption complexes. In contrast to the adsorption on the threefold hollow sites, NO molecules in the on-top position at Ru(001) bear a positive charge and vibrate at much higher frequencies. The importance of Pauli repulsion for the vibrational frequencies of adsorbed species is emphasized.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...