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We present experimental and theoretical results for the surface core-level binding-energy shifts of Al(100), representative of an sp metal, and Cu(100), representative of a transition metal. Our analysis of these results leads to a unified interpretation for the different behavior of sp and transition metals. The d-electron contribution to smaller surface core-level binding energies is elucidated.
No full textWe present experimental and theoretical results for the surface core-level binding-energy shifts of Al(100), representative of an sp metal, and Cu(100), representative of a transition metal. Our analysis of these results leads to a unified interpretation for the different behavior of sp and transition metals. The d-electron contribution to smaller surface core-level binding energies is elucidated
FINAL-STATE EFFECTS FOR THE CORE-LEVEL XPS SPECTRA OF NIO
No full textIonization of the Ni 3s core level in NiO has been studied using ab initio wavefunctions for an NiO6 cluster model. Three important final state effects are studied: (I ) ligand to Ni 3d charge transfer; (2) exchange coupling of the ionized core level within the open 3d shell; and (3) atomic correlation effects among the metal 3s, 3p, and 3d shells. Analysis of the cluster wave-functions shows that these mechanisms are strongly coupled and must be treated on an equal footing. The ligand to metal charge transfer is often fractional, i.e. intermediate between 0 and 1
Core binding-energies for clusters deposited on different insulating substrates - ESCA spectra and theoretical electronic-structure studie
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Chemisorption of CO on defect sites of MgO
No full textChemisorption of a CO molecule on regular and defect sites of the MgO(100) surface has been investigated by means of cluster model calculations. At all sites studied, CO bonds at the cation with the C atom closest to the surface. The bonding is considerably larger at a three-coordinated corner site than for a regular five-coordinated surface site. A blueshift in the C-O stretching frequency, ωe, of adsorbed CO compared to free CO is found; the shift is much higher for a corner than for a surface site because of the larger local electric field for low-coordinated cations. Both the bond strength and the ω shift are largely due to electrostatic effects and not to the formation of a dative σ-bond with the surface. Surface relaxation effects have also been considered. © 1992
Loss structures in the photoemission spectra of MnO: A careful analysis of peak intensities
No full textA careful and rigorous analysis of the intensities of several features of the Mn 3s x-ray photoemission spectra of MnO, including the satellites at 20-30 eV below the main exchange split peaks is carried out. The previous interpretation of the 20-30 eV satellite is that they arose from electron correlation effects relative to the near degeneracy of the atomic levels. Our work shows that loss processes must also be taken into account. In particular, it is shown that only about 60% of the broad 20-30 eV satellite is due to near degeneracy correlation effects, while a contribution from the shakeup and plasmon loss structures constitutes the remaining 40% of the intensities of this featur
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A PROPER ANDERSON-HAMILTONIAN TREATMENT OF THE 3S PHOTOELECTRON-SPECTRA OF MnO, FeO, CoO AND NiO
No full textX-ray photoelectron spectra of the 3s core lines of NiO, CoO, FeO and MnO obtained on high-quality single crystals are interpreted on the basis of an impurity-cluster configuration-interaction model where the exchange and the intra-atomic M-shell charge redistribution energies are evaluated ab initio, Good agreement between the experimental and calculated binding energies and the intensity of the spectral components is obtained. These results clarify the interplay among the charge transfer, exchange and intra-atomic charge redistribution effects on the spectral structure
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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