1,720,987 research outputs found
CoPc 2D and 1D arrangement on a ferromagnetic surface
No full textWe investigated the growth and electronic properties of Co-phthalocyanine(CoPc) molecule deposited on iron film with different structures (pseudomorph-fcc and bcc) and on iron nanowires by scanning tunnelling microscopy and X-ray absorption spec- troscopy (XAS). CoPc molecules self–assemble in a two–dimensional arrangement with the molecular plane parallel to the iron surfaces and the local order is lost after the first layer. The molecule–ferromagnet interaction causes the broadening of Co and N unoccupied molecular states as well as different electronic distribution of N states as a function of the atomic structure of iron surface. The ferromagnetic coupling between the molecule and the iron film is dominated by the electronic interaction between Co and the first Fe layer.
CoPc 2D arrangement turns into 1D by using as a template the iron nanowire grown on a facet surface of oxydized Cu(332) surface. CoPc molecules interact weakly with the iron nanowires manifesting a substantial Co 3 dz spectral feature in XAS spectrum and the possibility of a magnetic interaction between Co moment and iron nanowires. Both CoPc 2D and 1D arrangements can open up new interesting scenarios to tune the magnetic properties of hybrid interfaces involving metallorganic molecules
Electronic band and orbital properties of Cs-doped pentacene thin films
No full textWe studied the electronic band structure of Cs-doped pentacene films grown on Cu(119). The Cs doping of pentacene films grown on Cu(119) determines relevant changes in the band structure. Angle-resolved photoemission spectroscopy reveals a formation of a new electronic state at 0.6–0.7 eV below the Fermi energy. This state results from the filling of the lowest unoccupied molecular orbital as also shown by X-ray absorption at C 1s edge. At doping level of 1.8 Cs atom per molecule it disperses, forming an electronic band of 130 meV width along the direction perpendicular to the molecular plane, while no dispersion is observed in plane. Our results indicate that the anisotropic charge delocalization mediated by Cs atoms along the molecular stacking direction takes place in doped pentacene films
Interface magnetic coupling of Fe-phthalocyanine layers on a ferromagnetic surface
No full textFe-phthalocyanine (FePc) molecules bonded to metal surfaces form rehybridized interface states involving
the Fe central atom reflected in changes of orbital and spin configuration. X-ray absorption spectroscopy and
x-ray magnetic circular dichroism show the ferromagnetic coupling of the FePc molecules that are in contact
with the Co(001) surface, even at room temperature (300 K), while the overgrown parallel layers of FePc in
thicker molecular films are decoupled from the interface. The magnetized interface molecular layer reproduces
the magnetic structures of the substrate (domains, patterns)
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
Structure and electron states of Co-phthalocyanine interacting with the Cu(111) surface
No full textWe present a study of the growth and electronic properties of Co-Phthalocyanine(CoPc) molecular layers on Cu(111). Scanning tunnelling microscopy shows CoPc molecules adsorbing first at the Cu(111) step edges, lying “flat” i.e. parallel to the substrate. At monolayer saturation CoPc cover uniformly the Cu(111) surface with short range ordering. Angle dependent N 1s X-ray absorption spectroscopies (XAS) confirm the overall flat orientation. C 1s, N 1s, core-level photoemission and Co L3 edge XAS indicate selective participation of these atoms to the interface bonds. Angle resolved photoemission, up to 1ML, shows that the Cu(111) suface states undergo a shift to lower binding energies. This binding energy shift and the increase in the effective mass indicate a charge redistribution at CoPc/Cu(111) interface. At monolayer saturation the Cu(111) surface state is quenched and new molecular states appear at binding energies 0.9 eV and 1.37 eV
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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