1,721,338 research outputs found
Spin-resolved electron spectroscopy of the xenon N4,5O2,3O2,3 Auger lines
No full textSnell G, Drescher M, Müller N, Heinzmann U, Hergenhahn U, Becker U. Spin-resolved electron spectroscopy of the xenon N4,5O2,3O2,3 Auger lines. JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS. 1999;32(10):2361-2369.The spin polarization of the Xe N4,5O2,3O2,3 Auger lines was measured after ionization by circularly polarized synchrotron radiation of 93.8 eV photon energy. The circularly polarized radiation was produced by converting the linearly polarized light from a conventional undulator by a Mo/Si transmission multilayer acting as a quarter-wave plate. Nearly perfect circular polarization was obtained. In the framework of the two-step model of Auger decay the orientation of the primary hole stales 4d(-1) D-2(3/2) and 4d(-1) D-2(s/2) can be derived from the spin polarization of the S-1(0) Auger lines. Furthermore, the intrinsic parameters for all lines in this Auger group corresponding to the other 5p(-2) final states are determined and compared with theory
Nonlinear dispersion in resonant Auger decay of H2O molecules
No full textWe have measured the resonant Auger decay spectrum of the water molecule at the oxygen K edge. Strong deviations from the expected linear dispersion of the participator lines (which correspond to single-hole valence states) are observed. In a simplified picture the effect can be attributed to the combined effect of the intermediate- and final-state potential curves
Study of xenon 4d, 5p and 5s photoionization in the shape-resonance region using spin-resolved electron spectroscopy
Get PDFSnell G, Hergenhahn U, Müller N, et al. Study of xenon 4d, 5p and 5s photoionization in the shape-resonance region using spin-resolved electron spectroscopy. PHYSICAL REVIEW A. 2001;63(3): 032712.Photoionization of Xe atoms is investigated close to the maximum of the 4d shape resonance by means of spin-resolved photoelectron spectroscopy. Using circularly and linearly polarized synchrotron radiation of 93.8-eV energy, we investigate the photoionization processes of the 5p, 5s, and 4d shells. By combination of earlier data for the partial and differential cross sections with our measurements, we are able to perform a complete characterization of the Xe 4d photoionization process, i.e., we can determine all the relativistic dipole matrix elements. Comparison with different theoretical calculations shows the importance of relaxation effects st this photon energy
Angle-resolved electronic decay of the pi*, sigma* and Rydberg resonances below the O K-edge in O-2
No full textAngle-resolved electronic decay spectra of the O-2 molecule have been measured at photon energies corresponding to the excitation of core electrons into the pi*, sigma* and Rydberg levels. Asymmetry parameters have been determined for resonant Auger transitions and compared with previous data where available. The pi* spectrum has also been studied with a narrow photon bandwidth in different regions of the vibrationally unresolved absorption feature
Dynamically induced spin polarization of resonant Auger electrons
Get PDFHergenhahn U, Snell G, Drescher M, et al. Dynamically induced spin polarization of resonant Auger electrons. PHYSICAL REVIEW LETTERS. 1999;82(25):5020-5023.Resonant Anger electrons from the decay of the atomic Xe 4d(5/2)(-1)6p(J = 1) state excited with linearly polarized light are shown to have a strong spin polarization. The core hole states are not oriented in this case. We found polarization values ranging from -0.46 to 0.57. For the decay to the 5p(4)(D-1(2))6p(P-2(1/2)) state the ratio of the radiationless decay matrix elements and their relative phase, including its sign, are derived
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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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