1,720,994 research outputs found
Unusual magnetic properties of mixed-valence system: Multiconfigurational method theoretical study on Mn-2(+) cation
No full textThe geometry structure, dissociation energy, vibrational frequencies, and low-lying spin-state energy spectrum of Mn-2(+) are investigated by using ab initio CASSCF/ECP10MDF, complete active space self-consistent field/atomic natural orbital basis sets (CASSCF/ANO-s), CASPT2/ECP10MDF, and second-order perturbation theory with CASSCF reference function/atomic natural orbital basis sets (CASPT2/ANO-s) levels of theory. For the ground state the dissociation energy of 1.397 eV calculated at the CASPT2/ANO-s level supports Jarrlod's experimental value of 1.39 eV. The equilibrium bond length and vibrational frequency are 2.940 A calculated at the CASPT2/ANO-s level of theory and 214.4 cm(-1) calculated at the CASSCF/ANO-s level of theory, respectively. On the basis of the mixed-valence model, the Heisenberg exchange constant J(-71.2 cm(-1)) and the double-exchange constant B(647.7 cm(-1)) are extracted explicitly from the low-lying energy spectrum calculated at the higher levels of theory. The magnetic competition between the weaker Heisenberg exchange interactions and the stronger double-exchange interactions makes the ground state a (12)Sigma(g)(+) state, consistent with electron paramagnetic resonance experimental observation, which explains unusual magnetic properties of Mn-2(+), quite different from the antiferromagnetic ground state of Mn-2 and Cr-2. On the other hand, the results calculated at the higher levels of theory show the consistent antiferromagnetic Heisenberg exchange interactions between 3d-3d for Cr-2, Mn-2(+), and Mn-2 (c) 2005 American Institute of Physics.Physics, Atomic, Molecular & ChemicalSCI(E)EIPubMed5ARTICLE1313430612
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Electronic transfer dynamics for bridged binuclear mixed-valence compounds: Density functional theory study on electronic structure in the ground state for the Creutz-Taube ion under asymmetric distortions
No full textIn order to explore the dynamic problem of the electronic structure in the ground state for the Creutz-Taube ion, the calculations on the electronic potential surfaces along the totally symmetric vibrational difference coordinate of the Ru-N stretch and the net charge distribution on the Ru atoms are carried out by using the density functional theory in the two schemes with or without the Ru-N(pyz) vibration. It is shown that the vibration associated with the totally symmetric vibrational difference coordinate Q(-) can be regarded as a harmonic oscillation with 123.16 eV Angstrom(-2) of the force constant, and 430 cm(-1) of the fundamental frequency is obtained on the basis of the five-body vibrator model. From the electronic structure calculated in the ground state it is concluded that the asymmetric net distribution on the Ru atoms in the Creutz-Taube ion occurs in the vibration associated with the totally symmetric vibrational difference coordinate, and the charge transfer between the Ru atoms and the ligands is responsible for the asymmetric charge distribution. The total symmetric vibrations of Ru-N for the related monomer [(NH3)(5)Ru(pyz)](2+/3+) are further examined. It is found that the reduction of Ru(III) to Ru(II) corresponds to 0.05 Angstrom of the difference in Ru-N distance between the two Ru-subunits under the asymmetric distortion and to 0.012 eV of the potential energy over the zero point energy, which is comparable with kT. The Born-Oppenheimer approximation and the neglected coupling effect between the electronic and nuclear motion in the present paper are briefly discussed. (C) 1999 American Institute of Physics. [S0021-9606(99)30148-3].http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000084242200026&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, Atomic, Molecular & ChemicalSCI(E)EI10ARTICLE2410926-1093311
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