1,721,021 research outputs found
Continuum Distorted Wave and Wannier Methods
No full textThe continuum distorted wave model has been extensively applied to charge transfer and ionization processes. We present both the perturbative and variational capture theories as well as highlighting the suitability of this model in describing the continuum final states in both heavy and light particle ionization for both atomic and molecular targets. Particular emphasis will be put in the application of distorted wave theories to the description of recent complete experiments. We then develop the Wannier theory for threshold ionization and further theoretical work that led to the modern quantal semiclassical approximation. This very successful theory has provided the first absolute cross sections that are in good agreement with experiment. The present work is based on the previous one conceived by Crothers et al. 1 . Only a few minor modifications in the text have been introduced, and a complete subsection has been added in order to take into account the state of art of the subject.Fil: Rivarola, Roberto Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Fojon, Omar Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Ciappina, Marcelo Fabián. Technion - Israel Institute of Technology; Israel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Crothers, Derrick. The Queens University of Belfast; Irland
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
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
Erratum: Asymptotic expansion for -function matrix elements of helium (Phys. Rev. a (1992) 45,9 (6933-6934))
No full textThis article was first published in PHYSICAL REVIEW A. Copyright (2012) American Physical Society (APS). (http://dx.doi.org/10.1103/PhysRevA.45.70
Singlet-triplet mixing in the helium sequence
Full text linkThis article was first published in PHYSICAL REVIEW . Copyright (2012) American Physical Society (APS). (http://dx.doi.org/10.1103/PhysRev.181.23)Accurate variational calculations are presented for the off-diagonal matrix elements of the Breit interaction between the 2P1 and 2P3 states of several members of the helium iso-electronic sequence. A comparison is made with recent Z-expansion calculations, which are accurate through terms of order α2Z3. The comparison shows that the Z-expansion method for off-diagonal mixing is potentially useful in the theory of many-electron atoms. The effect of singlet-triplet mixing on the 2P3 excitation cross sections is briefly discussed. © 1969 The American Physical Society
Relativistic corrections to spin-forbidden electric-dipole transitions
No full textThis article is Copyright Institute of Physics (the "Institute") and IOP Publishing 2010. References to "IOP" mean the Institute and/or IOP Publishing, as appropriate. References to "this website" are to the IOP website from which the user is linking to this Copyright Notice - http://iopscience.iop.org/ Please read the following Copyright Notice carefully as your access to and use of this website will be deemed as acceptance of its terms. This Copyright Notice was last updated on 30 December 2009. The material featured on this website is subject to IOP copyright protection, unless otherwise indicated. Subject to subscriber status, reasonable amounts of IOP copyright-protected material (other than logos) may be reproduced, distributed or communicated to others free of charge in any format or media for the purposes of research for a non commercial purpose, or for private study, or for internal circulation within an organization. This is subject to the material being reproduced accurately and not being used in a misleading context. Where any IOP copyright items on this website are being reproduced, distributed or communicated to others, the source of the material must be identified and the copyright status acknowledged. In particular, where a third party wishes to include IOP copyright items on another website, they must only use non-locked-down content, link to the home-page of this website rather than reproducing the items, and fully credit this website and the copyright status of the item. Any other proposed use of IOP material will be subject to a copyright licence, available from IOP. Systematic downloading of files is prohibited. The permission to reproduce, distribute or communicate IOP-protected material does not extend to anything that is identified as being the copyright of a third party. Authorization to reproduce, distribute or communicate such material must be obtained from the copyright owner concerned. In addition, the names, images and logos identifying IOP are proprietary marks of IOP or its licensors. Other names, images and logos identifying third parties and their information, products and services are the proprietary marks of third parties. Copying or using IOP's logos and/or any third party logos accessed via this website is not permitted without the prior written approval of the relevant trade mark and/or copyright owner.Theoretical results for spin-forbidden electric-dipole transitions have recently been questioned on the grounds that relativistic corrections to the transition operator were not included. It is shown here that these corrections are automatically included when the transition operator is expressed in the dipole length form. The above criticism of previous dipole-length calculations is therefore unfounded. The 1s2p 3P1-1s21S0 and 1s2p 3P1-1s2s 1S0 transitions of helium are discussed as specific numerical examples
Erratum: Eigenvalues and retardation effects in the n = 10 states of helium (Journal of Physics B: Atomic, Molecular and Optical Physics (1989) 22 (L651-L657))
No full textThis article is copyright Institute of Physics (the "Institute") and IOP Publishing 2010. References to "IOP" mean the Institute and/or IOP Publishing, as appropriate. References to "this website" are to the IOP website from which the user is linking to this Copyright Notice - http://iopscience.iop.org/ Please read the following Copyright Notice carefully as your access to and use of this website will be deemed as acceptance of its terms. This Copyright Notice was last updated on 30 December 2009. The material featured on this website is subject to IOP copyright protection, unless otherwise indicated. Subject to subscriber status, reasonable amounts of IOP copyright-protected material (other than logos) may be reproduced, distributed or communicated to others free of charge in any format or media for the purposes of research for a non commercial purpose, or for private study, or for internal circulation within an organization. This is subject to the material being reproduced accurately and not being used in a misleading context. Where any IOP copyright items on this website are being reproduced, distributed or communicated to others, the source of the material must be identified and the copyright status acknowledged. In particular, where a third party wishes to include IOP copyright items on another website, they must only use non-locked-down content, link to the home-page of this website rather than reproducing the items, and fully credit this website and the copyright status of the item. Any other proposed use of IOP material will be subject to a copyright licence, available from IOP. Systematic downloading of files is prohibited. The permission to reproduce, distribute or communicate IOP-protected material does not extend to anything that is identified as being the copyright of a third party. Authorization to reproduce, distribute or communicate such material must be obtained from the copyright owner concerned. In addition, the names, images and logos identifying IOP are proprietary marks of IOP or its licensors. Other names, images and logos identifying third parties and their information, products and services are the proprietary marks of third parties. Copying or using IOP's logos and/or any third party logos accessed via this website is not permitted without the prior written approval of the relevant trade mark and/or copyright owner
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