1,720,976 research outputs found
Reinvestigation of the ν 3 – ν 6 Coriolis interaction in trifluoroiodomethane
No full textAn updated fit to the interacting levels ν 3 and ν 6 of CF 3 I has been evaluated in this work.The lowest-frequency fundamental ν 6 of trifluoroiodomethane (CF 3 I) has never been directly observed and analyzed at high resolution in the gas phase. The ν 6 (e) level interacts with ν 3 (a 1 ) at 286.297 cm −1 via a b -axis Coriolis interaction, which perturbs the rotational structure of both levels. In this work, we report low- J microwave transitions (for J ranging from 0–2) within the ν 6 vibrational level. The l -type doubling observed in our spectrum agreed poorly with the predictions of previously published models of the interacting ν 3 – ν 6 levels, prompting us to refine the model. We performed ab initio anharmonic force-field calculations, which were used to constrain some of the parameters, and which served as a check on some of the floated parameters. We fit a dataset consisting of 3593 transitions, which combined our measurements with previous microwave, millimeter wave, and high-resolution infrared observations. A reasonable set of fit parameters is obtained with ν 6 = 267.28 cm −1 , but we cannot rule out a lower value of ν 6 = 261.5 cm −1 consistent with analyses of the vibrational level structure.An updated fit to the interacting levels ν 3 and ν 6 of CF 3 I has been evaluated in this work.The lowest-frequency fundamental ν 6 of trifluoroiodomethane (CF 3 I) has never been directly observed and analyzed at high resolution in the gas phase. The ν 6 (e) level interacts with ν 3 (a 1 ) at 286.297 cm −1 via a b -axis Coriolis interaction, which perturbs the rotational structure of both levels. In this work, we report low- J microwave transitions (for J ranging from 0–2) within the ν 6 vibrational level. The l -type doubling observed in our spectrum agreed poorly with the predictions of previously published models of the interacting ν 3 – ν 6 levels, prompting us to refine the model. We performed ab initio anharmonic force-field calculations, which were used to constrain some of the parameters, and which served as a check on some of the floated parameters. We fit a dataset consisting of 3593 transitions, which combined our measurements with previous microwave, millimeter wave, and high-resolution infrared observations. A reasonable set of fit parameters is obtained with ν 6 = 267.28 cm −1 , but we cannot rule out a lower value of ν 6 = 261.5 cm −1 consistent with analyses of the vibrational level structure.Division of Chemistry https://doi.org/10.13039/10000016
Chirped-pulse Fourier transform microwave spectrum of the HCl–DCl heterodimer
No full textHydrohalic acid dimers provide a fundamental opportunity to study hydrogen bond rearrangement dynamics at a high level of detail. The (HCl)2 and (DCl)2 homodimers do not have a pure rotational spectrum due to rapid geared tunneling motions that interchange the role of the hydrogen bond donor and acceptor. In this work, we report the pure rotational spectrum of HCl–DCl, which has a preference for deuterium in the hydrogen bond donor position. However, the quadrupole coupling constants indicate a significant amount of geared tunneling, consistent with significant zero-point wavefunction amplitude in the less stable DCl–HCl configuration. A comparison of experimental results with previously published wavefunction calculations based on model and ab initio potentials is consistent with a picture in which about 14% of the probability density distribution is located in the less stable well.National Science Foundation 10.13039/10000000
Microwave spectroscopy of partially and fully deuterated HCl dihydrate clusters
No full textA detailed understanding of water’s remarkable ability to solvate small molecules is a central theme in chemistry. In this work, we have identified 12 new partially and fully deuterated isotopologues of the hydrochloric acid dihydrate cluster, (H2O)2 · HCl, by chirped-pulse Fourier transform microwave spectroscopy. We also performed high-level ab initio calculations relevant to the structure and dynamics of the cluster. The observation of singly substituted isotopologues at each unique hydrogen position enables a more detailed experimental characterization of the geometry than was possible previously. In addition, an analysis of splittings in the spectrum that are caused by population of more than one vibration-tunneling level enables a detailed characterization of hydrogen bond-breaking bifurcation tunneling motions that occur in the complex. Not only do our results confirm theoretical predictions about hydrogen atoms that are permuted by the tunneling motions—they also provide experimental evidence for concerted large-amplitude motions of other atoms. Finally, an analysis of the chlorine nuclear quadrupole coupling tensor suggests that the HCl bonding character might be influenced to a small extent by isotopic substitution of atoms involved in the Cl–H⋯O hydrogen bond due to zero-point vibrational effects.National Science Foundation 10.13039/10000000
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
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
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
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