1,721,012 research outputs found
High-resolution analysis of the nu(4) absorption band of (CH2BrF)-Br-79
No full textThe gas-phase infrared spectrum of the fundamental band of CH 79BrF was recorded in the 1010 –1116 cm1 wavenumber 42
79
region using a TDL spectrometer. In this first high-resolution investigation of the synthesized
Br isotopic form, more than
10 200 transitions of this a/b-hybrid band centered at 1068.5385 cm
1
were assigned and, using the Watson’s A-reduced
Hamiltonian in the Ir-representation, a reliable set of molecular constants for the excited state v 1 was determined. From
4
ground state combination differences having rotational quantum numbers J and Ka up to 97 and 21, respectively, improved and extended ground state rotational and centrifugal distortion constants were calculated as well. Comparison between the observed and calculated band intensities in appropriate regions of the spectrum gave an estimate of the transition dipole- moment ratio along the a and b axes as a/b 2.0 0.2, in agreement with the predicted theoretical value of 1.99
FTIR spectra and rovibrational analysis of the v11 band of trans-ClHC=CHF and v10 of trans-ClHC=CDF
Full text linkHigh-resolution Fourier transform infrared spectra of natural trans-ClHC@CHF and of its isotopologue trans-ClHC@CDF have been recorded in the region between 700 and 1150 cm1 with the purpose to ana- lyze the m11 fundamental of the main species and the m10 of its deuterated compound. Both bands, of sym- metry species A00, present c-type envelope absorptions. Beside the expected features, the K structure of the P(J), Q(J), and R(J) manifolds was resolved and identified; the assignment of the rovibrational transi- tions was extended up to J=92 and Ka =13 for the trans-35ClHC@CHF and up to J=86 and Ka =10 for trans-35ClHC@CDF. More than 2900 and 2700 lines for the main and deuterated species, respectively, were analyzed by a least-squares procedure and reliable spectroscopic molecular parameters were deter- mined for both isotopologues
High-resolution infrared study of vinyl fluoride in the 750-1050 cm-1 region: Rovibrational analysis and resonances involving the v(8), v(10), and v(11) fundamentals
No full textThe FTIR spectra of CH2=CHF have been investigated in the v(8), v(10), and v(11) region between 750 and 1050 cm(-1) at a resolution of about 0.002 cm(-1). The v(8) vibration of symmetry species A' gives rise to an a/b-type hybrid band, while the v(10) and v(11) modes of A" symmetry produce c-type absorptions. Due to the proximity of their band origins, the three vibrations perturb each other by Coriolis and high-order anharmonic resonances. In particular, the interactions between the v(8) and v(10) modes are very strong and widespread with band origins separated by only 1.37 cm(-1). Besides the expected c-type characteristics, the v(10) band shows a very intense pseudo a- type component caused by the strong first-order Coriolis resonances with the v(8) state. Furthermore, the 2"9 " dark state" was found to be involved in the interacting band systems. The spectral analysis resulted in the identification of 3144, 3235, and 3577 transitions of the v(8), v(10), and v(11) vibrations, respectively. Almost all the assigned data were simultaneously fitted using the Watson's A- reduction Hamiltonian in the Ir representation and the perturbation operators. The model employed includes nine types of resonances within the tetrad v(8)/v(10)/v(11)/2v(9) and a set of spectroscopic constants for the v(8), v(10), and v(11) fundamentals as well as parameters for the "dark state" 2v(9), and fourteen coupling terms have been determined
Tunable diode laser spectroscopy of cis-1,2-difluoroethylene: Rovibrational analysis of the nu(9) and nu(5)+nu(10) bands and anharmonic force field
No full textcis-1,2-Difluoroethylene was synthesized, and the gas-phase infrared spectrum was investigated in the upsilon(9) and nu(5)+nu(10) band region (1350-1391 cm(-1)), at a resolution of about 0.002 cm(-1), employing a tunable diode laser spectrometer. These vibrations of symmetry species B-1 yield strong a-type bands. Most of the J and K structure was recorded in different subbranches and the rovibrational analysis led to (t)he assignment of 2313 (J less than or equal to 64, K-a less than or equal to 26) and 1172 (J less than or equal to 57, K-a less than or equal to 20) transitions of the nu(9) and nu(5)+nu(10) bands, respectively. Using Watson's A-reduction Hamiltonian in the I-r representation a set of accurate spectroscopic parameters, up to four sextic centrifugal distortion terms, was obtained for both the excited states nu(9) = 1 and nu(5) = nu(10) = 1. A Fermi resonance coupling constant W = 4.2(5) cm(-1) was estimated for the perturbation between the nu(9) and nu(5)+nu(10) levels. Correlated harmonic force constants were obtained from coupled cluster CCSD(T) calculations with the cc-pVTZ basis set while the anharmonic force constants were computed at MP2 level using the same basis set. There is a good agreement with the available experimental data, in particular the equilibrium geometry compared with the experimental r(0) structure and the fundamental modes. In addition, the ab initio anharmonic force field of cis-1,2-difluoroethylene provided a critical assessment of the experimental spectroscopic parameters, especially in the treatments of strong Fermi interactions
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
Infrared Spectra, Integrated Band Intensities, and Anharmonic Force Field of H(2)C=CHF
No full textThe gas-phase infrared spectra of vinyl fluoride, H(2)C=CHF, have been examined at medium resolution in the range 400-8000 cm(-1). The assignment of the absorptions in terms of fundamental, overtone, and combination bands, assisted by quantum chemical calculations, is consistent all over the region investigated. Spectroscopic parameters, obtained from the analysis of partially resolved rotational structure of some bands, have been derived and compared with the corresponding calculated values. Accurate values of integrated band intensities have also been determined for the first time. High-level ab initio calculations with large basis sets have been performed. Correlated harmonic force fields have been obtained from coupled cluster CCSD(T) calculations with the cc-pVQZ basis set, while anharmonic force constants have been computed employing the less resource demanding cc-pVTZ basis set. A good agreement between the computed and the experimental data has been obtained including those for the integrated infrared band intensities
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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