1,721,022 research outputs found
Molecular vibrational spectroscopy by inelastic X ray scattering. Experimental determination of the absolute vibrational cross section in liquid nitrogen
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Ergodic to non-ergodic transition in liquids with a local order: the case of m-toluidine
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Non-ergodicity in a locally ordered fragile glass former
No full textWe measure the dynamic structure factor of m-toluidine through inelastic X-ray scattering in the mesoscopic Q range between 1 and 10 nm(-1), where the static structure factor exhibits a prepeak resulting from a molecular spatial organization in nanometer size clusters, due to the formation of hydrogen bonds. We present experimental evidence of the square-root cusp in the temperature behavior of the non-ergodicity factor of in-toluidine which supports the view that the mode-coupling theory succeeds in describing the dynamics of supercooled molecular liquids, even for liquids with a local order, notwithstanding the cage formation is controlled by a mechanism different from the packing constraints typical of simple liquids. Moreover, we report on the behavior of the non-ergodicity factor in the low-temperature and wavevector regimes, finding a confirmation of the phenomenologic law proposed by Scopigno et al. [T. Scopigno, G. Ruocco, F. Sette; G. Monaco, Science 302 (2003) 849] which correlates the vibrational dynamics of the glass to the fragility of the supercooled liquid
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
High energy-resolution set-up for Ir L3 edge RIXS experiments
No full textHigh energy-resolution resonant inelastic X-ray scattering (RIXS) at the L2,3 edges of 3d transition metal compounds has proved to be a very powerful technique for the study of elementary excitations of various nature. In the case of cuprates, in particular, it was realized that magnetic excitations can be directly accessed, thus complementing neutron scattering experiments. It is clearly desirable to extend this technique to 5d transition metal compounds, whose L2,3 edges lie in the hard X-ray energy range. In the case of Ir, the L3 edge is found at 11.215 keV. To access excitations energies similar to those of magnetic excitations in cuprates, a resolving power better than ≈105 is needed. Here, we describe the hard X-ray RIXS set-up at the ID16 beam line at the European Synchrotron Radiation Facility (ESRF), suitable for L3 edge RIXS studies of Ir oxides, with a combined energy-resolution of 36 meV, i.e. a resolving power of 3×105. © 2012 Elsevier B.V. All rights reserved
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