The effect of angular vibrations of the crystals in cryogenically cooled monochromators on the beam performance has been studied theoretically and experimentally. A simple relation between amplitude of the vibrations and size of the focused beam is developed. It is shown that the double-crystal monochromator vibrations affect not only the image size but also the image position along the optical axis. Several methods to measure vibrations with the X-ray beam are explained and analyzed. The methods have been applied to systematically study angular crystal vibrations at monochromators installed at the PETRA III light source. Characteristic values of the amplitudes of angular vibrations for different monochromators are presented.
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http://dx.doi.org/10.1107/S1600577516011188 | DOI Listing |
Phys Chem Chem Phys
January 2025
Abteilung für Molekulare Physikalische Chemie, Clausius-Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Wegelerstraße 12, 53115 Bonn, Germany.
The binding of carbon dioxide to a transition metal is a complex phenomenon that involves a major redistribution of electron density between the metal center and the triatomic ligand. The chemical reduction of the ligand reveals itself unambiguously by an angular distortion of the CO-molecule as a result of the occupation of an anti-bonding π-orbital and a shift of its antisymmetric stretching vibration, ν, to lower wavenumbers. Here, we generate a carbon dioxide complex of the heavier group-10 metal, platinum, by ultrafast electronic excitation and cleavage of CO from the photolabile oxalate precursor, oxaliplatin, and monitored the ensuing primary dynamics with ultrafast mid-infrared spectroscopy.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
January 2025
Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 China. Electronic address:
The line list is essential for accurately modeling various astrophysical phenomena, such as stellar photospheres and atmospheres of extrasolar planets. This paper introduces a new line database for the PS molecule spanning from the ultraviolet to the infrared regions, covering wavenumbers up to 45000 cm and containing over ten million transitions between 150,458 states with total angular momentum J < 160. Accurate line intensities for rotational, vibrational and electronic transitions are generated by using the general purpose variational code DUO.
View Article and Find Full Text PDFSensors (Basel)
December 2024
School of Physics and Information Engineering, Fuzhou University, Fuzhou 350108, China.
Permanent magnet synchronous motors (PMSMs) are widely used in a variety of fields such as aviation, aerospace, marine, and industry due to their high angular position accuracy, energy conversion efficiency, and fast response. However, driving errors caused by the non-ideal characteristics of the driver negatively affect motor control accuracy. Compensating for the errors arising from the non-ideal characteristics of the driver demonstrates substantial practical value in enhancing control accuracy, improving dynamic performance, minimizing vibration and noise, optimizing energy efficiency, and bolstering system robustness.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
School of Physics, Changchun University of Science and Technology, Changchun 130012, China.
Tungsten oxide (WO) electrochromic devices are obtaining increasing interest due to their color change and thermal regulation. However, most previous work focuses on the absorption or transmission spectra of materials, rather than the optical parameters evolution in full spectrum in the electrochromic processes. Herein, we developed a systematic protocol of ex situ methods to clarify the evolutions of subtle structure changes, Raman vibration modes, and optical parameters of WO thin films in electrochromic processes as stimulated by dosage-dependent Li insertion.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Group of Characterization of Materials, Departament de Física, Universitat Politècnica de Catalunya, Campus Diagonal-Besòs, Av. Eduard Maristany 10-14, Barcelona 08019, Spain.
Hybrid organic-inorganic perovskites (HOIP) have emerged in recent years as highly promising semiconducting materials for a wide range of optoelectronic and energy applications. Nevertheless, the rotational dynamics of the organic components and many-molecule interdependencies, which may strongly impact the functional properties of HOIP, are not yet fully understood. In this study, we quantitatively analyze the orientational disorder and molecular correlations in archetypal perovskite CHNHPbI (MAPI) by performing comprehensive molecular dynamics simulations and entropy calculations.
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