Author
Michal Dušek
Other affiliations: Brno University of Technology, Tarbiat Modares University, University of Lausanne ...read more
Bio: Michal Dušek is an academic researcher from Academy of Sciences of the Czech Republic. The author has contributed to research in topics: Crystal structure & Schiff base. The author has an hindex of 34, co-authored 511 publications receiving 7829 citations. Previous affiliations of Michal Dušek include Brno University of Technology & Tarbiat Modares University.
Papers published on a yearly basis
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TL;DR: JANA2006 as discussed by the authors is a widely used program for structure determination of standard, modulated and magnetic samples based on X-ray or neutron single crystal/ powder diffraction or on electron diffraction.
Abstract: Abstract JANA2006 is a freely available program for structure determination of standard, modulated and magnetic samples based on X-ray or neutron single crystal/ powder diffraction or on electron diffraction. The system has been developed for 30 years from specialized tool for refinement of modulated structures to a universal program covering standard as well as advanced crystallography. The aim of this article is to describe the basic features of JANA2006 and explain its scope and philosophy. It will also serve as a basis for future publications detailing tools and methods of JANA.
3,545 citations
TL;DR: In this article, defects acting as electron traps were investigated in the presence of oxygen vacancies acting as traps in rare-earth ionites, and the glow curves for both LSO and LYSO were compared by wavelength-resolved thermally stimulated luminescence (TSL) measurements from 20 to 400.
Abstract: We present an investigation of defects acting as electron traps in ${\text{Lu}}_{2}{\text{SiO}}_{5}$ (LSO) and ${\text{Lu}}_{x}{\text{Y}}_{2\ensuremath{-}x}{\text{SiO}}_{5}$ (LYSO) performed by wavelength-resolved thermally stimulated luminescence (TSL) measurements from 20 to $400\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ after room-temperature (RT) x-ray irradiation Single crystals doped with several rare-earth ions such as Ce, Tb, Tm, and Sm were considered A comparison between TSL and RT radio-luminescence (RL) emission spectra is also presented The glow curves for both LSO and LYSO are similar, showing a series of TSL peaks at 78, 135, 181, and $236\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ In addition, a further peak at about $300\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ is observed only in LYSO Our results confirm the role of oxygen vacancies as electron traps in the material; the presence of several glow peaks with a unique trap depth $(099\text{ }\text{eV}\ifmmode\pm\else\textpm\fi{}007\text{ }\text{eV})$ for the 78, 135, 181, and $236\text{ }\ifmmode^\circ\else\textdegree\fi{}\text{C}$ peaks is explained by suggesting that electrons stored in oxygen vacancies recombine through a thermally assisted tunneling mechanism with holes localized at ${\text{Ce}}^{3+}$ or ${\text{Tb}}^{3+}$ centers residing on Lu sites at different crystallographic distances from the traps This model is supported by the very good correlation among O-Lu distances in the monoclinic $C2/c$ structure of LSO and LYSO and the frequency factors of the traps containing the transmission coefficients of the potential barriers between traps and centers, evaluated in the framework of the thermally assisted tunneling process Tm and Sm ions do not act as TSL recombination centers possibly due to their tendency to trap electrons during irradiation with ionizing radiation
138 citations
TL;DR: In this article, a new Mo6 cluster complex and its silica and polyurethane composites have been synthesized and characterized, which are highly luminescent with emission above 650 nm, produce singlet oxygen with high efficiency, and can be excited up to 580 nm.
Abstract: A new Mo6 cluster complex and its silica and polyurethane composites have been synthesized and characterized. These materials are highly luminescent with emission above 650 nm, produce singlet oxygen with high efficiency, are photostable, and can be excited up to 580 nm. These properties are desirable for the construction of luminescent probes of oxygen, photoactive materials for oxidation reactions with easily separable active carriers, and bactericidal textile surfaces upon daylight irradiation.
120 citations
TL;DR: In this article, the authors presented the basic information about these compounds as well as their purification and the results obtained in crystal growth, and compared the crystal structures of these compounds and their comparison with that of PbCl2.
111 citations
TL;DR: JANA2000 as discussed by the authors is a computer program for the refinement and analysis of periodic and aperiodic (incommensurately modulated structures and composite crystals) crystal structures.
Abstract: JANA is a computer program for the refinement and analysis of periodic and aperiodic (incommensurately modulated structures and composite crystals) crystal structures. Here a new module is introduced that allows Rietveld refinements against powder diffraction data. It is shown that JANA2000 provides a state-of-the-art description of the peak profiles. A re-analysis of the low-temperature structure of (CO)xC60 showed that the application of icosahedral symmetry restrictions to the C60 molecule leads to a better description of the electron density and to a corrected position of the CO molecule as compared with a rigid-body refinement. The incommensurately modulated structure of NbTe4 has been successfully refined against X-ray powder diffraction data. The structural parameters are equal to, but less accurate, than the parameters obtained from a single-crystal study.
101 citations
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28,685 citations
TL;DR: JANA2006 as discussed by the authors is a widely used program for structure determination of standard, modulated and magnetic samples based on X-ray or neutron single crystal/ powder diffraction or on electron diffraction.
Abstract: Abstract JANA2006 is a freely available program for structure determination of standard, modulated and magnetic samples based on X-ray or neutron single crystal/ powder diffraction or on electron diffraction. The system has been developed for 30 years from specialized tool for refinement of modulated structures to a universal program covering standard as well as advanced crystallography. The aim of this article is to describe the basic features of JANA2006 and explain its scope and philosophy. It will also serve as a basis for future publications detailing tools and methods of JANA.
3,545 citations
TL;DR: The SQUEEZE method is documents as an alternative means of addressing the solvent disorder issue and conveniently interfaces with the 2014 version of the least-squares refinement program SHELXL, and many twinned structures containing disordered solvents are now also treatable by SQUEEze.
Abstract: The completion of a crystal structure determination is often hampered by the presence of embedded solvent molecules or ions that are seriously disordered. Their contribution to the calculated structure factors in the least-squares refinement of a crystal structure has to be included in some way. Traditionally, an atomistic solvent disorder model is attempted. Such an approach is generally to be preferred, but it does not always lead to a satisfactory result and may even be impossible in cases where channels in the structure are filled with continuous electron density. This paper documents the SQUEEZE method as an alternative means of addressing the solvent disorder issue. It conveniently interfaces with the 2014 version of the least-squares refinement program SHELXL [Sheldrick (2015). Acta Cryst. C71. In the press] and other refinement programs that accept externally provided fixed contributions to the calculated structure factors. The PLATON SQUEEZE tool calculates the solvent contribution to the structure factors by back-Fourier transformation of the electron density found in the solvent-accessible region of a phase-optimized difference electron-density map. The actual least-squares structure refinement is delegated to, for example, SHELXL. The current versions of PLATON SQUEEZE and SHELXL now address several of the unnecessary complications with the earlier implementation of the SQUEEZE procedure that were a necessity because least-squares refinement with the now superseded SHELXL97 program did not allow for the input of fixed externally provided contributions to the structure-factor calculation. It is no longer necessary to subtract the solvent contribution temporarily from the observed intensities to be able to use SHELXL for the least-squares refinement, since that program now accepts the solvent contribution from an external file (.fab file) if the ABIN instruction is used. In addition, many twinned structures containing disordered solvents are now also treatable by SQUEEZE. The details of a SQUEEZE calculation are now automatically included in the CIF archive file, along with the unmerged reflection data. The current implementation of the SQUEEZE procedure is described, and discussed and illustrated with three examples. Two of them are based on the reflection data of published structures and one on synthetic reflection data generated for a published structure.
2,712 citations