Search results for "Exafs spectroscopy"
showing 7 items of 7 documents
Local disorder studied inSrTiO3at low temperature by EXAFS spectroscopy
1994
The temperature dependence of the local distortions in ${\mathrm{SrTiO}}_{3}$ has been studied by EXAFS spectroscopy at the titanium K edge (4982 eV). The oxygen-ion Debye-Waller factor ${\mathrm{\ensuremath{\sigma}}}_{0}^{2}$ has been determined from 4.5 to 240 K. The antiferrodistortive transition at 105 K is evidenced by a step in this Debye-Waller factor. At about 31 K, a maximum of ${\mathrm{\ensuremath{\sigma}}}_{0}^{2}$ is detected and the EXAFS oscillations due to the first oxygen shell increase. This is the signature of a maximum disorder in the lattice vibrations in this temperature range. A quasiharmonic model with a sinusoidal modulation of the Ti-O distance cannot account for t…
Disappearance of correlations in the atom motion upon hydrogen intercalation into ReO3lattice
2016
The influence of hydrogen intercalation on the local structure of rhenium trioxide is studied in-situ by the Re L3-edge EXAFS spectroscopy and analysed using a novel approach, based on the use of evolutionary algorithm and wavelet transform. The proposed method allows us to perform accurate EXAFS analysis within the multiple-scattering approach taking into account contributions from outer coordination shells and to access the information on correlations in atomic thermal motion.
Probing the Thermochromic Phase Transition in CuMoO 4 by EXAFS Spectroscopy
2018
The work was supported by philanthropist MikroTik and administrated by the University of Latvia Foundation. The experiment at HASYLAB/DESY was performed within the project I-20160149 EC.
A spin transition molecular material with a wide bistability domain.
2002
International audience; [Fe(hyptrz)3](4-chloro-3-nitrophenylsulfonate)22 H2O (1; hyptrz=4-(3-hydroxypropyl)-1,2,4-triazole) has been synthesized and its physical properties have been investigated by several physical techniques including magnetic susceptibility measurements, calorimetry, and Mössbauer, optical, and EXAFS spectroscopy. Compound 1 exhibits a spin transition below room temperature, together with a very wide thermal hysteresis of about 50 K. This represents the widest hysteresis loop ever observed for an FeII-1,2,4-triazole spin transition material. The cooperativity is discussed on the basis of temperature-dependent EXAFS studies and of the structural features of a CuII analogu…
Photocontrolled On-Surface Pseudorotaxane Formation with Well-Ordered Macrocycle Multilayers.
2016
The photoinduced pseudorotaxane formation between a photoresponsive axle and a tetralactam macrocycle was investigated in solution and on glass surfaces with immobilized multilayers of macrocycles. In the course of this reaction, a novel photoswitchable binding station with azobenzene as the photoswitchable unit and diketopiperazine as the binding station was synthesized and studied by NMR and UV/Vis spectroscopy. Glass surfaces have been functionalized with pyridine-terminated SAMs and subsequently with multilayers of macrocycles through layer-by-layer self assembly. A preferred orientation of the macrocycles could be confirmed by NEXAFS spectroscopy. The photocontrolled deposition of the …
Role of Surface Chemistry in the Superhydrophobicity of the Springtail Orchesella cincta (Insecta:Collembola)
2020
Collembola are ancient arthropods living in soil with extensive exposure to dirt, bacteria, and fungi. To protect from the harsh environmental conditions and to retain a layer of air for breathing when submerged in water, they have evolved a superhydrophobic, liquid-repelling cuticle surface. The nonfouling and self-cleaning properties of springtail cuticle make it an interesting target of biomimetic materials design. Recent research has mainly focused on the intricate microstructures at the cuticle surface. Here we study the role of the cuticle chemistry for the Collembola species Orchesella cincta (Collembola, Entomobryidae). O. cincta uses a relatively simple cuticle structure with prima…
Octahedral Tilting in Homologous Perovskite Series CaMoO3-SrMoO3-BaMoO3 Probed by Temperature-Dependent EXAFS Spectroscopy
2022
This research was funded by the State Education Development Agency project No. 1.1.1.2/VIAA/3/19/444 (agreement No. 1.1.1.2/16/I/001) realized at the Institute of Solid State Physics, University of Latvia; the Institute of Solid State Physics, University of Latvia, as the Center of Excellence received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.