scholarly journals Electronic excitations in ZnWO4 and ZnxNi1−x WO4 (x = 0.1 − 0.9) using VUV synchrotron radiation

Open Physics ◽  
2011 ◽  
Vol 9 (2) ◽  
Author(s):  
Aleksandr Kalinko ◽  
Alexey Kotlov ◽  
Alexei Kuzmin ◽  
Vladimir Pankratov ◽  
Anatoli Popov ◽  
...  

AbstractThe photoluminescence spectra and luminescence excitation spectra of pure microcrystalline and nano-sized ZnWO4 as well as the ZnxNi1−x WO4 solid solutions were studied using vacuum ultraviolet (VUV) synchrotron radiation. The samples were also characterized by x-ray powder diffraction. We found that: (i) the shape of the photoluminescence band at 2.5 eV, being due to radiative electron transitions within the [WO6]6− anions, becomes modulated by the optical absorption of Ni2+ ions in the ZnxNi1−x WO4 solid solutions; and (ii) no significant change in the excitation spectra of Zn0.9Ni0.1WO4 is observed compared to pure ZnWO4. At the same time, a shift of the excitonic bands to smaller energies and a set of peaks, attributed to the one-electron transitions from the top of the valence band to quasi-localized states, were observed in the excitation spectrum of nano-sized ZnWO4.

2017 ◽  
Vol 24 (2) ◽  
pp. 521-530 ◽  
Author(s):  
S. Huotari ◽  
Ch. J. Sahle ◽  
Ch. Henriquet ◽  
A. Al-Zein ◽  
K. Martel ◽  
...  

An end-station for X-ray Raman scattering spectroscopy at beamline ID20 of the European Synchrotron Radiation Facility is described. This end-station is dedicated to the study of shallow core electronic excitations using non-resonant inelastic X-ray scattering. The spectrometer has 72 spherically bent analyzer crystals arranged in six modular groups of 12 analyzer crystals each for a combined maximum flexibility and large solid angle of detection. Each of the six analyzer modules houses one pixelated area detector allowing for X-ray Raman scattering based imaging and efficient separation of the desired signal from the sample and spurious scattering from the often used complicated sample environments. This new end-station provides an unprecedented instrument for X-ray Raman scattering, which is a spectroscopic tool of great interest for the study of low-energy X-ray absorption spectra in materials under in situ conditions, such as in operando batteries and fuel cells, in situ catalytic reactions, and extreme pressure and temperature conditions.


2014 ◽  
Vol 27 ◽  
pp. 1460142
Author(s):  
HUIRONG QI ◽  
MEI LIU

In the last few years, wire chambers have been frequently used for X-ray detection because of their low cost, large area and reliability. X-ray diffraction is an irreplaceable method for powder crystal lattice measurements. A one-dimensional single-wire chamber has been developed in our lab to provide high position resolution for powder diffraction experiments using synchrotron radiation. There are 200 readout strips of 0.5 mm width with a pitch of 1.0 mm in the X direction, and the working gas is a mixture of Ar and CO2 (90/10). The one-dimensional position of the original ionization point is determined by the adjacent strip's distribution information using the center of gravity method. Recently, a study of the detector's performance and diffraction image was completed at the 1W1B laboratory of the Beijing Synchrotron Radiation Facility (BSRF) using a sample of SiO2. Most of the relative errors between the measured values of diffraction angles and existing data were less than 1%. The best position resolution achieved for the detector in the test was 71 μm (σ value) with a 20 μm slit collimator. Finally, by changing the detector height in incremental distances from the center of the sample, the one-dimensional detector achieved a two-dimensional diffraction imaging function, and the results are in good agreement with standard data.


1986 ◽  
Vol 41 (9) ◽  
pp. 1091-1093 ◽  
Author(s):  
R. Tate ◽  
D. C. Driscoll ◽  
G. Stauf

We have investigated the optical absorption of CHCl3, CHBr3, and CHI3 in the vacuum ultraviolet, using synchrotron radiation as the light source. A number of absorption features have been observed and are assigned to n - σ*, n - s, n - p, and n - d, one electron excitations.


2013 ◽  
Vol 200 ◽  
pp. 186-192 ◽  
Author(s):  
Oksana Chukova ◽  
Sergiy G. Nedilko ◽  
Sergiy A. Nedilko ◽  
Vasyl Sherbatsky ◽  
Tetiana Voitenko

Luminescence properties of the two series of the La1-xEuxVO4 (x ranges from to 0.3) solid solutions synthesized by the solid state and co-precipitation methods were investigated.. Luminescence spectra of the investigated samples consist of narrow spectral lines caused by inner f - f electron transitions in the impurity Eu3+ ions. Excitation spectra consist of three main bands those correspond to different types of transitions in the investigated matrices. There are O - Eu3+ charge transfer transitions, band-to-band transitions in the matrix of the vanadate compounds and electron transitions in the VO43- vanadate anion. Dependences of the structure and luminescence properties on rate compositions and method of synthesis were studied. Origins of the observed differences between luminescence characteristics of the samples obtained by two different methods are discussed.


2000 ◽  
Vol 7 (4) ◽  
pp. 215-220 ◽  
Author(s):  
A. Baciero ◽  
K. J. McCarthy ◽  
M. A. Acedo ◽  
L. Rodriguez-Barquero ◽  
J.  Avila ◽  
...  

2015 ◽  
Vol 230 ◽  
pp. 172-177 ◽  
Author(s):  
Olesia Voloshyna ◽  
Ianina Boiaryntseva ◽  
Dmitry Spassky ◽  
Oleg Sidletskiy

Ceramic samples of tantalo-niobates solid solutions with yttrium and gadolinium cations (RE(NbxTa1-x)O4, RE = Y or Gd, and x=0÷1) have been obtained by solid-state synthesis. Luminescence properties of yttrium and gadolinium tantalo-niobates under X-ray and synchrotron radiation, UV and VUV radiation have been studied in visible and UV spectral regions. The luminescence mechanisms in yttrium and gadolinium tantalo-niobates have been determined as well.


2015 ◽  
Vol 22 (6) ◽  
pp. 1359-1363 ◽  
Author(s):  
Akio Toyoshima ◽  
Takashi Kikuchi ◽  
Hirokazu Tanaka ◽  
Kazuhiko Mase ◽  
Kenta Amemiya

Carbon-free chromium-coated optics are ideal in the carbonK-edge region (280–330 eV) because the reflectivity of first-order light is larger than that of gold-coated optics while the second-order harmonics (560–660 eV) are significantly suppressed by chromiumL-edge and oxygenK-edge absorption. Here, chromium-, gold- and nickel-coated mirrors have been adopted in the vacuum ultraviolet and soft X-ray branch beamline BL-13B at the Photon Factory in Tsukuba, Japan. Carbon contamination on the chromium-coated mirror was almost completely removed by exposure to oxygen at a pressure of 8 × 10−2 Pa for 1 h under irradiation of non-monochromated synchrotron radiation. The pressure in the chamber recovered to the order of 10−7 Pa within a few hours. The reflectivity of the chromium-coated mirror of the second-order harmonics in the carbonK-edge region (560–660 eV) was found to be a factor of 0.1–0.48 smaller than that of the gold-coated mirror.


1994 ◽  
Vol 348 ◽  
Author(s):  
C. Pedrini ◽  
A.N. Belsky ◽  
A.N. Vasil'ev ◽  
D. Bouttet ◽  
C. Dujardin ◽  
...  

ABSTRACTReflectivity and fluorescence excitation spectra and fluorescence decays of CeF3 and LaF3:Ce have been recorded and analyzed in the VUV range up to 120 eV and in the X-ray region using the synchrotron radiation. Dominant mechanisms are identified in various regions of excitation, leading to different shapes of the excitation spectra and typical profiles of the decay curves. Strong difference in the light yield of fluorides and oxides are shown and discussed in terms of relative energies of levels of cerium and of the valence and conduction bands of the solid compounds.


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