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Каталог книг и брошюр библиотеки ИФ СО РАН

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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Atuchin V. V., Bazarov B. G., Gavrilova T. A., Grossman V. G., Molokeev M. S., Bazarova Zh. G.
Заглавие : Preparation and structural properties of nonlinear optical borates K 2(1-x)Rb 2xAl 2B 2O 7, 0 ˂ x ˂ 0.75
Место публикации : J. Alloys Compd.: Elsevier, 2012. - Vol. 515. - P.119-122. - ISSN 0925-8388, DOI 10.1016/j.jallcom.2011.11.115
Примечания : Cited References: 30. - This study was supported by SB RAS (Grant 34) and RFBR Grants 11-02-90706-mob_st and 11-03-00867a.
Предметные рубрики: UV-light generation
Frequence-conversion
K2Al2B2O7 crystal
Composition ratio
Mixed-crystals
Growth
KRbAl2B2O7
NLO properties
Non-linear optical
Non-linear optical properties
Rietveld analysis of X-ray powder diffraction data
Solubility limits
Space Groups
Structural parameter
Ключевые слова (''Своб.индексиров.''): krbal2b2o7--solid solution--crystal structure--nlo properties
Аннотация: The structures of K 2(1-x)Rb 2xAl 2B 2O 7, x = 0.25, 0.5, 0.75, have been determined in space group P321 through Rietveld analysis of X-ray powder diffraction data. The solubility limit in K 2(1-x)Rb 2xAl 2B 2O 7 crystals has been estimated as x similar to 0.83-0.9. Nonlinear optical properties of KRbAl 2B 2O 7 have been verified by powder Kurtz-Perry method. Mechanisms of structural parameter variation in K 2Al 2B 2O 7 crystal family have been discussed.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Atuchin V. V., Molokeev M. S., Yurkin G. Yu., Gavrilova T. A., Kesler V. G., Laptash N. M., Flerov I. N., Patrin G. S.
Заглавие : Synthesis, structural, magnetic, and electronic properties of cubic CsMnMoO3F3 oxyfluoride
Место публикации : J. Phys. Chem. C: American Chemical Society, 2012. - Vol. 116, Is. 18. - P.10162-10170. - ISSN 1932-7447, DOI 10.1021/jp302020f
Примечания : Cited References: 64. - We thank Dr. A.M. Ziatdinov for the electron paramagnetic resonance measurements. This study was partly supported by SB RAS (Grant 28).
Предметные рубрики: RAY PHOTOELECTRON-SPECTROSCOPY
PHASE-TRANSITIONS
CORE LEVELS
SURFACE CHARACTERIZATION
CRYSTAL-STRUCTURE
CLEAVED SURFACE
MIXED-VALENCE
OXIDES
MN
MOLYBDENUM
Chemical bondings
Cubic phase
Energy differences
Heat capacity measurements
Oxyfluorides
Powder samples
Solid-state synthesis
Space Groups
Temperature range
Valence electron
Binding energy
Chemical bonds
Electronic structure
Fluorine compounds
Magnetic properties
Metal ions
Photoelectrons
Rietveld method
X ray photoelectron spectroscopy
Electronic properties
Аннотация: A powder sample of CsMnMoO3F3 oxyfluoride has been prepared by solid state synthesis. The pyrochlore-related crystal structure of CsMnMoO3F3 has been refined by the Rietveld method at T = 298 K (space group Fd-3m, a = 10.59141(4) angstrom, V = 1188.123(8) angstrom(3); R-B = 3.44%). The stability of the cubic phase has been obtained over the temperature range T = 110-293 K by heat capacity measurements. Magnetic properties have been measured over the range of T = 2-300 K. The electronic structure of CsMnMoO3F3 has been evaluated by X-ray photoelectron spectroscopy. Chemical bonding effects have been discussed for all metal ions using binding energy difference parameters and wide comparison with related oxides and fluorides. The competition between O-2(-) and F- ions for metal valence electrons has been found.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Atuchin V. V., Gavrilova T. A., Kesler V. G., Molokeev M. S., Aleksandrov K. S.
Заглавие : Low-temperature synthesis and structural properties of ferroelectric K 3WO3F3 elpasolite
Место публикации : Chem. Phys. Lett. - 2010. - Vol. 493, Is. 1-3. - P.83-86. - ISSN 0009-2614, DOI 10.1016/j.cplett.2010.05.023
Примечания : Cited References: 37
Предметные рубрики: PEROVSKITE-LIKE OXYFLUORIDES
CORE-LEVEL SPECTROSCOPY
PHASE-TRANSITIONS
SOLID-STATE
ELECTRON-DIFFRACTION
DIFFUSE-SCATTERING
RHEED ANALYSIS
POLAR
BEHAVIOR
(NH4)(3)TIOF5
Ключевые слова (''Своб.индексиров.''): chemical synthesis--elpasolite--ferroelectric phase transition--fluorine atoms--low temperature synthesis--low temperatures--oxyfluorides--partial ordering--room temperature--sem--space groups--structure parameter--xrd--chemical properties--ferroelectric materials--ferroelectricity--fluorine--oxygen--phase transitions--rietveld method--single crystals--synthesis (chemical)--x ray photoelectron spectroscopy--x ray powder diffraction--scanning electron microscopy
Аннотация: Low-temperature ferroelectric G2 polymorph of K3WO 3F3 has been prepared by chemical synthesis. Structural and chemical properties of the final product have been evaluated with X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Structure parameters of G2-K 3WO3F3 are refined by the Rietveld method from XRD data measured at room temperature (space group Cm, Z = 2, a = 8.7350(3), b = 8.6808(5), c = 6.1581(3), ? = 135.124(3), V = 329.46(3) 3; RB = 2.47%). Partial ordering of oxygen and fluorine atoms has been found over anion positions. Mechanism of ferroelectric phase transition in A2BMO3F3 oxyfluorides is discussed. В© 2010 Elsevier B.V. All rights reserved.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Molokeev M. S., Vasiliev A. D., Kocharova A. G.
Заглавие : Crystal structures of room- and low-temperature phases in oxyfluoride (NH4)(2)KWO3F3
Место публикации : Powder Diffr. - 2007. - Vol. 22, Is. 3. - P.227-230. - ISSN 0885-7156, DOI 10.1154/1.2759491
Примечания : Cited References: 8. - Cover image: Artwork representing main idea of this article
Ключевые слова (''Своб.индексиров.''): structure determination--rietveld analysis--powder diffraction--phase transition--oxyfluoride
Аннотация: Crystal structures of (NH4)2KWO(3)F(3) at 298 K and 113 K were solved from X-ray powder diffraction data and refined by the Rietveld technique. The compound is isostructural with elpasolite K2NaAlF6 at room temperature with space group Fm-3m, a=8.95850(5) angstrom, V=718.961(7) angstrom(3), Z =4, D-x=3.363 g/cm(3), and M-W=364.02. The structure was refined over 18 parameters to R-wp =12.6%, R-p=10.9%, R-exp=5.03%, and R-B=3.27% from 40 independent reflections. (NH4)2KWO(3)F(3) was transformed upon cooling to a ferroelastic monoclinic phase with space group P2(1)/n, a'=6.3072(3) angstrom, b'=6.3028(3) angstrom, c'=8.9882(3) angstrom, beta'=90.242(2)degrees, V=357.30(3) angstrom(3), Z =2, and D-x=3.383 g/cm(3). The low-temperature structure at 113 K was refined over 28 parameters,P to R-wp=20.9%, R-p=21.3%, R-exp= 12.5%, and R-B=6.93% from 453 independent reflections. (C) 2007 International Centre for Diffraction Data.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pustovarov V. A., Ogorodnikov I. N., Omelkov S. I., Molokeev M. S., Kozlov A. V., Isaenko L. I.
Заглавие : Photoluminescence of monoclinic Li3AlF6 crystals under vacuum ultraviolet and soft X-ray excitations
Место публикации : Opt. Mater.: Elsevier, 2015. - Vol. 49. - P.201-207. - ISSN 0925-3467, DOI 10.1016/j.optmat.2015.09.011
Примечания : Cited References: 49. - This work was partly supported by the Ministry of Education and Science of the Russian Federation (the basic part of the government mandate); Center of Excellence "Radiation and Nuclear Technologies" (Competitiveness Enhancement Program of Ural Federal University, Russia), HASYLAB DESY (Projects Nos. 20110843, 20080119EC), European Social Fund ("Mobilitas" program, MJD219), Estonian Research Council (Institutional Research Funding IUT02-26) and Baltic Science Link project coordinated by the Swedish Research Council, VR
Предметные рубрики: LiBaAlF6 single-crystals
F-type centers
LiBaF3 crystals
Color-centers
Recombination luminescence
Rietveld refinement
VUV spectroscopy
Trapped excitons
Energy-transfer
Pure
Ключевые слова (''Своб.индексиров.''): li3alf6--time-resolved luminescence--vuv spectroscopy--defects
Аннотация: Using Bridgman technique we have grown monoclinic β-LiAF crystals suitable for optical studies, performed XRD-identification and Rietveld refinement of the crystal structure and carried out a photoluminescence study upon vacuum ultraviolet (VUV) and extreme ultraviolet (XUV)-excitations, using the low-temperature (T = 7.2 K) time-resolved VUV-spectroscopy technique. The intrinsic PL emission band at 340–350 nm has been identified as due to radiative recombination of self-trapped excitons. The electronic structure parameters were determined: bandgap E g ≈ 12.5 eV, energy threshold for creation of unrelaxed excitons 11.8 eV < E n < 12.5 eV . The PL emission bands at 320–325 and 450 nm were attributed to luminescence caused by lattice defects. We have discovered an efficient excitation of PL emission bands in the energy range of interband transitions ( E ex > 13.5 eV), as well as in the energy range of core transitions at 130 eV. We have revealed UV–VUV PL emission bands at 170 and 208 nm due to defects. A reasonable assumptions about the origin of the UV–VUV bands were discussed.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhang M., Xia Z., Molokeev M. S., Shi L., Liu Q.
Заглавие : New insight into the crystal structure of Sr4Ca(PO4)2SiO4 and the photoluminescence tuning of Sr4Ca(PO4)2SiO4:Ce3+,Na+,Eu2+ phosphors
Место публикации : J. Mater. Chem. C: Royal Society of Chemistry, 2016. - Vol. 4, Is. 38. - P.9078-9084. - ISSN 20507534 (ISSN), DOI 10.1039/c6tc03373c
Примечания : Cited References: 31
Ключевые слова (''Своб.индексиров.''): calcium--energy transfer--europium--light emission--light emitting diodes--luminescence--phosphate minerals--phosphors--photoluminescence--positive ions--rietveld refinement--tuning--chemical compositions--energy transfer mechanisms--green component--hexagonal cells--luminescence properties--single phase--solid state method--white lightemitting diodes (wleds)--crystal structure
Аннотация: A new single phase based on the substitution of a Sr cation by a Ca cation in the apatite-type Sr5(PO4)2(SiO4) has been fabricated with the nominal chemical composition of Sr4Ca(PO4)2(SiO4), which appears as a definite compound rather than a solid solution between (Sr,Ca)3(PO4)2 and (Sr,Ca)2SiO4. The crystal structure of Sr4Ca(PO4)2(SiO4) has been firstly analysed by the difference electron map, and further resolved by the Rietveld refinement, and the final composition has been determined as Sr4Ca(PO4)(2+x)(SiO4)(1-x)(OH)x (x = 0.64) with a hexagonal cell (P63/m). The Ce3+/Eu2+ codoped Sr4Ca(PO4)2SiO4 phosphors have been designed and prepared by the solid state method, and the photoluminescence tuning from blue to green upon 365 nm ultraviolet (UV) radiation can be realized, which is ascribed to the energy transfer from Ce3+ to Eu2+ ions. The luminescence properties and the energy transfer mechanism in Ce3+/Eu2+ codoped Sr4Ca(PO4)2SiO4 phosphors have been discussed, which might act as potential candidates for blue-green components in UV-pumped white light emitting diodes (WLEDs). © 2016 The Royal Society of Chemistry.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Atuchin V. V., Subanakov A. K., Aleksandrovsky A. S., Bazarov B. G., Bazarova J. G., Dorzhieva S. G., Gavrilova T. A., Krylov A. S., Molokeev M. S., Oreshonkov A. S., Pugachev A. M., Tushinova Y. L., Yelisseyev A. P.
Заглавие : Exploration of structural, thermal, vibrational and spectroscopic properties of new noncentrosymmetric double borate Rb3NdB6O12
Место публикации : Adv. Powder Technol.: Elsevier, 2017. - Vol. 28, Is. 5. - P.1309-1315. - ISSN 09218831 (ISSN), DOI 10.1016/j.apt.2017.02.019
Примечания : Cited References: 42. - We are grateful to Guochun Zhang for the crystal structure data on K3YB6O12, and O. Tsydenova and A. Sarapulova for her consultations. This research was supported by SB RAS Program No.II.2P (No. 0356-2015-0412) and RSF (14-22-0143). The reported study was funded by RFBR according to the research projects 15-02-04950 and 15-52-53080, 16-32-00351, 16-52-48010 and 17-52-53031. Also, the work was supported by Act 211 Government of the Russian Federation, contract 02.A03.21.0011 and by the Ministry of Education and Science of the Russian Federation (4.1346.2017/PP).
Ключевые слова (''Своб.индексиров.''): rubidium neodymium borate--solid state reaction--rietveld refinement--dsc--raman scattering
Аннотация: New noncentrosymmetric rare earth borate Rb3NdB6O12 is found in the ternary system Rb2O–Nd2O3–B2O3. The Rb3NdB6O12 powder was fabricated by solid state synthesis at 1050 K for 72 h and the crystal structure was obtained by the Rietveld method. Rb3NdB6O12 crystallized in space group R32 with unit cell parameters a = 13.5236(4), c = 31.162(1) Å, Z = 3. From DSC measurements, the reversible phase transition (I type) in Rb3NdB6O12 is observed at 852–936 K. The 200 μm thick tablet is transparent over the spectral range of 0.3–6.5 μm and the band gap is found as Eg ∼ 6.29 eV. Nonlinear optical response of Rb3NdB6O12 tested via SHG is estimated to be higher than that of K3YB6O12. Blue shift of Nd luminescent lines is found in comparison with other borates. The vibrational parameters of Rb3NdB6O12 are evaluated by experimental methods.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Chen M., Xia Z., Molokeev M. S., Lin C. C., Su C., Chuang Y. -C., Liu Q.
Заглавие : Probing Eu2+ luminescence from different crystallographic sites in Ca10M(PO4)7:Eu2+ (M = Li, Na, and K) with β-Ca3(PO4)2-type structure
Место публикации : Chem. Mater.: American Chemical Society, 2017. - Vol. 29, Is. 17. - P.7563-7570. - ISSN 08974756 (ISSN), DOI 10.1021/acs.chemmater.7b02724
Примечания : Cited References: 34. - The present work was supported by the National Natural Science Foundation of China (Grants 51722202, 91622125, and 51572023), Natural Science Foundations of Beijing (2172036), and Fundamental Research Funds for the Central Universities (FRF-TP-16-002A3). C.C.L. and C.C.S. acknowledge the financial support from the Ministry of Science and Technology of Taiwan (Contract No. MOST 104-2113-M-027-007-MY3), and M. Molokeev acknowledges support of the Russian Foundation for Basic Research (17-52-53031).
Ключевые слова (''Своб.индексиров.''): calcium--doping (additives)--excited states--light emission--lithium--luminescence--phosphors--photoluminescence--positive ions--rietveld refinement--single crystals--color tuning--crystallographic sites--different distributions--emission bands--local environments--long wavelength bands--luminescent centers--power diffraction data--europium
Аннотация: Eu2+ local environments in various crystallographic sites enable the different distributions of the emission and excitation energies and then realize the photoluminescence tuning of the Eu2+ doped solid state phosphors. Herein we report the Eu2+-doped Ca10M(PO4)7 (M = Li, Na, and K) phosphors with β-Ca3(PO4)2-type structure, in which there are five cation crystallographic sites, and the phosphors show a color tuning from bluish-violet to blue and yellow with the variation of M ions. The difference in decay rate monitored at selected wavelengths is related to multiple luminescent centers in Ca10M(PO4)7:Eu2+, and the occupied rates of Eu2+ in Ca(1), Ca(2), Ca(3), Na(4), and Ca(5) sites from Rietveld refinements using synchrotron power diffraction data confirm that Eu2+ enters into four cation sites except for Ca(5). Since the average bond lengths d(Ca-O) remain invariable in the Ca10M(PO4)7:Eu2+, the drastic changes of bond lengths d(M-O) and Eu2+ emission depending on the variation from Li to Na and K can provide insight into the distribution of Eu2+ ions. It is found that the emission band at 410 nm is ascribed to the occupation of Eu2+ in the Ca(1), Ca(2), and Ca(3) sites with similar local environments, while the long-wavelength band (466 or 511 nm) is attributed to Eu2+ at the M(4) site (M = Na and K). We show that the crystal-site engineering approach discussed herein can be applied to probe the luminescence of the dopants and provide a new method for photoluminescence tuning.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Atuchin V. V., Subanakov A. K., Aleksandrovsky A. S., Bazarov B. G., Bazarova J. G., Gavrilova T. A., Krylov A. S., Molokeev M. S., Oreshonkov A. S., Stefanovich S. Y.
Заглавие : Structural and spectroscopic properties of new noncentrosymmetric self-activated borate Rb3EuB6O12 with B5O10 units
Место публикации : Mater. Des. - 2018. - Vol. 140. - P.488-494. - ISSN 02641275 (ISSN), DOI 10.1016/j.matdes.2017.12.004
Примечания : Cited References: 53. - We are grateful to Guochun Zhang for the crystal structure materials on K3YB6O12 and O. Tsydenova, A. Sarapulova for the consultations. The work was supported by Projects № 0356-2015-0412 of SB RAS Program № II.2P and № 0339-2016-0007. The reported study was funded by RFBR according to research projects 16-52-48010, 17-02-00920, 17-03-00886 and 17-52-53031 and RSF project 14-22-00143. The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0011, and by the Ministry of Education and Science of the Russian Federation (5.5523.2017/8.9). This research was supported by Grant no. 8.2.01.2017 of Tomsk State University Academic D.I. Mendeleev Fund Program.
Ключевые слова (''Своб.индексиров.''): rubidium rare earth borate--solid state reaction--rietveld refinement--raman--infrared spectroscopy--luminescence
Аннотация: New noncentrosymmetric double borate Rb3EuB6O12 was designed and synthesized by the solid state reaction method, and its crystallographic parameters were obtained by Rietveld analysis. This borate crystallizes in the trigonal space group R32 with cell parameters a = 13.4604(2) Å, c = 30.7981(5) Å, Z = 15. Its structure features a three-dimensional framework composed of the [B5O10]5 − groups that are bridged by Eu-O polyhedra. The existence of B5O10 group in the structure was confirmed by vibrational spectroscopy. Rb3EuB6O12 melts incongruently at 1101 K. The second harmonic generation effect of Rb3EuB6O12 is 16 times higher than that of the α-quartz standard. In the luminescence spectrum, the domination of a single prominent narrow line from the hypersensitive 5D0 - 7F2 manifold of Eu3 + ions is observed, while the 5D0 - 7F1 manifold and ultranarrow 5D0 - 7F0 line are of comparable peak intensity. These features are explained by a specific local symmetry of the Eu3+ ion within the crystal structure of Rb3EuB6O12.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Jiang C., Brik M. G., Li L., Li L., Peng J., Wu J., Molokeev M. S., Wong K. -L., Peng M.
Заглавие : The electronic and optical properties of a narrow-band red-emitting nanophosphor K2NaGaF6:Mn4+ for warm white light-emitting diodes
Место публикации : J. Mater. Chem. C. - 2018. - Vol. 6, Is. 12. - P.3016-3025. - ISSN 20507534 (ISSN), DOI 10.1039/c7tc05098d
Примечания : Cited References: 55. - We acknowledge the financial support received from the Program for Innovative Research Team in University of Ministry of Education of China (Grant No. IRT_17R38), the Key Program of Guangzhou Scientific Research Special Project (Grant No. 201607020009), the National Natural Science Foundation of China (Grant No. 51672085, 51322208, 3160440), and the Fundamental Research Funds for the Central Universities. M. G. Brik acknowledges the supports received from the Recruitment Program of High-end Foreign Experts (Grant No. GDW20145200225), the Programme for the Foreign Experts offered by Chongqing University of Posts and Telecommunications, Ministry of Education and Research of Estonia, (Project PUT430) and European Regional Development Fund (Project TK141), and the Guest Professorship at Kyoto University (Prof. S. Tanabe laboratory). The first-principles calculations were carried out using the resources provided by the Wroclaw centre for Networking and Supercomputing (http://wcss.pl; Grant No. WCSS#10117290).
Ключевые слова (''Своб.индексиров.''): energy efficiency--gallium compounds--light emission--light emitting diodes--manganese--manganese compounds--optical properties--phosphors--precipitation (chemical)--quenching--rietveld refinement--sodium compounds
Аннотация: Recently, as a key red component in the development of warm white light-emitting diodes (WLEDs), Recently, as a key red component in the development of warm white light-emitting diodes (WLEDs), Mn4+-doped fluorides with narrow red emission have sparked rapidly growing interest because they improve color rendition and enhance the visual energy efficiency. Herein, a red nanophosphor, K2NaGaF6:Mn4+, with a diameter of 150-250 nm has been synthesized using a simple co-precipitation method. Rietveld refinement reveals that it crystallizes in the space group Fm3m with the cell parameter a = 8.25320(4) Å. The exchange charge model (ECM) has been used to calculate the energy levels of Mn4+ ions in K2NaGaF6, which match well with the experimental spectra. The as-synthesized phosphor exhibits a narrow red emission at around 630 nm (spin-forbidden 2Eg → 4A2 transition of Mn4+ ions) when excited at 365 nm (4A2g → 4T1g) and 467 nm (4A2g → 4T2g), with a quantum efficiency (QE) of 61% and good resistance to thermal quenching. Based on the structure, the formation mechanism of ZPL has been discussed. In addition, the concentration-dependent decay curves of Mn4+ in K2NaGaF6 were fitted using the Inokuti-Hirayama model, suggesting that the dipole-dipole interactions determine the concentration quenching. Finally, encouraged by the good performance, a warm LED with a CRI of 89.4 and CCT of 3779 K was fabricated by employing the title nanophosphor as the red component. Our findings suggest that K2NaGaF6:Mn4+ can be a viable candidate for the red phosphor used in warm WLEDs.
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