2014 Journal Articles
Journal Articles
- Malakhovskii A.V., Kutsak T.V., Sukhachev A.L., Aleksandrovsky A.S., Krylov A.S., Gudim I.A., Molokeev M.S. Spectroscopic properties of ErAl3(BO3)4single crystal // Chemical Physics. 2014. V. 428.P 137–143.
Single crystal of ErAl3(BO3)4 was grown and its structure was studied. Polarized absorption spectra of ErAl3(BO3)4 single crystal were measured in the spectral range 1670–330 nm (6000–30000 cm1). The Judd–Ofelt spectroscopic parameters have been determined: O2 = 4.87 x 10-20 cm2, O4 = 2.49 x 10-20 cm2, O6 = 2.72 x 10-20 cm2. These parameters have been used to calculate the radiative transition probabilities, the multiplet luminescence branching ratios and the fluorescence life times of the manifolds. The luminescence spectra due to transitions 2H11/2 → 4I15/2 (526 nm), 4S3/2 → 4I15/2 (548 nm), 4F9/2 → 4I15/2 (662 nm), 2H11/2 → 4I13/2 + 4I9/2 → 4I15/2 (800 nm) and 4S3/2 → 4I13/2 (855 nm) were recorded in a, r and p polarizations. The most intensive luminescence belonged to 4S3/2 → 4I15/2 transition (548 nm).
- Krylov A.S, Goryainov S.V., Laptash N.M., Vtyurin A.N., Melnikova S.V., Krylova S.N. Influence of the Molecular Groups Ordering on Structural Phase Transitions in (NH4)2WO2F4Crystal // Cryst. Growth Des. 2014. V 14, P 374−380.
Phase transitions of the (NH4)2WO2F4 crystal were studied by Raman spectroscopy in the range from 10 to 350 K. The mechanism of two phase transitions at T1 = 201 and T2 = 160 K was proposed. The significant spectra changes occur in the range corresponding to the W−O vibrations. The first temperature phase transition is due to the ordering of the quasi-octahedral groups [WO2F4]2− and partial ordering of ammonium groups. Experimental data allow for attributing the first (T1 = 201 K) phase transition to the first order close to the tricritical point. The noticeable changes of the Raman spectrum have been found in the range corresponding to the ammonium vibrations below the temperature T2. The second phase transition is associated with the further ordering of ammonium groups. Room temperature (296 K) experiments have been carried out under high hydrostatic pressure up to 10 GPa. Above 2 GPa, new spectral features appear, allowing for the assumption of the existence of a new high-pressure phase of (NH4)2WO2F4, which is mainly connected with ordering of the [WO2F4]2− quasioctahedral groups.
- Krylov A.S, Kolesnikova E.M., Isaenko L.I., Krylova S.N., Vtyurin A.N. Measurement of Raman-Scattering Spectra of Rb2KMoO3F3 Crystal: Evidence for Controllable Disorder in the Lattice Structure// Cryst. Growth Des. 2014. V 14, P 923−927.
The λ-shaped line width broadening anomalies of octahedron group vibrations in Rb2KMoO3F3 disordered crystal have been revealed in the wide temperature range by Raman technique. The line width of Mo−O and Mo−F vibrations in this crystal is connected with the lattice disorder. The dependence of ordering degree passing the phase transition point history has been discovered. Wide temperature−line width area is found below structural phase transition where different lattice disorder can be obtained at a given temperature by varying the rate of sample cooling. The current study demonstrates the ability of a dynamic temperature regime to control ordering processes in crystals.
- Герасимова Ю.В., Орешонков А.С., Иваненко А.А., Молокеев М.С., Исаенко Л.И., Флеров И.Н., Богданов Е.В., Горев М.В., Карташев А.В., Крылов А.С. Структурные, спектроскопические и теплофизические исследования оксифторидов CsZnMoO3F3 и CsMnMoO3F3со структурой пирохлора // ФТТ. 2014. Т 56, Вып. 3. С 577-582.
Исследования структуры, спектров ИК и КР, теплоемкости и теплового расширения показали, что вплоть до гелиевых температур кубическая структура пирохлора в CsMnMoO3F3 и CsZnMoO3F3 остается стабильной. Выполнен анализ влияния катионного замещения на индивидуальные особенности свойств оксифторидов.
- Krylov A.S., Sofronova S.N., Kolesnikova E.M., Ivanov Yu.N., Sukhovsky A.A., Goryainov S.V., Ivanenko A.A., Shestakov N.P., Kocharova A.G., Vtyurin A.N. Experimental and theoretical methods to study structural phase transition mechanisms in K3WO3F3oxyfluoride // J. Solid State Chem. 2014. V. 218. P 32–37.
The results of structural phase transitions mechanisms study in K3WO3F3 oxyfluoride are represented by different experimental and theoretical methods. The structural phase transition anomalies at T1=452 K and T2=414 K of Raman and IR spectra have been analyzed. Using vibrational spectroscopy methods, the NMR-experiment has been done to clarify the nature of found phase transitions: displacive types or order-disorder types. The model of “disordered” crystal was proposed, and the results of lattice dynamics calculation in frameworks of the generalized Gordon–Kim method of ordered (R3) and “disordered” crystals were compared. The high pressure phases were studied by the Raman technique too.
- Atuchin V.V., Aleksandrovsky A.S., Chimitova O.D., Krylov A.S., Molokeev M.S., Bazarov B.G., Bazarova J.G., Zhiguo Xia. Synthesis and spectroscopic properties of multiferroic β-Tb2(MoO4)3// Optical Materials. 2014. V. 36, Nos. 10. P 1631–1635.
Orthorhombic terbium molybdate, β-Tb2(MoO4)3, microcrystals have been fabricated by solid state synthesis at T = 750–1270 K for t = 290 h. The crystal structure β-Tb2(MoO4)3 has been refined by Rietveld method in space group Pba2 with cell parameters of a = 10.35387(6), b = 10.38413(6) and c = 10.65695(7) Å (RB = 1.83%). About 40 narrow Raman lines have been observed in the Raman spectrum recorded for the β-Tb2(MoO4)3 powder sample. The luminescence spectrum of β-Tb2(MoO4)3 has been measured under the excitation at 355 nm, and the intensive photoluminescence band at 540–550 nm has been found.
- Atuchin V.V., Aleksandrovsky A.S., Chimitova O.D., Gavrilova T.А., Krylov A.S., Molokeev M.S., Oreshonkov A.S., Bazarov B.G., Bazarova J.G. Synthesis and Spectroscopic Properties of Monoclinic ?-Eu2(MoO4)3// J. Phys. Chem. C. 2014.
The microcrystals of monoclinic europium molybdate, α-Eu2(MoO4)3, have been fabricated by solid-state synthesis at T = 753−1273 K for 300 h. The crystal structure of α-Eu2(MoO4)3 has been refined by the Rietveld method and was found to belong to the space group C2/c with unit cell parameters a = 7.5576(1), b = 11.4709(2), c = 11.5158(2) Å, and β = 109.278(1)° (RB = 3.39%). About 40 narrow Raman lines have been observed in the Raman spectrum of the α-Eu2(MoO4)3 powder sample. The luminescence spectra of α-Eu2(MoO4)3 under excitation at 355 and 457.9 nm reveal domination of induced electric dipole transition 5D0 → 7F2 and the presence of ultranarrow lines at 5D0 → 7F0 and 5D1 → 7F0 transitions
- Ikonnikov D.A., Malakhovskii A.V., Sukhachev A.L., Temerov V.L., Krylov A.S., Bovina A.F., Aleksandrovsky A.S. Spectroscopic properties of HoAl3(BO3)4single crystal // Optical Materials. 2014.
The Judd–Ofelt theory has been applied to analyze absorption spectra of Ho3+ ion in HoAl3(BO3)4 measured in spectral range 300–700 nm at room temperature. The Judd–Ofelt spectroscopic parameters have been determined as: Ω2 = 18.87 × 10−20 cm2, Ω4 = 17.04 × 10−20 cm2, Ω6 = 9.21 × 10−20 cm2. These parameters have been used to calculate radiative lifetimes and branching ratios of the luminescence manifolds. Three luminescent bands were found in the spectral range 450–700 nm ascribed to transitions from the 5F5, (5F4, 5S2) and 3K8 states to the ground state 5I8. Experimental intensities of these luminescence transitions were compared with those calculated by using Judd–Ofelt theory and the system of kinetic equations for populations of starting luminescing states. Probabilities of radiativeless transitions were evaluated from this comparison.