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1.

Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Ovchinnikov S. G., Makarov I. A., Kozlov P. A.
Заглавие : Multiphonon contribution to the polaron formation in cuprates with strong electron correlations and strong electron-phonon interaction
Коллективы : Oxide-Based Materials and Devices
Место публикации : Proceedings of SPIE - The International Society for Optical Engineering: SPIE, 2017. - Vol. 10105. - , DOI 10.1117/12.2266799
Примечания : Cited References: 17. - Authors are thankful to Russian Science Foundation (project No. 14-12-00061) for financial support.
Ключевые слова (''Своб.индексиров.''): high-temperature superconductivity--cuprates--strong electronic correlations--cluster form of perturbation theory--hubbard operator--three-band p-d model--electron-phonon interaction--polaron--franck-condon broadening
Аннотация: In this work dependences of the electron band structure and spectral function in the HTSC cuprates on magnitude of electron-phonon interaction (EPI) and temperature are investigated. We use three-band p-d model with diagonal and offdiagonal EPI with breathing and buckling phonon mode in the frameworks of polaronic version of the generalized tight binding (GTB) method. The polaronic quasiparticle excitation in the system with EPI within this approach is formed by a hybridization of the local multiphonon Franck-Condon excitations with lower and upper Hubbard bands. Increasing EPI leads to transfer of spectral weight to high-energy multiphonon excitations and broadening of the spectral function. Temperature effects are taken into account by occupation numbers of local excited polaronic states and variations in the magnitude of spin-spin correlation functions. Increasing the temperature results in band structure reconstruction, spectral weight redistribution, broadening of the spectral function peak at the top of the valence band and the decreasing of the peak intensity. The effect of EPI with two phonon modes on the polaron spectral function is discussed. © 2017 SPIE.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Komogortsev S. V., Iskhakov R. S.
Заглавие : Law of approach to magnetic saturation in nanocrystalline and amorphous ferromagnets with improved transition behavior between power-law regimes
Коллективы : Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium, Институт физики им. Л.В. Киренского Сибирского отделения РАН
Место публикации : J. Magn. Magn. Mater.: Elsevier, 2017. - Vol. 440. - P.213-216. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2016.12.145
Примечания : Cited References: 41. - The work has been supported by Russian Foundation for Basic Research, Grant nos. 16-03-00256, 15-08-06673 and RFBR-KRFS 15–42-04171.
Ключевые слова (''Своб.индексиров.''): ferromagnetic materials--ferromagnetism--magnetic anisotropy--magnetism--magnets--nanocrystals--perturbation techniques--asymptotic regimes--law of approaches--nanocrystalline and amorphous--perturbation theory--power law regime--random magnetic anisotropies--transition behavior--transition modes--saturation magnetization
Аннотация: New law of the approach to magnetic saturation is proposed based on scaling in ferromagnets with random magnetic anisotropy. This law is consistent with the known laws derived within perturbation theory in extreme cases, but it describes the transition mode between the power-low asymptotic regimes better. The improved law is proper for reliable fitting the approach magnetization to saturation in nanocrystalline and amorphous ferromagnets. © 2017 Elsevier B.V.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Timofeev I. V., Pankin, Pavel S., Vetrov S. Ya., Arkhipkin V. G., Lee, Wei, Zyryanov V. Ya.
Заглавие : Chiral optical Tamm states: temporal coupled-mode theory
Коллективы : Ministry of Science and Technology (MOST), Taiwan [106-2923-M-009-002-MY3]; Russian Foundation for Basic Research; Krasnoyarsk Region Science and Technology [17-42-240464]; Scholarship of the President of the Russian Federation [SP-227.2016.5]; Siberian Branch of the Russian Academy of Sciences [0356-2015-0410, 0356-2015-0411]; Government of Krasnoyarsk Territory
Место публикации : Crystals. - 2017. - Vol. 7, Is. 4. - Ст.113. - ISSN 2073-4352, DOI 10.3390/cryst7040113
Примечания : Cited References:71. - This work was financially sponsored by the Ministry of Science and Technology (MOST), Taiwan, under Grant No. 106-2923-M-009-002-MY3, the Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, the Krasnoyarsk Region Science and Technology Support Fund to the research project No. 17-42-240464, the Scholarship of the President of the Russian Federation No. SP-227.2016.5 and by the Siberian Branch of the Russian Academy of Sciences under Complex Program II.2P (Project Nos. 0356-2015-0410 and 0356-2015-0411). The authors are thankful to A.F. Sadreev, E.N. Bulgakov, N.V. Rudakova, Y.-C. Hsiao and L.V. Pertseva for valuable discussions and comments.
Предметные рубрики: CHOLESTERIC LIQUID-CRYSTAL
SCULPTURED THIN-FILMS
PHOTONIC DEFECT
Ключевые слова (''Своб.индексиров.''): optical tamm state--cholesteric liquid crystal--handedness-preserving mirror
Аннотация: The chiral optical Tamm state (COTS) is a special localized state at the interface of a handedness-preserving mirror and a structurally chiral medium such as a cholesteric liquid crystal or a chiral sculptured thin film. The spectral behavior of COTS, observed as reflection resonances, is described by the temporal coupled-mode theory. Mode coupling is different for two circular light polarizations because COTS has a helical structure replicating that of the cholesteric. The mode coupling for co-handed circularly polarized light exponentially attenuates with the cholesteric layer thickness since the COTS frequency falls into the stop band. Cross-handed circularly polarized light freely goes through the cholesteric layer and can excite COTS when reflected from the handedness-preserving mirror. The coupling in this case is proportional to anisotropy of the cholesteric and theoretically only anisotropy in magnetic permittivity can ultimately cancel this coupling. These two couplings being equal result in a polarization crossover (the Kopp-Genack effect) for which a linear polarization is optimal to excite COTS. The corresponding cholesteric thickness and scattering matrix for COTS are generally described by simple expressions.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Паршин, Александр Михайлович, Зырянов, Виктор Яковлевич, Шабанов, Александр Васильевич
Заглавие : Использование теории катастроф для изучения крупномасштабных флуктуаций в нематических каплях, изготовленных в присутствии магнитного поля
Место публикации : Жидк. кристаллы и их практич. использ. - 2017. - Т. 17, Вып. 1. - С. 83-92. - ISSN 19913966 (ISSN), DOI 10.18083/LCAppl.2017.1.83; \b Liquid Crystals and their Application
Примечания : Библиогр.: 19
Ключевые слова (''Своб.индексиров.''): капсулированный полимером жидкий кристалл--энергия сцепления--катастрофа сборки--управляющие параметры--структурный переход--nematic--polymer--anchoring energy--cups catastrophe--control parameters--structural transition
Аннотация: В рамках теории катастроф изучены крупномасштабные флуктуации в каплях нематического жидкого кристалла 5ЦБ, изготовленных по растворной технологии в присутствии магнитного поля. Из анализа потенциальных кривых установлено, что флуктуации обусловлены вариацией директора нематика между потенциальными минимумами, связанными с энергией сцепления жидкий кристалл–полимер и магнитным полем. Определена связь управляющих параметров катастрофы сборки с параметрами сцепления. Рассмотрено влияние магнитного поля на управляющие параметры, ведущее к структурному переходу в капле жидкого кристалла, который соответствует трансформации директора из биполярной структуры с расширенными полюсами в радиальную конфигурацию. На основании проведенного анализа оценены значения энергий сцепления жидкого кристалла с полимерной поверхностью.In the framework of catastrophe theory the large-scale fluctuations in droplets of nematic 5CB prepared by solution technology under magnetic field have been studied. From the analysis of the potential curves it was found that the fluctuations caused by the variation of the nematic director between potential minima connected with the anchoring energy of a liquid crystal-polymer and magnetic field. A relation between the control parameters of cusp catastrophe with the anchoring parameters has been determined. The influence of magnetic field on the control parameters leading to a structural transition in the droplet of the liquid crystal that corresponds to the director transformation of the bipolar structure with extended pole to a radial configuration has been analyzed. On the basis of the performed analysis the values of the anchoring energies of the liquid crystal with the polymer surface were estimated.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuzubov A. A., Kovaleva E. A., Popova M. I., Kholtobina A. S., Mikhaleva N. S., Visotin M. A., Fedorov A. S.
Заглавие : DFT investigation of electronic structures and magnetic properties of halides family MeHal3 (Me=Ti, Mo,Zr,Nb, Ru, Hal=Cl,Br,I) one dimensional structures
Коллективы : Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium, Институт физики им. Л.В. Киренского Сибирского отделения РАН , Russian Science Foundation [16-13-00060]; Russian Foundation for Basic Research [RFBR 16-32-60003 mol_a_dk]
Место публикации : J. Magn. Magn. Mater.: Elsevier Science, 2017. - Vol. 440: EURO-Asian Symposium on Trends in Magnetism (EASTMAG) (AUG 15-19, 2016, Siberian Fed Univ, Krasnoyarsk, RUSSIA). - P.93-96. - ISSN 0304-8853, DOI 10.1016/j.jmmm.2016.12.054. - ISSN 1873-4766(eISSN)
Примечания : Cited References:16. - This work was supported by the Russian Science Foundation, Project no. 16-13-00060. N.S.M. thanks the Russian Foundation for Basic Research, project RFBR 16-32-60003 mol_a_dk, for the financial support of ZrIINF3/INF, TiIINF3/INF and NbIINF3/INF electronic structure calculations
Предметные рубрики: INITIO MOLECULAR-DYNAMICS
TOTAL-ENERGY CALCULATIONS
AUGMENTED-WAVE
Ключевые слова (''Своб.индексиров.''): transition metal trihalides--magnetic properties--thermoelectric--conversion--density functional theory
Аннотация: Using DFT GGA calculations, electronic structure and magnetic properties of wide family of transition metal trihalides (TMHal3) (Zr, Ti and Nb iodides, Mo, Ru, Ti and Zr bromides and Ti or Zr chlorides) are investigated. These structures consist of transition metal atoms chains surrounded by halides atoms. Chains are connected to each other by weak interactions. All TMHal3 compounds were found to be conductive along chain axis except of MoBr3 which is indirect gap semiconductor. It was shown that NbI3 and MoBr3 have large magnetic moments on metal atoms (1.17 and 1.81 µB, respectively) but other TMHal3 materials have small or zero magnetic moments. For all structures ferromagnetic and anti-ferromagnetic phases have almost the same energies. The causes of these properties are debated.
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6.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Ignatchenko V. A., Polukhin D. S.
Заглавие : Development of the magnetoelastic resonance theory in ingomogeneous media
Коллективы : Moscow International Symposium on Magnetism, Московский государственный университет им. М.В. Ломоносова, Российский фонд фундаментальных исследований
Место публикации : Moscow Int. Symp. on Magnet. (MISM-2017): 1-7 July 2017 : book of abstracts. - 2017. - Ст.2PO-K-20. - P.223
Примечания : Cited References: 3
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhao M., Xia Z., Molokeev M. S., Ning L., Liu Q.
Заглавие : Temperature and Eu2+-doping induced phase selection in NaAlSiO4 polymorphs and the controlled yellow/blue emission
Место публикации : Chem. Mater.: American Chemical Society, 2017. - Vol. 29, Is. 15. - P.6552-6559. - ISSN 08974756 (ISSN), DOI 10.1021/acs.chemmater.7b02548
Примечания : Cited References: 48. - The present work was supported by the National Natural Science Foundation of China (Grants 91622125 and 51572023 and 11574003), Natural Science Foundations of Beijing (2172036), and Fundamental Research Funds for the Central Universities (FRF-TP-16-002A3). L.N. acknowledges the support from the Special and Excellent Research Fund of Anhui Normal University.
Ключевые слова (''Своб.индексиров.''): chemical modification--coordination reactions--europium--light emitting diodes--photoluminescence--functional properties--high color rendering index--local coordination structures--near ultraviolet excitations--structural transformation--synthesis temperatures--temperature dependent--white light emitting diodes--density functional theory
Аннотация: The union of temperature-dependent phase transition and relating structural transformation via modification of chemical compositions is of fundamental importance for the discovery of new materials or their functional properties optimization. Herein, the synthesis temperature and Eu2+-doping content induced phase selection and variations of the local structures in nepheline, low-carnegieite and high-carnegieite types of NaAlSiO4 polymorphs were studied in detail. The luminescence of Eu2+ in low-carnegieite and nepheline phases shows blue (460 nm) and yellow (540 nm) broad-band emissions, respectively, under near-ultraviolet excitation. The photoluminescence evolution can be triggered by the different synthesis temperatures in relation to the Eu2+-doping concentration, as corroborated by density functional theory calculations on the local coordination structures and corresponding mechanical stabilities in terms of the Debye temperature. The fabricated white light-emitting diode device with high color rendering index demonstrates that the multicolor phosphors from one system provides a new gateway for the photoluminescence tuning. © 2017 American Chemical Society.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Martynov S. N., Tugarinov V. I., Martynov A. S.
Заглавие : Continual approach at T=0 in the mean field theory of incommensurate magnetic states in the frustrated Heisenberg ferromagnet with an easy axis anisotropy
Коллективы : Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium, Институт физики им. Л.В. Киренского Сибирского отделения РАН
Место публикации : J. Magn. Magn. Mater.: Elsevier Science, 2017. - Vol. 440: EURO-Asian Symposium on Trends in Magnetism (EASTMAG) (AUG 15-19, 2016, Siberian Fed Univ, Krasnoyarsk, RUSSIA). - P.47-49. - ISSN 0304-8853, DOI 10.1016/j.jmmm.2016.12.086. - ISSN 1873-4766(eISSN)
Примечания : Cited References:9
Предметные рубрики: FERRIMAGNET
Аннотация: The algorithm of approximate solution was developed for the differential equation describing the anharmonical change of the spin orientation angle in the model of ferromagnet with the exchange competition between nearest and next nearest magnetic neighbors and the easy axis exchange anisotropy. The equation was obtained from the collinearity constraint on the discrete lattice. In the low anharmonicity approximation the equation is resulted to an autonomous form and is integrated in quadratures. The obvious dependence of the angle velocity and second derivative of angle from angle and initial condition was derived by expanding the first integral of the equation in the Taylor series in vicinity of initial condition. The ground state of the soliton solutions was calculated by a numerical minimization of the energy integral. The evaluation of the used approximation was made for a triple point of the phase diagram.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Roginskii E. M., Krylov A. S., Markov Y. F., Smirnov M. B.
Заглавие : Lattice dynamics and baric behavior of phonons in Hg2Cl2 crystals at high hydrostatic pressures
Место публикации : Bull. Russ. Acad. Sci. Phys.: Allerton Press, 2016. - Vol. 80, Is. 9. - P.1033-1037. - ISSN 10628738 (ISSN), DOI 10.3103/S1062873816090409
Примечания : Cited References: 12
Ключевые слова (''Своб.индексиров.''): chlorine compounds--crystal lattices--density functional theory--hydraulics--hydrostatic pressure--inorganic compounds--density functionals--high hydrostatic pressure--intermolecular interactions--orthorhombic phase--phonon spectrum--range dispersion--structural phase transition--theoretical modeling--phonons
Аннотация: A theoretical model based on long-range dispersion corrections of the charge density functional is proposed for model Hg2Cl2 calomel crystals, typical representatives of molecular inorganic compounds where the intermolecular interaction is found to play an important role. This model successfully describes the electronic state and the phonon spectrum of the above crystal, predicts the earlier unstudied phase transition at high hydrostatic pressure. Study of the baric behavior of the phonon spectrum with Raman spectroscopy observes the soft mode in the low-symmetry orthorhombic phase with the frequency softening as the pressure rises. Pressures above 9 GPa considerably transform the Raman spectra, indicating a structural phase transition. © 2016, Allerton Press, Inc.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kudashkin K., Nikolaev S. V., Ovchinnikov S. G.
Заглавие : Spectral properties of the Bose-Hubbard model within the cluster perturbation theory in X-operators representation
Коллективы : RFBR [16-02-00098, 16-42-243048, 16-42-240511, 16-42-240769]; Government of Krasnoyarsk Territory; Russian President Grant [NSh-7559.2016.2]
Место публикации : J. Supercond. Nov. Magn.: Springer, 2017. - Vol. 30, Is. 1. - P.103-107. - ISSN 1557-1939, DOI 10.1007/s10948-016-3781-y. - ISSN 1557-1947(eISSN)
Примечания : Cited References:16. - This work was supported by RFBR grant 16-02-00098, Government of Krasnoyarsk Territory and RFBR according to the research projects 16-42-243048, 16-42-240511, and 16-42-240769, and the Russian President Grant NSh-7559.2016.2.
Предметные рубрики: TRANSITION
SUPERFLUID
INSULATOR
ATOMS
Ключевые слова (''Своб.индексиров.''): bose-hubbard model--ultracold gases--cluster perturbation theory--density of states--spectral properties
Аннотация: We study the two-dimensional ultracold Bose gas in optical lattice. We use cluster perturbation theory based on Hubbard X-operators to calculate the spectral function and phase diagram of Bose-Hubbard model which is minimal model to describe behavior of ultracold gases in optical lattices. We have analyzed spectral properties of spinless bosons in a square lattice taking into account the short-range correlation.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Nikolaev S. V., Korshunov M. M.
Заглавие : Spin and charge susceptibilities of the two-orbital model within the cluster perturbation theory for Fe-based materials
Место публикации : J. Supercond. Nov. Magn.: Springer, 2016. - Vol. 29, Is. 12. - P.3093-3097. - ISSN 15571939 (ISSN), DOI 10.1007/s10948-016-3784-8
Примечания : Cited References: 40. - We acknowledge partial support by RFBR (grants 12-02-31534, 13-02-01395, and 16-02-00098), and Government Support of the Leading Scientific Schools of the Russian Federation (NSh-7559.2016.2).
Ключевые слова (''Своб.индексиров.''): fe-based superconductors--mutiorbital models--cluster perturbation theory
Аннотация: Cluster perturbation theory is used to calculate band structure, spectral functions, Fermi surface, and spin and charge susceptibilities for the two-orbital model of iron pnictides with the on-site multiorbital Hubbard interactions. Susceptibilities are calculated within the approximation combining the cluster perturbation theory for the self-energy corrections and the random-phase approximation (RPA) for the vertex renormalizations. Calculations for the small values of Hubbard repulsion U ≤ 2 eV confirm that the rigid band approximation and RPA for the spin and charge susceptibilities are suitable approaches for the case of weak interactions. © 2016, Springer Science+Business Media New York.
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12.

Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Maximova O. M., Maximova O. A.
Заглавие : Neural-net modeling for direct and inverse problems of shell theory
Коллективы : International Scientific and Research Conference on Topical Issues
Место публикации : IOP Conf. Ser.: Mater. Sci. Eng. - 2016. - Vol. 155, Is. 1. - Ст.012031. - , DOI 10.1088/1757-899X/155/1/012031
Примечания : Cited References:5
Аннотация: Effectiveness of the use of neural-net technology for the solving of shell theory problems is shown. Some results of neural-net interpolation and extrapolation for direct and inverse problems are discussed. Exact accuracy of neural-net solving opens wide latitude for shell constructions engineering design and optimization.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kolovsky A. R.
Заглавие : Treating many-body quantum systems by means of classical mechanics
Коллективы : International Conference on Nonlinear Dynamics of Electronic Systems
Место публикации : Springer Proceedings in Physics: Springer, 2017. - Vol. 191. - P.37-48. - ISSN 09308989 (ISSN); 9783319478081 (ISBN), DOI 10.1007/978-3-319-47810-4_4
Примечания : Cited References: 16
Ключевые слова (''Своб.индексиров.''): dynamical systems--dynamics--hubbard model--optical lattices--quantum optics--classical mechanics--energy spectra--identical particles--many-body quantum systems--paradigmatic models--quantum many-body systems--quantum physics--semiclassical approaches--quantum theory
Аннотация: Many-body physics of identical particles is commonly believed to be a sovereign territory of Quantum Mechanics. The aim of this contribution is to show that it is actually not the case and one gets useful insights into a quantum many-body system by using the theory of classical dynamical systems. In the contribution we focus on one paradigmatic model of many-body quantum physics - the Bose– Hubbard model which, in particular, describes interacting ultracold Bose atoms in an optical lattice. We show how one can find/deduce the energy spectrum of the Bose–Hubbard model by using a kind of the semiclassical approach. © Springer International Publishing AG 2017.
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14.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Nikolaev S., Kuz'min V. I., Ovchinnikov S. G.
Заглавие : Electronic structure and Fermi surface within the cluster perturbation theory in X-operators representation : Invited
Коллективы : Federal Research Center KSC SB RAS, Kirensky Institute of Physics, Siberian Federal Univercity, International Workshop on Actual Problems of Condensed Matter Physics
Место публикации : International workshop on actual problems of condensed matter physics: Program. Book of abstracts/ Fed. Res. Center KSC SB RAS, Kirensky Inst. of phys., Sib. Fed. Univ. - Krasnoyarsk, 2017. - P,27 (Шифр В37/H99-812624296)
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Martynov S. N., Tugarinov V. I., Martynov A. S.
Заглавие : Continual approach in the mean field theory of incommensurate magnetic states in the Frustrated Heisenberg ferromagnet
Место публикации : J. Sib. Fed. Univ. Math. Phys. - 2017. - Vol. 10, Is. 1. - P.55-59. - ISSN 1997-1397, DOI 10.17516/1997-1397-2017-10-1-55-59; Журн. СФУ. Сер. "Математика и физика"
Примечания : Cited References: 3
Аннотация: The algorithm of approximate solution has been developed for the differential equation describing the anharmonical change of the spin orientation angle in the model of ferromagnet with the exchange competition between nearest and next nearest magnetic neighbors and the easy axis exchange anisotropy. The obvious dependence of the angle velocity from angle and initial condition has been derived by expanding the first integral of the equation in the Taylor series in vicinity of initial condition. © Siberian Federal University. All rights reserved.Разработан алгоритм приближенного решения дифференциального уравнения, описывающего ангармоническое изменение угла ориентации спина в модели легкоосного ферромагнетика с конкуренцией обменов между ближайшими и следующими за ближайшими магнитными соседями. Явная зависимость угловой скорости от угла и начального условия получена путем разложения первого интеграла уравнения в ряд Тейлора в окрестности начального условия
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mel'nikova S. V., Molokeev M. S., Laptash N. M., Pogoreltsev E. I., Misyul S. V., Flerov I. N.
Заглавие : Sequence of phase transitions in (NH4)3SiF7
Место публикации : Dalton Trans.: Royal Society of Chemistry, 2017. - Vol. 46, Is. 8. - P.2609-2617. - ISSN 14779226 (ISSN), DOI 10.1039/c6dt04874a
Примечания : Cited References: 26. - The reported study was partially supported by RFBR, research project no. 15-02-02009a.
Ключевые слова (''Своб.индексиров.''): group theory--single crystals--x ray diffraction--atomic displacement--double salts--driving forces--group-theoretical analysis--order parameter--polarization optics--temperature changes--hydrogen bonds
Аннотация: Single crystals of silicon double salt (NH4)3SiF7 = (NH4)2SiF6·NH4F = (NH4)3[SiF6]F were grown and studied by the methods of polarization optics, X-ray diffraction and calorimetry. A sequence of symmetry transformations with the temperature change was established: P4/mbm (Z = 2) (G1) ↔ Pbam (Z = 4) (G2) ↔ P21/c (Z = 4) (G3) ↔ P1 (Z = 4) (G4) ↔ P21/c (Z = 8) (G5). Crystal structures of different phases were determined. The experimental data were also interpreted by a group-theoretical analysis of the complete condensate of order parameters taking into account critical and noncritical atomic displacements. Strengthening of the N–H⋯F hydrogen bonds can be a driving force of the observed phase transitions.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sofronova S. N., Nazarenko I. I.
Заглавие : Super-Superexchange Influence on Magnetic Ordering in Ni3B2O6 Kotoite
Место публикации : Phys. Status Solidi B. - 2019. - Vol. 256, Is. 10. - Ст.1900060. - ISSN 03701972 (ISSN) , DOI 10.1002/pssb.201900060
Примечания : Cited References: 22. - The study was carried out with the financial support of the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Territory, the Krasnoyarsk Regional Science Foundation as part of a research project: “Low-dimensional and frustrated magnetism in nickel oxyborates and manganites with the substitution of manganese by Yang-Teller ions,” No. 18-42-240007.
Аннотация: Using ab initio software package WIEN2k, the calculations of electronic propertiesand of the energies of various magnetically ordered structures are carried out and possible mechanisms of magnetic ordering are analyzed in Ni3B2O6. The superexchange (Ni-O-Ni) and super-superexchange interactions (Ni-O-B-O-Ni) are calculated, a magnetic ordering model is proposed.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : da Cruz V. V., Ignatova N., Couto R. C., Fedotov D. A., Rehn D. R., Savchenko V., Norman P., Agren H., Polyutov S. P., Niskanen J., Eckert S., Jay R. M., Fondell M., Schmitt T., Pietzsch A., Fohlisch A., Gel'mukhanov F., Odelius M., Kimberg V.
Заглавие : Nuclear dynamics in resonant inelastic X-ray scattering and X-ray absorption of methanol
Коллективы : Swedish Research Council [VR 2015-04510, 2015-03781, 2015-03956, 2016-03619]; Knut and Alice Wallenberg Foundation [KAW-2013.0020]; Carl Tryggers Foundation; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico [CNPq 234625/2014-7]; European Research Council under the European Union [669531 EDAX]; Helmholtz Virtual Institute "Dynamic Pathways in Multidimensional Landscapes" [VI419]; Swedish National Infrastructure for Computing [SNIC 2018/3-104, 023/07-18]; Ministry of Education and Science of the Russian Federation [3.2662.2017]
Место публикации : J. Chem. Phys. - 2019. - Vol. 150, Is. 23. - Ст.234301. - ISSN 0021-9606, DOI 10.1063/1.5092174. - ISSN 1089-7690(eISSN)
Примечания : Cited References: 80. - We acknowledge Emelie Ertan for sharing insights into performing the RASPT2 calculations. This work was supported by the Swedish Research Council (Nos. VR 2015-04510, 2015-03781, 2015-03956, and 2016-03619), the Knut and Alice Wallenberg Foundation (Grant No. KAW-2013.0020), Carl Tryggers Foundation, and within the State Contract of the Ministry of Education and Science of the Russian Federation for Siberian Federal University for Scientific Research in 2017-2019 (Project No. 3.2662.2017). V.V.C. and R.C.C. acknowledge the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (No. CNPq 234625/2014-7). A.F. acknowledges support by the European Research Council Advanced Grants 2014 Advanced Investigator Grant No. 669531 EDAX under the Horizon 2020 European Union Framework Program for Research and Innovation. M.O. acknowledges support from the Helmholtz Virtual Institute VI419 "Dynamic Pathways in Multidimensional Landscapes." Numerical simulations were performed on the resources provided by the Swedish National Infrastructure for Computing (SNIC 2018/3-104, 023/07-18). The experimental RIXS data were obtained at the ADRESS beamline of the Swiss Light Source at the Paul Scherrer Institut.
Предметные рубрики: MANY-BODY THEORY
VIBRATIONAL STRUCTURE
LIQUID METHANOL
Аннотация: We report on a combined theoretical and experimental study of core-excitation spectra of gas and liquid phase methanol as obtained with the use of X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). The electronic transitions are studied with computational methods that include strict and extended second-order algebraic diagrammatic construction [ADC(2) and ADC(2)-x], restricted active space second-order perturbation theory, and time-dependent density functional theory—providing a complete assignment of the near oxygen K-edge XAS. We show that multimode nuclear dynamics is of crucial importance for explaining the available experimental XAS and RIXS spectra. The multimode nuclear motion was considered in a recently developed “mixed representation” where dissociative states and highly excited vibrational modes are accurately treated with a time-dependent wave packet technique, while the remaining active vibrational modes are described using Franck–Condon amplitudes. Particular attention is paid to the polarization dependence of RIXS and the effects of the isotopic substitution on the RIXS profile in the case of dissociative core-excited states. Our approach predicts the splitting of the 2a″ RIXS peak to be due to an interplay between molecular and pseudo-atomic features arising in the course of transitions between dissociative core- and valence-excited states. The dynamical nature of the splitting of the 2a″ peak in RIXS of liquid methanol near pre-edge core excitation is shown. The theoretical results are in good agreement with our liquid phase measurements and gas phase experimental data available from the literature.
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19.

Вид документа : Статья из сборника (выпуск монографической серии)
Шифр издания :
Автор(ы) : Balyzin M., Sadrieva Z., Belyakov M. A., Kapitanova P., Sadreev A. F., Bogdanov A. A.
Заглавие : Quasi-bound States in the Continuum in a Finite Chain of Dielectric Scatterers: Theory and Experiment
Коллективы : Progress in Electromagnetics Research Symposium 2018 , Russian Foundation for Basic Research [16-37-60064, 17-02-01234, 16-02-00314]; Ministry of Education and Science of the Russian Federation [3.1668.2017/4.6]; Russian Federation [MK-403.2018.2]
Место публикации : Progress in Electromagnetics Research Symposium (PIERS-Toyama): IEEE, 2018. - Vol. 2018-August. - P.2516-2519. - (Progress in Electromagnetics Research Symposium). - , DOI 10.23919/PIERS.2018.8598011
Примечания : Cited References: 27. - This work was supported by the Russian Foundation for Basic Research (16-37-60064, 17-02-01234, 16-02-00314), the Ministry of Education and Science of the Russian Federation (3.1668.2017/4.6), the President of Russian Federation (MK-403.2018.2).
Предметные рубрики: LIGHT
Аннотация: In this work we experimentally observe a symmetry protected optical bound state in the continuum (BIC) with zero angular momentum in 1D array of ceramic disks at GHz frequencies. We analyze the dependence of Q factor of BIC on the number of the disks and the level of the material losses. We confirmed theoretical prediction about quadratic growth of the Q factor with the number of the disks and its following saturation due to material losses.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Smyslov, Ruslan Yu, Tomilin F. N., Shchugoreva I. A., Nosova G. I., Zhukova E. V., Litvinova L. S., Yakimansky A. V., Kolesnikov I., Abramov I. G., Ovchinnikov S. G., Avramov P. V.
Заглавие : Synthesis and photophysical properties of copolyfluorenes for light-emitting applications: Spectroscopic experimental study and theoretical DFT consideration
Место публикации : Polymer. - 2019. - Vol. 168. - P.185-198. - ISSN 0032-3861, DOI 10.1016/j.polymer.2019.02.015. - ISSN 1873-2291(eISSN)
Примечания : Cited References: 45. - The quantum yield measurements were performed at the Center for Optical and Laser Materials Research, St. Petersburg State University. P. Avramov gratefully acknowledges the financial support of National Research Foundation of Republic of Korea under Grant No. NRF-2017R1A2B4004440. This work has been carried out using computing resources of the federal collective usage center Complex for Simulation and Data Processing for Mega-science Facilities at NRC "Kurchatov Institute"
Предметные рубрики: BETA-PHASE FORMATION
SINGLE POLYMER
POLYFLUORENE
BLUE
COPOLYMERS
Аннотация: Using Suzuki and Yamamoto coupling reactions, copoly-(9,9-dioctylfluorenes) (CPF) were synthesized and compared regarding their photophysical properties using the spectroscopic and ab initio DFT approaches. The CPFs were functionalized by benzo [2,3,5] thiadiazole (BT) or carbazole-3,6-diyl (3,6-Cz). The latter was used to introduce different luminophore fragments, including Nile red and 4-pyrrolidinyl-1,8-naphthalimide derivatives. The effect of the two synthesis techniques on the polymer microstructure, the influence of embedding of 3,6-Cz moieties in the polymer backbone on polymer structuring, and the impact of the end groups like novel quinoxaline-containing compounds on the luminescent properties of CPFs were investigated. By comparing electron density distribution using the ab initio DFT approach with photoluminescence, it was shown that Suzuki reaction provides a chain microstructure with individual BT fragments separated by 9,9-dioctylfluorene monomeric units, while Yamamoto reaction leads to the blocks of BT units. This effect leads to different CPF photophysical properties (absorption and emission spectra).
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