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1.


    Zobov, V. E.
    Modeling multiparticle coherences in solid-state nuclear spin systems using infinite-range interaction / V. E. Zobov, A. A. Lundin // Theor. Math. Phys. - 2004. - Vol. 141, Is. 3. - P. 1737-1749, DOI 10.1023/B:TAMP.0000049765.41265.dd. - Cited References: 24 . - ISSN 0040-5779
РУБ Physics, Multidisciplinary + Physics, Mathematical
Рубрики:
MULTIPLE-QUANTUM DYNAMICS
   NMR-SPECTRA

   TEMPERATURE DYNAMICS

   SHAPE

   VAN

Кл.слова (ненормированные):
multipulse method -- dipole-dipole interaction -- multispin coherence -- time correlation function -- rotating reference frame -- dipole-dipole interaction -- multipulse method -- multispin coherence -- rotating reference frame -- time correlation function
Аннотация: Using the exactly solvable model known in statistical physics as the infinite-range interaction model (the van der Waals model), we obtain expressions for the hierarchy of multispin multiquantum time correlation functions for a solid-state paramagnetic nuclear spin system with magnetic dipole-dipole interaction between nuclei. These functions are observed experimentally using contemporary multiquantum NMR spectroscopy methods. We write the complete set of orthogonal multispin operators explicitly and find the time dependence for amplitudes of multiparticle time correlation functions. The proposed model describes the behavior of multiparticle correlation functions well, at least for not very large numbers n of expansion harmonics. The theoretical results agree well with the experimental data obtained for hexamethylbenzol.

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Держатели документа:
RAS, Siberian Branch, Kirenskii Inst Phys, Krasnoyarsk, Russia
RAS, NN Semenov Chem Phys Inst, Moscow, Russia
ИФ СО РАН
Kirenskii Institute for Physics, Siberian Branch, RAS, Krasnoyarsk, Russia, Russian Federation
Semenov Inst. for Chemical Physics, RAS, Moscow, Russia, Russian Federation

Доп.точки доступа:
Lundin, A. A.; Зобов, Владимир Евгеньевич
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2.


   
    Orientational dependence of the tails of dipole-broadened NMR spectra in crystals / V. E. Zobov [et al.] // J. Exp. Theor. Phys. - 1999. - Vol. 88, Is. 1. - P. 157-167, DOI 10.1134/1.558778. - Cited References: 36 . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
NUCLEAR-DOUBLE-RESONANCE
   FLUCTUATION SPECTRUM

   CROSS-RELAXATION

   SOLIDS

   DIFFUSION

   MEMORY

   SHAPE

Аннотация: This paper describes experimental and theoretical studies of the tails of the dipole-broadened nuclear magnetic resonance (NMR) absorption spectra of F-19 in isomorphic single crystals of BaF2 and CaF2 with the magnetic field directed along three crystallographic axes. The results obtained by directly measuring the derivative of the tail of the NMR absorption spectrum and the falloffs of the Engelsberg-Lowe free precession after Fourier transformation qualitatively agree. It is shown that the shape of the tail is well described by an exponential function in which the orientational dependence of the exponent does not reduce to variation of the second moment. The observed shape of the tail and the orientational dependence of its parameters are explained on the basis of a self-consistent fluctuating-local-field theory. Nonlinear integral equations are derived for the correlation functions, taking into account the changes of the actual number of nearest neighbors caused by the anisotropy of the dipole-dipole interaction and the contribution of lattice sums with loops. The equations are solved numerically. Good agreement is obtained for the computed dropoffs of the free precession, the NMR spectra, and the cross-polarization rates with the experimental results. (C) 1999 American Institute of Physics. [S1063-7761(99)02401-4].

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Div, Krasnoyarsk 660036, Russia
Krasnoyarsk State Univ, Krasnoyarsk 660041, Russia
Russian Acad Sci, Siberian Branch, Inst Chem & Chem Technol, Krasnoyarsk 660036, Russia
ИФ СО РАН
ИХХТ СО РАН

Доп.точки доступа:
Zobov, V. E.; Зобов, Владимир Евгеньевич; Ivanov, Y. N.; Иванов, Юрий Николаевич; Popov, M. A.; Livshits, A. I.
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3.


    Lundin, A. A.
    Solid-state NMR free induction decay, simulated by the system of classical magnetic moments and quantum correlations / A. A. Lundin, V. E. Zobov // Russ. J. Phys. Chem. B. - 2021. - Vol. 15, Is. 5. - P. 839-847, DOI 10.1134/S1990793121050079. - Cited References: 34. - This study was carried out as part of state assignment 0082-2019-0001 (registration number AAAA-A19-119012890064-7) . - ISSN 1990-7931. - ISSN 1990-7923
РУБ Physics, Atomic, Molecular & Chemical
Рубрики:
HIGH-TEMPERATURE DYNAMICS
   HEISENBERG-MODEL

   SPIN SIMULATIONS

   SHAPE

Кл.слова (ненормированные):
spin -- paramagnetic -- quantum technology -- spin dynamics -- quantum computing
Аннотация: In the past decade, nuclear magnetic resonance (NMR) has been actively used to study the basic principles of quantum computers. It is assumed that quantum correlations play a significant role in their performance. They exist at both low and high temperatures. At the same time, the time correlation functions of nuclear spin systems of solids determine the observed signals in traditional NMR implementations. The separation of such signals into quantum and classical components has not previously been carried out and will be performed in this study for the most important of the correlational functions observed in magnetic resonance: the free induction decay (FID).

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Публикация на русском языке Лундин, Андрей Арнольдович. Сигнал свободной прецессии ЯМР твердого тела, его моделирование посредством системы классических магнитных моментов и квантовые корреляции [Текст] / А. А. Лундин, В. Е. Зобов // Химич. физика. - 2021. - Т. 40 № 9. - С. 41-49

Держатели документа:
Russian Acad Sci, Semenov Fed Res Ctr Chem Phys, Moscow, Russia.
Russian Acad Sci, Siberian Branch, Krasnoyarsk Sci Ctr, Kirensky Inst Phys,Fed Res Ctr, Krasnoyarsk, Russia.

Доп.точки доступа:
Zobov, V. E.; Зобов, Владимир Евгеньевич; [AAAA-A19-119012890064-7]
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4.


    Ignatchenko, V. A.
    Magnetostatic fields in planar assemblies of magnetic nanoparticles / V. A. Ignatchenko, I. S. Edelman, D. A. Petrov // Phys. Rev. B. - 2010. - Vol. 81, Is. 5. - Ст. 54419, DOI 10.1103/PhysRevB.81.054419. - Cited References: 25. - This study was supported in part by the Grant from the President of the Russian Federation for leading scientific schools Project No. 3818.2008.3, the State Contract of the Federal Program No. 02.740.11.0220, the RFBR-CNRS Grant No. 07-02-92174, and the State Program "Development of the Scientific Potential of the Higher Education School," Project No 2.1.1/6038. We wish to acknowledge Janis Kliva for the helpful discussion. . - ISSN 1098-0121
РУБ Physics, Condensed Matter
Рубрики:
SINGLE-DOMAIN PARTICLES
   FERROMAGNETIC-RESONANCE

   TAPES

   SHAPE

Аннотация: Magnetostatic fields are studied in the model of a planar assembly of magnetic particles forming a periodic lattice infinite in the xy plane and finite along the z axis. Two types of lattices are considered: simple cubic and body-centered cubic. Exact analytical expressions of the magnetostatic fields for the magnetization perpendicular and parallel to the xy plane, H(perpendicular to)(x, y, z) and H(parallel to) (x, y, z), are obtained in the form of Fourier series both inside the particles, and in the surrounding matrix. Exact formulas for mean magnetostatic fields inside the particles, (H) over bar (perpendicular to) and (H) over bar (parallel to), are obtained by averaging over the particle volume. A numerical analysis of these formulas shows linear dependences of (H) over bar (perpendicular to) and (H) over bar (parallel to) on the volume filling factor c. A comparison of these exact solutions with the results of earlier works where such dependences were obtained using different approximate approaches, confirms the correctness of some of them. The correctness of methods allowing the estimation of the filling factor c from both magnetic resonance and magnetometric data is also confirmed.

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Держатели документа:
[Ignatchenko, V. A.
Edelman, I. S.
Petrov, D. A.] RAS, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
ИФ СО РАН
L. V. Kirensky Institute of Physics Siberian Branch, RAS, 660036 Krasnoyarsk, Russian Federation

Доп.точки доступа:
Edelman, I. S.; Эдельман, Ирина Самсоновна; Petrov, D. A.; Петров, Дмитрий Анатольевич; Игнатченко, Вальтер Алексеевич
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5.


   
    Unusual magnetic transitions and nature of magnetic resonance spectra in oxide glasses containing gadolinium / J. . Kliava [et al.] // Phys. Rev. B. - 2005. - Vol. 71, Is. 10. - Ст. 104406, DOI 10.1103/PhysRevB.71.104406. - Cited References: 40 . - ISSN 1098-0121
РУБ Physics, Condensed Matter
Рубрики:
ELECTRON-PARAMAGNETIC-RESONANCE
   BORATE GLASSES

   IONS

   BEHAVIOR

   GD3+

   SPECTROSCOPY

   SYSTEMS

   GD-3+

   FIELD

   SHAPE

Кл.слова (ненормированные):
gadolinium -- glass -- lanthanide -- oxide -- anisotropy -- article -- chemical structure -- concentration response -- electron spin resonance -- energy -- magnetism -- molecular physics -- nanoparticle -- phase transition -- refraction index -- temperature sensitivity
Аннотация: Magnetic susceptibility, electron paramagnetic resonance (EPR), and optical properties have been studied in a glass system {20La(2)O(3)-22Al(2)O(3)-23B(2)O(3)-35(SiO2+GeO2)} with a part of La2O3 substituted by Gd2O3 in different concentrations. Positive Weiss constants have been found in the more heavily doped glasses and ascribed to clustering of Gd3+ ions. Two magnetic phase transitions at 55 and 12 K were detected and ascribed, respectively, to ferromagnetic and antiferromagnetic clusters containing Gd ions. The overall shape of the EPR spectra shows the presence of clustering at the higher Gd contents. At low temperatures the cluster-related resonance signal is altered in shape, indicating an onset of magnetic anisotropy field. This signal is convincingly fitted to superparamagnetic resonance arising from ferromagnetic nanoparticles. The clustering, depending on the Gd concentration, correlates with a significant shift to lower energies of the strong optical absorption band edge, ascribed to a charge transfer transition between Gd ions. A nonmonotonous change of refractive index with the increase of the Gd content indicates changes in the glass matrix and in Gd cluster structure.

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Держатели документа:
Univ Bordeaux 1, CNRS, UMR 5798, CPMOH, F-33405 Talence, France
Bar Ilan Univ, Dept Chem, IL-52900 Ramat Gan, Israel
RAS, SB, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
SI Vavilov State Opt Inst, St Petersburg 199034, Russia
Bar Ilan Univ, Dept Phys, IL-52900 Ramat Gan, Israel
ИФ СО РАН
CPMOH, UMR 5798, CNRS-Universite Bordeaux-I, 33405 Talence Cedex, France
Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
L. V. Kirensky Institute of Physics SB RAS, Krasnoyarsk 660036, Russian Federation
S. V. Vavilov State Optical Institute, St. Petersburg 199034, Russian Federation
Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel

Доп.точки доступа:
Kliava, J.; Malakhovskii, A. V.; Малаховский, Александр Валентинович; Edelman, I. S.; Эдельман, Ирина Самсоновна; Potseluyko, A. M.; Petrakovskaja, E. A.; Петраковская, Элеонора Анатольевна; Melnikova, S.V.; Мельникова, Светлана Владимировна; Zarubina, T. V.; Petrovskii, G.; Bruckental, Y.; Yeshurun, Y.
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6.


    Zobov, V. E.
    The coordinate of a singular point of the time correlation functions for a heteronuclear spin system of a crystal / V. E. Zobov, M. A. Popov // J. Exp. Theor. Phys. - 2005. - Vol. 100, Is. 4. - P. 775-783, DOI 10.1134/1.1926438. - Cited References: 24 . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
FLUCTUATION SPECTRUM
   CROSS-RELAXATION

   NMR ABSORPTION

   SHAPE

   WINGS

   LINE

Кл.слова (ненормированные):
Correlation methods -- Crystal lattices -- Crystallography -- Functions -- Integral equations -- Lithium compounds -- Nuclear magnetic resonance -- Quantum theory -- Random processes -- Autocorrelation functions (ACF) -- Dipole-dipole interactions (DDI) -- Heteronuclear spin systems -- Self-consistent fluctuating field (SCFF) -- Crystals
Аннотация: The singularities of the time autocorrelation functions (ACFs) for a heteronuclear spin system of a crystal are investigated. Exact expressions are obtained for ten moments of the spectra of ACFs in the approximation of a self-consistent fluctuating field (SCFF) with arbitrary axial symmetry. These expressions are applied to determine the coordinate of the lowest singular point of these functions on the imaginary-time axis for a spin system with a dipole-dipole interaction (DDI). The leading corrections to this coordinate due to the correlation of local fields in real crystals are calculated. These corrections are determined by lattice sums with triangles of four bonds and pairs of four bonds. Numerical values of the coordinate are obtained for a LiF crystal in a magnetic field directed along three crystallographic axes. An increase in the coordinate of the singular point, which follows from the theory and leads to a faster falloff of the wings of the ACF spectra, qualitatively agrees with experiment. © 2005 Pleiades Publishing, Inc.

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Держатели документа:
Russian Acad Sci, Siberian Div, Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
Krasnoyarsk State Univ, Krasnoyarsk 660041, Russia
ИФ СО РАН
Kirenskii Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation
Krasnoyarsk State University, Krasnoyarsk, 660041, Russian Federation

Доп.точки доступа:
Popov, M. A.; Зобов, Владимир Евгеньевич
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