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
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