Тип публикации: статья из журнала
Год издания: 2005
Идентификатор DOI: 10.1134/1.1926438
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 determПоказать полностьюine 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.
Журнал: JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS
Выпуск журнала: Vol. 100, Is. 4
Номера страниц: 775-783
ISSN журнала: 10637761
Место издания: MELVILLE
Издатель: AMER INST PHYSICS