Книга
93 17857

Chukov, Vitalii N.
The new laws of the Rayleigh wave diffuse scattering and the Laue-Bragg-Wulff law violation for a periodical lattice of discontinuities / V. N. Chukov; Russian acad. of sciences, N. M. Emanuel inst. of biochemical physics, Center of acoustic microscopy. – Moscow : Preprint : IBCP RAS, 2018. – 25 p. : fig.
Бібліогр.: с. 22 -24 (50 назв).

The problem of the surface acoustic Rayleigh wave scattering on the deterministic cylindrically symmetrical isotropic solid surface roughness, having arbitrary lattice of discontinuities, is solved in the Born (the Rayleigh-Born) approximation of the perturbation theory in the roughness amplitude for the diffuse scattering when the wavelength is more less than the coordinate of any discontinuity. The new laws of the scattering indicatrix dependence on the ratio of the wavelength to the radius of a rough region and on the angle of scatte¬ring are obtained. The classical Laue-Bragg-Wulff scattering on the periodical lattice of a surface roughness discontinuities is considered in their limit, when the wavelength is more less than the size of the lattice primitive unit cell. It is obtained that cylindrical symmetry influences the positions of the Laue-Bragg-Wulff maxima. They dance around the value of a product of the unit cell size and absolute value of the wave-vector, transmitted in the scattering, defined by the Laue-Bragg-Wulff law in dependence on the unit cell configuration; and tend to its values when the number of the unit cells tends to infinity. It is obtained that the indicatrix of scattering oscillates between the Laue-Bragg-Wulff maxi¬ma as well. The frequency of these generalized Laue-Bragg-WuIff oscillations as a function of the transmitted wave-vector and unit cell size product depends on the unit cells configuration and number contrary to the classical Laue-Bragg-Wulff resonances. The new laws of the diffuse scattering, in particular the phenomenon of the scattering indicatrix strong dependence on the amplitude form-factor of the discontinuities, can violate the classical Laue-Bragg-Wulff law of scattering. They can modulate the amplitudes of the Laue-Bragg-Wulff resonances, which can increase or decrease with increasing of the number of the unit cells. The phenomenon of the classical Laue-Bragg-WrulfF resonances bifurcation due to the different scale oscillations of the amplitude form-factor of a periodical discontinuities lattice, violating the Laue-Bragg-Wulff law of scattering, is obtained. The nonperiodical pseudo Bragg lattice having diffe¬rent distances between discontinuities, that gives exactly the Bragg spectrum of scattering on the periodical Bragg lattice in the finite region of the lattice unit cell size and transmitted wave-vector product values, is constructed theoretically. The solution of the problem of scattering obtained in the present work gives a full theoretical explanation of sub-Bragg scattering considered in the theoretical and experimental works in literature. Obtained results themselves are theoretical predictions of the new phenomena of sub-Bragg scattering.



Предметні рубрики = МАТЕМАТИКА. ПРИРОДНИЧІ НАУКИ : Фізика : оптика : розповсюдження, відбиття, заломлення, поглинання, випромінювання світлових променів : розсіяння світла, дифузія
Предметні рубрики = МАТЕМАТИКА. ПРИРОДНИЧІ НАУКИ : Хімія. Кристалографія. Мінералогія : мінералогічні науки, кристалографія, мінералогія : кристалографія : тонка структура кристалів, теорія дисконтинууму кристалів : аналіз кристалів із застосуванням рентгенівських променів, рентгенографічний аналіз, рентгенографічне дослідження структури кристалів
Предметні рубрики = МАТЕМАТИКА. ПРИРОДНИЧІ НАУКИ : Хімія. Кристалографія. Мінералогія : мінералогічні науки, кристалографія, мінералогія : кристалографія : тонка структура кристалів, теорія дисконтинууму кристалів : аналіз кристалів із застосуванням рентгенівських променів, рентгенографічний аналіз, рентгенографічне дослідження структури кристалів : рентгенооптика, закон Брега, кут відбиття

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