Dynamical Calculation in a Two-beam Approximation for Three-beam X-ray Diffraction

Horn-Hsiang Tseng；Shih-Lin Chang

Chinese Journal of Physics

30卷3期（1992 / 06 / 01）

389 - 404

英文

The formulation of a two-beam approximation for three-beam diffraction is derived from the dynamical theory of X-ray diffraction, with and without the assumption that the wavefield amplitudes Do of the diffracted waves are much smaller than the amplitude Do of the incident wave. Based on this formulation, calculations for the dispersion surface, intensity, excitation of mode of wave-propagation, and absorption are performed for several three-beam diffractions from centric and acentric crystals. The results are compared with those calculated without approximation. It is shown that the hvo-beam approximation without Do ＜ ＜ Do gives a better agreement with the exact solution than that with the Do ＜ ＜ Do assumption.