Bragg-surface dynamical diffraction

In this work, the dispersion surface of Bragg-surface diffraction (BSD) is presented. A symmetric Bragg reflection plus a secondary diffracted wave ne arly parallel to in-plane directions distinguish the BSD from an ordinary t hree-beam diffraction. The solutions of the fundamental equations of the dy namical theory of X-ray diffraction for the BSD demonstrate that measurable specular-reflected secondary waves are simultaneously excited with the dif fracted waves.