Abstract
Dynamical X-ray diffraction during total external reflection has been studied by measuring rocking curves from Bragg planes nearly perpendicular to the flat surface of a germanium single crystal. The rocking-curve profiles for both the diffracted and specular beams observed from slightly asymmetric Bragg planes were found to be quite different from those from the symmetric plane. Experiments using a parallel X-ray beam and a surface passivated sample confirmed the rocking-curve features arising from the excitation and de-excitation of the wave fields in shallow surface layers of the bulk crystal.