X-Ray Standing Waves
One of the more fascinating aspects of dynamical Bragg diffraction of x-rays is the excitation of standing wave fields inside the crystal. Direct experimental manifestations of standing wave effects were evident in the discovery of anomalous transmission in the case of the Laue geometry by (1941) and in studies of fluorescent scattering in the Bragg geometry initiated by (1964). Experiments in the Bragg geometry (i.e., the diffracted beam exits the crystal through the same face that the incident beam enters) had the peculiar advantage that only a single standing wave-type eigenfunction is excited in the crystal and this field could be manipulated experimentally to probe atom sites in the diffracting crystal. It was later pointed out by (1974) that studies directly within the Bragg band gap could lead to comprehensive atom-location information. Subsequent work has demonstrated that both surface and near-surface impurities can be localized to approximately one hundredth of a lattice constant (Andersen, Golovchenko and Mair, 1976).
KeywordsStanding Wave Fluorescence Yield Bragg Reflection Reciprocal Lattice Vector Atom Location
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