Borrmann effect
From Online Dictionary of Crystallography
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Effet Borrmann (Fr). Borrmann Effekt (Ge). Efecto Borrmann (Sp). Effetto Borrmann (It)
Definition
Due to anomalous absorption, type 1 wavefields propagate in a perfect or nearly perfect crystal with a less than normal absorption. For details and the physical interpretation, see anomalous absorption.
Super-Borrmann effect
It is the enhancement of the Borrmann effect in a three-beam case, e.g. when the [math]111 [/math] and [math]{\bar 1}11 [/math] reflections are simultaneously excited in a silicon or germanium crystal.
History
The Borrmann effect was first discovered in quartz [Borrmann, G. (1941). Physik Z., 42, 157-162. Über Extinktionsdiagramme der Röntgenstrahlen von Quarz] and then in calcite crystals (Borrmann G., 1950, Die Absorption von Röntgenstrahlen in Fall der Interferenz. Z. Phys., 127, 297-323), and interpreted by Laue (Laue, M. von, 1949, Die Absorption der Röntgenstrahlen in Kristallen im Interferenzfall. Acta Crystallogr. 2, 106-113).
The super-Borrmann effect was first observed by Borrmann G. and Hartwig W. (1965), Die Absorption der Röntgenstrahlen im Dreistrahlfall der Interferenz. Z. Krist., 121, 401-409.
See also
Section 5.1 of International Tables of Crystallography, Volume B for X-rays
Section 5.2 of International Tables of Crystallography, Volume B for electrons
Section 5.3 of International Tables of Crystallography, Volume B for neutrons