Borrmann effect

From Online Dictionary of Crystallography

Jump to: navigation, search

Effet Borrmann (Fr). Borrmann Effekt (Ge). Efecto Borrmann (Sp). Effetto Borrmann (It)

Contents

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 111 and {\bar 1}11 reflections are simultaneously excited in a silicon or germanium crystal.

History

The Borrmann effect was first discovered in quartz (Borrmann G., 1941, Über Extinktionsdiagramme der Röntgenstrahlen von Quarz. Physik Z., 42, 157-162) 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