Nonsymmetrical X-ray diffraction in a perfect rectangular t x l crystal. Extinction and absorption.
A theoretical investigation of diffraction in a rectangular t x l crystal for nonsymmetrical coplanar scattering has been undertaken. The asymmetry in the scattering geometry, measured by an angle gamma, causes different weights for the mixed Laue-Bragg contributions to the integrated power. Primary extinction and ordinary absorption are only moderately affected when the value of the geometrical parameter zeta = (t/l)tanstraight theta(oh) < 1, straight theta(oh) being the Bragg angle. For increasing values of zeta and gamma the surface integration set-up for the Laue and Bragg regions is extensively changed, leading to pronounced effects. Analytical results for the normal absorption factor are presented.
Department of Mathematics and Natural Science, Stavanger College, Ullandhaug, 4004 Stavanger, Norway. gunnar.thorkildsen@tn.his.no
G
Thorkildsen
HB
Larsen