International
Tables for Crystallography Volume B Reciprocal space Edited by U. Shmueli © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. B. ch. 5.1, p. 540
Section 5.1.3.7.1. Transmission geometry
a
Laboratoire de Minéralogie-Cristallographie, Université P. et M. Curie, 4 Place Jussieu, F-75252 Paris CEDEX 05, France |
In this case (Fig. 5.1.3.4) is +1 and (5.1.3.10) may be written
Let and be the intersections of the normal to the crystal surface drawn from the Lorentz point with the two branches of the dispersion surface (Fig. 5.1.3.4). From Sections 5.1.3.3 and 5.1.3.4, they are the tie points excited for and correspond to the middle of the reflection domain. Let us further consider the tangents to the dispersion surface at and and let , and , be their intersections with and , respectively. It can be shown that and intersect the dispersion surface at the tie points excited for and , respectively, and that the Pendellösung distance , the width of the rocking curve and the deviation parameter , where and are the intersections of the normal to the crystal surface drawn from the extremity of any incident wavevector OM with and , respectively.