Prediction of Holz Pattern Shifts in Convergent Beam Diffraction
In general, diffraction patterns from the higher-order Laue zones are shifted with respect to the zero-order pattern. Expressions for the shift (t) have been derived in terms of the indices [u, v, w] of a zone, the interplanar spacing (H), and a reciprocal lattice vector [gL (hkl)] in a holz. The resulting vector possesses the direction of t in terms of a zolz reciprocal lattice vector and has a magnitude which is a fraction of that of the zolz vector. Hence, the calculation of t allows quantitative determination of the location of specific planes in a holz with respect to the zolz, thus simplifying the determination of plane indices consistent with those used in the zolz. The expressions for determining t for cubic, hexagonal close-packed (hep), tetragonal, orthorhombic, and monoclinic crystal types are presented in a table and, when applied, allow calculation of t expressed as a fraction of a zolz vector. An example for graphite is presented to illustrate the use of the equation, and tvectors for several zones for the simple cubic system are tabulated.
Jackson, A. G.
(1987). Prediction of Holz Pattern Shifts in Convergent Beam Diffraction. Journal of Electron Microscopy Technique, 5 (4), 373-377.