spec

Software for Diffraction

4.4.1.1.1. - Zone or χ and φ Fixed (g_mode = 2)

A zone of reciprocal space is a plane passing through the origin. A zone axis is the direction of the normal to this plane. The zone axis can be specified by the vector product of any two non-colinear points in the zone. Zone mode forces the specified zone axis to be normal to the scattering plane. In other words, a zone of the crystal is leveled into the scattering plane of the spectrometer. Any point in this plane can then be reached with θ and 2θ (i.e., χ and φ are fixed). The geometry code provides for the calculation of the χ and φ necessary to put any two reciprocal space positions in the scattering plane via the cz, sz or mz macros. These macros are explained later.