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