Authors: Doug du Boulay
Contact: Syd Hall, Crystallography Centre, University of Western Australia, Nedlands 6907, Australia
CBAZA requires diffractometer and crystal orientation settings, in conjunction with the diffractometer based PSI angle to calculate and store the Flack and Schwarzenbach, Crystal based Azimuthal PSI angle. This quantity is a prerequisite for LSABS and LSLS anisotropic extinction refinement, but has previously been unavailable to those who do not use the DIFRAC and CIFENT reflection data entry method.
This program requires a specification of the diffractometer and crystal orientation following the methods of ABSORB. For each reflection on the archive the Azimuthal PSI angle (measured with respect to reference vectors (k-l,l-h,h-k) or (h,-h,0) if h==k==l) is calculated. The diffractometer specific psi angle from lrrefl: item 1011 is read, if it exists for non bisecting mode reflections, and the calculated crystal based angle is written back as item 1011