Dear Sergey (& All),
The default values of omega, chi & phi (0,90,0), which you will find under
'A' in histogram editing, are appropriate for Bragg-Brentano diffraction
geometry. For Debye-Scherrer geometry these should be set to (0,0,0). Since
experience has shown that texture is "rare" for D-S data, changing these is
rarely needed. The sample rotation angles found in the spherical harmonics
texture menu are only needed for "full" texture analysis to correct for
small sample orientation errors. If you "tilt" the sample then the
appropriate values must be changed to reflect the rotation of the sample.
See p141-144 of the GSAS Manual for a full description of the coordinate
systems and Eulerian rotation angles used for spherical harmonics texture.
Bob Von Dreele
At 07:30 PM 5/30/01 -0800, you wrote:
>Dear All,
>
>Could somebody give me a hint on what should be omega, phi and chi angles
>ideally for Bragg-Bretano geometry (or tell why they should change)?
>
>Thanks in advance,
>Sergey
>
>----------------------------------
>Sergey Ushakov
>
>post-doc
>University of California at Davis
>Thermochemistry Facility
>Dept. of Chem.Engr.&Mat.Sci.
>One Shields Ave., Davis, CA 95616
>ph 530/754-5863
>fax 530/752-9307
