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Re: [sdpd] overlapping reflections / preferred orientation

António Moreira dos Santos wrote:
> On another note a "theoretical question": in the same way 
> one can derive the zero shift on a diffraction pattern by 
> harmonic analysis without an internal standard, is there a 
> way to derive a possible preferred orientation vector 
> without a structural model? and where can I learn more 
> about that?

A. Altomare, M.C. Burla, G. Cascarano, C. Giacovazzo, A. Guagliardi, 
A.G.G. Moliterni and G. Polidori (1996), "Early Finding of Preferred 
Orientation: Applications to Direct Methods", J. Appl. Cryst. 29, pp. 
341-345.

If the preferred orientation is extreme, you might be able to predict 
the orientation by inspecting the unit-cell parameters: if one unit-cell 
parameter is very long or very short compared to the other two, then 
that is probably your preferred orientation direction. This can be 
refined by taking the space group (if known) into account and 
calculating the Bravais Friedel Donnay Harker morphology.

Best wishes,
-- 
Dr Jacco van de Streek
Research Scientist
Cambridge Crystallographic Data Centre
Cambridge, United Kingdom



 
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