I have a question concerning the systematic line shifts due to sample
off-centering in the Debye-Scherrer-geometry. The shift D2Theta due to an
eccentricity e in the incident beam direction is always given as
(1) D2Theta = (e/R)*sin(2*Theta)
with R being the radius of the goniometer circle. For the shift caused by
an eccentricity normal to the incident beam direction it is given in the
literature and used in refinement programms as
(2) D2Theta = (e/R)*cos(Theta)
When I tried to comprehend this equations I had no problems with (1), but
for the eccentricity normal to the incident beam direction I always got
D2Theta = (e/R)*cos(2*Theta)
instead of (2). So, does anybody here in the list know the article in
which the development of (2) is described?
Daniel Toebbens
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Daniel M. Toebbens Tel.: +49 30 8062-2793
Hahn-Meitner-Institut Fax : +49 30 8062-2999
Glienicker Strasse 100
D-14109 Berlin, Deutschland http://www.hmi.de/people/toebbens/
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