Dear Dr. Lee:
At 10:51 AM 6/15/01 +0200, you wrote:
>Hi all,
>
>I have a problem concerning the refinement of the cell parameters of a
>rhombohedral space group (R-3c) in Fullprof. The documentation says to use
>the hexagonal description of the unit cell and that is what I do: a=b, c,
>alpha=90, beta=90, gamma=120. a and b are the refinable parameters, the
>angles should be kept fixed.
>
>The program tries nonetheless to refine the gamma angle although its code
>is set to zero. The output shows however that the associated standard
>deviation is equal to zero.
>The total number of parameters is four in profile matching mode with
>constant relative intensities (jbt=3): one scale factor, one zero error and
>two cell parameters (a and b). The profile parameters are kept fixed for
>the moment.
>
>Who recognises this problem? Thanks in advance.
>
>Arie van der Lee
>
>
>**************************************************
>Dr. A. van der Lee
>Institut Europ�en des Membranes
>Universit� de Montpellier II - cc 047
>2 place E. Bataillon
>34095 Montpellier CEDEX 5
>
>Visiting address:
>240 Avenue du Professeur Emile Jeanbrau
>Montpellier
>
>Phone: (33) 467 14 9135
>Phone: (alternative) (33) 467 14 9100
>FAX: (33) 467 14 9119
>**************************************************
This sounds like a problem you would have with DBWS. In that progra, the
solution is to assign the same codeword to gamma that a and b have. The
mathematical reason(in DBWS) is that the calculation is done with
reciprocal space vectors.You will have ht eame problemiwth a hexagonal
space group.
Sincerely,
Ray YOung
Prof. R. A. Young
School of Physics
Georgia Institute of Technology
Atlanta, GA 30332 USA
Tel: 404-894-5208
FAX 404-894-9958
e-mail [EMAIL PROTECTED]
