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Orientation matrix

  • To: Multiple recipients of list <comcifs-l@iucr.org>
  • Subject: Orientation matrix
  • From: Brian McMahon <bm@iucr.org>
  • Date: Wed, 18 Sep 2002 09:44:21 +0100 (BST)
Dear Colleagues

A small query, less weighty than many we consider, but I am hoping that the
answer lies in the wise heads of some members of the group:

Paula Fitzgerald, while working on a revised draft of Chapter 2.2 of ITG,
inquired what the "UB" meant in the _diffrn_orient_matrix_UB_11 (etc) data
names. On checking my records I noticed that the original CIF paper
manuscript on submission designated these data names as
_diffrn_orient_matrix_11 etc, but this was obviously changed at some stage
during the handling of that paper. After a bit of detective work, I
formulated the following hypothesis:

"The terminology UB refers to the conventional designation of the matrix
 relating reciprocal space and the reference frame of a six-circle
 diffractometer, calculated as the product of the orientation matrix
 \textbf{U} and the material matrix \textbf{B} in the manner of
 Busing \& Levy (1967)."

Can anyone confirm (or refute) this, and comment on adding this wording to
the draft chapter?

Thanks
Brian