RE: [sdpd] error measurements

["Peter Y. Zavalij" <zavalij...@binghamton.edu>]

Of course Rwp is very important as well as Rp. I do not insist on using Rp
only but it is "pure" R-factor while Rwp depends on what weight is used.

-----Original Message-----
From: cockcroft...@img.cryst.bbk.ac.uk
[mailto:cockcroft...@img.cryst.bbk.ac.uk]
Sent: Tuesday, January 23, 2001 9:55 AM
To: sdpd...@egroups.com
Subject: Re: [sdpd] error measurements


To add to my recent comments, I disagree with quoting Rp (as used
in the original JAC paper) - weights should be used - especially when
X-ray data is collected repeatedly at higher two-theta angles so
as to improve statistics. So I disagree with you, Peter Zavalij, re the
use of Rp. I would also add that R-factors based on both total peak
intensities and structure factors-squared are also useful, but they
should be treated with some caution if the data has been collected for
different time periods for different two-theta ranges (since they are
difficult to weight properly).
  Jeremy Karl Cockcroft
  School of Crystallography, Birkbeck College, UK.