Yes - the main demonstrated benefit is in structure refinement. The
coordinates, thermal parameters and SOF's of 'light' atoms are more stable
than with fixed count time data. A summary of the other benefits can be
found in the references:-
Madsen & Hill, (1992) Advances in X-ray Analysis, Vol 35, 39-47.
Madsen & Hill, (1994) J.Appl. Cryst., 27, 385-392.
>In which cases the technique can be useful?
>After conversion with a suitable program, are the data well treatable
>with the usual Rietveld programs (for example GSAS)?
The important point to remember is to carry through the time and the
accumulated count at each point - do not normalise the raw data back to a
fixed count time data set. The benefit of the variable counting time regime
is realised by carrying the accumulated counts into the analysis program and
using them to set the weights at each point.
>I found a program which is able to manage a Philips PW1710 and work out
>data according to VCT acquisitions. It is named XRDTIME, by CSIRO.
>Does anyone of you know it?
XRDTIME was written in FORTRAN for PC computers and outputs a string of
commands for the PW1710 controllers we use. However, the routine which
writes out the commands could be easily modified to suit other controllers
if necessary. Contact me if you would like any further details - contact
information should appear below.
Regards
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Ian Madsen
CSIRO Division Of Minerals
P.O. BOX 124
Port Melbourne 3207
Victoria
AUSTRALIA
Phone +61 3 9647 0366 direct
+61 3 9647 0211 switch
FAX +61 3 9646 3223
Email Ian.Madsen@minerals.csiro.au
XRD laboratory 'tour' starts at
http://www.minerals.csiro.au/tour/begin.htm
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