Re: [sdpd] planar restraints

[Jonathan WRIGHT <wright...@esrf.fr>]

Eva,

If you are after soft restraints as opposed to rigid constraints then in
theory any program which does distance restraints can do planar restraints
as well, see "Least squares refinement with subsidiary conditions" J.
Waser, Acta Cryst (1963) 16, 1091. The plane can be specified in terms of
the non bonded distances between atoms in the plane, although this does not
lead to a very rigid plane. In a case like ferrocene the distances to
something which is perpendicular to the plane do a much better job (an atom
with zero occupancy can always be placed at some distance perpendicular to
a plane, and it's position refined). 

It is of course, much easier to use a program which handles all this
internally!

Good luck,

Jon

At 05:21 PM 6/20/01 +0200, you wrote:
>Hi,
>could someone please inform me if there are more Rietveld refinement 
>programs (besides GSAS) with
>planar-restraints option available?
>Thanks,
>Eva Dova 



 

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