[sdpd] One question about molecule location methods

[Armel Le Bail <armel... @fluo.univ-lemans.fr>]

OK, I know that not a lot of software allowing molecule location
are easily available nowadays (PATSEE, DIRDIF, ESPOIR...),
but the question is :

Suppose your molecule or starting fragment cannot be inserted
as such because the structure of the unknown has a much higher
symmetry, what is the best to do ? For instance, suppose you
are sure that the compound is a C60 derivative, but the cell is
either Im3m, I-43m, I432, or even Im3, I23, I213. Then, will you
have to try to do the job by using the I222 space group, 
allowing to put all the 60 C atoms in general position ? That
problem is rare for organic compounds, since they are almost
always of low symmetry. If you look inside the SDPD database
for structures solved by the molecule location method, in all
cases the fragment could be inserted in a general position as
a whole. Hence the question: what to do if this is impossible ?

Any hint ?

Armel Le Bail
http://www.cristal.org/course/