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[sdpd] Scratch

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It is timely for having some discussion, not only
announcing.

Recent success in determining structures from
scratch may suggest that a chemical analysis,
plus an indexed powder pattern would be sufficient
for a structure determination even if the Patterson
and direct methods fail. I mean that the molecular
structure may become unnecessary when dealing with
organic compounds. This implies that the work of
determining the molecular structure, which precede
necessarily the application of methods of molecule
location, becomes possibly useless. Investment
in a laboratory powder diffractometer is quite
less expensive than buying a big NMR. The recent
redetermination of the cimetidine structure from
scratch (a set of random positions as starting model), 
by Monte Carlo process (with the Espoir software),
is quite encouraging. Moreover, the GNU license
authorizes you to hack this code at your convenience.
Nothing is better than Linux and the other open source
software on which independent and free workers are 
heavily busy : this opinion is frequently presented in 
most computer journals. Why not to do the same in
crystallography ?

Best

Armel Le Bail - Universite du Maine, Laboratoire des Fluorures,
CNRS ESA 6010, Av. O. Messiaen, 72085 Le Mans Cedex 9, France
http://www.cristal.org/