I have followed with interest the discussion initiated by Armel le Bail on
the Rietveld mailing list and now on that of the Association Francaise de
Cristallographie, critical of the ICDD powder diffraction database.
Certainly a (diplomatic :-) debate about how to collect, distribute and pay
for crystallographic databases is appropriate in this age of new
information technology.
Armel Le Bail <[EMAIL PROTECTED]> wrote:
>Cette année pourrait voir la commercialisation de PDF-3
>par l'ICDD, une base de données contenant 3000 diagrammes....
>
>Une alternative, PowBase, mise en place il y a 2 mois, contient
>actuellement exactement 150 diagrammes....
Actually the ICDD database contains many more patterns, and contrary to
what was written, does contain calculated patterns from most of the ICSD
database as well (50479 entries) *including* single crystal entries.
>RELEASE 99 of the PDF contains over 70,000 experimental patterns compiled
>by the ICDD since 1941, as well as more than 42,000 calculated patterns
>from the ICSD database.
There might be more sympathy if the criticism was restricted to the COST of
databases. But with the technology used until now, it IS expensive to
collect and verify data and then to distribute the database. Some-one has
to pay.
Armel has an interesting point though. Now that everyone has internet
access it is certainly possible for people to submit data to an automatic
WWW server, which might rapidly build up a useful database at little cost.
Being on the WWW, it would then be available to all, and always up-to-date.
He is right to at least question the present (expensive) methods used to
gather, verify and distribute data.
On the other hand, if a few more people were willing to pay for the work of
maintaining databases, the cost to individual labs. would come down. As an
example, national science organisations in several countries (The
Netherlands, Spain, Switzerland, Taiwan, the UK...) as well as national
labs in Germany, the USA..., subscribe to the inorganic database ICSD,
which means that every academic in that country/lab has instant access to
the whole database via the WWW.
BTW Armel, calculated powder patterns for any of the 50479 ICSD structures
can be generated via WWW (by academics within the subscriber countries),
and everyone else has free access to the ~2000 entries on our demo server.
Alan Hewat, ILL Grenoble, FRANCE <[EMAIL PROTECTED]> tel (33) 4.76.20.72.13
ftp://ftp.ill.fr/pub/dif fax (33) 4.76.20.76.48 http://www.ill.fr/dif/
