Re: [sdpd] Re: Welcome to sdpd

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

At 06:14 PM 8/22/01 +0200, alb...@cristal.org wrote:
>This mail was sent personnally to a new SDPD mailing list
>subscriber who asked :
>
>>I want to know, what I have to do now.
>[...]
>Other (general and informative) links to SDPD welcome.

One factor to bear in mind is that better data generally helps. In order of
preference for structure solution one might propose:

1. Grow a single crystal
(if it's very small you might try a microcrystal diffraction beamline at a
synchrotron)
2. Obtain a highly crystalline powder and collect powder data at a synchrotron
3. When crystallinity limits the peak widths then collect the best data you
can manage.

For certain problems (not too many hydrogen atoms?) neutron data will also
help. "Best" data and "better" data are both subjective concepts which
would depend on the sample and the structure you are trying to solve. For
indexing a difficult unit cell (and trying to solve a structure) it's
probably worth remembering that electron diffraction methods also exist.

Anyone who noted a recurring theme of synchrotrons above might be surprised
to find that I'm currently employed at one! So I should avoid impropriety
and not plug the esrf website or mention that applications deadlines are
(always) fast approaching (somewhere). Robert Dinnebier has collected a
useful list of various facilities where you might try to find "better" data:
http://www.pulverdiffraktometrie.de/Links/measurement/measurement.html
The site also contains a number of other links which may be of interest to
readers of this list.

Jon

[As always, these are my own opinions]


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