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Re: [sdpd] Recent Congress and comiing ones about SDPD
>Sure, but who will start the recording of a series of experimental
>datasets without knowing the cell ? Nobody I guess. So that programs
>able to index by using informations from multiple datasets will not be
>used very frequently ;-). The risk is to record effects of anisotropic
>thermal expansion on multiphase samples, etc, and to realize it
>too late. Single powder patterns have still some future.
>
>
Sometimes one of the phases will decompose or transform when you heat
the sample up and lots of chemical synthesis can be done on a
diffractometer. If you don't know the cell and cannot index it, then a
few patterns at higher or lower temperatures would seem like a good
experimental strategy for sorting out which peaks go with which phase
(some people do it routinely already). Using the thermal expansion
information is for pulling the subtle details from the data, when there
are hopefully going to be far more obvious things in there. It might be
a last hope for a desparate researcher (... for whatever reason electron
diffraction didn't work) and perhaps more interesting for anyone looking
at compressibility, as I guess line shifts are quite common for people
working at high pressure?
Anyway, I thought most lab diffractometers had some sort of temperature
attachment, and that a reasonable pattern for indexing could be
collected in less than an hour. When the instruments start to go faster,
as they all are, you have to find something to do with them. Don't you
need to go home and sleep sometimes??
Cheers,
Jon
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