Hongwu,
Tony Cheetham wrote a good summary which is the last chapter of "The
Rietveld Method", edited by Young. Since you don't know the atomic
positions, you'll need to get a good approximation of those before you
can use GSAS. Start by indexing the structure (Dicvol and Treor are
both good, and can be found free on the web). Also try to get a good
idea of the possible space groups by looking at systematic absences.
Next, you'll need to try to find the atomic positions. This is probably
the most difficult part. You may try direct methods or simulated
annealing to get a starting structure. From there, you can use GSAS to
refine the structure.
Good luck, you'll need it!
Paul Forster
Hongwu Xu wrote:
>
> Dear All,
>
> Could someone out there recommend me several papers regarding ab initio
> Rietveld refinement? I have a nanomaterial phase whose structure is
> completely unknown and I would like to solve the structure using power
> x-ray data. Can GSAS alone do this or will I need other softwares? Your
> suggestions are greatly appreciated.
>
> Hongwu
