As I know how to do refinement of pure sample by Fullprof software, how should done perform the refinement when doping is done into the pure sample, where substitution doping occurs. My concerns are:
1) Whether should I refine the whole doped sample by not incorporating the doped compound in atoms section in the Fullprof software and at last incorporate it (i.e. without adding the doped atoms and just doing a normal refinement of a pure compound)
or
2) When the cif file is added, then in the atoms section should I add them before performing the refinement.(I tried this way but was getting scattering errors).
3) What changes must be done, like in atoms does x,y and z changes or just the occupancy part changes. Say for example the occupancy is 0.4912 of A atoms and one is doing, say 10% of B atoms such that it will replace A atoms, so does A occupancy becomes then 0.44208 and B atoms occupancy as 0.04912 and what about its x y and z parameters?
To perform the refinement you should have an idea of the sites on which your dopant ions could be located. If you don't know the exact sites, you can try different models and compare the results (agreement factors and graphical comparison). You need a detailed pattern to have reliable results. Then only the site occupancy changes, not the coordinates. The values of occupancies usually are those of the prepared stoichiometry of the sample, as you wrote in your query. If you want to determine (i.e. refine) the occupancy factors, you should have a sufficient contrast between the atoms occupying the same sites (i.e. to have different atomic scattering factors). You can certainly refine the atomic coordinates, some variations can occur with respect to the undoped phase, but for the dopant ions the coordinates are the same of the original ions.
Marcella Bini ,Thank you for your valuable response. As you said, I know at which site that dopant will go but as I said I don't know how to proceed with the refinement when doing in Fullprof. And the calculations I showed are they correct if the site which gets replaced and occupies are those only?
Yes, the occupation of the dopant is the same of the atomic percent in your stoichiometric formula
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