How to use constraint in Rietveld refinement?

29 June 2020 1 4K Report

I am working on spinel ferrites (AB2O4). Since cations in spinels can occupy both tetrahedral and octhedral sites, I need to find out the amount of cations occupying the tetrahedral and octahedral sites. I have found that use of constraint (or restraint) is necessary for the correct evaluation of site occupancy, in particular in AB2O4. It will be good to learn from you on how to use constraint/restraint for this purpose.

Götz Schuck

This depends on which Reitveld software is used. In Fullprof, for example, the occupation of a disordered position can be set to one and then the atoms can be refined accordingly. See also: https://www.researchgate.net/post/How_to_define_occupancy_in_FullProf_when_atoms_are_disordered_to_higher_multiplicity_positions

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