>Dear all, I have three questions as follows,
>1.If there are three or more atoms in the same
>site(e.g.,LiNi1-x-y-zCoxMgyTizO2£©,how to set the constraints and refine
>their fractions?
From a single diffraction dataset you can not refine more than one
occupancy parameter per site. You must think that, with x-ray diffraction
(resp. neutron diffraction), you are able to refine electron density (resp.
nuclear density) at each site and several combinations of substitutents can
lead to the same global electron (resp. nuclear) density.
To solve multisubstuent problems you must use joint refinement of neutron
and x-ray data, or anomalous x-ray diffraction.
In addition, in your case, you will have the problem to distinguish between
Ni, Co and Ti because thay have poor x-ray contrast. However Mg content can
be refined easily if you fix Ni/Co and Ni/Ti ratii.
Best regards.
------------------------------------
Jean-Marc Joubert
Chargé de recherche
Laboratoire de Chimie Métallurgique des Terres Rares
CNRS - UPR 209
2 - 8 rue Henri Dunant - 94320 THIAIS Cedex - FRANCE
phone : 33 1 49 78 12 11
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email : [EMAIL PROTECTED]
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