I am performing Rietveld refinement on a material in which a site is shared between Iron and Nickel. Fullprof is not capable of refining the occupation of those atoms since their atomic number is too similar, however would it be possible to refine the occupation of the site, while keeping the Fe/Ni ratio constant? I tried fidgeting with the constraints, but I'm not very good with those.
hi,
the first pic is undoped material and im trying to refine it.
we have an expert in refinement but they do not teach things in detail.
so, I am doping little amounts of C into AB2. since it doesn't affect the structure much, I'd be using Rietveld refinement to compare the lattice parameters.
is this correct?
also, in the C doped AB2 (Next Pic) there are some peaks that I haven't found in the database (PDF5). the green and blue peaks cannot be considered, right? Since not all the peaks correspond with my xrd.
Here just trying the fitting for dolomite
Hi everyone,
I’m fairly new to XRD and Rietveld refinement, and I’m currently trying to estimate the dolomite content in samples that also contain clays (mainly montmorillonite).
I keep running into the same issue: the dolomite phase starts fitting the broad low-angle peak that I believe belongs to montmorillonite, producing an obviously unrealistic fit in the low-2θ region. Even when the higher-angle dolomite reflections fit reasonably well, the refinement still tries to use dolomite intensity to account for that broad clay feature.
I'm using Profex as software, any advice or best practices would be greatly appreciated! Thanks!
Who is using the Bruker? Do you have any advice?
I’m having problems with this mineral. It’s not in the database, and I have no idea how to add it…
Good afternoon!
I use the Profex-XRD to interpret diffraction patterns of the clay minerals. We recently got a new Bruker D2 Phaser with copper radiation, and to properly measure low angles on it, I use a 0.6 mm primary beam slit and a 0.5 mm knife . However, the instrument configuration I created in Profex does not allow for an adequate refinement model.
The simulated intensities of all peaks, especially those of the clay minerals and calcite, are underestimated up to about 30° 2θ. In the 30–45° range, everything is fine, but after 45° the model systematically overestimates the intensities.
Could you please tell me whether anyone has encountered this problem and how it can be solved?
