Rietveld fit: Y₂O₃, SPODI¶

The same staged fit as the Python and Command line tutorials, in the app. Its structure and experiment come from EasyDiffraction's collection with Load ▾ From web…, and each stage frees its parameters in the Parameters table on Analysis before the fit.

Create a project¶

Press Start on Home, then Create a new project, and give it a name.

Load the structure¶

On Structure, choose Load ▾ From web…, search for each entry by its id and click it:

• pd-neut-cwl_y2o3-spodi-y2o3

Load the experiment¶

On Experiment, choose Load ▾ Full experiment From web…, search for each entry by its id and click it:

• pd-neut-cwl_y2o3-spodi-spodi

Estimate the background¶

On Experiment → Extra, set the number of points under Background estimation, then press Estimate in the Background group on Main.

Set the minimizer¶

On Analysis → Extra, set the Minimizer as the case's project does: the Shift/s.u. stop rule and room for more iterations.

Start with nothing free¶

On Analysis, open the Free column header of the Parameters table and fix every parameter, so the stages below free one group at a time.

Scale, 2θ zero and cell¶

The scale, the zero shift and the cell length put the peaks in place and at the right height.

Filter the Linked structures and Cell parameters, one category at a time, using the category filter and the Instrument parameters with calib in their name using the category filter and the name filter, click the Free column header and choose Free · all, then press Fit in the status bar.

Background¶

The estimated points are a starting point; fit them now that the peaks are in place.

Filter the Background parameters using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.

Peak widths¶

Filter the Peak profile parameters with gauss in their name using the category filter and the name filter, click the Free column header and choose Free · all, then press Fit in the status bar.

Atom positions¶

Y1's x and O1's three coordinates are the ones the symmetry leaves free.

Filter the Atomic coordinates parameters using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.

Anisotropic displacements¶

Last, the displacement tensors, each with only the components its site symmetry leaves free.

Filter the Atomic displacement parameters using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.

Starting and fitted patterns¶

Correlations¶

The Correlations view on Analysis shows which fitted parameters move together.

Report¶

The Report page collects the structure, the experiment and the fit.