Rietveld fit: herbertsmithite, HRPT¶

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_hs-hrpt-hs

Load the experiment¶

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

• pd-neut-cwl_hs-hrpt-hrpt

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.

Cell, scale and 2θ zero¶

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

Filter the Cell and Linked structures 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¶

The Gaussian widths and the mixing η₀, with the background staying free. diffraction-lib frees the Lorentzian Y where this profile has η₀.

Filter the Peak broadening parameters using the category filter and the Peak mixing parameters with eta_0 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¶

The coordinates the symmetry leaves free: O and H in x and z, Cl in z.

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.

Displacements¶

Every site's displacement.

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.

Asymmetry¶

Last, the four Bérar-Baldinozzi asymmetry terms.

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

Correlations¶

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

Report¶

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