Joint fit: Na₂Ca₃Al₂F₁₄, WISH¶

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-tof_ncaf-wish-ncaf

Load the experiments¶

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

• pd-neut-tof_ncaf-wish-wish_1_10
• pd-neut-tof_ncaf-wish-wish_2_9
• pd-neut-tof_ncaf-wish-wish_3_8
• pd-neut-tof_ncaf-wish-wish_4_7
• pd-neut-tof_ncaf-wish-wish_5_6

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.

Scales and time-of-flight calibration¶

Each bank's scale and DIFC offset and linear term put its peaks in place and at the right height.

Filter the Linked structures parameters of wish_1_10, wish_2_9, wish_3_8, wish_4_7 and wish_5_6, choosing each in the datablock filter using the category filter and the Instrument parameters of wish_1_10, wish_2_9, wish_3_8, wish_4_7 and wish_5_6, choosing each in the datablock filter using the category filter, click the Free column header and choose Free · all; then type quadratic in the name filter and choose Fixed · all in the same menu, then press Fit in the status bar.

Background¶

Each bank's background points; bank 1-10's first and last stay fixed, as its source has them.

Filter the Background parameters using the category filter, click the Free column header and choose Free · all; then filter the Background parameters of wish_1_10, choosing each in the datablock filter using the category filter, click the Free column header and choose Fixed · all, then press Fit in the status bar.

Peak asymmetry¶

Each bank's back-to-back exponentials, the terms its data determine; bank 1-10 keeps its instrument values.

Filter the Peak asymmetry parameters of wish_2_9, wish_3_8, wish_4_7 and wish_5_6, choosing each in the datablock filter using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.

Gaussian widths¶

The Gaussian width terms the banks' data determine.

Filter the Peak broadening parameters with sigma_1 in their name of wish_2_9, wish_3_8 and wish_4_7, choosing each in the datablock filter using the category filter and the name filter and the Peak broadening parameters with sigma_2 in their name of wish_2_9, wish_3_8, wish_4_7 and wish_5_6, choosing each in the datablock filter using the category filter and the name filter, click the Free column header and choose Free · all, then press Fit in the status bar.

Lorentzian width¶

Bank 2-9's Lorentzian term.

Choose wish_2_9 in the datablock filter, then filter the Peak broadening parameters with gamma_1 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.

Absorption¶

Banks 2-9 to 5-6 each fit their absorption.

Filter the Absorption parameters of wish_2_9, wish_3_8, wish_4_7 and wish_5_6, choosing each in the datablock filter using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.

Atom positions¶

The coordinates the cubic symmetry leaves free.

Choose ncaf in the datablock filter, then 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¶

Choose ncaf in the datablock filter, then 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.

Correlations¶

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

Report¶

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