Single-crystal fit: Co₂SiO₄ at three temperatures, HEiDi¶
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 structures¶
On Structure, choose Load ▾ From web…, search for each entry by its id and click it:
sc-neut-cwl_cosio-heidi-cosio_300ksc-neut-cwl_cosio-heidi-cosio_55ksc-neut-cwl_cosio-heidi-cosio_2k5
Load the experiments¶
On Experiment, choose Load ▾ Full experiment From web…, search for each entry by its id and click it:
sc-neut-cwl_cosio-heidi-heidi_300ksc-neut-cwl_cosio-heidi-heidi_55ksc-neut-cwl_cosio-heidi-heidi_2k5
Fit each experiment on its own¶
On Analysis → Extra, set the fitting mode to independent, so each experiment is fitted alone against its structure, with its own goodness of fit.
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.
300 K: scale¶
The scale brings the calculated intensities to the measured ones.
Choose heidi_300k in the datablock filter, then filter the Linked structures parameters using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.
300 K: coordinates¶
Choose cosio_300k 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.
300 K: displacements¶
Choose cosio_300k 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.
300 K: extinction¶
Larson's anisotropic extinction, its six coefficients starting at zero.
Choose heidi_300k in the datablock filter, then filter the Extinction parameters using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.
55 K: scale¶
The 300 K parameters stay free, so the 300 K experiment is fitted again from where it ended.
Choose heidi_55k in the datablock filter, then filter the Linked structures parameters using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.
55 K: coordinates¶
Choose cosio_55k 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.
55 K: extinction¶
At 55 K the displacements are small. Freed before the extinction, they would take its place and Co1's tensor would stop being positive definite, so the extinction comes before them here.
Choose heidi_55k in the datablock filter, then filter the Extinction parameters using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.
55 K: displacements¶
Choose cosio_55k 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.
2.5 K: scale¶
The nuclear structure first, with every moment still at zero, in the order 55 K needed.
Choose heidi_2k5 in the datablock filter, then filter the Linked structures parameters using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.
2.5 K: coordinates¶
Choose cosio_2k5 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.
2.5 K: extinction¶
Choose heidi_2k5 in the datablock filter, then filter the Extinction parameters using the category filter, click the Free column header and choose Free · all, then press Fit in the status bar.
2.5 K: displacements¶
Choose cosio_2k5 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.
2.5 K: the magnetic moments¶
Free the moment components the magnetic space group allows. They start at zero, where the magnetic intensity has no slope, so the fit starts them at 1 μB and says so.
Choose cosio_2k5 in the datablock filter, then filter the Magnetic moments 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.
