ess.diffraction.peaks.dspacing_peaks_from_cif#

ess.diffraction.peaks.dspacing_peaks_from_cif(cif, intensity_threshold=None, **kwargs)[source]#

Retrieves a data array representing the bragg peaks of the given material.

The material is represented by a cif file or a codid or similar. The number of peaks retrieved can be controlled by setting the intensity threshold argument to only retrieve prominent peaks.

Parameters:

  • cif –

    Generalised CIF source, either in the form of text data, a file path, a database ID (in the form of a string like “codid::9008460” or “mpid::87)”, for either the Crystallography Open Database (https://www.crystallography.net/cod/) or the Materials Project (https://www.materialsproject.org/).

    For more details, see ncrystal.cifutils.CIFSource.

  • intensity_threshold (default: None) – The minimum intensity of the peaks to return. Intensity is here defined as the squared structure factor times the multiplicity of the peak. The intensity_threshold must be convertible to unit barn.

  • kwargs – Can be anything that :py:`NCrystal.NCMATComposer.from_cif` supports. For example: uiso_temperature or override_spacegroup.

Returns:

DataArray – Data array representing peak amplitudes and peak positions in dspacing. The full NCrystal information object is added as a coordinate with the name info. The input arguments are added as scalar coordinates.

Examples

>>> from ess.diffraction.peaks import dspacing_peaks_from_cif
>>> dspacing_peaks_from_cif(
...     'codid::9008460',
...     uiso_temperature=400,
...     override_spacegroup='F d -3 m:1',
... )
<scipp.DataArray>
Dimensions: Sizes[peaks:162, ]
Coordinates:
* cif                        string        <no unit>  ()  "codid::9008460"
* dspacing                  float64             [Å]  (peaks)  [2.33803, 2.02479, ..., 0.243756, 0.243756]
* info                     PyObject        <no unit>  ()  <NCrystal.core.Info object at ...>
* override_spacegroup        string        <no unit>  ()  "F d -3 m:1"
* uiso_temperature            int64  [dimensionless]  ()  400
Data:
                            float64           [barn]  (peaks)  [13.3631, 9.59562, ..., 0.000556426, 0.000556426]