Getting the diffraction pattern data

Materials Project
1

I used the interactive “Binder” notebook, preinstalled with Materials Project software, and get the below errors when I run the sample code snippet to retrieve the data.

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Input In [5], in <module>
      7     structure = mpr.get_structure_by_material_id('mp-998908')
      9 # important to use the conventional structure to ensure
     10 # that peaks are labelled with the conventional Miller indices
---> 11 sga = SpacegroupAnalyzer(structure)
     12 conventional_structure = sga.get_conventional_standard_structure()
     14 # this example shows how to obtain an XRD diffraction pattern
     15 # these patterns are calculated on-the-fly from the structure

File /srv/conda/envs/notebook/lib/python3.9/site-packages/pymatgen/symmetry/analyzer.py:59, in SpacegroupAnalyzer.__init__(self, structure, symprec, angle_tolerance)
     57 self._angle_tol = angle_tolerance
     58 self._structure = structure
---> 59 self._siteprops = structure.site_properties
     60 latt = structure.lattice.matrix
     61 positions = structure.frac_coords

AttributeError: 'NoneType' object has no attribute 'site_properties'
2

Hi @jaidah_mohan. I can’t reproduce this. I copied the example below, except pasting in my own personal API key:

from mp_api import MPRester
from pymatgen.analysis.diffraction.xrd import XRDCalculator
from pymatgen.symmetry.analyzer import SpacegroupAnalyzer

with MPRester(api_key='<enter your api key>') as mpr:
    # first retrieve the relevant structure
    structure = mpr.get_structure_by_material_id('mp-998908')

# important to use the conventional structure to ensure
# that peaks are labelled with the conventional Miller indices
sga = SpacegroupAnalyzer(structure)
conventional_structure = sga.get_conventional_standard_structure()

# this example shows how to obtain an XRD diffraction pattern
# these patterns are calculated on-the-fly from the structure
calculator = XRDCalculator(wavelength='CuKa')
pattern = calculator.get_pattern(conventional_structure)

And this works fine.

image
image1728×1740 362 KB

Is there any other information you can provide to help reproduce the issue?

Best,

Matt

3

Hi. To get XRD data for material mp-17254 I ran above script (and other similar ones) several times. But each time I got an error on the first line: launcher cannot find or install MPRester. Then naturally it cannot proceed to generate XRD data for the material. How can I solve this problem. PS: I am not a programmer guy. Thanks in advance.

4

Please try to follow the docs and install mp_api in a python environment on your computer. We do not maintain an up-to-date notebook on Binder anymore, unfortunately.

1 Like
5

Oh thanks, I’ll try it, and be sure come back with lots of new questions :slight_smile: