Fitting pd-neut-cwl LBCO-HRPT¶

This example shows how to refine the crystal structure parameters of La0.5Ba0.5CoO3 from neutron diffraction data in a constant wavelength experiment performed on HRPT diffractometer at PSI.

Import EasyDiffraction¶

In [2]:

import easydiffraction as ed

import easydiffraction as ed

Create a job¶

Create a job — the main object to store all the information

In [3]:

job = ed.Job()
print(job.type)

job = ed.Job() print(job.type)

Job type: pd-cwl-unp-1d-neut

Define a model¶

Download the CIF file from the EasyDiffraction repository on GitHub

In [4]:

ed.download_from_repository('lbco.cif', destination='data')

ed.download_from_repository('lbco.cif', destination='data')

Load a phase from the downloaded CIF file

In [5]:

job.add_phase_from_file('data/lbco.cif')
print(job.phases)

job.add_phase_from_file('data/lbco.cif') print(job.phases)

Collection of 1 phases: ['lbco']

Show phase info in CIF format

In [6]:

print(job.phases['lbco'].cif)

print(job.phases['lbco'].cif)

data_lbco
_cell_length_a 3.88
_cell_length_b 3.88
_cell_length_c 3.88
_cell_angle_alpha 90.00000000
_cell_angle_beta 90.00000000
_cell_angle_gamma 90.00000000
_space_group_name_H-M_ref 'P m -3 m'

loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_adp_type
_atom_site_B_iso_or_equiv
La La 0.00000000 0.00000000 0.00000000 0.5 Biso 0.1
Ba Ba 0.00000000 0.00000000 0.00000000 0.5 Biso 0.1
Co Co 0.5 0.5 0.5 1.00000000 Biso 0.1
O O 0.00000000 0.5 0.5 1.00000000 Biso 0.1

Display the crystal structure of a given model

In [7]:

job.show_crystal_structure(id='lbco')

job.show_crystal_structure(id='lbco')

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Define an experiment¶

Download the data file from the EasyDiffraction repository on GitHub

In [8]:

ed.download_from_repository('hrpt.xye', destination='data')

ed.download_from_repository('hrpt.xye', destination='data')

Show content of the downloaded file (first 6 lines)

In [9]:

with open('data/hrpt.xye') as f:
    print(''.join(f.readlines()[:6]))

with open('data/hrpt.xye') as f: print(''.join(f.readlines()[:6]))

#  2theta intensity   su
   10.00    167.00   12.60
   10.05    157.00   12.50
   10.10    187.00   13.30
   10.15    197.00   14.00
   10.20    164.00   12.50

Load experimentally measured data from a file in XYE format

In [10]:

job.add_experiment_from_file('data/hrpt.xye')

job.add_experiment_from_file('data/hrpt.xye')

Display the experimentally measured data

In [11]:

job.show_experiment_chart()

job.show_experiment_chart()