Calculation Without Data: NaCl, X-ray¶

This is the most minimal "calculation without data" example. It defines an X-ray powder experiment for NaCl, accepts the default calculation range, and plots the calculated pattern — no data file and no manual range setup.

The default data_range is derived from the instrument (here the X-ray wavelength), so a structure-only experiment is calculable immediately.

🛠️ Import Library¶

In [2]:

import numpy as np

import easydiffraction as edi

import numpy as np import easydiffraction as edi

📦 Define Project¶

In [3]:

project = edi.Project(name='nacl_simulation')

project = edi.Project(name='nacl_simulation')

🧩 Define Structure¶

In [4]:

project.structures.create(name='nacl')

project.structures.create(name='nacl')

In [5]:

structure = project.structures['nacl']

structure = project.structures['nacl']

In [6]:

structure.space_group.name_h_m = 'F m -3 m'
structure.space_group.coord_system_code = '1'

structure.space_group.name_h_m = 'F m -3 m' structure.space_group.coord_system_code = '1'

In [7]:

structure.cell.length_a = 5.62

structure.cell.length_a = 5.62

In [8]:

structure.atom_sites.create(
    id='Na',
    type_symbol='Na',
    fract_x=0,
    fract_y=0,
    fract_z=0,
    adp_iso=0.5,
)
structure.atom_sites.create(
    id='Cl',
    type_symbol='Cl',
    fract_x=0.5,
    fract_y=0.5,
    fract_z=0.5,
    adp_iso=0.5,
)

structure.atom_sites.create( id='Na', type_symbol='Na', fract_x=0, fract_y=0, fract_z=0, adp_iso=0.5, ) structure.atom_sites.create( id='Cl', type_symbol='Cl', fract_x=0.5, fract_y=0.5, fract_z=0.5, adp_iso=0.5, )

🔬 Define Experiment¶

Create Experiment Without Data¶

In [9]:

project.experiments.create(
    name='sim',
    sample_form='powder',
    beam_mode='constant wavelength',
    radiation_probe='xray',
)

project.experiments.create( name='sim', sample_form='powder', beam_mode='constant wavelength', radiation_probe='xray', )

In [10]:

experiment = project.experiments['sim']

experiment = project.experiments['sim']

Set Instrument¶

In [11]:

experiment.instrument.setup_wavelength = 1.5406

experiment.instrument.setup_wavelength = 1.5406

Set Peak Profile¶

In [12]:

experiment.peak.broad_gauss_u = 0.1
experiment.peak.broad_gauss_v = -0.1
experiment.peak.broad_gauss_w = 0.1

experiment.peak.broad_gauss_u = 0.1 experiment.peak.broad_gauss_v = -0.1 experiment.peak.broad_gauss_w = 0.1

Set Linked Structures¶

In [13]:

experiment.linked_structures.create(structure_id='nacl', scale=1.0)

experiment.linked_structures.create(structure_id='nacl', scale=1.0)

Inspect the Default Calculation Range¶

No range is set explicitly: the default window (derived from the wavelength) is used as-is.

In [14]:

print('min:', experiment.data_range.two_theta_min.value)
print('max:', experiment.data_range.two_theta_max.value)
print('inc:', experiment.data_range.two_theta_inc.value)

print('min:', experiment.data_range.two_theta_min.value) print('max:', experiment.data_range.two_theta_max.value) print('inc:', experiment.data_range.two_theta_inc.value)

min: 8.835740516099717
max: 170.0
inc: 0.16132558506896924

Set X-ray Polarization Optics¶

The polarization coefficient defaults to 0.0. Setting it to a nonzero value includes the Lorentz-polarization optics in the calculated X-ray intensities.

In [15]:

project.analysis.calculate()
unpolarized_intensity = np.asarray(experiment.data.intensity_calc).copy()

project.analysis.calculate() unpolarized_intensity = np.asarray(experiment.data.intensity_calc).copy()

In [16]:

experiment.instrument.setup_polarization_coefficient = 0.5
experiment.instrument.setup_monochromator_twotheta = 26.5650511771

experiment.instrument.setup_polarization_coefficient = 0.5 experiment.instrument.setup_monochromator_twotheta = 26.5650511771

In [17]:

project.analysis.calculate()
polarized_intensity = np.asarray(experiment.data.intensity_calc).copy()

project.analysis.calculate() polarized_intensity = np.asarray(experiment.data.intensity_calc).copy()

In [18]:

print('max intensity change:', np.max(np.abs(polarized_intensity - unpolarized_intensity)))

print('max intensity change:', np.max(np.abs(polarized_intensity - unpolarized_intensity)))

max intensity change: 236202.50313200592

🚀 Perform Calculation¶

Display Pattern¶

In [19]:

project.display.pattern(expt_name='sim')

project.display.pattern(expt_name='sim')

Loading plot…

💾 Save Project¶

In [20]:

project.save_as(dir_path='projects/simulate-nacl-xray')

project.save_as(dir_path='projects/simulate-nacl-xray')

Saving project 📦 'nacl_simulation' to '../../../projects/simulate-nacl-xray'

├── 📄 project.edi

├── 📁 structures/

│   └── 📄 nacl.edi

├── 📁 experiments/

│   └── 📄 sim.edi

├── 📁 analysis/

│   └── 📄 analysis.edi

└── 📁 reports/

    └── 📄 nacl_simulation.html