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Features

Find a capability by its scientific role, then follow a feature link for its equations, parameters and conventions in Physics. Available, planned and proposed features appear together in their scientific groups.

How to read this page

Interfaces — each cell says whether that interface works with the feature. How a structure or experiment is defined differs between interfaces: see Defining structures and experiments. Command line works with every feature a saved project holds.

  • Application (browser or desktop)
  • Python library
  • Command line

Feature status

  • Available
  • Partial — not fully complete yet; the cell says what is missing
  • Work in progress — being built now, not available yet
  • Planned — a recorded roadmap item, not available yet
  • Proposed — a candidate still under discussion
  • Unavailable

Defining structures and experiments

This is where the interfaces differ. The application and Python define structures and experiments in several ways; the Command line runs a saved project, which any interface can prepare. Every other table on this page says whether an interface works with a feature once the model exists, however it was defined.

Crystal structures

Way Python
From a CIF file All types
From the Crystallography Open Database All types
From EasyDiffraction’s collection All types
Created by hand All types
From a saved project All types

Magnetic structures

Commensurate magnetic structures come from an .edi file: EasyDiffraction’s collection holds the Co₂SiO₄ structures at 2.3 K, and the Crystallography Open Database has none. Magnetic CIF files are not read yet.

Way Python
From an .edi file neut
From EasyDiffraction’s collection neut
Created by hand neut
From a saved project neut

Experiments

Way Python
A full experiment from a file All types
A full experiment from the web All types
Measured data from a file All types
Measured data from the web All types
Several datasets as experiments All types
Several datasets as a scan pd
Created by hand All types
From a saved project All types

Structure model

Symmetry and cell

Feature Python
Space group and setting All types
Unit-cell lengths and angles All types

Atom sites

Feature Python
Atom labels and scattering species All types
Fractional coordinates All types
Occupancies All types
Wyckoff positions All types

Atomic displacement

Feature Python
Isotropic Biso and Uiso All types
Anisotropic Bani, Uani and beta All types

Scattering models

Feature Python
Nuclear neutron structure factors neut
X-ray atomic form factors and dispersion xray
Select scattering-table and dispersion sources All types
Total scattering and PDF pd
Incommensurate and modulated structures All types
Symmetry modes: displacive, occupational and magnetic All types

Magnetic structures

A magnetic structure gives each magnetic atom a moment. Commensurate structures are available; the other kinds are planned.

Feature Python
Commensurate magnetic structures neut
Incommensurate magnetic structures neut
Magnetic domains neut
Classical polarised neutron diffraction (flipping ratios) sc neut

Linked structures

Feature Python
Multiple phases and phase scales pd
Derived mass fractions pd

Experiment model

Diffraction modes

Feature Python
Neutron powder pd neut cwl
X-ray powder pd xray cwl
Neutron powder pd neut tof
Neutron single crystal sc neut
2D Rietveld fitting pd

Constant-wavelength peak profiles

Feature Python
Gaussian and Lorentzian pd cwl
Pseudo-Voigt · direct width and mixing pd cwl
Thompson–Cox–Hastings pseudo-Voigt pd cwl
Bérar–Baldinozzi asymmetry pd cwl
Finger–Cox–Jephcoat axial asymmetry pd cwl

Time-of-flight peak profiles

Feature Python
Jorgensen · Gaussian pulse convolution pd tof
Jorgensen–Von Dreele · mixed profile pd tof
Symmetric pseudo-Voigt pd tof
Gaussian and Lorentzian width terms pd tof
Ikeda–Carpenter pulse profile pd tof

Instrument resolution

Feature Python
Separate instrument resolution parameters pd
Import an instrument resolution file pd

Calibration

Feature Python
Wavelength and CW zero offset cwl
CW displacement and transparency shifts pd cwl
TOF zero, linear and quadratic calibration pd tof

Radiation settings

Feature Python
X-ray wavelength doublet pd xray cwl
X-ray polarization and monochromator pd xray cwl

Absorption

Feature Python
Hewat cylinder pd cwl
Lobanov cylinder pd cwl
Wavelength-dependent cylinder (ABSCOR1) pd tof

Preferred orientation

Feature Python
March–Dollase preferred orientation pd

Single-crystal extinction

Feature Python
Becker–Coppens · type I, type II and mixed sc
Gaussian and Lorentzian mosaic distributions sc
Larson · isotropic and anisotropic sc
Structural twinning sc

Background models

Feature Python
Line-segment background pd
Polynomial background pd
Chebyshev background pd

Background estimation

Feature Python
Automatic estimation · arPLS, SNIP and FABC pd

Observation exclusions

Feature Python
Powder excluded regions pd
Single-crystal reflection exclusions sc

Analysis and fitting

Pattern calculation

Feature Python
Forward calculation without observations All types

Pattern fitting

Feature Python
Rietveld fitting pd
Le Bail intensity extraction pd
Pawley intensity extraction pd

Fitting modes

Feature Python
Single-experiment fitting All types
Joint multi-experiment fitting All types
Sequential scans pd
Independent scans pd

Fit controls

Feature Python
Independent free-parameter selection All types
Descent strategy from saved analysis settings All types

Fitting methods

Feature Python
Weighted least squares · Levenberg–Marquardt All types
Maximum likelihood All types
Bayesian analysis · MCMC sampling All types

Fit assessment

Feature Python
Covariance, uncertainties and correlations All types
Profile and background-subtracted R factors pd
Phase Bragg and F factors pd
Single-crystal factors and reflection subsets sc

Projects and results

Project files

Feature Python
Open and save a complete project All types
Import/export a project archive All types
Import TOPAS projects pd
Import FullProf projects All types
Import GSAS-II projects All types

Structure viewer

The application provides an interactive 3D view. Python and Command line can include structure views in an HTML report.

Feature Python
Atoms and symmetry copies All types
Atom labels All types
Bonds All types
Unit-cell outline All types
Crystal axes All types
Rotation, pan and zoom All types
Views along a, b and c All types
Atom radii and displacement ellipsoids All types
Magnetic-moment arrows neut
Polyhedra around atoms All types

Visual inspection

Feature Python
Pattern and reflection charts pd
Single-crystal calculated versus measured F² sc
Parameter correlation matrix All types
Stacked patterns for multiple datasets pd
Intensity map for multiple datasets pd
Parameter evolution across a scan pd

Report export

Feature Python
Interactive and offline HTML reports All types
PDF reports All types
CIF reports All types
Saved-report freshness checks All types

Installation

The desktop application's and the command line's installers are not signed yet, so macOS and Windows warn before they run; Install and update says what to do.

Feature Python
Code signing on macOS All types
Code signing on Windows All types