Viewing and solving crystal structures from powder diffraction data
The FOX program was made for the ab initio crystal structure solution from diffraction data (mostly powder diffraction data). Its most interesting features for ab initio structure determination are:
* a versatile description of the crystal contents: either isolated atoms, molecules described using a bond length, bond angles and dihedral angles, and polyhedra for inorganic compounds. You can describe your structure by using any combination of groups of atoms, using a chemist's or crystallographer knowledge about the connectivity in your sample to constrain possible solutions;
* an automatic correction for special positions and shared atoms between polyhedra, suitable for global optimization algorithms;
* the ability to use simultaneously multiple powder patterns (X-rays, neutrons), as well as single crystal data (e.g. extracted from a powder pattern);
* smart global optimization algorithms which can get out of false minima;
* a graphical interface with a 3D crystal structure view, with live updates during the optimization process.
This program can be used also for educational purposes, to show a 3D display of Crystal structures, and the associated powder pattern(s) (see how adding atoms, changing the lattice, or changing the spacegroup affects the powder pattern and the 3D structure).
J. Appl. Cryst. 35 (2002), 734-743, V. Favre-Nicolin and R. Cerny, FOX, 'free objects for crystallography': a modular approach to ab initio structure determination from powder diffraction