The FOX program was made for 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 (see the screenshots) with a 3D crystal structure view, with live updates during the optimization process.
Moldy is a C program for performing molecular-dynamics simulations of solids and liquids using periodic boundary conditions. The model system is completely specified in a run-time input file and may contain atoms, molecules or ions in any mixture. Molecules or molecular ions are treated in the rigid-molecule approximation and their rotational motion is modeled using quaternion methods. The equations of motion are integrated using a modified form of the Beeman algorithm. Simulations may be performed in the usual NVE ensemble or in isobaric and/or isothermal ensembles. Potential functions of the Lennard–Jones, 6-exp and MCY forms are supported and the code is structured to give an straightforward interface to add a new functional form. The Ewald method is used to calculate long-ranged electrostatic forces.
NanoMAD stands for Multiwavelength Anomalous Diffraction for Nano-structures: it is a command-line tool to analyze x-ray diffraction data collected at several wavelengths around one element's absorption edge, and extract the partial structure factor for the resonant atom.
OASYS (OrAnge SYnchrotron Suite) is an open-source Graphical Environment for optic simulation software packages used in synchrotron facilities, based on [Orange 3](http://orange.biolab.si/orange3/). It includes SHADOWOUI, a port to the [SHADOW](https://github.com/srio/shadow3) ray-tracing code and XOPPY (the Python version of [XOP](http://www.esrf.eu/Instrumentation/software/data-analysis/xop2.4)
SASfit has been written for analyzing and plotting small angle scattering data. It can calculate integral structural parameters like radius of gyration, scattering invariant, Porod constant. Furthermore it can fit size distributions together with several form factors including different structure factors. Additionally an algorithm has been implemented, which allows to simultaneously fit several scattering curves with a common set of (global) parameters. This last option is especially important in contrast variation experiments or measurements with polarised neutrons. The global fit helps to determine fit parameters unambiguously which by analyzing a single curve would be otherwise strongly correlated.
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