The DISCUS package consists of four sections. The top section is a short rooftop to the three working sections DISCUS, DIFFEV, KUPLOT. The first section in the package is DISCUS itself and the development started some 30 years ago by Reinhard Neder. DISCUS is a general program to generate disordered atomic structures and compute the corresponding experimental data such as single crystal diffuse scattering or the powder pair distribution function (PDF) or the 3D-PDF.

The main strength of the program package is the extensive tool box used to create a broad topic of defects into the host structure such as: Stacking faults, generalized domains, chemical short range order (SRO), modulated structures. Nanopartricles my be created at arbitrary shapes and can easily be decorated by further molecules. More recently DISCUS developments include the simulation of nanoparticles. DISCUS is the engine behind the new Nanoparticle Builder hosted by Los Alamos National Laboratory.

The second section is DIFFEV. This is a generic minimization program using an evolutionary algorithm. It is designed to work with the other programs in the package.

The third section is REFINE. This is a Least Squares based refinement section. It is designed to work with the other programs in the package.

Finally the package contains a general plotting section called KUPLOT.

Thomas Proffen and Reinhard Neder