LEV00 & TETR:
user-friendly packages for DFT codes
VASP/SIESTA/CASTEP

L. N. Kantorovich

This is a documentation for a package of utilities which have been written (initially at Keele and then continued in London at UCL and KCL) as pre- and post-processing tools for DFT codes working with periodic boundary conditions. At the beginning, DFT codes CASTEP and CETEP were supported. At a later stage a complete support for the VASP code has also been added. Then, the whole structure of the two codes has been reshuffled in order to allow for a more flexible support for other codes and input/output formats. Recently, an almost complete support for the SIESTA code has also been added.

The applications (i.e. offered functionality) include:

• various modifications of the system geometry (e.g. changing lattice vectors, breeding the system (supercells), merging geometries from several files of different formats (e.g. adding a molecule from another file to the surface), constructing a surface cell from a bulk one, etc.);
• construction of molecular clusters with specific boundary conditions out of a bulk unit cell;
• a powerful engine for phonons calculations (molecules and crystals);
• calculations of the electronic Density of States (DOS),
• plotting of charge and spin total and partial densities, calculating atomic charges, saving the cube format file for gOpenMol contour plotting, etc.
• an intelligent search for surface states, exploration of the (partial) electronic (spin) density
• and a lot more!