The group Structure analysis methods deals with the development of programs for solving the phase problem, refining crystal structures and their interpretation.
Our main and traditional product is the crystallographic system Jana, which has been developed since 1984.Its main author is Dr. Václav Petříček.
Originally, it was a program specialized in refining the structure of aperiodic crystals, ie substances whose translation periodicity is violated in a defined way. Position of atoms and other characteristics in these compounds can be determined by describing the so-called modulation function of the studied parameter. To determine the modulation function, it is necessary to work in a so-called superspace, which has more than three dimensions. The program Jana has gradually included all basic crystallographic methods generalized for superspace and became basically the only program used worldwide for the calculation of aperiodic crystals. In 1996 was interconnected with the simultaneously developed SDS program, so that it would be possible to solve both classical and aperiodic structures in one graphic environment and similar tools. In 2000, the program included the possibility to work with powder data, and since 2010 it has also been able to calculate magnetic structures. Jana current program is an exceptionally complex and versatile instrument cited over 400 times a year.
Program Superflip, written by Dr. Lukáš Palatinus, was published in 2007 as a tool for solving crystal structure in any dimension by charge flipping. It requires only indexed diffraction data to solve the structure, without knowing symmetry and composition. There is a number of programs based on the charge reversal method, but only Superflip can work in the so-called superspace, in which the modulation functions of aperiodic crystals are defined. Superflip thus provides an ab initio solution for aperiodic crystal structure. It is distributed together with the Jana program and several other programs for solving standard structures. It has around 300 citations on average per year.
Program Dyngo was written by Dr. Lukáš Palatinus and serves for refining structures from electron diffraction data. Its unique algorithm enables to include so-called dynamic effects, which earlier prevented the obtaining of precise crystallographic structures from electron diffraction tomography data. More information is available on the Electron diffraction group website.