We generously share our software under the conditions of the GNU GPLv3 license, but we need your help to guarantee the continuity of these projects. Therefore we kindly ask a few favors in return for the use of our software:

  • Register for free.
  • Cite the appropriate papers when you use our software for your research or to prepare publications.
  • Provide feedback by using the mailing list of the software package.

Read our flyer (version 07/2012)


Zeobuilder is a user-friendly GUI toolkit for the construction of advanced molecular models (biological, inorganic, reactants in a catalyst, ...). The program contains several advanced tools to build, align, manipulate and analyze molecular structures. Most of its novel functionality is based on a hierarchical data-structure of reference frames to represent a molecular structure. Furthermore, Zeobuilder is extensible. The core program is compact and nearly all of the functionality is implemented through a plug-ins.


TAMkin is a post-processing toolkit for normal mode analysis, thermochemistry and reaction kinetics. It uses a Hessian computation from a standard computational chemistry program as its input. CHARMM, CP2K, CPMD, GAMESS, GAUSSIAN, QCHEM and VASP are supported. Multiple methods are implemented to perform a normal mode analysis (NMA). The frequencies from the NMA can be used to construct a molecular partition function to derive thermodynamic and kinetic parameters.


MD-Tracks is a trajectory analysis toolkit for molecular dynamics and Monte Carlo simulations. It is designed to interact with several simulation codes that generate trajectory data: CP2K, CPMD, DLPOLY, GROMACS, LAMMPS. The trajectory output files are first converted into a in a uniform binary format, which can then be processed with a bundle of analysis scripts, e.g. for the analysis of vibrational spectra, diffusion constants, radial distribution functions, and so on.


HiPart is a program to analyze the electronic structure of molecules with fuzzy-atom partitioning methods. It now supports four schemes to define atomic partitions: the Becke scheme, the Hirshfeld scheme, the Iterative Hirshfeld scheme, and the Iterative Stockholder Analysis. Within each scheme the following quantities can be computed: atomic charges, atomic dipoles, quality of charges and dipoles with respect to the ESP, the atomic multipole expansion, net and overlap populations, bond orders, spin charges, atomic overlap matrices in the orbital basis and in the basis of contracted Gaussians.


A free open-source spin-adapted implementation of the density matrix renormalization group for ab initio quantum chemistry


QuickFF is a software package to derive accurate force fields for isolated and complex molecular systems in a quick and easy manner. The force field parameters for the covalent interaction are derived from ab initio data, i.e. an equilibrium structure and a Hessian matrix, which needs to be produced by the user. QuickFF is a tool that can easily be used by anyone with a basic knowledge of performing ab initio calculations. As a result accurate force fields are generated with minimal effort.


Motivated by our frustration with the difficulty of adding new features to existing quantum chemistry programs, we decided to create our own Helpful Open-source Research TOol for N-fermion systems (HORTON). The emphasis here is on the world helpful. HORTON is not intended to be a replacement for existing quantum chemistry software, but a helpful supplement to it. Our ambition is to provide a research tool that is computationally-efficient enough to be helpful, without compromising code-readability and user-friendliness. Our hope is that users will find HORTON helpful for developing and exploring new methods, for interpreting the results of electronic structure calculations, and for interacting with other computational modeling software.


Yaff is created to provide a good reference implementation of the force fields developed at the Center for Molecular Modeling at the Ghent University. In its current version, Yaff is general and flexible enough to handle a large variety of force field models.


MolMod is the underlying Python library for Zeobuilder, TAMkin, HiPart, MD-Tracks and other projects at the CMM. It contains several auxiliary modules for the development of molecular modeling programs.


ThermoLIB is a Python/Cython library to construct and manipulate free energy surfaces (FES) as a function of a (set of) priori chosen collective variable(s) from output of molecular simulations. The package allows to transform, project and deproject the FES a posteriori to different collective variables as well as to extract thermodynamic and kinetic properties. Furthermore, ThermoLIB also fully supports error estimation on these properties.

Acces to the Github repository for downloading ThermoLIB can be provided upon request to