The DFTB program is orders of magnitude faster than DFT, but requires parameter files to be installed for all pair-wise combinations of atoms in a molecule. Unfortunately, parameters are not available for some elements, but calculations for many common molecules should be possible.
The ADF package contains an implementation of the DFTB method. It can be used to perform single point calculations, geometry optimizations, transition state searches, and frequency calculations. It can be used as a stand-alone program, or as a pre-optimizer with the ADF-GUI.
To use DFTB you need parameter files. Only one set of parameter files is available within the ADF package. To use other sets of parameter files you will need to download them yourself.
