DFTB Features single point calculations geometry optimizations transition state searches frequency calculations molecular dynamics Molecules as well as periodic systems can be handled ensuring a smooth link with full DFT codes ADF and BAND. Three models within the DFTB framework are available: standard DFTB, SCC-DFTB (DFTB with self-consistent-charge correction), and DFTB3 (SCC-DFTB with third-order correction).