UFF (Universal Forcefield) is a full periodic table forcefield that can be used to calculate single point energies, do geometry optimizations, calculate frequencies and to do transition state searches. It is also the default pre-optimizer in the Graphical User interface (ADF GUI) to clean up manualy drawn structures. UFF can also do calculations with chain, slab or bulk periodicity. For details on the inner workings of the forcefield, see the 1992 paper by Rappe et al. [1].


Note that the graphical user interface UFF-GUI enables all users to set up UFF calculations with a few mouse clicks. When using UFF, also for pre-optimizing, it is important to remember that any forcefield method relies on a set of parameters. This means that even though UFF supports all elements up to Z=103, it might not generate the desired structures for uncommon oxidation states in metallic structures. If this is the case, you could add new parameters to UFF or attach dummy hydrogen atoms to the metal atom.