MOPAC Fast semi-empirical with integrated GUI MOPAC is bringing the quantum precision you need to study large molecules or periodic systems. A good trade-off between speed and accuracy is achieved through a minimal basis and parameterization, with parameters for most elements. Selected MOPAC features Easy to run, set up and analyze with integrated Graphical interface Geometry optimizations, also interactively Transition states Frequencies Molecules, polymers, surfaces and solids Database of solids Solvation effects (with COSMO) Latest parameters: PM7, PM7-TS Older parameters (AM1, MNDO, PM6, …) Sparkle: lanthanides MOZYME: linear-scaling SCF for large systems