MOPAC Step#
MOPAC is a high-performance semiempircal Hartree-Fock code that can optimize structures, predict enthalpies of formation, calculate thermodynamic properties, vibrational frequencies, etc. for molecular and periodic compounds containing elements through element 83, bismuth. It cannot, however, handle systems without a band-gap, so metals and metal clusters are not an appropriate target.
MOPAC has an order-N approach suitable for larger systems with thousands of atoms, both molecular and periodic. The method works well for systems with a well-defined Lewis structure, i.e. organic molecules, biological systems, MOF’s, zerolites, etc. The order-N approach out-performs the tradtional approach beyond a few hundred atoms.