MOPAC  is a general-purpose semiempirical quantum chemistry engine for the study of molecular and periodic structures. A good trade-off between speed and accuracy is achieved through a minimal basis and parameterization against experimental data, with parameters for most elements.
As of the 2021.1 release of the Amsterdam Modeling Suite, MOPAC has become an engine in the new AMS driver setup. If you have not done so yet, we highly recommend you to first read the General section of the AMS Manual. In practice the inclusion of MOPAC into AMS means that MOPAC can now be used for many applications that were previously not supported:
- Linear transit and PES scan
- Constrained geometry optimizations
- Molecular dynamics simulations
- Lattice optimization (also under pressure)
- Elastic tensor and related properties (e.g. Bulk modulus)
- Phonon calculations
Please refer to the AMS manual for a complete overview.
What’s new in MOPAC 2019¶
- MOPAC has been fully integrated as an Engine in the Amsterdam Modeling Suite; this significantly speeds up the execution of MOPAC via AMS.
- Parallel binaries.
New input options (also available via the Graphical User Interface):