Interface to the MOPAC package version 2016 (http://openmopac.net, free for academic use). MOPAC implements wide range of semiempirical methods and features the linear scaling algorithm MOZYME[1] (see Example 2).
Older versions starting with MOPAC 2009 will work with the interface but some features might not be available.
It is possible to use the public domain version, MOPAC 7, but the support by the interface is very limited. This mode has to be switched on using the mopac_version keyword. So far, only single-point AM1 calculations were tested. Moreover, MOPAC 7 can not read cartesian geometry for small molecules, therefore the interface supports only molecules with at least 4 atoms.
The mopac interface supports the native_opt protocol which allows offloading a geometry optimization to MOPAC. The optimization can be then controlled only by the native mopac keywords accessible from the cuby input using mopac_keywords.
COSMO2 is a reparametrization of the COSMO model including a SASA-dependent non-polar term, parameterized to a large database of solvation energies in water.[2] It substantially reduces the error of calculated solvation energies with respect to the experiment. It is available for PM6 and PM7. When the keyword solvent_model is set to COSMO2, cuby automatically loads all the method-specific parameters and passes them to MOPAC. This default setup should reproduce the published results.