Ghemical is a computational chemistry software package, 

Ghemical relies on external code to provide the quantum-mechanical calculations.
Semi-empirical methods MNDO, MINDO/3, AM1 and PM3 come from the MOPAC7 package,
and are included in the source distribution. The
MPQC package (GNU GPL) is used to provide ab initio methods.

WWW: http://www.uku.fi/~thassine/ghemical/