The MOPAC engine in the 2022.1 of the Amsterdam Modeling Suite is a modified version of the standalone MOPAC2016 program developed by Dr. Jimmy Stewart.

  1. AMS 2022.1 MOPAC: MOPAC Engine based on the MOPAC2016 source code (James J.P.
  1. James J.P. Stewart, Optimization of parameters for semiempirical methods VI: more modifications to the NDDO approximations and re-optimization of parameters, J. Mol. Modeling 19, 1-32 (2013)

A full list of references for the MOPAC package can be found on the official MOPAC references page.