All information related to Mulliken's population of the HOMO is extracted from the GAMESS output file using the Extractor. The module calculates R X for each of the X atoms of the monomer unit and ranks R X in descending order. In a next step, monomers containing two or more functional groups compatible with existing polymer definitions are classified as follows: the functional group with the highest R X is identified as the monomer's polymerization site and the monomer is assigned to the respective polymer class.