environmental point charges
Environmental point charges are added for MNDO series(MNDO, AM1, PM3, AM1-D, PM3-D, and PDDG/PM3).
This is a cheap version of the QM/MM. Although interactions between QM region and MM region are electrostatic and van der Waals interactions in the QM/MM, electrostatic interaction from the environmental point charges to QM part is only included in this method. Besides environmental point charges are fixed in space although atoms of MM part can move in the QM/MM.
The QM/MM will be implemented to MolDS in future. For the semiempirical methods in QM/MM, see: