Are point charges in the $external_charges part of the input file used to polarize the QM system or are they ignored when QM_MM and QM_MM_INTERFACE are not specified?
The $external_charges functionality is separate from QM/MM. In the former, the charges are absolutely fixed (therefore not appropriate for geometry optimization or dynamics). If you want to move the atoms around, you need QM/MM and $external_charges is not used for that.
Thanks John. That will teach me to not use an AI chatbot to help set up QChem calculations. I’ll just have to actually read the whole of the manual!