I would like to add in extra point of charge in my molecule system (EP) and calculate the resulting RESP charges. Parameters for the EP has been defined in a separate frcmod file. However, I am not sure on how to incorporate the EP into the RESP calculation. I have generated the .esp file beforehand from a QM calculation (Gaussian 09). Any help would be greatly appreciated. Thanks! FYI, I am using AMBER16. P.S. Somehow cannot post in the AMBER mailing list, hence asking here.