Hello, I am a Masters student of VIT University India. I am using chimera to prepare my ligand. In the add charge option I noticed that if my ligand has negative or positive charge and I try to add AM1-BCC it gives error but I can add Gasteiger charge. Even if I set charge to +0 for the ligands that have charge like -1 or +1  and try to add  AM1-BCC it gives error. I want to know what is the reason that Gasteiger charge can be added but AM1-BCC cannot be added..Kindly help me in this regard.