I'm doing a polarization calculation for the first time. To specify one of the input parameters (the "reference point") correctly, I have to figure out if my system is "charged." If it is not charged, I don't have to worry about the reference point.
Could anyone please help ensure I understand what "charged" means in this context?
On one hand, I understand that a system made up of water molecules (for example) is not charged. But what if some of the water molecules dissociate or we add salt that ends up as Cl- and a corresponding +1 ion? I.e., does "charged system" refer to the entire system or does it mean that we need to account for what's going on locally inside the system?