The bonding energy E bond , on the other hand, is more strongly affected by the presence of the field (see Figure ). While this is the case for both categories, the effect is particularly strong for the standing molecule. For the investigated fields, E bond of the standing molecule changes by more than 1 eV. This is because the electric field not only affects how much charge is transferred between metal and molecule but also where (in the molecule) the charge density is localized.