  We have recently developed the QTPIE (charge transfer with polarization
current equilibration) fluctuating-charge model, a new model with correct
dissociation behavior for nonequilibrium geometries. The correct asymptotics
originally came at the price of representing the solution in terms of
charge-transfer variables instead of atomic charges. However, we have found an
exact reformulation of fluctuating-charge models in terms of atomic charges
again, which is made possible by the symmetries of classical electrostatics. We
show how this leads to the distinguishing between two types of atomic
electronegativities in our model. While one is a intrinsic property of
individual atoms, the other takes into account the local electrical
surroundings. This suggests that this distinction could resolve some confusion
surrounding the concept of electronegativity as to whether it is an intrinsic
property of elements, or otherwise.
