Are There Atoms Inside Atomic Anions? H^- and Li^- Revisited

Yes, atoms are still there. We show that the inner electrons of H^- and Li^- behave almost as if the outer electrons were not present and that the effect of electron correlation is such that the outer loosely bound electron tries to stay as close as possible to the nucleus but without interfering too much with the electronic distribution of the inner electrons in such a way that the electronic densities of H and Li are still recognizable inside the respective negative ions. We introduce the concept of partial electronic distribution, one for each electron: a particular decomposition of the electronic density. Equipped with this tool, we analyze the internal structure of the anions to recover the chemical intuition of an atomic negative ion on firm quantum mechanical grounds: that of an atom, almost unperturbed, with a loosely bound electron.