Additional non-Coulomb electron-electon interaction in multielectron   systems
  The author suggests an approach based on the separation of total energy of multielectron systems into the semi-classical Coulomb part and the non-classical additional part. This approach allows on the one hand to simplify calculations and on the other hand to see very simple and very interesting relations. These relations were not obvious when using more complex methods. The most interesting aspect is that on all levels of chemical matter - from two-electron atoms up to molecules and crystals - we find additional non-classical electron-electron attraction. The most important practical consequence is the discovery that under certain conditions additional electron-electron attraction can exceed usual electron-electron repulsion. It can result in existence of ordered structures of a new type in a special-way exited matter 
Vadim Kavera