Relativistic effects in the electronic structure for the 3d paramagnetic ions

It has been shown that relativistic spin-orbit effects have enormous influence on the electronic structure of the correlated electron systems 3dn. The s-o coupling produces the fine electronic structure with a large number of low- energy, < 10 meV, localized states, These states affect enormously electronic and magnetic properties of 3d-ion compounds at low- and room-temperature regions. It is inferred that the relativistic s-o effects and the multiplet structure on individual atoms are indispensable for the proper evaluation of the electronic structure of paramagnetic 3d ions.