The L\"owdin orthogonalization and magnetoelectric coupling for   noncentrosymmetric ions
  The Loewdin orthogonalization procedure being the well-known technique, particularly in quantum chemistry, however, gives rise to novel effects missed in earlier studies. Making use of the technique of irreducible tensorial operators we have developed a regular procedure for account of the orthogonalization effects. For illustration we address the emergence of a specific magnetoelectric coupling for noncentrosymmetric 3d or 4f ions. 
A.S. Moskvin
cond-mat.str-el cond-mat.mtrl-sci