EFFECT OF COULOMB INTERACTION ON THE X-RAY MAGNETIC CIRCULAR-DICHROISM SPIN SUM-RULE IN 3D TRANSITION-ELEMENTS

A deviation from the X-ray magnetic circular dichroism (MCD) spin sum rule, which is derived assuming well separated core spin-orbit multipl ets in the final state of X-ray absorption, is calculated for the L(2, 3) edge in the magnetized Ni, Co, Fe and Mn ions on the basis of an at omic model including the full multiplet and the crystal field with O-h symmetry. Due to the Coulomb interaction between electrons, which mix es the so-called L(3) and L(2) regions with each other, it is found th at the deviation can be similar to 10 percent for the former three ion s, while for Mn2+ it amounts to more than 30 percent. A list of the de viations for various ionic states for the above elements is presented, which may serve as a correction factor in the estimation of expectati on values of magnetic quantities from MCD data.