ATOMIC ORBITAL MOMENT SUM-RULE FOR ISOTROPIC X-RAY-ABSORPTION SPECTRUM IN MORE-THAN-HALF FILLED VALENCE SHELLS

The relationship between the deviation of core spin-orbit branching ra tio from the statistical one in isotropic core-to-valence x-ray absorp tion spectrum (XAS) and the valence atomic orbital moment is discussed on the basis of symmetry consideration for more-than-half filled vale nce shells in the high-spin state. The deviation is shown to he propor tional to the magnitude of atomic orbital moment. This finding applies not only to ferromagnets but also to systems with no net magnetizatio n such as antiferromagnets and paramagnets. By examining errors of the stun rule in some examples, an actual utilization of the sum rule is proposed.