Core Hole Polarization in X-Ray Absorption Studied by Magnetic Circular Dichroism in 2p3p3p Resonant Photoemission

We show that the possibilities of x-ray absorption spectroscopy are strongly increased when we detect the polarization of the core hole by the angle dependence of the resonant photoemission, where the polarization of the hole is transferred to the localized final state LS terms and the emitted photoelectron. In the geometry where the dichroism in the 2 p absorption is forbidden, a circular dichroism of 9% is observed in the autoionization decay into a 3 p 4 state. The effect provides a way to separate the ground state spin magnetic moment from the magnetic dipole moment.