Fig. 1. Illustration of the Fe X-ray spectroscopic techniques with the associated transitions. (a) L2,3-edge absorption probes unoccupied 3d orbitals. Spin–orbit coupling within the 2p5 core-hole splits the absorption into the 2p1/2 and 2p3/2 edges. (b) K-edge pre-edge, edge and EXAFS correspond to 1s absorptions into unoccupied 3d, 4p and continuum respectively. (c) Following the ejection of a 1s electron, Kβ XES involves the decay of Fe 3p and occupied valence electrons into the 1s core-hole.
