Electronic Structure from Iron L-edge Spectroscopy:An Example of Spin Transition Evidenced by Soft X-ray Absorption Spectroscopy

Soft X-ray Absorption Spectroscopy at the transition metal L2,3 edges provides information about the 3d unoccupied states by dipole allowed transitions. We have recorded iron L2,3 edges in order to follow the reversible thermal spin interconversion (S=2 S=0) of the Fe(II)(o-phenantroline)2(NCS)2. Huge differences are observed which demonstrate that the L2,3 metal edges are a good fingerprint of the spin state and can be used to evidence an interconversion of the spin state