Spin Transition Evidenced by Soft X-ray Absorption Spectroscopy

Iron L2,3 X-ray absorption spectra have been recorded in order to follow the thermal reversible spin interconversion of the FeII(phen)2(NCS)2 (phen = o- phenanthroline). Important differences are observed which show that this spectroscopy is a fingerprint of the spin state. The evolution of the branching ratio is discussed and found to be consistent with the expected valueobtained by multipletcalculations.