Light-Induced Spin Crossover Probed by Ultrafast Optical and X-ray Spectroscopies

Abstract

The photoinduced energy and structural relaxation of aqueous iron(II)-tris-bipyridine ([FeII(bpy)3]2+), upon excitation into its singlet metal-to-ligand charge transfer (1MLCT) band, and the population of its short-lived (?0.6 ns) high-spin excited state have been characterized by combined ultrafast optical and X-ray spectroscopies. Polychromatic femtosecond fluorescence up-conversion reveals a very short lived 1MLCT emission band, which decays in ?20 fs by intersystem crossing to a 3MLCT, whose very weak emission is also observed. Transient absorption studies show that the latter decays in

Keywords

• Fluorescence
• Iron (ii) complexes
• Optical absorption
• Spin crossover
• Ultrafast
• X-ray absorption