Picosecond Time‐Resolved X‐Ray Emission Spectroscopy: Ultrafast Spin‐State Determination in an Iron Complex

Abstract

Ultrafast spin probe: A short-lived transient species of light-excited [Fe(bpy)3]2+ (bpy=2,2′-bipyridine) shows geometry variations that correspond to excitation to a high-spin state, in which the spin momentum of FeII has now been directly determined to be S=2 by spin-sensitive ultrafast X-ray emission spectroscopy.