  Non-radiative decay channels in the L-edge fluorescence spectra from
transition metal-aqueous solutions give rise to spectral dips in X-ray
transmission spectra. Their origin is unraveled here using partial and inverse
partial fluorescence yields on the micro-jet combined with multi-reference ab
initio electronic structure calculations. Comparing Fe2+, Fe3+, and Co2+
systems we demonstrate unequivocally that spectral dips are due to a
state-dependent electron delocalization within the manifold of d-orbitals.
