Nonradiative decay channels in the $L$-edge fluorescence yield spectra from transition-metal–aqueous solutions give rise to spectral distortions with respect to x-ray transmission spectra. Their origin is unraveled here using partial and inverse partial fluorescence yields on the microjet combined with multireference ab initio electronic structure calculations. Comparing ${\mathrm{Fe}}^{2+}$, ${\mathrm{Fe}}^{3+}$, and ${\mathrm{Co}}^{2+}$ systems we demonstrate and quantify unequivocally the state-dependent electron delocalization within the manifold of $d$ orbitals as one origin of this observation.

• Received 28 January 2013

DOI:https://doi.org/10.1103/PhysRevLett.111.083002