68 research outputs found
Soft-X-Ray Absorption Spectroscopy and Ab Initio Calculations
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 Fe2+,
Fe3+, and Co2+ systems we demonstrate and quantify unequivocally the state-
dependent electron delocalization within the manifold of d orbitals as one
origin of this observation
Multi-reference approach to the calculation of photoelectron spectra including spin-orbit coupling
X-ray photoelectron spectra provide a wealth of information on the electronic
structure. The extraction of molecular details requires adequate theoretical
methods, which in case of transition metal complexes has to account for effects
due to the multi-configurational and spin-mixed nature of the many-electron
wave function. Here, the Restricted Active Space Self-Consistent Field method
including spin-orbit coupling is used to cope with this challenge and to
calculate valence and core photoelectron spectra. The intensities are estimated
within the frameworks of the Dyson orbital formalism and the sudden
approximation. Thereby, we utilize an efficient computational algorithm that is
based on a biorthonormal basis transformation. The approach is applied to the
valence photoionization of the gas phase water molecule and to the core
ionization spectrum of the complex.
The results show good agreement with the experimental data obtained in this
work, whereas the sudden approximation demonstrates distinct deviations from
experiments
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