Benchmark Results and Theoretical Treatments for Valence-to-Core X-ray Emission Spectroscopy in Transition Metal Compounds

TL;DR

This paper compares experimental valence-to-core X-ray emission spectra of Zn and Fe compounds with theoretical models, highlighting the importance of dipole and quadrupole contributions and guiding future DFT method development.

Contribution

It provides a critical comparison of experimental data with multiple theoretical treatments for VTC-XES in transition metal compounds, emphasizing the need to consider both dipole and quadrupole effects.

Findings

Good agreement between theory and experiment for Zn and Fe compounds

Dipole and quadrupole contributions vary between Zn and Fe materials

Results will aid in improving DFT and time-dependent DFT predictions

Abstract

We report measurement of the valence-to-core (VTC) region of the K-shell x-ray emission spectra from several Zn and Fe inorganic compounds, and their critical comparison with several existing theoretical treatments. We find generally good agreement between the respective theories and experiment, and in particular find an important admixture of dipole and quadrupole character for Zn materials that is much weaker in Fe-based systems. These results on materials whose simple crystal structures should not, a prior, pose deep challenges to theory, will prove useful in guiding the further development of DFT and time-dependent DFT methods for VTC-XES predictions and their comparison to experiment.