2 research outputs found
Chemical Bonding in Aqueous Ferrocyanide: Experimental and Theoretical X‑ray Spectroscopic Study
Resonant inelastic X-ray scattering
(RIXS) and X-ray absorption
(XA) experiments at the iron L- and nitrogen K-edge are combined with
high-level first-principles restricted active space self-consistent
field (RASSCF) calculations for a systematic investigation of the
nature of the chemical bond in potassium ferrocyanide in aqueous solution.
The atom- and site-specific RIXS excitations allow for direct observation
of ligand-to-metal (Fe L-edge) and metal-to-ligand (N K-edge) charge-transfer
bands and thereby evidence for strong σ-donation and π-backdonation.
The effects are identified by comparing experimental and simulated
spectra related to both the unoccupied and occupied molecular orbitals
in solution
Core-Level Spectroscopy with Hard and Soft X‑rays on Phosphorus-Containing Compounds for Energy Conversion and Storage
The electronic properties of nine solid phosphorus (P)-containing
compounds with varying oxidation states and chemical environments,
including GaP(‑III), InP(‑III), red-P(0), H3P(III)O3, Na2H2P2(IV)O6, H3P(V)O4, KH2P(V)O4, Na2HP(V)O4, and InP(V)O4, are investigated using X-ray
absorption near-edge structure (XANES) spectroscopy in the hard (P K-edge) and soft X-ray regime (P L2,3-edge). We find shifts in the absorption-edge positions
and correlate them with the ligands surrounding the P atom, likely
causing a different core–hole interaction screening for different
compounds. Complementing the experimental analysis, ab initio many-body calculations of XANES spectra provide insights into the
excitonic nature of the observed spectral features and their impact
on the electronic structure of the materials. Furthermore, we report
on P K-edge XANES measurements on aqueous phosphorus-containing
acids, including H3PO3, H3PO4, and their mixtures. At first sight, the spectra of the aqueous
acids are similar to those of their solid counterparts. However, close
inspection reveals a slight red shift of the absorption edge and the
presence of fewer spectral features compared with spectra of the respective
solids. Mixtures of aqueous acids display spectral features corresponding
to the individual components, indicating the potential for speciation
and quantification through fingerprinting