18 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
pH and Solvent Influence on p-Aminobenzoic Acid
Through X-ray absorption and emission spectroscopies, the chemical, electronic
and structural properties of organic species in solution can be observed.
Near-edge X-ray absorption fine structure (NEXAFS) and resonant inelastic
X-ray scattering (RIXS) measurements at the nitrogen K-edge of para-
aminobenzoic acid reveal both pH- and solvent-dependent variations in the
ionisation potential (IP), 1s→π* resonances and HOMO–LUMO gap. These changes
unequivocally identify the chemical species (neutral, cationic or anionic)
present in solution. It is shown how this incisive chemical state sensitivity
is further enhanced by the possibility of quantitative bond length
determination, based on the analysis of chemical shifts in IPs and σ* shape
resonances in the NEXAFS spectra. This provides experimental access to
detecting even minor variations in the molecular structure of solutes in
solution, thereby providing an avenue to examining computational predictions
of solute properties and solute–solvent interactions
oxygen K-edge X-ray absorption and emission spectroscopy on micro-jets
Oxygen K-edge X-ray absorption, emission, and resonant inelastic X-ray
scattering spectra were measured to site selectively gain insights into the
electronic structure of aqueous zinc acetate solution. The character of the
acetate ion and the influence of zinc and water on its local electronic
structure are discussed
High-resolution nonresonant x-ray Raman scattering study on rare earth phosphate nanoparticles
Peer reviewe
Ion pairing versus water structure modifications
The effect of monovalent cations (Li+, K+, NH4 +, Na +) on the water structure
in aqueous chloride and acetate solutions was characterized by oxygen K-edge
X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy, and resonant
inelastic X-ray scattering (RIXS) of a liquid microjet. We show ion- and
counterion dependent effects on the emission spectra of the oxygen K-edge,
which we attribute to modifications of the hydrogen bond network of water. For
acetates, ion pairing with carboxylates was also probed selectively by XAS and
RIXS. We correlate our experimental results to speciation data and to the
salting-out properties of the cations