Dresden 2026 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 36: Focus Session: Water – from Atmosphere to Space V (joint session CPP/DY)
DY 36.2: Vortrag
Mittwoch, 11. März 2026, 11:15–11:30, ZEU/0260
Advances in absolute-scale electronic structure measurements of liquid water and aqueous solutions — •Florian Trinter — Fritz-Haber-Institut, Berlin, Germany
Recent advances in liquid-jet photoelectron spectroscopy (LJ-PES) have enabled the precise determination of absolute electronic energetics of liquid water and aqueous solutions, both in the bulk and at interfaces. By implementing refined vacuum and Fermi-level referencing procedures, rooted in condensed-matter concepts, vertical ionization energies (VIEs) and solution work functions can now be measured with high accuracy. We show that binding energy determinations near the ionization threshold are strongly influenced by quasi elastic electron scattering and indirect ionization processes. Vibrational excitation and autoionization via super-excited states lead to spectral distortions at electron kinetic energies below ∼14 eV, necessitating careful data interpretation to extract intrinsic properties. Applying these methods to neat water and aqueous solutions of sodium iodide (NaI) and tetrabutylammonium iodide (TBAI), we reveal solute-specific effects: NaI primarily alters water’s bulk structure, increasing the 1b1 binding energy with concentration, while TBAI affects surface potentials through interfacial dipole formation, leading to an apparent binding energy decrease. Additionally, we determine the work function of neat water as 4.73 ± 0.09 eV and quantify its reduction in TBAI solutions. These findings establish a framework for quantitative studies of molecular interactions and electronic-structure modifications in aqueous systems, with implications for electrochemical and interfacial science.
Keywords: Liquid jet; Photoelectron spectroscopy; Electronic structure; Absolute binding energy; Work function