Dynamik und Spektroskopie chemischer Reaktionen an der Oberfläche von Wasser und Lösungen (SDynG-LI)
Experimentelle Physik der kondensierten Materie
Zusammenfassung der Projektergebnisse
This project aimed to investigate chemical reactions and reaction intermediates on a water surface by using photoelectron spectroscopy of a liquid microjet (LJ-PES) as a tool. Due to its surface sensitivity and sensitivity to the chemical state of a substance, this seemed a particularly suitable technique. A new apparatus was built as a flexible, advanced platform for LJ-PES experiments. This investment led to two results of fundamental importance for the field: (1) Systematic studies of the behaviour of photoelectron lines at low kinetic energies, not possible with earlier instruments, showed the existence of a universal low-energy limit, at approximately 10 eV, for PES measurements from aqueous samples. For lower kinetic energies, spectral features are drastically distorted by inelastic and quasi-elastic electron scattering. (2) We established a protocol to determine electronic binding energies of neat water and liquid solutions on an absolute scale, thus strongly improving earlier ad hoc methods that were based on comparison to the respective gas-phase signal. Using in particular the latter result for studies of the reaction between a sample gas and an aqueous solution was hampered in practice since we found earlier estimates of the number of detectable intermediates in a liquid microjet too optimistic for the systems of our interest. We have addressed this problem by establishing a collaboration that will allow us to carry out future studies using a Langmuir trough as a more suitable sample environment. Studies mentioned so far were carried out with conventional, cylindrical microjets. In order to carry out molecular scattering experiments on a liquid, jets that present a planar surface in vacuum are more suitable. Together with our partner group at EPFL Lausanne, in the course of this project we developed a novel flatjet system suitable for both scattering and PES studies. This jet was also used successfully for a first, ground-breaking study of a chemical reaction at a liquid-liquid interface. Finally, in a newly established collaboration with UC Berkeley, involving also our DFG funded project partners at U Leipzig, towards the end of the project the first successful molecular scattering experiment on a planar liquid surface in vacuum succeeded. Here, the scattering of a neon beam on a dodecanol liquid jet was used as prototype system.
Projektbezogene Publikationen (Auswahl)
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Probing the Electronic Structure of Bulk Water at the Molecular Length Scale with Angle-Resolved Photoelectron Spectroscopy. The Journal of Physical Chemistry Letters, 11(13), 5162-5170.
Gozem, Samer; Seidel, Robert; Hergenhahn, Uwe; Lugovoy, Evgeny; Abel, Bernd; Winter, Bernd; Krylov, Anna I. & Bradforth, Stephen E.
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Core level photoelectron spectroscopy of heterogeneous reactions at liquid–vapor interfaces: Current status, challenges, and prospects. The Journal of Chemical Physics, 154(6).
Dupuy, Rémi; Richter, Clemens; Winter, Bernd; Meijer, Gerard; Schlögl, Robert & Bluhm, Hendrik
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Low-energy constraints on photoelectron spectra measured from liquid water and aqueous solutions. Physical Chemistry Chemical Physics, 23(14), 8246-8260.
Malerz, Sebastian; Trinter, Florian; Hergenhahn, Uwe; Ghrist, Aaron; Ali, Hebatallah; Nicolas, Christophe; Saak, Clara-Magdalena; Richter, Clemens; Hartweg, Sebastian; Nahon, Laurent; Lee, Chin; Goy, Claudia; Neumark, Daniel M.; Meijer, Gerard; Wilkinson, Iain; Winter, Bernd & Thürmer, Stephan
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A setup for studies of photoelectron circular dichroism from chiral molecules in aqueous solution. Review of Scientific Instruments, 93(1).
Malerz, Sebastian; Haak, Henrik; Trinter, Florian; Stephansen, Anne B.; Kolbeck, Claudia; Pohl, Marvin; Hergenhahn, Uwe; Meijer, Gerard & Winter, Bernd
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Evaporation and molecular beam scattering from a flat liquid jet. American Chemical Society (ACS).
Lee, Chin; Pohl, Marvin; Ramphal, Isaac; Yang, Walt; Winter, Bernd; Abel, Bernd & Neumark, Daniel
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Imaging of Chemical Kinetics at the Water–Water Interface in a Free-Flowing Liquid Flat-Jet. Journal of the American Chemical Society, 144(17), 7790-7795.
Schewe, H. Christian; Credidio, Bruno; Ghrist, Aaron M.; Malerz, Sebastian; Ozga, Christian; Knie, André; Haak, Henrik; Meijer, Gerard; Winter, Bernd & Osterwalder, Andreas
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Quantitative electronic structure and work-function changes of liquid water induced by solute. Physical Chemistry Chemical Physics, 24(3), 1310-1325.
Credidio, Bruno; Pugini, Michele; Malerz, Sebastian; Trinter, Florian; Hergenhahn, Uwe; Wilkinson, Iain; Thürmer, Stephan & Winter, Bernd
