Spectroscopy and Dynamics at the Gas-Liquid Interface (SDynG-LI)

• Applicants: Professor Dr. Bernd Abel, since 3/2018; Privatdozent Dr. Uwe Hergenhahn; Dr. Bernd Jürgen Winter
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Experimental Condensed Matter Physics
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 340714732

This proposal describes a joint effort to elucidate chemical interactions at liquid water surfaces. Little is known about the detailed dynamics of gas-phase molecules interacting with a liquid surface. While spectroscopy and scattering experiments in the past decades have established a firm understanding of the dynamics of chemical reactions on solids and in the gas-phase, equivalent experiments on liquids and the gas-liquid interface are largely missing.In order to touch on various aspects of these dynamics, we propose a three-pronged approach, realized by a collaborative effort between three nodes located in Leipzig, Berlin, and Lausanne. The central tool in these experiments will be liquid microjets, and at each node one such device will be used. By combining the liquid jets with different molecular beam and probing methods, we will address different aspects of gas-liquid interactions as follows: In a first experiment, conducted at the Helmholtz-Zentrum in Berlin, the liquid jet, propagating through a gas atmosphere, will be used in synchrotron core level electron spectroscopy experiments to detect the species produced at the surface; the second experiment, located at the University of Leipzig and the Leibniz Institute of Surface Modification, Leipzig, will deposit gas-phase molecules on a liquid surface by impinging a molecular beam on the jet, followed by photoelectron spectroscopy using higher harmonic generation; finally, in the third experiment, conducted at the Ecole Polytechnique Fédérale de Lausanne (EPFL, Switzerland), a liquid flat-jet will be crossed with a molecular beam in order to elucidate the gas-liquid scattering dynamics.This collaboration brings together leading groups in the fields of molecular beams, liquid water jets, X-Ray photoelectron spectroscopy, and high-harmonic generation spectroscopy. The three teams combined provide a pool of know-how that assembles precisely those ingredients required to tackle the investigation of molecular scattering dynamics at liquid interfaces.In the framework of this proposal we will demonstrate the potential of our different but complementary approaches on three prototypical systems: halogen hydrides, where we will address the fundamentally important issue of hydrogen exchange dynamics at the surface of an aqueous solution; NOx molecules, where we probe the reaction dynamics of one of the cornerstone molecules in atmospheric chemistry and in particular acid rain; and NH3, which combines fundamental interest in the context of hydrogen exchange with atmospheric relevance, in particular in combination with the nitric oxide molecules.We expect that this collaboration will do no less than to kick-start a new branch of chemical physics that will allow us to reach the same level of understanding of gas-liquid chemistry that we already have of gas-surface and pure gas-phase chemistry. 

• DFG Programme: Research Grants
• International Connection: Switzerland
• Partner Organisation: Schweizerischer Nationalfonds (SNF)
• Cooperation Partner: Dr. Andreas Osterwalder
• Ehemaliger Antragsteller: Professor Dr. Emad Flear Aziz, until 3/2018