High repetition-rate 2D SFG Spectrometer

• Subject Area: Chemical Solid State and Surface Research
• Term: Funded in 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 432349002

Water is essential as a solvent for biochemical processes and in technological applications alike. Here water is not merely a passive background but is fundamental to the structure and function of biochemical processes and play an active role in biochemical recognition and proton transfer processes. What makes water unique among solvents is the hydrogen-bonded network, which fluctuate on a very short timescale. Characterizing the fluctuations of the hydrogen-bonded network is key to understand the molecular properties of water. When water is in contact with a biomolecule or at a surface, the properties of the hydrogen-bonded network is changed, which determine the properties of the interfacial water molecules. Biomolecules and technological interfaces typically exhibit complex structures with both hydrophobic and hydrophilic domains, which influence the hydrogen-bonded network is different ways. Advanced time-resolved ultrafast spectroscopy has provided a good understanding of the hydrogen-bonded network in bulk water, but we do not have the same understanding for water at interfaces. The proposed research will fill this knowledge gap and provide the missing information about the rapid dynamics of the hydrogen-bonded network of water at surfaces. In order to do so, we need to perform surface-specific versions of the advanced bulk time-resolved ultrafast spectroscopic methods. The proposed equipment purchase will make such experiments possible. Furthermore, the proposed experiments will characterize the ultrafast dynamics of the hydrogen-bonded network of water as a function of the surface chemistry. This will be done by examining solid-water interfaces, where the surface chemistry of the solid surface can be varied by functionalizing the surface with different self-assembled monolayers. Such self-assembled monolayers bind to the surface and by varying the chemical functionality of the tails, can make the solid surface hydrophilic, hydrophobic, or mixed to mimic complex biological or technological surfaces.The proposed equipment purchase will make advanced surface-specific time-resolved spectroscopic experiments of interfacial water possible. These experiments will characterize the ultrafast dynamics of the hydrogen-bonded network of interfacial water and provide a detailed molecular-level understanding of interfacial water as a function of the surface chemistry. This will provide this missing information for obtaining a detailed understanding of chemical processes in biochemical and technological systems alike, which occur on hydrated surfaces.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: 2D SFG-Spektrometer mit hoher Wiederholrate
• Instrumentation Group: 5700 Festkörper-Laser
• Applicant Institution: Ruhr-Universität Bochum
• Leader: Professor Dr. Poul Bering Petersen