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Identifying Eigen-Like Hydrated Protons at Negatively Charged Interfaces

submitted on 21.08.2019, 17:50 and posted on 22.08.2019, 16:45 by Eric Tyrode, Sanghamitra Sengupta, Adrien Sthoer
Despite the importance of the hydrogen ion in a wide range of biological, chemical, and physical processes, its molecular structure in solution remains lively debated. Progress has been primarily hampered by the extreme diffuse nature of the vibrational signatures of hydrated protons in bulk solution. Using the inherently surface-specific vibrational sum frequency spectroscopy, we show that at selected negatively charged interfaces, a resolved spectral feature directly linked to the H3O+ core in an Eigen-like species can be readily identified in a biologically compatible pH range. The results offer a new molecular perspective for tracking and understanding the behaviour of hydrated protons at interfaces.


Swedish Foundation for Strategic Research (FFL-5)

Swedish Research Council (VR)


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KTH Royal Institute of Technology



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