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arXiv · 2310.00302

Femtosecond electron transfer dynamics across the D$_2$O/Cs$^+$/Cu(111) interface: The impact of hydrogen bonding

John Thomas·Jayita Patwari·Inga Langguth·Christopher Penschke·Ping Zhou·Karina Morgenstern·Uwe Bovensiepen
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Abstract

Hydrogen bonding is essential in electron transfer processes at water-electrode interfaces. We study the impact of the H-bonding of water as a solvent molecule on real-time electron transfer dynamics across a Cs+-Cu(111) ion-metal interface using femtosecond time-resolved two-photon photoelectron spectroscopy. We distinguish in the formed water-alkali aggregates two regimes below and above two water molecules per ion. Upon crossing the boundary of these regimes, the lifetime of the excess electron localized transiently at the Cs+ ion increases from 40 to 60 femtoseconds, which indicates a reduced alkali-metal interaction. Furthermore, the energy transferred to a dynamic structural rearrangement due to hydration is reduced from 0.3 to 0.2 eV concomitantly. These effects are a consequence of H-bonding and the beginning formation of a nanoscale water network. This finding is supported by real-space imaging of the solvatomers and vibrational frequency shifts of the OH stretch and bending modes calculated for these specific interfaces.

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John Thomas, Jayita Patwari, Inga Langguth, Christopher Penschke, Ping Zhou, Karina Morgenstern, Uwe Bovensiepen. 2023-09-30. Femtosecond electron transfer dynamics across the D$_2$O/Cs$^+$/Cu(111) interface: The impact of hydrogen bonding. https://doi.org/10.1021/acs.jpcc.3c06172

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