Spectral Similarity Masks Structural Diversity at Hydrophobic Water Interfaces

2025/04/08 by Yong Wang, Wang, Yong, Yifan Li +13 · 6 citations
Physics and Astronomy · Chemistry · #Spectroscopy and Quantum Chemical Studies #Random lasers and scattering media #Surfactants and Colloidal Systems

paper · pdf · doi:10.48550/arxiv.2504.05593

Abstract

The air-water and graphene-water interfaces represent quintessential examples of the liquid-gas and liquid-solid boundaries, respectively. While the sum-frequency generation (SFG) spectra of these interfaces exhibit certain similarities, a consensus on their signals and interpretations has yet to be reached. Leveraging deep learning, we accessed fully first-principles SFG spectra for both systems, addressing recent experimental discrepancies. Despite both interfaces exhibiting microscopically hydrophobic characteristics, our findings reveal that similarities in SFG signals do not translate into comparable interfacial microscopic properties. Instead, graphene-water and air-water interfaces exhibit fundamental differences in SFG-active thicknesses, hydrogen-bonding networks, and dynamic diffusion behavior. These distinctions underscore the stronger confinements imposed by the solid-liquid interface compared with the weaker constraints of the gas-liquid interface.

Citations

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Cited by

• Wetting Transparency of Graphene: A macroscopic Window but Nanoscopic Mirror
• Water structuring at stacked graphene interfaces unveiled by machine-learning molecular dynamics
• Machine Learning Accelerated Computational Surface-Specific Vibrational Spectroscopy Reveals Oxidation Level of Graphene in Contact with Water

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