Surface-specific vibrational Sum-Frequency Generation (vSFG) spectroscopy provides information about the chemical environment at an interface.  However, unambiguous interpretation of vSFG data, to answer questions like how deep into bulk media is solvent structure disrupted, is challenging.  Moreover, spectroscopic methods fail to provide a molecular level view of the interface.  We present a molecular dynamics study of the structure of water at charged surfaces using the TIP3P water model and 2D square lattice idealized surface representing homogenous and localized surface charge distributions, revealing the effect of surface charge and ions on the structuring of interfacial water at a molecular level.  Although water distribution function recovers to bulk level after about three layers from surface, orientational ordering prevails over a greater depth.  This study guides the interpretation of vSFG of water at charged surfaces, by complementing electrostatic model predictions, where solvent is either a dielectric continuum or a set of point dipoles.

Structure of water at charged surfaces: A molecular picture

244th National Meeting (2012)

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