In this talk we will present our recent investigations of the vibrational spectroscopy of complex inhomogeneous systems: mineral/water/electrolytes interfaces and alcohol/liquid water mixtures. We apply first principles DFT-based molecular dynamics simulations (DFT-MD) in order to unravel the microscopic structural organization of these inhomogeneous systems and further extract theoretical vibrational spectra from the simulations. In the case of mineral/liquid water interfaces containing electrolytes, we calculate theoretical non-linear SFG spectra from our DFT-MD simulations, compare theoretical spectra to experiments and provide detailed analyses of the signatures in terms of interfacial structure, thickness of water interfacial layer(s), 3D structural organisation of the water molecules, and how electrolytes are organised at the interface. For alcohol/liquid water mixtures, we have more specifically investigated Tera-Hertz vibrational spectra to be compared to experiments (from the Havenith group in Germany). We analyse the spectral signatures in this low frequency domain in terms of 3D structural organisation of the water molecules within the layers solvating the alcohols, which is directly probed in the experiments.<br/> <br/>Works performed by Morgane Pfeiffer-Laplaud (PhD), Simone Pezzotti (PhD), Daria Galimberti (Post-Doc), Debora Beeri (Master student)<br/>

Non-linear SFG spectroscopy of mineral/water interfaces containing electrolytes & tera-hertz spectroscopy in liquid water: A DFT-MD theoretical perspective

253rd National Meeting (2017)

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