We will present a few facets of our theoretical works on hydration by DFT-based molecular dynamics simulations coupled to vibrational spectroscopies (experiments and theory). We will especially present some of our most recent works on the hydration of Cs+ ions by water molecules in Cs+(H2O)3 clusters, for the probing of the clusters structures and of their vibrational signatures both experimentally (IR-PD) and theoretically. In particular, we will show how some structures can be kinetically trapped at low temperatures and how this trapping depends on Ar/D2 being tagged to the cluster for the IR-PD spectroscopy. We will present some of our most recent theoretical DFT-MD simulations on the hydration of mineral-water and semi-conductor oxide-water interfaces, and especially how water can be accommodated at the interface when going from hydrophobic to hydrophilic surfaces, with consequences for e.g. chemical reactions at the interface, adsorption of molecules at the interface, accommodation of electrolytes at the interface. We will hence show results on the BIL (Binding Interfacial Layer, i.e. the interfacial water) and DL (Diffuse Layer) water organization at hydrophobic/hydrophilic oxide-water interfaces, their spectroscopic SFG (Sum Frequency Generation) signatures, and the interplay/fight in between horizontal and vertical ordering of the water and some ‘undisciplined’ water behaviours at some of these interfaces. We will also show how nominal hydrophilic surfaces (e.g. silica) can have ‘hydrophobic patches’ over the surface and how these patches have direct spectroscopic SFG signatures of hydrophobicity.

Hydration revealed by DFT-MD simulations: From gas phase ionic clusters to mineral-water interfaces

2019 Fall National Meeting

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