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RESEARCH PRODUCT

The Fluorite/Water Interfaces: Structure and Spectroscopy from First Principles Simulations

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Despite its relevance to industrial, environmental and medical application, the fluorite/water interface still lacks a microscopic/atomistic characterization. In this contribution we provide the first atomistic description of such interface using first principles molecular dynamics simulations. Our models, which explore a wide range of pH, are able to provide a rational of the recent vibrational spectroscopy experiments. In particular we find that at neutral pH the water at the interface is disordered, in agreement with the experimental data, and explaining why no Vibrational Sum Frequency Generation (VSFG) signal is recorded. At high pH, OH groups which localize at the interface are responsible for the “free OH signal” recorded in the vibrational spectroscopy experiments. Finally we propose one possible model for the low pH condition where the F− vacancies induce a strong layering of the interfacial water.