Marialore Sulpizi (Johannes Gutenberg Universität Mainz, Allemagne), actuellement professeur invitée UPMC dans notre laboratoire, présentera un séminaire le vendredi 24 octobre 2014 à 14h00 dans la bibliothèque du laboratoire PHENIX (7e étage, bâtiment F, porte 754) intitulé :
Microscopic characterization of the fluorite/water interface from theory and experiments
Résumé
The crystal growth and dissolution processes of fluorite (CaF2) crystals have attracted much attention due to the importance in the industrial, environmental, and medical applications. While previous studies clarified nanoscale processes at the fluorite–water interface, atomic scale origins of the processes have yet to be understood. In this study, we combine Density Functional Theory based molecular dynamics simulation and interface selective spectroscopy in order to investigate atomicscale structure at the fluorite–water interface as function of pH. We probe for the first time the absolute orientation of the water molecules at the interface and provide a microscopic interpretation for the vibrational spectroscopic signal. Under basic conditions the experimental spectra can be explained by a substitution of F by HO at the interface. Moreover under acidic condition a microscopic model for the charged interface is provided.
