YIJING YANG

Titre de la thèse

N DFT-MD simulations of aqueous silica surfaces: a playground of structural motifs and SFG fingerprints

Résumé

Silica, as one of the Earth's most abundant minerals, possesses unique chemical and physical properties that make it highly valuable for various high-performance applications. Among these applications, characterizing the structure and dynamics of the silica/water interface has the potential to significantly impact fields such as geology, biology, and industry, opening up new avenues for technological advancements and deepening our understanding of natural processes. However, the molecular-level understanding of the dynamical processes involving dissolution and sorption and the hydrophobic and hydrophilic interactions at the solid-water interface are still in the developmental stage.

In this project, we employ the ab-initio molecular dynamics (DFT-MD) method to investigate the structure and dynamics of liquid water at the interface with the silica surface. Our findings reveal several H-bonded silica/water structural motifs, which can be either specific of one given facet or transferrable from one interface to another. These motifs furthermore exhibit transferrable spectroscopic signatures in SFG (Sum Frequency Generation) optical spectroscopy. Building on these results, we aim to develop a comprehensive SFG-structural motif database that will help us build the structure of any aqueous silica oxide interface under any condition of e.g. pH, electrolyte concentration, surface charge, without running simulations. This is under development by combining graph theory and learning techniques from artificial intelligence.

Superviseur

• Prof. Marie-Pierre GAIGEOT

Ecole doctorale

• Structure et dynamique des systèmes vivants (SDSV)