(86f) Modeling Aqueous Environments in Pre-Nucleation Silicate Species

The events occurring during the first few hours of particle formation in sol-gel solutions can have a significant influence on the structural properties of the resulting crystalline solid. Experimental investigations of these systems are limited by the length and time scales under which the reactions occur. A theoretical means to model the solute-solvent and solute-template interactions is needed. Here, we present DFT-based calculations of silicate-solvent interactions, modeled using an entirely quantum mechanical description of the solvent by explicitly incorporating water molecules into the system. With this technique we gain valuable insight into the nature of the interaction of the silicate species with excess water. We explore the details of the hydrolysis and condensation reactions of several prenucleation silicate species using electronic density functional theory. In particular, we investigate the mechanism and energetics of the reactions in an aqueous environment and compare those to previous calculation performed in the gas phase. Using thermochemical analysis, we calculate free energies of solvation to obtain information about the equilibrium distribution of each species in solution.