Simulation of Crystal Growth by an Innovative Hybrid Density Functional Theory Continuum Solvation Approach: Kink Site Formation on Barite (001)

Abstract

We have tested the ability of a hybrid density functional theory (DFT)−continuum solvation approach to simulate processes relevant to sorption and crystal growth at the solid−water interface with the largest possible accuracy. The focus was on the study of Ba 2+ kink-site nucleation at the (001) surface relevant for barite growth. For the first time, a complete Ba 2+ -ion uptake process at the water mineral interface was simulated using ab initio-based methods while maintaining reasonable computational effort. The Ba 2+ attachment path is mainly determined by dehydration of the attached ion and chemical bond formation. For all intermediate steps starting from the hydrated ion to the completely attached ion, a full representation of the chemical bonds as well as effects of the aqueous phase were considered. Previous results of simulations with classical force fields could be qualitatively reproduced, and new details on the attachment path emerged. This study indicates that energy differences between Ba 2+ attachment processes at different sites are mainly due to the influence of step morphologies at the atomic scale. The hybrid DFT continuum solvation approach enables ab initio-based simulations of solid surface−aqueous interfaces, which may be applied to other relevant problems, for example, adsorption processes, complex formation at surfaces, or electrochemical processes.