The interfacial structure of liquid water next to mineral surfaces plays a crucial role in geochemical processes such as adsorbing heavy metal contaminants in groundwater. First principles electronic structure calculations are useful tools to predict the energetics of ion adsorption, but their ability to provide realistic structural models requires careful validation with experimental measurements. We combine calculations of interfacial X-ray structure factors from ab-initio and classical molecular dynamics trajectories with experimental X-ray reflectivity measurements to obtain a validation protocol for structural models of aqueous interfaces. Simultaneously, we provide a means to interpret both specular and nonspecular X-ray reflectivity measurements without the need for model-dependent empirical fitting, offering unique insight into the influence of atomic-scale liquid structure upon reaction mechanisms at surfaces. We will discuss in particular the case of the water/Al2O3 (001) interface, demonstrating the important role of van der Waals interactions on the structure and energetics of the interfacial water.

Validating molecular dynamics simulations of the Al2O3/water interface with specular and nonspecular X-ray reflectivity

2019 Spring National Meeting

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