The Calcite (104) Surface - Electrolyte Structure: A 3D Comparison of Surface X-Ray Diffraction and Simulations

Abstract

<div>Adsorption and incorporation of ions is known to influence the morphology and growth of calcite. Using surface X-ray diffraction, the interfacial structure of calcite in contact with CaCO3, MgCl2, CaCl2</div><div>and BaCl2 solutions was determined. All of these conditions yield a comparable interfacial structure,</div><div>meaning that there is no significant ion adsorption. This allows for the first time a thorough comparison in all three dimensions with state-of-the-art computer simulations, involving molecular dynamics</div><div>based on both DFT and two different force field models. Additionally, the simulated structures are</div><div>used to calculate the corresponding structure factors, which in turn are compared to those obtained</div><div>from experiment, thereby avoiding the need for fitting or subjective interpretation. In general, there</div><div>is a good agreement between experiment and the simulations, though there are some small discrepancies in the atomic positions, which lead to an inadequate fit of certain features characteristic of the</div><div>structure of water at the interface. Of the three simulation methods examined, the DFT results were</div><div>found to agree best with the experimental structure.</div>