Modeling of n -Alkanes on Calcite/Dolomite by Molecular Dynamics Simulations and First-Principles Calculations

Using a combination of molecular dynamics simulations and first-principles calculations, the interaction of n-alkanes with {101⎯⎯4} calcite/dolomite is investigated. It is observed that the n-alkane molecules align preferentially parallel to the interface, despite interaction by weak physisorption, and give rise to distinct adsorption layers. The ordering turns out to be more pronounced on calcite than dolomite due to a smaller average velocity of the n-alkane molecules. The observations are explained in terms of adsorption energies and charge transfers. The results show that functionalization is no prerequisite of structural ordering and a distinct mass density profile perpendicular to the interface.