Interactions at the Organic/Inorganic Interface: Molecular Modeling of the Interaction between Diphosphonates and the Surfaces of Barite Crystals

Molecular modeling techniques are used to investigate
the interaction of alkyldiphosphonate molecular
anions with the surfaces of barium sulfate. We show that the most
stable sites are on the (100) and (011) surfaces
with the [PO3]2- groups of the
diphosphonates replacing surface sulfate ions. These results are
compared with
experimental observations; and analysis of the calculated energies
demonstrates that the overall binding energy
represents a subtle balance between the internal energy of the
diphosphonate and the binding energy of the distorted
diphosphonate in the site.