Abstract: Joseph Kinghorn-Taenzer

Theoretical Investigation of Hydrated {110} Aragonite Surface

An investigation of the ground-state structural and energetic properties of the hydrated {110} aragonite surface was carried out using Roothaan-Hartree-Fock molecular orbital methods.  Cluster models of the form Can(CO3)n, where n=10,16,20 were used with varying numbers of H2O monomers, which allowed for a detailed 3D description of the hydrated aragonite surface at the 6-31G(d,p) level of theory.  The possibility that a detailed molecular mechanism for dissolution of crystal structures in water could be found was investigated but was not confirmed except at the lowest level of theory used in this study, 3-21G.  Agreement with previous theoretical studies performed using atomistic simulations is nominal, with some minor differences in the precise configuration of adsorbed water molecules and the extent of the reconstruction of the hydrated surface.

Aragonite appears in a wide variety of biological substances, most notable in nacre, the substance used by mollusks to construct their shells.  It is our belief that a detailed theoretical understanding of hydrated aragonite at the molecular level will be helpful to those studying the crystal structure both as mineralogists or geologists and as [marine] biologists.