Coarse-Grained Simulation of CaCO₃ Aggregation and Crystallization Made Possible by Non-Bonded Three-Body Interactions

Abstract

Calcium-containing minerals are key model systems to investigate fundamental principles of nucleation and mineral formation both experimentally and by simulation. Due to the rare event character of nucleation, the different dimensions of pre- and postnucleation stages and the possible relevance of non-classical nucleation pathways, such investigations require advanced sampling techniques and simulation models on a range of resolution levels. To this end we have developed coarse-grained (CG) models for calcium carbonate. We present a strategy to devise CG parameters - including non-bonded angular-dependent terms - such that the model correctly represents the calcite phase along with properties of the constituents in solution. We show how the CG interactions affect the crystallization pathways by stabilizing different intermediates - spanning a wide range of degrees of crystallinity and water content. This will allow us to investigate contributions to crystallization transitions and link them to experimentally observed non-classical crystallization intermediates.