Modeling Impurity-Mediated Crystal Growth and Morphologies of Centrosymmetric Molecules

Foreign molecules in solution often disrupt crystal growth mechanisms and alter the crystal morphology. In this article, we predict crystal morphologies for molecules of interest by combining step velocity model theory, kinetic Monte Carlo simulations, and existing visualization frameworks. We first validate the methodology by comparing simulation results to verified step velocity models for crystal growth systems without impurities present. We then introduce impurities (both thermoneutral and energetically attractive/repulsive) to the system and examine the change in step behavior to inform impurity-mediated crystal growth models. We demonstrate the approach with a visualization of morphology for the centrosymmetric molecule naphthalene grown under a variety of growth conditions, including from impure solutions. We comment on the applicability of this approach for more complex structures, including noncentrosymmetric molecular growth units.