Groweth, my seed, groweth!
The video reflects our seeded simulation strategy to study sodium chloride (NaCl) nucleation from brines. Cubes represent ions that originated from the seed. The seed was cut from a bulk rock-salt lattice and placed in a box of supersaturated aqueous NaCl solution. Overlapping solution ions and molecules were removed with the constraint of electroneutrality. Spheres respresent ions that came from the solution configuration. Colored cubes and spheres are ions that belong to the largest cluster (nucleus) in the simulation box. Objects in gray are "free" ions; that is, they do not belong to the largest cluster. Note, first, that there is no color coding pertaining to the ion type (i.e., Na and Cl ions have the same color), and, second, that water molecules have been omitted for clarity.
The related article, which can be found here,
- introduces valuable polymorph-specific order parameters (tetrahedra vs octahedra),
- introduces test criteria to check monomer depletion (driving-force change),
- highlights how to test different attachment kinetics to a critical nucleus (diffusion vs ion-desolvation limitation),
- introduces an upper-bound estimate of the nucleation rate based on ion-association times from a correlation-function formulation, and
- underlines that determining nucleation rates for solute precipitation remains a difficult scientific and technological task—be it via simulations or experiments—, even for allegedly simple systems such as NaCl in water.