MONOCRYSTALLOMIMICRY IN THE AEROSOLS OF AMMONIUM AND CESIUM HALOGENIDES

It was experimentally shown that primary CsI and NH(4)Hal nanocrystals are formed during the cocrystallization of ammonium halogenides and c esium iodide from a highly supersaturated vapor. The nanocrystals are combined into mixed aggregates assuming a polyhedral shape (pseudomono crystals), Both the nucleation and growth of pseudomonocrystals due to the consecutive joining of primary crystals are described by the Fokk er-Planck equation. The appearance of pseudomonocrystals is a result o f the morphological selection of the densest packing of crystals with a sharp dependence of the frequency of joining crystals to an aggregat e versus the consistency between the habitus of the crystals and the r elief of the aggregate surface.