The Structure of Water Condensate Nuclei in the Field of Surface Crystalline Defects on the Basal Face of β-AgI

Resumo

The basal face of the silver iodide crystal in the absence of defects in unsaturated water vapors is covered with a continuous monomolecular film with a marked honeycomb-like cellular structure. Nanoscopic surface defects in the shape of a rectangular tower lead to the complete destruction of the film, so that the adsorption mechanism is changed entirely. The adsorption begins on the lateral faces of the defects, where the crystalline electric field prevents the formation of intermolecular hydrogen bonds. Water molecules are held by direct interactions with the crystal lattice ions and are aligned in the form of chains along the force lines of the electric field of the defect without forming stable clusters. At the next stage, the molecules are attached to the top of the defect, and only then the carrying surface between defects is filled. The adsorbate structure is resistant to temperature variations in the range from the freezing point to the boiling point of water. Computer simulation is performed by the Monte Carlo method using a detailed model implying the summation of polarization interactions over large distances.