Coalescence of clusters or microparticles in buffer gas

The coalescence, or the Ostwald ripening, process proceeds under equilibrium between clusters or microparticles and the parent vapor located in a buffer gas, so that the equilibrium results from processes of cluster evaporation and attachment of free molecules to a cluster. A slow cluster growth takes place because this equilibrium is not fulfilled exactly for clusters of different sizes. It is shown that the coalescence process slows down due to a difference between the cluster temperature and the buffer gas temperature near the cluster, and a decrease in the coalescence rate due to this effect is evaluated. The results are applied to the analysis of the growth of water aerosols located in atmospheric air of cumulus clouds where a time of coalescence aerosol growth differs from a time of establishment the aerosol-vapor equilibrium by 4–5 orders of magnitude.