Activation barriers for the complete dissolution of condensation nucleus and its reverse crystallization in droplets in the undersaturated solvent vapor

摘要

The behavior of minima and the saddle point of the work of the droplet formation on soluble condensation nucleus as a function of the chemical potential of undersaturated (over the plane surface of pure solvent) solvent vapor is studied. Activation barriers for the direct transition of droplet from the state with partially dissolved nucleus to the state with completely dissolved nucleus and for the reverse transition of the crystallization of nucleus in the droplet are numerically determined within the wide range of the chemical potentials of undersaturated vapor. It is shown that the activation barrier for the direct transition increases rapidly, whereas the activation barrier for reverse transition lowers (although remaining finite) with a decrease in the chemical potential of vapor below its threshold value for the barrierless transition to the state with completely dissolved nucleus. As a result, droplets with completely or partially dissolved nucleus actually do not coexist in the atmosphere of undersaturated vapor. It is demonstrated that, upon variations in the relative humidity of undersaturated vapor, the change in thermodynamically stable and unstable description variables of the states of near-critical droplet takes place and physical meaning of these variables is explained.